| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Tom Lendacky | 4198 | 34.52% | 40 | 24.39% |
| Joerg Roedel | 2414 | 19.85% | 30 | 18.29% |
| Nikunj A. Dadhania | 1722 | 14.16% | 15 | 9.15% |
| Brijesh Singh | 1573 | 12.93% | 17 | 10.37% |
| Ashish Kalra | 1014 | 8.34% | 4 | 2.44% |
| Borislav Petkov | 360 | 2.96% | 14 | 8.54% |
| Michael Roth | 318 | 2.61% | 8 | 4.88% |
| Kirill A. Shutemov | 179 | 1.47% | 3 | 1.83% |
| Michael Sterritt | 116 | 0.95% | 1 | 0.61% |
| Alexey Kardashevskiy | 67 | 0.55% | 2 | 1.22% |
| Dionna Glaze | 64 | 0.53% | 3 | 1.83% |
| Ard Biesheuvel | 18 | 0.15% | 4 | 2.44% |
| Li RongQing | 17 | 0.14% | 1 | 0.61% |
| Peter Gonda | 17 | 0.14% | 1 | 0.61% |
| Kevin Loughlin | 13 | 0.11% | 1 | 0.61% |
| Jason A. Donenfeld | 13 | 0.11% | 1 | 0.61% |
| Dan J Williams | 12 | 0.10% | 1 | 0.61% |
| Thomas Gleixner | 11 | 0.09% | 5 | 3.05% |
| Martin Radev | 11 | 0.09% | 1 | 0.61% |
| Ashwin Dayanand Kamat | 7 | 0.06% | 1 | 0.61% |
| Ingo Molnar | 6 | 0.05% | 4 | 2.44% |
| Jack Steiner | 2 | 0.02% | 1 | 0.61% |
| Harvey Harrison | 2 | 0.02% | 1 | 0.61% |
| Linus Torvalds (pre-git) | 2 | 0.02% | 1 | 0.61% |
| Andrew Morton | 2 | 0.02% | 1 | 0.61% |
| Haowen Bai | 1 | 0.01% | 1 | 0.61% |
| guoweikang | 1 | 0.01% | 1 | 0.61% |
| Peter Zijlstra | 1 | 0.01% | 1 | 0.61% |
| Total | 12161 | 164 |
// SPDX-License-Identifier: GPL-2.0-only /* * AMD Memory Encryption Support * * Copyright (C) 2019 SUSE * * Author: Joerg Roedel <jroedel@suse.de> */ #define pr_fmt(fmt) "SEV: " fmt #include <linux/sched/debug.h> /* For show_regs() */ #include <linux/percpu-defs.h> #include <linux/cc_platform.h> #include <linux/printk.h> #include <linux/mm_types.h> #include <linux/set_memory.h> #include <linux/memblock.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/cpumask.h> #include <linux/efi.h> #include <linux/platform_device.h> #include <linux/io.h> #include <linux/psp-sev.h> #include <linux/dmi.h> #include <uapi/linux/sev-guest.h> #include <crypto/gcm.h> #include <asm/init.h> #include <asm/cpu_entry_area.h> #include <asm/stacktrace.h> #include <asm/sev.h> #include <asm/insn-eval.h> #include <asm/fpu/xcr.h> #include <asm/processor.h> #include <asm/realmode.h> #include <asm/setup.h> #include <asm/traps.h> #include <asm/svm.h> #include <asm/smp.h> #include <asm/cpu.h> #include <asm/apic.h> #include <asm/cpuid.h> #include <asm/cmdline.h> #define DR7_RESET_VALUE 0x400 /* AP INIT values as documented in the APM2 section "Processor Initialization State" */ #define AP_INIT_CS_LIMIT 0xffff #define AP_INIT_DS_LIMIT 0xffff #define AP_INIT_LDTR_LIMIT 0xffff #define AP_INIT_GDTR_LIMIT 0xffff #define AP_INIT_IDTR_LIMIT 0xffff #define AP_INIT_TR_LIMIT 0xffff #define AP_INIT_RFLAGS_DEFAULT 0x2 #define AP_INIT_DR6_DEFAULT 0xffff0ff0 #define AP_INIT_GPAT_DEFAULT 0x0007040600070406ULL #define AP_INIT_XCR0_DEFAULT 0x1 #define AP_INIT_X87_FTW_DEFAULT 0x5555 #define AP_INIT_X87_FCW_DEFAULT 0x0040 #define AP_INIT_CR0_DEFAULT 0x60000010 #define AP_INIT_MXCSR_DEFAULT 0x1f80 static const char * const sev_status_feat_names[] = { [MSR_AMD64_SEV_ENABLED_BIT] = "SEV", [MSR_AMD64_SEV_ES_ENABLED_BIT] = "SEV-ES", [MSR_AMD64_SEV_SNP_ENABLED_BIT] = "SEV-SNP", [MSR_AMD64_SNP_VTOM_BIT] = "vTom", [MSR_AMD64_SNP_REFLECT_VC_BIT] = "ReflectVC", [MSR_AMD64_SNP_RESTRICTED_INJ_BIT] = "RI", [MSR_AMD64_SNP_ALT_INJ_BIT] = "AI", [MSR_AMD64_SNP_DEBUG_SWAP_BIT] = "DebugSwap", [MSR_AMD64_SNP_PREVENT_HOST_IBS_BIT] = "NoHostIBS", [MSR_AMD64_SNP_BTB_ISOLATION_BIT] = "BTBIsol", [MSR_AMD64_SNP_VMPL_SSS_BIT] = "VmplSSS", [MSR_AMD64_SNP_SECURE_TSC_BIT] = "SecureTSC", [MSR_AMD64_SNP_VMGEXIT_PARAM_BIT] = "VMGExitParam", [MSR_AMD64_SNP_IBS_VIRT_BIT] = "IBSVirt", [MSR_AMD64_SNP_VMSA_REG_PROT_BIT] = "VMSARegProt", [MSR_AMD64_SNP_SMT_PROT_BIT] = "SMTProt", }; /* For early boot hypervisor communication in SEV-ES enabled guests */ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); /* * Needs to be in the .data section because we need it NULL before bss is * cleared */ static struct ghcb *boot_ghcb __section(".data"); /* Bitmap of SEV features supported by the hypervisor */ static u64 sev_hv_features __ro_after_init; /* Secrets page physical address from the CC blob */ static u64 secrets_pa __ro_after_init; /* * For Secure TSC guests, the BSP fetches TSC_INFO using SNP guest messaging and * initializes snp_tsc_scale and snp_tsc_offset. These values are replicated * across the APs VMSA fields (TSC_SCALE and TSC_OFFSET). */ static u64 snp_tsc_scale __ro_after_init; static u64 snp_tsc_offset __ro_after_init; static u64 snp_tsc_freq_khz __ro_after_init; /* #VC handler runtime per-CPU data */ struct sev_es_runtime_data { struct ghcb ghcb_page; /* * Reserve one page per CPU as backup storage for the unencrypted GHCB. * It is needed when an NMI happens while the #VC handler uses the real * GHCB, and the NMI handler itself is causing another #VC exception. In * that case the GHCB content of the first handler needs to be backed up * and restored. */ struct ghcb backup_ghcb; /* * Mark the per-cpu GHCBs as in-use to detect nested #VC exceptions. * There is no need for it to be atomic, because nothing is written to * the GHCB between the read and the write of ghcb_active. So it is safe * to use it when a nested #VC exception happens before the write. * * This is necessary for example in the #VC->NMI->#VC case when the NMI * happens while the first #VC handler uses the GHCB. When the NMI code * raises a second #VC handler it might overwrite the contents of the * GHCB written by the first handler. To avoid this the content of the * GHCB is saved and restored when the GHCB is detected to be in use * already. */ bool ghcb_active; bool backup_ghcb_active; /* * Cached DR7 value - write it on DR7 writes and return it on reads. * That value will never make it to the real hardware DR7 as debugging * is currently unsupported in SEV-ES guests. */ unsigned long dr7; }; struct ghcb_state { struct ghcb *ghcb; }; /* For early boot SVSM communication */ static struct svsm_ca boot_svsm_ca_page __aligned(PAGE_SIZE); static DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data); static DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); static DEFINE_PER_CPU(struct svsm_ca *, svsm_caa); static DEFINE_PER_CPU(u64, svsm_caa_pa); static __always_inline bool on_vc_stack(struct pt_regs *regs) { unsigned long sp = regs->sp; /* User-mode RSP is not trusted */ if (user_mode(regs)) return false; /* SYSCALL gap still has user-mode RSP */ if (ip_within_syscall_gap(regs)) return false; return ((sp >= __this_cpu_ist_bottom_va(VC)) && (sp < __this_cpu_ist_top_va(VC))); } /* * This function handles the case when an NMI is raised in the #VC * exception handler entry code, before the #VC handler has switched off * its IST stack. In this case, the IST entry for #VC must be adjusted, * so that any nested #VC exception will not overwrite the stack * contents of the interrupted #VC handler. * * The IST entry is adjusted unconditionally so that it can be also be * unconditionally adjusted back in __sev_es_ist_exit(). Otherwise a * nested sev_es_ist_exit() call may adjust back the IST entry too * early. * * The __sev_es_ist_enter() and __sev_es_ist_exit() functions always run * on the NMI IST stack, as they are only called from NMI handling code * right now. */ void noinstr __sev_es_ist_enter(struct pt_regs *regs) { unsigned long old_ist, new_ist; /* Read old IST entry */ new_ist = old_ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]); /* * If NMI happened while on the #VC IST stack, set the new IST * value below regs->sp, so that the interrupted stack frame is * not overwritten by subsequent #VC exceptions. */ if (on_vc_stack(regs)) new_ist = regs->sp; /* * Reserve additional 8 bytes and store old IST value so this * adjustment can be unrolled in __sev_es_ist_exit(). */ new_ist -= sizeof(old_ist); *(unsigned long *)new_ist = old_ist; /* Set new IST entry */ this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], new_ist); } void noinstr __sev_es_ist_exit(void) { unsigned long ist; /* Read IST entry */ ist = __this_cpu_read(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC]); if (WARN_ON(ist == __this_cpu_ist_top_va(VC))) return; /* Read back old IST entry and write it to the TSS */ this_cpu_write(cpu_tss_rw.x86_tss.ist[IST_INDEX_VC], *(unsigned long *)ist); } /* * Nothing shall interrupt this code path while holding the per-CPU * GHCB. The backup GHCB is only for NMIs interrupting this path. * * Callers must disable local interrupts around it. */ static noinstr struct ghcb *__sev_get_ghcb(struct ghcb_state *state) { struct sev_es_runtime_data *data; struct ghcb *ghcb; WARN_ON(!irqs_disabled()); data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; if (unlikely(data->ghcb_active)) { /* GHCB is already in use - save its contents */ if (unlikely(data->backup_ghcb_active)) { /* * Backup-GHCB is also already in use. There is no way * to continue here so just kill the machine. To make * panic() work, mark GHCBs inactive so that messages * can be printed out. */ data->ghcb_active = false; data->backup_ghcb_active = false; instrumentation_begin(); panic("Unable to handle #VC exception! GHCB and Backup GHCB are already in use"); instrumentation_end(); } /* Mark backup_ghcb active before writing to it */ data->backup_ghcb_active = true; state->ghcb = &data->backup_ghcb; /* Backup GHCB content */ *state->ghcb = *ghcb; } else { state->ghcb = NULL; data->ghcb_active = true; } return ghcb; } static inline u64 sev_es_rd_ghcb_msr(void) { return __rdmsr(MSR_AMD64_SEV_ES_GHCB); } static __always_inline void sev_es_wr_ghcb_msr(u64 val) { u32 low, high; low = (u32)(val); high = (u32)(val >> 32); native_wrmsr(MSR_AMD64_SEV_ES_GHCB, low, high); } static int vc_fetch_insn_kernel(struct es_em_ctxt *ctxt, unsigned char *buffer) { return copy_from_kernel_nofault(buffer, (unsigned char *)ctxt->regs->ip, MAX_INSN_SIZE); } static enum es_result __vc_decode_user_insn(struct es_em_ctxt *ctxt) { char buffer[MAX_INSN_SIZE]; int insn_bytes; insn_bytes = insn_fetch_from_user_inatomic(ctxt->regs, buffer); if (insn_bytes == 0) { /* Nothing could be copied */ ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR | X86_PF_USER; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; } else if (insn_bytes == -EINVAL) { /* Effective RIP could not be calculated */ ctxt->fi.vector = X86_TRAP_GP; ctxt->fi.error_code = 0; ctxt->fi.cr2 = 0; return ES_EXCEPTION; } if (!insn_decode_from_regs(&ctxt->insn, ctxt->regs, buffer, insn_bytes)) return ES_DECODE_FAILED; if (ctxt->insn.immediate.got) return ES_OK; else return ES_DECODE_FAILED; } static enum es_result __vc_decode_kern_insn(struct es_em_ctxt *ctxt) { char buffer[MAX_INSN_SIZE]; int res, ret; res = vc_fetch_insn_kernel(ctxt, buffer); if (res) { ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = X86_PF_INSTR; ctxt->fi.cr2 = ctxt->regs->ip; return ES_EXCEPTION; } ret = insn_decode(&ctxt->insn, buffer, MAX_INSN_SIZE, INSN_MODE_64); if (ret < 0) return ES_DECODE_FAILED; else return ES_OK; } static enum es_result vc_decode_insn(struct es_em_ctxt *ctxt) { if (user_mode(ctxt->regs)) return __vc_decode_user_insn(ctxt); else return __vc_decode_kern_insn(ctxt); } static enum es_result vc_write_mem(struct es_em_ctxt *ctxt, char *dst, char *buf, size_t size) { unsigned long error_code = X86_PF_PROT | X86_PF_WRITE; /* * This function uses __put_user() independent of whether kernel or user * memory is accessed. This works fine because __put_user() does no * sanity checks of the pointer being accessed. All that it does is * to report when the access failed. * * Also, this function runs in atomic context, so __put_user() is not * allowed to sleep. The page-fault handler detects that it is running * in atomic context and will not try to take mmap_sem and handle the * fault, so additional pagefault_enable()/disable() calls are not * needed. * * The access can't be done via copy_to_user() here because * vc_write_mem() must not use string instructions to access unsafe * memory. The reason is that MOVS is emulated by the #VC handler by * splitting the move up into a read and a write and taking a nested #VC * exception on whatever of them is the MMIO access. Using string * instructions here would cause infinite nesting. */ switch (size) { case 1: { u8 d1; u8 __user *target = (u8 __user *)dst; memcpy(&d1, buf, 1); if (__put_user(d1, target)) goto fault; break; } case 2: { u16 d2; u16 __user *target = (u16 __user *)dst; memcpy(&d2, buf, 2); if (__put_user(d2, target)) goto fault; break; } case 4: { u32 d4; u32 __user *target = (u32 __user *)dst; memcpy(&d4, buf, 4); if (__put_user(d4, target)) goto fault; break; } case 8: { u64 d8; u64 __user *target = (u64 __user *)dst; memcpy(&d8, buf, 8); if (__put_user(d8, target)) goto fault; break; } default: WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); return ES_UNSUPPORTED; } return ES_OK; fault: if (user_mode(ctxt->regs)) error_code |= X86_PF_USER; ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = error_code; ctxt->fi.cr2 = (unsigned long)dst; return ES_EXCEPTION; } static enum es_result vc_read_mem(struct es_em_ctxt *ctxt, char *src, char *buf, size_t size) { unsigned long error_code = X86_PF_PROT; /* * This function uses __get_user() independent of whether kernel or user * memory is accessed. This works fine because __get_user() does no * sanity checks of the pointer being accessed. All that it does is * to report when the access failed. * * Also, this function runs in atomic context, so __get_user() is not * allowed to sleep. The page-fault handler detects that it is running * in atomic context and will not try to take mmap_sem and handle the * fault, so additional pagefault_enable()/disable() calls are not * needed. * * The access can't be done via copy_from_user() here because * vc_read_mem() must not use string instructions to access unsafe * memory. The reason is that MOVS is emulated by the #VC handler by * splitting the move up into a read and a write and taking a nested #VC * exception on whatever of them is the MMIO access. Using string * instructions here would cause infinite nesting. */ switch (size) { case 1: { u8 d1; u8 __user *s = (u8 __user *)src; if (__get_user(d1, s)) goto fault; memcpy(buf, &d1, 1); break; } case 2: { u16 d2; u16 __user *s = (u16 __user *)src; if (__get_user(d2, s)) goto fault; memcpy(buf, &d2, 2); break; } case 4: { u32 d4; u32 __user *s = (u32 __user *)src; if (__get_user(d4, s)) goto fault; memcpy(buf, &d4, 4); break; } case 8: { u64 d8; u64 __user *s = (u64 __user *)src; if (__get_user(d8, s)) goto fault; memcpy(buf, &d8, 8); break; } default: WARN_ONCE(1, "%s: Invalid size: %zu\n", __func__, size); return ES_UNSUPPORTED; } return ES_OK; fault: if (user_mode(ctxt->regs)) error_code |= X86_PF_USER; ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.error_code = error_code; ctxt->fi.cr2 = (unsigned long)src; return ES_EXCEPTION; } static enum es_result vc_slow_virt_to_phys(struct ghcb *ghcb, struct es_em_ctxt *ctxt, unsigned long vaddr, phys_addr_t *paddr) { unsigned long va = (unsigned long)vaddr; unsigned int level; phys_addr_t pa; pgd_t *pgd; pte_t *pte; pgd = __va(read_cr3_pa()); pgd = &pgd[pgd_index(va)]; pte = lookup_address_in_pgd(pgd, va, &level); if (!pte) { ctxt->fi.vector = X86_TRAP_PF; ctxt->fi.cr2 = vaddr; ctxt->fi.error_code = 0; if (user_mode(ctxt->regs)) ctxt->fi.error_code |= X86_PF_USER; return ES_EXCEPTION; } if (WARN_ON_ONCE(pte_val(*pte) & _PAGE_ENC)) /* Emulated MMIO to/from encrypted memory not supported */ return ES_UNSUPPORTED; pa = (phys_addr_t)pte_pfn(*pte) << PAGE_SHIFT; pa |= va & ~page_level_mask(level); *paddr = pa; return ES_OK; } static enum es_result vc_ioio_check(struct es_em_ctxt *ctxt, u16 port, size_t size) { BUG_ON(size > 4); if (user_mode(ctxt->regs)) { struct thread_struct *t = ¤t->thread; struct io_bitmap *iobm = t->io_bitmap; size_t idx; if (!iobm) goto fault; for (idx = port; idx < port + size; ++idx) { if (test_bit(idx, iobm->bitmap)) goto fault; } } return ES_OK; fault: ctxt->fi.vector = X86_TRAP_GP; ctxt->fi.error_code = 0; return ES_EXCEPTION; } static __always_inline void vc_forward_exception(struct es_em_ctxt *ctxt) { long error_code = ctxt->fi.error_code; int trapnr = ctxt->fi.vector; ctxt->regs->orig_ax = ctxt->fi.error_code; switch (trapnr) { case X86_TRAP_GP: exc_general_protection(ctxt->regs, error_code); break; case X86_TRAP_UD: exc_invalid_op(ctxt->regs); break; case X86_TRAP_PF: write_cr2(ctxt->fi.cr2); exc_page_fault(ctxt->regs, error_code); break; case X86_TRAP_AC: exc_alignment_check(ctxt->regs, error_code); break; default: pr_emerg("Unsupported exception in #VC instruction emulation - can't continue\n"); BUG(); } } /* Include code shared with pre-decompression boot stage */ #include "shared.c" static inline struct svsm_ca *svsm_get_caa(void) { /* * Use rIP-relative references when called early in the boot. If * ->use_cas is set, then it is late in the boot and no need * to worry about rIP-relative references. */ if (RIP_REL_REF(sev_cfg).use_cas) return this_cpu_read(svsm_caa); else return RIP_REL_REF(boot_svsm_caa); } static u64 svsm_get_caa_pa(void) { /* * Use rIP-relative references when called early in the boot. If * ->use_cas is set, then it is late in the boot and no need * to worry about rIP-relative references. */ if (RIP_REL_REF(sev_cfg).use_cas) return this_cpu_read(svsm_caa_pa); else return RIP_REL_REF(boot_svsm_caa_pa); } static noinstr void __sev_put_ghcb(struct ghcb_state *state) { struct sev_es_runtime_data *data; struct ghcb *ghcb; WARN_ON(!irqs_disabled()); data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; if (state->ghcb) { /* Restore GHCB from Backup */ *ghcb = *state->ghcb; data->backup_ghcb_active = false; state->ghcb = NULL; } else { /* * Invalidate the GHCB so a VMGEXIT instruction issued * from userspace won't appear to be valid. */ vc_ghcb_invalidate(ghcb); data->ghcb_active = false; } } static int svsm_perform_call_protocol(struct svsm_call *call) { struct ghcb_state state; unsigned long flags; struct ghcb *ghcb; int ret; /* * This can be called very early in the boot, use native functions in * order to avoid paravirt issues. */ flags = native_local_irq_save(); /* * Use rip-relative references when called early in the boot. If * ghcbs_initialized is set, then it is late in the boot and no need * to worry about rip-relative references in called functions. */ if (RIP_REL_REF(sev_cfg).ghcbs_initialized) ghcb = __sev_get_ghcb(&state); else if (RIP_REL_REF(boot_ghcb)) ghcb = RIP_REL_REF(boot_ghcb); else ghcb = NULL; do { ret = ghcb ? svsm_perform_ghcb_protocol(ghcb, call) : svsm_perform_msr_protocol(call); } while (ret == -EAGAIN); if (RIP_REL_REF(sev_cfg).ghcbs_initialized) __sev_put_ghcb(&state); native_local_irq_restore(flags); return ret; } void noinstr __sev_es_nmi_complete(void) { struct ghcb_state state; struct ghcb *ghcb; ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_NMI_COMPLETE); ghcb_set_sw_exit_info_1(ghcb, 0); ghcb_set_sw_exit_info_2(ghcb, 0); sev_es_wr_ghcb_msr(__pa_nodebug(ghcb)); VMGEXIT(); __sev_put_ghcb(&state); } static u64 __init get_snp_jump_table_addr(void) { struct snp_secrets_page *secrets; void __iomem *mem; u64 addr; mem = ioremap_encrypted(secrets_pa, PAGE_SIZE); if (!mem) { pr_err("Unable to locate AP jump table address: failed to map the SNP secrets page.\n"); return 0; } secrets = (__force struct snp_secrets_page *)mem; addr = secrets->os_area.ap_jump_table_pa; iounmap(mem); return addr; } static u64 __init get_jump_table_addr(void) { struct ghcb_state state; unsigned long flags; struct ghcb *ghcb; u64 ret = 0; if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return get_snp_jump_table_addr(); local_irq_save(flags); ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_JUMP_TABLE); ghcb_set_sw_exit_info_1(ghcb, SVM_VMGEXIT_GET_AP_JUMP_TABLE); ghcb_set_sw_exit_info_2(ghcb, 0); sev_es_wr_ghcb_msr(__pa(ghcb)); VMGEXIT(); if (ghcb_sw_exit_info_1_is_valid(ghcb) && ghcb_sw_exit_info_2_is_valid(ghcb)) ret = ghcb->save.sw_exit_info_2; __sev_put_ghcb(&state); local_irq_restore(flags); return ret; } static void __head early_set_pages_state(unsigned long vaddr, unsigned long paddr, unsigned long npages, enum psc_op op) { unsigned long paddr_end; u64 val; vaddr = vaddr & PAGE_MASK; paddr = paddr & PAGE_MASK; paddr_end = paddr + (npages << PAGE_SHIFT); while (paddr < paddr_end) { /* Page validation must be rescinded before changing to shared */ if (op == SNP_PAGE_STATE_SHARED) pvalidate_4k_page(vaddr, paddr, false); /* * Use the MSR protocol because this function can be called before * the GHCB is established. */ sev_es_wr_ghcb_msr(GHCB_MSR_PSC_REQ_GFN(paddr >> PAGE_SHIFT, op)); VMGEXIT(); val = sev_es_rd_ghcb_msr(); if (GHCB_RESP_CODE(val) != GHCB_MSR_PSC_RESP) goto e_term; if (GHCB_MSR_PSC_RESP_VAL(val)) goto e_term; /* Page validation must be performed after changing to private */ if (op == SNP_PAGE_STATE_PRIVATE) pvalidate_4k_page(vaddr, paddr, true); vaddr += PAGE_SIZE; paddr += PAGE_SIZE; } return; e_term: sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); } void __head early_snp_set_memory_private(unsigned long vaddr, unsigned long paddr, unsigned long npages) { /* * This can be invoked in early boot while running identity mapped, so * use an open coded check for SNP instead of using cc_platform_has(). * This eliminates worries about jump tables or checking boot_cpu_data * in the cc_platform_has() function. */ if (!(RIP_REL_REF(sev_status) & MSR_AMD64_SEV_SNP_ENABLED)) return; /* * Ask the hypervisor to mark the memory pages as private in the RMP * table. */ early_set_pages_state(vaddr, paddr, npages, SNP_PAGE_STATE_PRIVATE); } void __head early_snp_set_memory_shared(unsigned long vaddr, unsigned long paddr, unsigned long npages) { /* * This can be invoked in early boot while running identity mapped, so * use an open coded check for SNP instead of using cc_platform_has(). * This eliminates worries about jump tables or checking boot_cpu_data * in the cc_platform_has() function. */ if (!(RIP_REL_REF(sev_status) & MSR_AMD64_SEV_SNP_ENABLED)) return; /* Ask hypervisor to mark the memory pages shared in the RMP table. */ early_set_pages_state(vaddr, paddr, npages, SNP_PAGE_STATE_SHARED); } static unsigned long __set_pages_state(struct snp_psc_desc *data, unsigned long vaddr, unsigned long vaddr_end, int op) { struct ghcb_state state; bool use_large_entry; struct psc_hdr *hdr; struct psc_entry *e; unsigned long flags; unsigned long pfn; struct ghcb *ghcb; int i; hdr = &data->hdr; e = data->entries; memset(data, 0, sizeof(*data)); i = 0; while (vaddr < vaddr_end && i < ARRAY_SIZE(data->entries)) { hdr->end_entry = i; if (is_vmalloc_addr((void *)vaddr)) { pfn = vmalloc_to_pfn((void *)vaddr); use_large_entry = false; } else { pfn = __pa(vaddr) >> PAGE_SHIFT; use_large_entry = true; } e->gfn = pfn; e->operation = op; if (use_large_entry && IS_ALIGNED(vaddr, PMD_SIZE) && (vaddr_end - vaddr) >= PMD_SIZE) { e->pagesize = RMP_PG_SIZE_2M; vaddr += PMD_SIZE; } else { e->pagesize = RMP_PG_SIZE_4K; vaddr += PAGE_SIZE; } e++; i++; } /* Page validation must be rescinded before changing to shared */ if (op == SNP_PAGE_STATE_SHARED) pvalidate_pages(data); local_irq_save(flags); if (sev_cfg.ghcbs_initialized) ghcb = __sev_get_ghcb(&state); else ghcb = boot_ghcb; /* Invoke the hypervisor to perform the page state changes */ if (!ghcb || vmgexit_psc(ghcb, data)) sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PSC); if (sev_cfg.ghcbs_initialized) __sev_put_ghcb(&state); local_irq_restore(flags); /* Page validation must be performed after changing to private */ if (op == SNP_PAGE_STATE_PRIVATE) pvalidate_pages(data); return vaddr; } static void set_pages_state(unsigned long vaddr, unsigned long npages, int op) { struct snp_psc_desc desc; unsigned long vaddr_end; /* Use the MSR protocol when a GHCB is not available. */ if (!boot_ghcb) return early_set_pages_state(vaddr, __pa(vaddr), npages, op); vaddr = vaddr & PAGE_MASK; vaddr_end = vaddr + (npages << PAGE_SHIFT); while (vaddr < vaddr_end) vaddr = __set_pages_state(&desc, vaddr, vaddr_end, op); } void snp_set_memory_shared(unsigned long vaddr, unsigned long npages) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; set_pages_state(vaddr, npages, SNP_PAGE_STATE_SHARED); } void snp_set_memory_private(unsigned long vaddr, unsigned long npages) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); } void snp_accept_memory(phys_addr_t start, phys_addr_t end) { unsigned long vaddr, npages; if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; vaddr = (unsigned long)__va(start); npages = (end - start) >> PAGE_SHIFT; set_pages_state(vaddr, npages, SNP_PAGE_STATE_PRIVATE); } static int vmgexit_ap_control(u64 event, struct sev_es_save_area *vmsa, u32 apic_id) { bool create = event != SVM_VMGEXIT_AP_DESTROY; struct ghcb_state state; unsigned long flags; struct ghcb *ghcb; int ret = 0; local_irq_save(flags); ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); if (create) ghcb_set_rax(ghcb, vmsa->sev_features); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_CREATION); ghcb_set_sw_exit_info_1(ghcb, ((u64)apic_id << 32) | ((u64)snp_vmpl << 16) | event); ghcb_set_sw_exit_info_2(ghcb, __pa(vmsa)); sev_es_wr_ghcb_msr(__pa(ghcb)); VMGEXIT(); if (!ghcb_sw_exit_info_1_is_valid(ghcb) || lower_32_bits(ghcb->save.sw_exit_info_1)) { pr_err("SNP AP %s error\n", (create ? "CREATE" : "DESTROY")); ret = -EINVAL; } __sev_put_ghcb(&state); local_irq_restore(flags); return ret; } static int snp_set_vmsa(void *va, void *caa, int apic_id, bool make_vmsa) { int ret; if (snp_vmpl) { struct svsm_call call = {}; unsigned long flags; local_irq_save(flags); call.caa = this_cpu_read(svsm_caa); call.rcx = __pa(va); if (make_vmsa) { /* Protocol 0, Call ID 2 */ call.rax = SVSM_CORE_CALL(SVSM_CORE_CREATE_VCPU); call.rdx = __pa(caa); call.r8 = apic_id; } else { /* Protocol 0, Call ID 3 */ call.rax = SVSM_CORE_CALL(SVSM_CORE_DELETE_VCPU); } ret = svsm_perform_call_protocol(&call); local_irq_restore(flags); } else { /* * If the kernel runs at VMPL0, it can change the VMSA * bit for a page using the RMPADJUST instruction. * However, for the instruction to succeed it must * target the permissions of a lesser privileged (higher * numbered) VMPL level, so use VMPL1. */ u64 attrs = 1; if (make_vmsa) attrs |= RMPADJUST_VMSA_PAGE_BIT; ret = rmpadjust((unsigned long)va, RMP_PG_SIZE_4K, attrs); } return ret; } static void snp_cleanup_vmsa(struct sev_es_save_area *vmsa, int apic_id) { int err; err = snp_set_vmsa(vmsa, NULL, apic_id, false); if (err) pr_err("clear VMSA page failed (%u), leaking page\n", err); else free_page((unsigned long)vmsa); } static void set_pte_enc(pte_t *kpte, int level, void *va) { struct pte_enc_desc d = { .kpte = kpte, .pte_level = level, .va = va, .encrypt = true }; prepare_pte_enc(&d); set_pte_enc_mask(kpte, d.pfn, d.new_pgprot); } static void unshare_all_memory(void) { unsigned long addr, end, size, ghcb; struct sev_es_runtime_data *data; unsigned int npages, level; bool skipped_addr; pte_t *pte; int cpu; /* Unshare the direct mapping. */ addr = PAGE_OFFSET; end = PAGE_OFFSET + get_max_mapped(); while (addr < end) { pte = lookup_address(addr, &level); size = page_level_size(level); npages = size / PAGE_SIZE; skipped_addr = false; if (!pte || !pte_decrypted(*pte) || pte_none(*pte)) { addr += size; continue; } /* * Ensure that all the per-CPU GHCBs are made private at the * end of the unsharing loop so that the switch to the slower * MSR protocol happens last. */ for_each_possible_cpu(cpu) { data = per_cpu(runtime_data, cpu); ghcb = (unsigned long)&data->ghcb_page; /* Handle the case of a huge page containing the GHCB page */ if (addr <= ghcb && ghcb < addr + size) { skipped_addr = true; break; } } if (!skipped_addr) { set_pte_enc(pte, level, (void *)addr); snp_set_memory_private(addr, npages); } addr += size; } /* Unshare all bss decrypted memory. */ addr = (unsigned long)__start_bss_decrypted; end = (unsigned long)__start_bss_decrypted_unused; npages = (end - addr) >> PAGE_SHIFT; for (; addr < end; addr += PAGE_SIZE) { pte = lookup_address(addr, &level); if (!pte || !pte_decrypted(*pte) || pte_none(*pte)) continue; set_pte_enc(pte, level, (void *)addr); } addr = (unsigned long)__start_bss_decrypted; snp_set_memory_private(addr, npages); __flush_tlb_all(); } /* Stop new private<->shared conversions */ void snp_kexec_begin(void) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; if (!IS_ENABLED(CONFIG_KEXEC_CORE)) return; /* * Crash kernel ends up here with interrupts disabled: can't wait for * conversions to finish. * * If race happened, just report and proceed. */ if (!set_memory_enc_stop_conversion()) pr_warn("Failed to stop shared<->private conversions\n"); } /* * Shutdown all APs except the one handling kexec/kdump and clearing * the VMSA tag on AP's VMSA pages as they are not being used as * VMSA page anymore. */ static void shutdown_all_aps(void) { struct sev_es_save_area *vmsa; int apic_id, this_cpu, cpu; this_cpu = get_cpu(); /* * APs are already in HLT loop when enc_kexec_finish() callback * is invoked. */ for_each_present_cpu(cpu) { vmsa = per_cpu(sev_vmsa, cpu); /* * The BSP or offlined APs do not have guest allocated VMSA * and there is no need to clear the VMSA tag for this page. */ if (!vmsa) continue; /* * Cannot clear the VMSA tag for the currently running vCPU. */ if (this_cpu == cpu) { unsigned long pa; struct page *p; pa = __pa(vmsa); /* * Mark the VMSA page of the running vCPU as offline * so that is excluded and not touched by makedumpfile * while generating vmcore during kdump. */ p = pfn_to_online_page(pa >> PAGE_SHIFT); if (p) __SetPageOffline(p); continue; } apic_id = cpuid_to_apicid[cpu]; /* * Issue AP destroy to ensure AP gets kicked out of guest mode * to allow using RMPADJUST to remove the VMSA tag on it's * VMSA page. */ vmgexit_ap_control(SVM_VMGEXIT_AP_DESTROY, vmsa, apic_id); snp_cleanup_vmsa(vmsa, apic_id); } put_cpu(); } void snp_kexec_finish(void) { struct sev_es_runtime_data *data; unsigned long size, addr; unsigned int level, cpu; struct ghcb *ghcb; pte_t *pte; if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; if (!IS_ENABLED(CONFIG_KEXEC_CORE)) return; shutdown_all_aps(); unshare_all_memory(); /* * Switch to using the MSR protocol to change per-CPU GHCBs to * private. All the per-CPU GHCBs have been switched back to private, * so can't do any more GHCB calls to the hypervisor beyond this point * until the kexec'ed kernel starts running. */ boot_ghcb = NULL; sev_cfg.ghcbs_initialized = false; for_each_possible_cpu(cpu) { data = per_cpu(runtime_data, cpu); ghcb = &data->ghcb_page; pte = lookup_address((unsigned long)ghcb, &level); size = page_level_size(level); /* Handle the case of a huge page containing the GHCB page */ addr = (unsigned long)ghcb & page_level_mask(level); set_pte_enc(pte, level, (void *)addr); snp_set_memory_private(addr, (size / PAGE_SIZE)); } } #define __ATTR_BASE (SVM_SELECTOR_P_MASK | SVM_SELECTOR_S_MASK) #define INIT_CS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_READ_MASK | SVM_SELECTOR_CODE_MASK) #define INIT_DS_ATTRIBS (__ATTR_BASE | SVM_SELECTOR_WRITE_MASK) #define INIT_LDTR_ATTRIBS (SVM_SELECTOR_P_MASK | 2) #define INIT_TR_ATTRIBS (SVM_SELECTOR_P_MASK | 3) static void *snp_alloc_vmsa_page(int cpu) { struct page *p; /* * Allocate VMSA page to work around the SNP erratum where the CPU will * incorrectly signal an RMP violation #PF if a large page (2MB or 1GB) * collides with the RMP entry of VMSA page. The recommended workaround * is to not use a large page. * * Allocate an 8k page which is also 8k-aligned. */ p = alloc_pages_node(cpu_to_node(cpu), GFP_KERNEL_ACCOUNT | __GFP_ZERO, 1); if (!p) return NULL; split_page(p, 1); /* Free the first 4k. This page may be 2M/1G aligned and cannot be used. */ __free_page(p); return page_address(p + 1); } static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip) { struct sev_es_save_area *cur_vmsa, *vmsa; struct svsm_ca *caa; u8 sipi_vector; int cpu, ret; u64 cr4; /* * The hypervisor SNP feature support check has happened earlier, just check * the AP_CREATION one here. */ if (!(sev_hv_features & GHCB_HV_FT_SNP_AP_CREATION)) return -EOPNOTSUPP; /* * Verify the desired start IP against the known trampoline start IP * to catch any future new trampolines that may be introduced that * would require a new protected guest entry point. */ if (WARN_ONCE(start_ip != real_mode_header->trampoline_start, "Unsupported SNP start_ip: %lx\n", start_ip)) return -EINVAL; /* Override start_ip with known protected guest start IP */ start_ip = real_mode_header->sev_es_trampoline_start; /* Find the logical CPU for the APIC ID */ for_each_present_cpu(cpu) { if (arch_match_cpu_phys_id(cpu, apic_id)) break; } if (cpu >= nr_cpu_ids) return -EINVAL; cur_vmsa = per_cpu(sev_vmsa, cpu); /* * A new VMSA is created each time because there is no guarantee that * the current VMSA is the kernels or that the vCPU is not running. If * an attempt was done to use the current VMSA with a running vCPU, a * #VMEXIT of that vCPU would wipe out all of the settings being done * here. */ vmsa = (struct sev_es_save_area *)snp_alloc_vmsa_page(cpu); if (!vmsa) return -ENOMEM; /* If an SVSM is present, the SVSM per-CPU CAA will be !NULL */ caa = per_cpu(svsm_caa, cpu); /* CR4 should maintain the MCE value */ cr4 = native_read_cr4() & X86_CR4_MCE; /* Set the CS value based on the start_ip converted to a SIPI vector */ sipi_vector = (start_ip >> 12); vmsa->cs.base = sipi_vector << 12; vmsa->cs.limit = AP_INIT_CS_LIMIT; vmsa->cs.attrib = INIT_CS_ATTRIBS; vmsa->cs.selector = sipi_vector << 8; /* Set the RIP value based on start_ip */ vmsa->rip = start_ip & 0xfff; /* Set AP INIT defaults as documented in the APM */ vmsa->ds.limit = AP_INIT_DS_LIMIT; vmsa->ds.attrib = INIT_DS_ATTRIBS; vmsa->es = vmsa->ds; vmsa->fs = vmsa->ds; vmsa->gs = vmsa->ds; vmsa->ss = vmsa->ds; vmsa->gdtr.limit = AP_INIT_GDTR_LIMIT; vmsa->ldtr.limit = AP_INIT_LDTR_LIMIT; vmsa->ldtr.attrib = INIT_LDTR_ATTRIBS; vmsa->idtr.limit = AP_INIT_IDTR_LIMIT; vmsa->tr.limit = AP_INIT_TR_LIMIT; vmsa->tr.attrib = INIT_TR_ATTRIBS; vmsa->cr4 = cr4; vmsa->cr0 = AP_INIT_CR0_DEFAULT; vmsa->dr7 = DR7_RESET_VALUE; vmsa->dr6 = AP_INIT_DR6_DEFAULT; vmsa->rflags = AP_INIT_RFLAGS_DEFAULT; vmsa->g_pat = AP_INIT_GPAT_DEFAULT; vmsa->xcr0 = AP_INIT_XCR0_DEFAULT; vmsa->mxcsr = AP_INIT_MXCSR_DEFAULT; vmsa->x87_ftw = AP_INIT_X87_FTW_DEFAULT; vmsa->x87_fcw = AP_INIT_X87_FCW_DEFAULT; /* SVME must be set. */ vmsa->efer = EFER_SVME; /* * Set the SNP-specific fields for this VMSA: * VMPL level * SEV_FEATURES (matches the SEV STATUS MSR right shifted 2 bits) */ vmsa->vmpl = snp_vmpl; vmsa->sev_features = sev_status >> 2; /* Populate AP's TSC scale/offset to get accurate TSC values. */ if (cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) { vmsa->tsc_scale = snp_tsc_scale; vmsa->tsc_offset = snp_tsc_offset; } /* Switch the page over to a VMSA page now that it is initialized */ ret = snp_set_vmsa(vmsa, caa, apic_id, true); if (ret) { pr_err("set VMSA page failed (%u)\n", ret); free_page((unsigned long)vmsa); return -EINVAL; } /* Issue VMGEXIT AP Creation NAE event */ ret = vmgexit_ap_control(SVM_VMGEXIT_AP_CREATE, vmsa, apic_id); if (ret) { snp_cleanup_vmsa(vmsa, apic_id); vmsa = NULL; } /* Free up any previous VMSA page */ if (cur_vmsa) snp_cleanup_vmsa(cur_vmsa, apic_id); /* Record the current VMSA page */ per_cpu(sev_vmsa, cpu) = vmsa; return ret; } void __init snp_set_wakeup_secondary_cpu(void) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return; /* * Always set this override if SNP is enabled. This makes it the * required method to start APs under SNP. If the hypervisor does * not support AP creation, then no APs will be started. */ apic_update_callback(wakeup_secondary_cpu, wakeup_cpu_via_vmgexit); } int __init sev_es_setup_ap_jump_table(struct real_mode_header *rmh) { u16 startup_cs, startup_ip; phys_addr_t jump_table_pa; u64 jump_table_addr; u16 __iomem *jump_table; jump_table_addr = get_jump_table_addr(); /* On UP guests there is no jump table so this is not a failure */ if (!jump_table_addr) return 0; /* Check if AP Jump Table is page-aligned */ if (jump_table_addr & ~PAGE_MASK) return -EINVAL; jump_table_pa = jump_table_addr & PAGE_MASK; startup_cs = (u16)(rmh->trampoline_start >> 4); startup_ip = (u16)(rmh->sev_es_trampoline_start - rmh->trampoline_start); jump_table = ioremap_encrypted(jump_table_pa, PAGE_SIZE); if (!jump_table) return -EIO; writew(startup_ip, &jump_table[0]); writew(startup_cs, &jump_table[1]); iounmap(jump_table); return 0; } /* * This is needed by the OVMF UEFI firmware which will use whatever it finds in * the GHCB MSR as its GHCB to talk to the hypervisor. So make sure the per-cpu * runtime GHCBs used by the kernel are also mapped in the EFI page-table. */ int __init sev_es_efi_map_ghcbs(pgd_t *pgd) { struct sev_es_runtime_data *data; unsigned long address, pflags; int cpu; u64 pfn; if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) return 0; pflags = _PAGE_NX | _PAGE_RW; for_each_possible_cpu(cpu) { data = per_cpu(runtime_data, cpu); address = __pa(&data->ghcb_page); pfn = address >> PAGE_SHIFT; if (kernel_map_pages_in_pgd(pgd, pfn, address, 1, pflags)) return 1; } return 0; } /* Writes to the SVSM CAA MSR are ignored */ static enum es_result __vc_handle_msr_caa(struct pt_regs *regs, bool write) { if (write) return ES_OK; regs->ax = lower_32_bits(this_cpu_read(svsm_caa_pa)); regs->dx = upper_32_bits(this_cpu_read(svsm_caa_pa)); return ES_OK; } /* * TSC related accesses should not exit to the hypervisor when a guest is * executing with Secure TSC enabled, so special handling is required for * accesses of MSR_IA32_TSC and MSR_AMD64_GUEST_TSC_FREQ. */ static enum es_result __vc_handle_secure_tsc_msrs(struct pt_regs *regs, bool write) { u64 tsc; /* * GUEST_TSC_FREQ should not be intercepted when Secure TSC is enabled. * Terminate the SNP guest when the interception is enabled. */ if (regs->cx == MSR_AMD64_GUEST_TSC_FREQ) return ES_VMM_ERROR; /* * Writes: Writing to MSR_IA32_TSC can cause subsequent reads of the TSC * to return undefined values, so ignore all writes. * * Reads: Reads of MSR_IA32_TSC should return the current TSC value, use * the value returned by rdtsc_ordered(). */ if (write) { WARN_ONCE(1, "TSC MSR writes are verboten!\n"); return ES_OK; } tsc = rdtsc_ordered(); regs->ax = lower_32_bits(tsc); regs->dx = upper_32_bits(tsc); return ES_OK; } static enum es_result vc_handle_msr(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { struct pt_regs *regs = ctxt->regs; enum es_result ret; bool write; /* Is it a WRMSR? */ write = ctxt->insn.opcode.bytes[1] == 0x30; switch (regs->cx) { case MSR_SVSM_CAA: return __vc_handle_msr_caa(regs, write); case MSR_IA32_TSC: case MSR_AMD64_GUEST_TSC_FREQ: if (sev_status & MSR_AMD64_SNP_SECURE_TSC) return __vc_handle_secure_tsc_msrs(regs, write); break; default: break; } ghcb_set_rcx(ghcb, regs->cx); if (write) { ghcb_set_rax(ghcb, regs->ax); ghcb_set_rdx(ghcb, regs->dx); } ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_MSR, write, 0); if ((ret == ES_OK) && !write) { regs->ax = ghcb->save.rax; regs->dx = ghcb->save.rdx; } return ret; } static void snp_register_per_cpu_ghcb(void) { struct sev_es_runtime_data *data; struct ghcb *ghcb; data = this_cpu_read(runtime_data); ghcb = &data->ghcb_page; snp_register_ghcb_early(__pa(ghcb)); } void setup_ghcb(void) { if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) return; /* * Check whether the runtime #VC exception handler is active. It uses * the per-CPU GHCB page which is set up by sev_es_init_vc_handling(). * * If SNP is active, register the per-CPU GHCB page so that the runtime * exception handler can use it. */ if (initial_vc_handler == (unsigned long)kernel_exc_vmm_communication) { if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) snp_register_per_cpu_ghcb(); sev_cfg.ghcbs_initialized = true; return; } /* * Make sure the hypervisor talks a supported protocol. * This gets called only in the BSP boot phase. */ if (!sev_es_negotiate_protocol()) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); /* * Clear the boot_ghcb. The first exception comes in before the bss * section is cleared. */ memset(&boot_ghcb_page, 0, PAGE_SIZE); /* Alright - Make the boot-ghcb public */ boot_ghcb = &boot_ghcb_page; /* SNP guest requires that GHCB GPA must be registered. */ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) snp_register_ghcb_early(__pa(&boot_ghcb_page)); } #ifdef CONFIG_HOTPLUG_CPU static void sev_es_ap_hlt_loop(void) { struct ghcb_state state; struct ghcb *ghcb; ghcb = __sev_get_ghcb(&state); while (true) { vc_ghcb_invalidate(ghcb); ghcb_set_sw_exit_code(ghcb, SVM_VMGEXIT_AP_HLT_LOOP); ghcb_set_sw_exit_info_1(ghcb, 0); ghcb_set_sw_exit_info_2(ghcb, 0); sev_es_wr_ghcb_msr(__pa(ghcb)); VMGEXIT(); /* Wakeup signal? */ if (ghcb_sw_exit_info_2_is_valid(ghcb) && ghcb->save.sw_exit_info_2) break; } __sev_put_ghcb(&state); } /* * Play_dead handler when running under SEV-ES. This is needed because * the hypervisor can't deliver an SIPI request to restart the AP. * Instead the kernel has to issue a VMGEXIT to halt the VCPU until the * hypervisor wakes it up again. */ static void sev_es_play_dead(void) { play_dead_common(); /* IRQs now disabled */ sev_es_ap_hlt_loop(); /* * If we get here, the VCPU was woken up again. Jump to CPU * startup code to get it back online. */ soft_restart_cpu(); } #else /* CONFIG_HOTPLUG_CPU */ #define sev_es_play_dead native_play_dead #endif /* CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_SMP static void __init sev_es_setup_play_dead(void) { smp_ops.play_dead = sev_es_play_dead; } #else static inline void sev_es_setup_play_dead(void) { } #endif static void __init alloc_runtime_data(int cpu) { struct sev_es_runtime_data *data; data = memblock_alloc_node(sizeof(*data), PAGE_SIZE, cpu_to_node(cpu)); if (!data) panic("Can't allocate SEV-ES runtime data"); per_cpu(runtime_data, cpu) = data; if (snp_vmpl) { struct svsm_ca *caa; /* Allocate the SVSM CA page if an SVSM is present */ caa = memblock_alloc_or_panic(sizeof(*caa), PAGE_SIZE); per_cpu(svsm_caa, cpu) = caa; per_cpu(svsm_caa_pa, cpu) = __pa(caa); } } static void __init init_ghcb(int cpu) { struct sev_es_runtime_data *data; int err; data = per_cpu(runtime_data, cpu); err = early_set_memory_decrypted((unsigned long)&data->ghcb_page, sizeof(data->ghcb_page)); if (err) panic("Can't map GHCBs unencrypted"); memset(&data->ghcb_page, 0, sizeof(data->ghcb_page)); data->ghcb_active = false; data->backup_ghcb_active = false; } void __init sev_es_init_vc_handling(void) { int cpu; BUILD_BUG_ON(offsetof(struct sev_es_runtime_data, ghcb_page) % PAGE_SIZE); if (!cc_platform_has(CC_ATTR_GUEST_STATE_ENCRYPT)) return; if (!sev_es_check_cpu_features()) panic("SEV-ES CPU Features missing"); /* * SNP is supported in v2 of the GHCB spec which mandates support for HV * features. */ if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) { sev_hv_features = get_hv_features(); if (!(sev_hv_features & GHCB_HV_FT_SNP)) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); } /* Initialize per-cpu GHCB pages */ for_each_possible_cpu(cpu) { alloc_runtime_data(cpu); init_ghcb(cpu); } /* If running under an SVSM, switch to the per-cpu CA */ if (snp_vmpl) { struct svsm_call call = {}; unsigned long flags; int ret; local_irq_save(flags); /* * SVSM_CORE_REMAP_CA call: * RAX = 0 (Protocol=0, CallID=0) * RCX = New CA GPA */ call.caa = svsm_get_caa(); call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA); call.rcx = this_cpu_read(svsm_caa_pa); ret = svsm_perform_call_protocol(&call); if (ret) panic("Can't remap the SVSM CA, ret=%d, rax_out=0x%llx\n", ret, call.rax_out); sev_cfg.use_cas = true; local_irq_restore(flags); } sev_es_setup_play_dead(); /* Secondary CPUs use the runtime #VC handler */ initial_vc_handler = (unsigned long)kernel_exc_vmm_communication; } static void __init vc_early_forward_exception(struct es_em_ctxt *ctxt) { int trapnr = ctxt->fi.vector; if (trapnr == X86_TRAP_PF) native_write_cr2(ctxt->fi.cr2); ctxt->regs->orig_ax = ctxt->fi.error_code; do_early_exception(ctxt->regs, trapnr); } static long *vc_insn_get_rm(struct es_em_ctxt *ctxt) { long *reg_array; int offset; reg_array = (long *)ctxt->regs; offset = insn_get_modrm_rm_off(&ctxt->insn, ctxt->regs); if (offset < 0) return NULL; offset /= sizeof(long); return reg_array + offset; } static enum es_result vc_do_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt, unsigned int bytes, bool read) { u64 exit_code, exit_info_1, exit_info_2; unsigned long ghcb_pa = __pa(ghcb); enum es_result res; phys_addr_t paddr; void __user *ref; ref = insn_get_addr_ref(&ctxt->insn, ctxt->regs); if (ref == (void __user *)-1L) return ES_UNSUPPORTED; exit_code = read ? SVM_VMGEXIT_MMIO_READ : SVM_VMGEXIT_MMIO_WRITE; res = vc_slow_virt_to_phys(ghcb, ctxt, (unsigned long)ref, &paddr); if (res != ES_OK) { if (res == ES_EXCEPTION && !read) ctxt->fi.error_code |= X86_PF_WRITE; return res; } exit_info_1 = paddr; /* Can never be greater than 8 */ exit_info_2 = bytes; ghcb_set_sw_scratch(ghcb, ghcb_pa + offsetof(struct ghcb, shared_buffer)); return sev_es_ghcb_hv_call(ghcb, ctxt, exit_code, exit_info_1, exit_info_2); } /* * The MOVS instruction has two memory operands, which raises the * problem that it is not known whether the access to the source or the * destination caused the #VC exception (and hence whether an MMIO read * or write operation needs to be emulated). * * Instead of playing games with walking page-tables and trying to guess * whether the source or destination is an MMIO range, split the move * into two operations, a read and a write with only one memory operand. * This will cause a nested #VC exception on the MMIO address which can * then be handled. * * This implementation has the benefit that it also supports MOVS where * source _and_ destination are MMIO regions. * * It will slow MOVS on MMIO down a lot, but in SEV-ES guests it is a * rare operation. If it turns out to be a performance problem the split * operations can be moved to memcpy_fromio() and memcpy_toio(). */ static enum es_result vc_handle_mmio_movs(struct es_em_ctxt *ctxt, unsigned int bytes) { unsigned long ds_base, es_base; unsigned char *src, *dst; unsigned char buffer[8]; enum es_result ret; bool rep; int off; ds_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_DS); es_base = insn_get_seg_base(ctxt->regs, INAT_SEG_REG_ES); if (ds_base == -1L || es_base == -1L) { ctxt->fi.vector = X86_TRAP_GP; ctxt->fi.error_code = 0; return ES_EXCEPTION; } src = ds_base + (unsigned char *)ctxt->regs->si; dst = es_base + (unsigned char *)ctxt->regs->di; ret = vc_read_mem(ctxt, src, buffer, bytes); if (ret != ES_OK) return ret; ret = vc_write_mem(ctxt, dst, buffer, bytes); if (ret != ES_OK) return ret; if (ctxt->regs->flags & X86_EFLAGS_DF) off = -bytes; else off = bytes; ctxt->regs->si += off; ctxt->regs->di += off; rep = insn_has_rep_prefix(&ctxt->insn); if (rep) ctxt->regs->cx -= 1; if (!rep || ctxt->regs->cx == 0) return ES_OK; else return ES_RETRY; } static enum es_result vc_handle_mmio(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { struct insn *insn = &ctxt->insn; enum insn_mmio_type mmio; unsigned int bytes = 0; enum es_result ret; u8 sign_byte; long *reg_data; mmio = insn_decode_mmio(insn, &bytes); if (mmio == INSN_MMIO_DECODE_FAILED) return ES_DECODE_FAILED; if (mmio != INSN_MMIO_WRITE_IMM && mmio != INSN_MMIO_MOVS) { reg_data = insn_get_modrm_reg_ptr(insn, ctxt->regs); if (!reg_data) return ES_DECODE_FAILED; } if (user_mode(ctxt->regs)) return ES_UNSUPPORTED; switch (mmio) { case INSN_MMIO_WRITE: memcpy(ghcb->shared_buffer, reg_data, bytes); ret = vc_do_mmio(ghcb, ctxt, bytes, false); break; case INSN_MMIO_WRITE_IMM: memcpy(ghcb->shared_buffer, insn->immediate1.bytes, bytes); ret = vc_do_mmio(ghcb, ctxt, bytes, false); break; case INSN_MMIO_READ: ret = vc_do_mmio(ghcb, ctxt, bytes, true); if (ret) break; /* Zero-extend for 32-bit operation */ if (bytes == 4) *reg_data = 0; memcpy(reg_data, ghcb->shared_buffer, bytes); break; case INSN_MMIO_READ_ZERO_EXTEND: ret = vc_do_mmio(ghcb, ctxt, bytes, true); if (ret) break; /* Zero extend based on operand size */ memset(reg_data, 0, insn->opnd_bytes); memcpy(reg_data, ghcb->shared_buffer, bytes); break; case INSN_MMIO_READ_SIGN_EXTEND: ret = vc_do_mmio(ghcb, ctxt, bytes, true); if (ret) break; if (bytes == 1) { u8 *val = (u8 *)ghcb->shared_buffer; sign_byte = (*val & 0x80) ? 0xff : 0x00; } else { u16 *val = (u16 *)ghcb->shared_buffer; sign_byte = (*val & 0x8000) ? 0xff : 0x00; } /* Sign extend based on operand size */ memset(reg_data, sign_byte, insn->opnd_bytes); memcpy(reg_data, ghcb->shared_buffer, bytes); break; case INSN_MMIO_MOVS: ret = vc_handle_mmio_movs(ctxt, bytes); break; default: ret = ES_UNSUPPORTED; break; } return ret; } static enum es_result vc_handle_dr7_write(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { struct sev_es_runtime_data *data = this_cpu_read(runtime_data); long val, *reg = vc_insn_get_rm(ctxt); enum es_result ret; if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP) return ES_VMM_ERROR; if (!reg) return ES_DECODE_FAILED; val = *reg; /* Upper 32 bits must be written as zeroes */ if (val >> 32) { ctxt->fi.vector = X86_TRAP_GP; ctxt->fi.error_code = 0; return ES_EXCEPTION; } /* Clear out other reserved bits and set bit 10 */ val = (val & 0xffff23ffL) | BIT(10); /* Early non-zero writes to DR7 are not supported */ if (!data && (val & ~DR7_RESET_VALUE)) return ES_UNSUPPORTED; /* Using a value of 0 for ExitInfo1 means RAX holds the value */ ghcb_set_rax(ghcb, val); ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WRITE_DR7, 0, 0); if (ret != ES_OK) return ret; if (data) data->dr7 = val; return ES_OK; } static enum es_result vc_handle_dr7_read(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { struct sev_es_runtime_data *data = this_cpu_read(runtime_data); long *reg = vc_insn_get_rm(ctxt); if (sev_status & MSR_AMD64_SNP_DEBUG_SWAP) return ES_VMM_ERROR; if (!reg) return ES_DECODE_FAILED; if (data) *reg = data->dr7; else *reg = DR7_RESET_VALUE; return ES_OK; } static enum es_result vc_handle_wbinvd(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { return sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_WBINVD, 0, 0); } static enum es_result vc_handle_rdpmc(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { enum es_result ret; ghcb_set_rcx(ghcb, ctxt->regs->cx); ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_RDPMC, 0, 0); if (ret != ES_OK) return ret; if (!(ghcb_rax_is_valid(ghcb) && ghcb_rdx_is_valid(ghcb))) return ES_VMM_ERROR; ctxt->regs->ax = ghcb->save.rax; ctxt->regs->dx = ghcb->save.rdx; return ES_OK; } static enum es_result vc_handle_monitor(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { /* * Treat it as a NOP and do not leak a physical address to the * hypervisor. */ return ES_OK; } static enum es_result vc_handle_mwait(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { /* Treat the same as MONITOR/MONITORX */ return ES_OK; } static enum es_result vc_handle_vmmcall(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { enum es_result ret; ghcb_set_rax(ghcb, ctxt->regs->ax); ghcb_set_cpl(ghcb, user_mode(ctxt->regs) ? 3 : 0); if (x86_platform.hyper.sev_es_hcall_prepare) x86_platform.hyper.sev_es_hcall_prepare(ghcb, ctxt->regs); ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_VMMCALL, 0, 0); if (ret != ES_OK) return ret; if (!ghcb_rax_is_valid(ghcb)) return ES_VMM_ERROR; ctxt->regs->ax = ghcb->save.rax; /* * Call sev_es_hcall_finish() after regs->ax is already set. * This allows the hypervisor handler to overwrite it again if * necessary. */ if (x86_platform.hyper.sev_es_hcall_finish && !x86_platform.hyper.sev_es_hcall_finish(ghcb, ctxt->regs)) return ES_VMM_ERROR; return ES_OK; } static enum es_result vc_handle_trap_ac(struct ghcb *ghcb, struct es_em_ctxt *ctxt) { /* * Calling ecx_alignment_check() directly does not work, because it * enables IRQs and the GHCB is active. Forward the exception and call * it later from vc_forward_exception(). */ ctxt->fi.vector = X86_TRAP_AC; ctxt->fi.error_code = 0; return ES_EXCEPTION; } static enum es_result vc_handle_exitcode(struct es_em_ctxt *ctxt, struct ghcb *ghcb, unsigned long exit_code) { enum es_result result = vc_check_opcode_bytes(ctxt, exit_code); if (result != ES_OK) return result; switch (exit_code) { case SVM_EXIT_READ_DR7: result = vc_handle_dr7_read(ghcb, ctxt); break; case SVM_EXIT_WRITE_DR7: result = vc_handle_dr7_write(ghcb, ctxt); break; case SVM_EXIT_EXCP_BASE + X86_TRAP_AC: result = vc_handle_trap_ac(ghcb, ctxt); break; case SVM_EXIT_RDTSC: case SVM_EXIT_RDTSCP: result = vc_handle_rdtsc(ghcb, ctxt, exit_code); break; case SVM_EXIT_RDPMC: result = vc_handle_rdpmc(ghcb, ctxt); break; case SVM_EXIT_INVD: pr_err_ratelimited("#VC exception for INVD??? Seriously???\n"); result = ES_UNSUPPORTED; break; case SVM_EXIT_CPUID: result = vc_handle_cpuid(ghcb, ctxt); break; case SVM_EXIT_IOIO: result = vc_handle_ioio(ghcb, ctxt); break; case SVM_EXIT_MSR: result = vc_handle_msr(ghcb, ctxt); break; case SVM_EXIT_VMMCALL: result = vc_handle_vmmcall(ghcb, ctxt); break; case SVM_EXIT_WBINVD: result = vc_handle_wbinvd(ghcb, ctxt); break; case SVM_EXIT_MONITOR: result = vc_handle_monitor(ghcb, ctxt); break; case SVM_EXIT_MWAIT: result = vc_handle_mwait(ghcb, ctxt); break; case SVM_EXIT_NPF: result = vc_handle_mmio(ghcb, ctxt); break; default: /* * Unexpected #VC exception */ result = ES_UNSUPPORTED; } return result; } static __always_inline bool is_vc2_stack(unsigned long sp) { return (sp >= __this_cpu_ist_bottom_va(VC2) && sp < __this_cpu_ist_top_va(VC2)); } static __always_inline bool vc_from_invalid_context(struct pt_regs *regs) { unsigned long sp, prev_sp; sp = (unsigned long)regs; prev_sp = regs->sp; /* * If the code was already executing on the VC2 stack when the #VC * happened, let it proceed to the normal handling routine. This way the * code executing on the VC2 stack can cause #VC exceptions to get handled. */ return is_vc2_stack(sp) && !is_vc2_stack(prev_sp); } static bool vc_raw_handle_exception(struct pt_regs *regs, unsigned long error_code) { struct ghcb_state state; struct es_em_ctxt ctxt; enum es_result result; struct ghcb *ghcb; bool ret = true; ghcb = __sev_get_ghcb(&state); vc_ghcb_invalidate(ghcb); result = vc_init_em_ctxt(&ctxt, regs, error_code); if (result == ES_OK) result = vc_handle_exitcode(&ctxt, ghcb, error_code); __sev_put_ghcb(&state); /* Done - now check the result */ switch (result) { case ES_OK: vc_finish_insn(&ctxt); break; case ES_UNSUPPORTED: pr_err_ratelimited("Unsupported exit-code 0x%02lx in #VC exception (IP: 0x%lx)\n", error_code, regs->ip); ret = false; break; case ES_VMM_ERROR: pr_err_ratelimited("Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n", error_code, regs->ip); ret = false; break; case ES_DECODE_FAILED: pr_err_ratelimited("Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n", error_code, regs->ip); ret = false; break; case ES_EXCEPTION: vc_forward_exception(&ctxt); break; case ES_RETRY: /* Nothing to do */ break; default: pr_emerg("Unknown result in %s():%d\n", __func__, result); /* * Emulating the instruction which caused the #VC exception * failed - can't continue so print debug information */ BUG(); } return ret; } static __always_inline bool vc_is_db(unsigned long error_code) { return error_code == SVM_EXIT_EXCP_BASE + X86_TRAP_DB; } /* * Runtime #VC exception handler when raised from kernel mode. Runs in NMI mode * and will panic when an error happens. */ DEFINE_IDTENTRY_VC_KERNEL(exc_vmm_communication) { irqentry_state_t irq_state; /* * With the current implementation it is always possible to switch to a * safe stack because #VC exceptions only happen at known places, like * intercepted instructions or accesses to MMIO areas/IO ports. They can * also happen with code instrumentation when the hypervisor intercepts * #DB, but the critical paths are forbidden to be instrumented, so #DB * exceptions currently also only happen in safe places. * * But keep this here in case the noinstr annotations are violated due * to bug elsewhere. */ if (unlikely(vc_from_invalid_context(regs))) { instrumentation_begin(); panic("Can't handle #VC exception from unsupported context\n"); instrumentation_end(); } /* * Handle #DB before calling into !noinstr code to avoid recursive #DB. */ if (vc_is_db(error_code)) { exc_debug(regs); return; } irq_state = irqentry_nmi_enter(regs); instrumentation_begin(); if (!vc_raw_handle_exception(regs, error_code)) { /* Show some debug info */ show_regs(regs); /* Ask hypervisor to sev_es_terminate */ sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); /* If that fails and we get here - just panic */ panic("Returned from Terminate-Request to Hypervisor\n"); } instrumentation_end(); irqentry_nmi_exit(regs, irq_state); } /* * Runtime #VC exception handler when raised from user mode. Runs in IRQ mode * and will kill the current task with SIGBUS when an error happens. */ DEFINE_IDTENTRY_VC_USER(exc_vmm_communication) { /* * Handle #DB before calling into !noinstr code to avoid recursive #DB. */ if (vc_is_db(error_code)) { noist_exc_debug(regs); return; } irqentry_enter_from_user_mode(regs); instrumentation_begin(); if (!vc_raw_handle_exception(regs, error_code)) { /* * Do not kill the machine if user-space triggered the * exception. Send SIGBUS instead and let user-space deal with * it. */ force_sig_fault(SIGBUS, BUS_OBJERR, (void __user *)0); } instrumentation_end(); irqentry_exit_to_user_mode(regs); } bool __init handle_vc_boot_ghcb(struct pt_regs *regs) { unsigned long exit_code = regs->orig_ax; struct es_em_ctxt ctxt; enum es_result result; vc_ghcb_invalidate(boot_ghcb); result = vc_init_em_ctxt(&ctxt, regs, exit_code); if (result == ES_OK) result = vc_handle_exitcode(&ctxt, boot_ghcb, exit_code); /* Done - now check the result */ switch (result) { case ES_OK: vc_finish_insn(&ctxt); break; case ES_UNSUPPORTED: early_printk("PANIC: Unsupported exit-code 0x%02lx in early #VC exception (IP: 0x%lx)\n", exit_code, regs->ip); goto fail; case ES_VMM_ERROR: early_printk("PANIC: Failure in communication with VMM (exit-code 0x%02lx IP: 0x%lx)\n", exit_code, regs->ip); goto fail; case ES_DECODE_FAILED: early_printk("PANIC: Failed to decode instruction (exit-code 0x%02lx IP: 0x%lx)\n", exit_code, regs->ip); goto fail; case ES_EXCEPTION: vc_early_forward_exception(&ctxt); break; case ES_RETRY: /* Nothing to do */ break; default: BUG(); } return true; fail: show_regs(regs); sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SEV_ES_GEN_REQ); } /* * Initial set up of SNP relies on information provided by the * Confidential Computing blob, which can be passed to the kernel * in the following ways, depending on how it is booted: * * - when booted via the boot/decompress kernel: * - via boot_params * * - when booted directly by firmware/bootloader (e.g. CONFIG_PVH): * - via a setup_data entry, as defined by the Linux Boot Protocol * * Scan for the blob in that order. */ static __head struct cc_blob_sev_info *find_cc_blob(struct boot_params *bp) { struct cc_blob_sev_info *cc_info; /* Boot kernel would have passed the CC blob via boot_params. */ if (bp->cc_blob_address) { cc_info = (struct cc_blob_sev_info *)(unsigned long)bp->cc_blob_address; goto found_cc_info; } /* * If kernel was booted directly, without the use of the * boot/decompression kernel, the CC blob may have been passed via * setup_data instead. */ cc_info = find_cc_blob_setup_data(bp); if (!cc_info) return NULL; found_cc_info: if (cc_info->magic != CC_BLOB_SEV_HDR_MAGIC) snp_abort(); return cc_info; } static __head void svsm_setup(struct cc_blob_sev_info *cc_info) { struct svsm_call call = {}; int ret; u64 pa; /* * Record the SVSM Calling Area address (CAA) if the guest is not * running at VMPL0. The CA will be used to communicate with the * SVSM to perform the SVSM services. */ if (!svsm_setup_ca(cc_info)) return; /* * It is very early in the boot and the kernel is running identity * mapped but without having adjusted the pagetables to where the * kernel was loaded (physbase), so the get the CA address using * RIP-relative addressing. */ pa = (u64)&RIP_REL_REF(boot_svsm_ca_page); /* * Switch over to the boot SVSM CA while the current CA is still * addressable. There is no GHCB at this point so use the MSR protocol. * * SVSM_CORE_REMAP_CA call: * RAX = 0 (Protocol=0, CallID=0) * RCX = New CA GPA */ call.caa = svsm_get_caa(); call.rax = SVSM_CORE_CALL(SVSM_CORE_REMAP_CA); call.rcx = pa; ret = svsm_perform_call_protocol(&call); if (ret) sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SVSM_CA_REMAP_FAIL); RIP_REL_REF(boot_svsm_caa) = (struct svsm_ca *)pa; RIP_REL_REF(boot_svsm_caa_pa) = pa; } bool __head snp_init(struct boot_params *bp) { struct cc_blob_sev_info *cc_info; if (!bp) return false; cc_info = find_cc_blob(bp); if (!cc_info) return false; if (cc_info->secrets_phys && cc_info->secrets_len == PAGE_SIZE) secrets_pa = cc_info->secrets_phys; else return false; setup_cpuid_table(cc_info); svsm_setup(cc_info); /* * The CC blob will be used later to access the secrets page. Cache * it here like the boot kernel does. */ bp->cc_blob_address = (u32)(unsigned long)cc_info; return true; } void __head __noreturn snp_abort(void) { sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); } /* * SEV-SNP guests should only execute dmi_setup() if EFI_CONFIG_TABLES are * enabled, as the alternative (fallback) logic for DMI probing in the legacy * ROM region can cause a crash since this region is not pre-validated. */ void __init snp_dmi_setup(void) { if (efi_enabled(EFI_CONFIG_TABLES)) dmi_setup(); } static void dump_cpuid_table(void) { const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); int i = 0; pr_info("count=%d reserved=0x%x reserved2=0x%llx\n", cpuid_table->count, cpuid_table->__reserved1, cpuid_table->__reserved2); for (i = 0; i < SNP_CPUID_COUNT_MAX; i++) { const struct snp_cpuid_fn *fn = &cpuid_table->fn[i]; pr_info("index=%3d fn=0x%08x subfn=0x%08x: eax=0x%08x ebx=0x%08x ecx=0x%08x edx=0x%08x xcr0_in=0x%016llx xss_in=0x%016llx reserved=0x%016llx\n", i, fn->eax_in, fn->ecx_in, fn->eax, fn->ebx, fn->ecx, fn->edx, fn->xcr0_in, fn->xss_in, fn->__reserved); } } /* * It is useful from an auditing/testing perspective to provide an easy way * for the guest owner to know that the CPUID table has been initialized as * expected, but that initialization happens too early in boot to print any * sort of indicator, and there's not really any other good place to do it, * so do it here. * * If running as an SNP guest, report the current VM privilege level (VMPL). */ static int __init report_snp_info(void) { const struct snp_cpuid_table *cpuid_table = snp_cpuid_get_table(); if (cpuid_table->count) { pr_info("Using SNP CPUID table, %d entries present.\n", cpuid_table->count); if (sev_cfg.debug) dump_cpuid_table(); } if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) pr_info("SNP running at VMPL%u.\n", snp_vmpl); return 0; } arch_initcall(report_snp_info); static void update_attest_input(struct svsm_call *call, struct svsm_attest_call *input) { /* If (new) lengths have been returned, propagate them up */ if (call->rcx_out != call->rcx) input->manifest_buf.len = call->rcx_out; if (call->rdx_out != call->rdx) input->certificates_buf.len = call->rdx_out; if (call->r8_out != call->r8) input->report_buf.len = call->r8_out; } int snp_issue_svsm_attest_req(u64 call_id, struct svsm_call *call, struct svsm_attest_call *input) { struct svsm_attest_call *ac; unsigned long flags; u64 attest_call_pa; int ret; if (!snp_vmpl) return -EINVAL; local_irq_save(flags); call->caa = svsm_get_caa(); ac = (struct svsm_attest_call *)call->caa->svsm_buffer; attest_call_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer); *ac = *input; /* * Set input registers for the request and set RDX and R8 to known * values in order to detect length values being returned in them. */ call->rax = call_id; call->rcx = attest_call_pa; call->rdx = -1; call->r8 = -1; ret = svsm_perform_call_protocol(call); update_attest_input(call, input); local_irq_restore(flags); return ret; } EXPORT_SYMBOL_GPL(snp_issue_svsm_attest_req); static int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input, struct snp_guest_request_ioctl *rio) { struct ghcb_state state; struct es_em_ctxt ctxt; unsigned long flags; struct ghcb *ghcb; int ret; rio->exitinfo2 = SEV_RET_NO_FW_CALL; /* * __sev_get_ghcb() needs to run with IRQs disabled because it is using * a per-CPU GHCB. */ local_irq_save(flags); ghcb = __sev_get_ghcb(&state); if (!ghcb) { ret = -EIO; goto e_restore_irq; } vc_ghcb_invalidate(ghcb); if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { ghcb_set_rax(ghcb, input->data_gpa); ghcb_set_rbx(ghcb, input->data_npages); } ret = sev_es_ghcb_hv_call(ghcb, &ctxt, req->exit_code, input->req_gpa, input->resp_gpa); if (ret) goto e_put; rio->exitinfo2 = ghcb->save.sw_exit_info_2; switch (rio->exitinfo2) { case 0: break; case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_BUSY): ret = -EAGAIN; break; case SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN): /* Number of expected pages are returned in RBX */ if (req->exit_code == SVM_VMGEXIT_EXT_GUEST_REQUEST) { input->data_npages = ghcb_get_rbx(ghcb); ret = -ENOSPC; break; } fallthrough; default: ret = -EIO; break; } e_put: __sev_put_ghcb(&state); e_restore_irq: local_irq_restore(flags); return ret; } static struct platform_device sev_guest_device = { .name = "sev-guest", .id = -1, }; static int __init snp_init_platform_device(void) { if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return -ENODEV; if (platform_device_register(&sev_guest_device)) return -ENODEV; pr_info("SNP guest platform device initialized.\n"); return 0; } device_initcall(snp_init_platform_device); void sev_show_status(void) { int i; pr_info("Status: "); for (i = 0; i < MSR_AMD64_SNP_RESV_BIT; i++) { if (sev_status & BIT_ULL(i)) { if (!sev_status_feat_names[i]) continue; pr_cont("%s ", sev_status_feat_names[i]); } } pr_cont("\n"); } void __init snp_update_svsm_ca(void) { if (!snp_vmpl) return; /* Update the CAA to a proper kernel address */ boot_svsm_caa = &boot_svsm_ca_page; } #ifdef CONFIG_SYSFS static ssize_t vmpl_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf) { return sysfs_emit(buf, "%d\n", snp_vmpl); } static struct kobj_attribute vmpl_attr = __ATTR_RO(vmpl); static struct attribute *vmpl_attrs[] = { &vmpl_attr.attr, NULL }; static struct attribute_group sev_attr_group = { .attrs = vmpl_attrs, }; static int __init sev_sysfs_init(void) { struct kobject *sev_kobj; struct device *dev_root; int ret; if (!cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) return -ENODEV; dev_root = bus_get_dev_root(&cpu_subsys); if (!dev_root) return -ENODEV; sev_kobj = kobject_create_and_add("sev", &dev_root->kobj); put_device(dev_root); if (!sev_kobj) return -ENOMEM; ret = sysfs_create_group(sev_kobj, &sev_attr_group); if (ret) kobject_put(sev_kobj); return ret; } arch_initcall(sev_sysfs_init); #endif // CONFIG_SYSFS static void free_shared_pages(void *buf, size_t sz) { unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; int ret; if (!buf) return; ret = set_memory_encrypted((unsigned long)buf, npages); if (ret) { WARN_ONCE(ret, "failed to restore encryption mask (leak it)\n"); return; } __free_pages(virt_to_page(buf), get_order(sz)); } static void *alloc_shared_pages(size_t sz) { unsigned int npages = PAGE_ALIGN(sz) >> PAGE_SHIFT; struct page *page; int ret; page = alloc_pages(GFP_KERNEL_ACCOUNT, get_order(sz)); if (!page) return NULL; ret = set_memory_decrypted((unsigned long)page_address(page), npages); if (ret) { pr_err("failed to mark page shared, ret=%d\n", ret); __free_pages(page, get_order(sz)); return NULL; } return page_address(page); } static u8 *get_vmpck(int id, struct snp_secrets_page *secrets, u32 **seqno) { u8 *key = NULL; switch (id) { case 0: *seqno = &secrets->os_area.msg_seqno_0; key = secrets->vmpck0; break; case 1: *seqno = &secrets->os_area.msg_seqno_1; key = secrets->vmpck1; break; case 2: *seqno = &secrets->os_area.msg_seqno_2; key = secrets->vmpck2; break; case 3: *seqno = &secrets->os_area.msg_seqno_3; key = secrets->vmpck3; break; default: break; } return key; } static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen) { struct aesgcm_ctx *ctx; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return NULL; if (aesgcm_expandkey(ctx, key, keylen, AUTHTAG_LEN)) { pr_err("Crypto context initialization failed\n"); kfree(ctx); return NULL; } return ctx; } int snp_msg_init(struct snp_msg_desc *mdesc, int vmpck_id) { /* Adjust the default VMPCK key based on the executing VMPL level */ if (vmpck_id == -1) vmpck_id = snp_vmpl; mdesc->vmpck = get_vmpck(vmpck_id, mdesc->secrets, &mdesc->os_area_msg_seqno); if (!mdesc->vmpck) { pr_err("Invalid VMPCK%d communication key\n", vmpck_id); return -EINVAL; } /* Verify that VMPCK is not zero. */ if (!memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { pr_err("Empty VMPCK%d communication key\n", vmpck_id); return -EINVAL; } mdesc->vmpck_id = vmpck_id; mdesc->ctx = snp_init_crypto(mdesc->vmpck, VMPCK_KEY_LEN); if (!mdesc->ctx) return -ENOMEM; return 0; } EXPORT_SYMBOL_GPL(snp_msg_init); struct snp_msg_desc *snp_msg_alloc(void) { struct snp_msg_desc *mdesc; void __iomem *mem; BUILD_BUG_ON(sizeof(struct snp_guest_msg) > PAGE_SIZE); mdesc = kzalloc(sizeof(struct snp_msg_desc), GFP_KERNEL); if (!mdesc) return ERR_PTR(-ENOMEM); mem = ioremap_encrypted(secrets_pa, PAGE_SIZE); if (!mem) goto e_free_mdesc; mdesc->secrets = (__force struct snp_secrets_page *)mem; /* Allocate the shared page used for the request and response message. */ mdesc->request = alloc_shared_pages(sizeof(struct snp_guest_msg)); if (!mdesc->request) goto e_unmap; mdesc->response = alloc_shared_pages(sizeof(struct snp_guest_msg)); if (!mdesc->response) goto e_free_request; return mdesc; e_free_request: free_shared_pages(mdesc->request, sizeof(struct snp_guest_msg)); e_unmap: iounmap(mem); e_free_mdesc: kfree(mdesc); return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(snp_msg_alloc); void snp_msg_free(struct snp_msg_desc *mdesc) { if (!mdesc) return; kfree(mdesc->ctx); free_shared_pages(mdesc->response, sizeof(struct snp_guest_msg)); free_shared_pages(mdesc->request, sizeof(struct snp_guest_msg)); iounmap((__force void __iomem *)mdesc->secrets); memset(mdesc, 0, sizeof(*mdesc)); kfree(mdesc); } EXPORT_SYMBOL_GPL(snp_msg_free); /* Mutex to serialize the shared buffer access and command handling. */ static DEFINE_MUTEX(snp_cmd_mutex); /* * If an error is received from the host or AMD Secure Processor (ASP) there * are two options. Either retry the exact same encrypted request or discontinue * using the VMPCK. * * This is because in the current encryption scheme GHCB v2 uses AES-GCM to * encrypt the requests. The IV for this scheme is the sequence number. GCM * cannot tolerate IV reuse. * * The ASP FW v1.51 only increments the sequence numbers on a successful * guest<->ASP back and forth and only accepts messages at its exact sequence * number. * * So if the sequence number were to be reused the encryption scheme is * vulnerable. If the sequence number were incremented for a fresh IV the ASP * will reject the request. */ static void snp_disable_vmpck(struct snp_msg_desc *mdesc) { pr_alert("Disabling VMPCK%d communication key to prevent IV reuse.\n", mdesc->vmpck_id); memzero_explicit(mdesc->vmpck, VMPCK_KEY_LEN); mdesc->vmpck = NULL; } static inline u64 __snp_get_msg_seqno(struct snp_msg_desc *mdesc) { u64 count; lockdep_assert_held(&snp_cmd_mutex); /* Read the current message sequence counter from secrets pages */ count = *mdesc->os_area_msg_seqno; return count + 1; } /* Return a non-zero on success */ static u64 snp_get_msg_seqno(struct snp_msg_desc *mdesc) { u64 count = __snp_get_msg_seqno(mdesc); /* * The message sequence counter for the SNP guest request is a 64-bit * value but the version 2 of GHCB specification defines a 32-bit storage * for it. If the counter exceeds the 32-bit value then return zero. * The caller should check the return value, but if the caller happens to * not check the value and use it, then the firmware treats zero as an * invalid number and will fail the message request. */ if (count >= UINT_MAX) { pr_err("request message sequence counter overflow\n"); return 0; } return count; } static void snp_inc_msg_seqno(struct snp_msg_desc *mdesc) { /* * The counter is also incremented by the PSP, so increment it by 2 * and save in secrets page. */ *mdesc->os_area_msg_seqno += 2; } static int verify_and_dec_payload(struct snp_msg_desc *mdesc, struct snp_guest_req *req) { struct snp_guest_msg *resp_msg = &mdesc->secret_response; struct snp_guest_msg *req_msg = &mdesc->secret_request; struct snp_guest_msg_hdr *req_msg_hdr = &req_msg->hdr; struct snp_guest_msg_hdr *resp_msg_hdr = &resp_msg->hdr; struct aesgcm_ctx *ctx = mdesc->ctx; u8 iv[GCM_AES_IV_SIZE] = {}; pr_debug("response [seqno %lld type %d version %d sz %d]\n", resp_msg_hdr->msg_seqno, resp_msg_hdr->msg_type, resp_msg_hdr->msg_version, resp_msg_hdr->msg_sz); /* Copy response from shared memory to encrypted memory. */ memcpy(resp_msg, mdesc->response, sizeof(*resp_msg)); /* Verify that the sequence counter is incremented by 1 */ if (unlikely(resp_msg_hdr->msg_seqno != (req_msg_hdr->msg_seqno + 1))) return -EBADMSG; /* Verify response message type and version number. */ if (resp_msg_hdr->msg_type != (req_msg_hdr->msg_type + 1) || resp_msg_hdr->msg_version != req_msg_hdr->msg_version) return -EBADMSG; /* * If the message size is greater than our buffer length then return * an error. */ if (unlikely((resp_msg_hdr->msg_sz + ctx->authsize) > req->resp_sz)) return -EBADMSG; /* Decrypt the payload */ memcpy(iv, &resp_msg_hdr->msg_seqno, min(sizeof(iv), sizeof(resp_msg_hdr->msg_seqno))); if (!aesgcm_decrypt(ctx, req->resp_buf, resp_msg->payload, resp_msg_hdr->msg_sz, &resp_msg_hdr->algo, AAD_LEN, iv, resp_msg_hdr->authtag)) return -EBADMSG; return 0; } static int enc_payload(struct snp_msg_desc *mdesc, u64 seqno, struct snp_guest_req *req) { struct snp_guest_msg *msg = &mdesc->secret_request; struct snp_guest_msg_hdr *hdr = &msg->hdr; struct aesgcm_ctx *ctx = mdesc->ctx; u8 iv[GCM_AES_IV_SIZE] = {}; memset(msg, 0, sizeof(*msg)); hdr->algo = SNP_AEAD_AES_256_GCM; hdr->hdr_version = MSG_HDR_VER; hdr->hdr_sz = sizeof(*hdr); hdr->msg_type = req->msg_type; hdr->msg_version = req->msg_version; hdr->msg_seqno = seqno; hdr->msg_vmpck = req->vmpck_id; hdr->msg_sz = req->req_sz; /* Verify the sequence number is non-zero */ if (!hdr->msg_seqno) return -ENOSR; pr_debug("request [seqno %lld type %d version %d sz %d]\n", hdr->msg_seqno, hdr->msg_type, hdr->msg_version, hdr->msg_sz); if (WARN_ON((req->req_sz + ctx->authsize) > sizeof(msg->payload))) return -EBADMSG; memcpy(iv, &hdr->msg_seqno, min(sizeof(iv), sizeof(hdr->msg_seqno))); aesgcm_encrypt(ctx, msg->payload, req->req_buf, req->req_sz, &hdr->algo, AAD_LEN, iv, hdr->authtag); return 0; } static int __handle_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, struct snp_guest_request_ioctl *rio) { unsigned long req_start = jiffies; unsigned int override_npages = 0; u64 override_err = 0; int rc; retry_request: /* * Call firmware to process the request. In this function the encrypted * message enters shared memory with the host. So after this call the * sequence number must be incremented or the VMPCK must be deleted to * prevent reuse of the IV. */ rc = snp_issue_guest_request(req, &req->input, rio); switch (rc) { case -ENOSPC: /* * If the extended guest request fails due to having too * small of a certificate data buffer, retry the same * guest request without the extended data request in * order to increment the sequence number and thus avoid * IV reuse. */ override_npages = req->input.data_npages; req->exit_code = SVM_VMGEXIT_GUEST_REQUEST; /* * Override the error to inform callers the given extended * request buffer size was too small and give the caller the * required buffer size. */ override_err = SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN); /* * If this call to the firmware succeeds, the sequence number can * be incremented allowing for continued use of the VMPCK. If * there is an error reflected in the return value, this value * is checked further down and the result will be the deletion * of the VMPCK and the error code being propagated back to the * user as an ioctl() return code. */ goto retry_request; /* * The host may return SNP_GUEST_VMM_ERR_BUSY if the request has been * throttled. Retry in the driver to avoid returning and reusing the * message sequence number on a different message. */ case -EAGAIN: if (jiffies - req_start > SNP_REQ_MAX_RETRY_DURATION) { rc = -ETIMEDOUT; break; } schedule_timeout_killable(SNP_REQ_RETRY_DELAY); goto retry_request; } /* * Increment the message sequence number. There is no harm in doing * this now because decryption uses the value stored in the response * structure and any failure will wipe the VMPCK, preventing further * use anyway. */ snp_inc_msg_seqno(mdesc); if (override_err) { rio->exitinfo2 = override_err; /* * If an extended guest request was issued and the supplied certificate * buffer was not large enough, a standard guest request was issued to * prevent IV reuse. If the standard request was successful, return -EIO * back to the caller as would have originally been returned. */ if (!rc && override_err == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) rc = -EIO; } if (override_npages) req->input.data_npages = override_npages; return rc; } int snp_send_guest_request(struct snp_msg_desc *mdesc, struct snp_guest_req *req, struct snp_guest_request_ioctl *rio) { u64 seqno; int rc; guard(mutex)(&snp_cmd_mutex); /* Check if the VMPCK is not empty */ if (!mdesc->vmpck || !memchr_inv(mdesc->vmpck, 0, VMPCK_KEY_LEN)) { pr_err_ratelimited("VMPCK is disabled\n"); return -ENOTTY; } /* Get message sequence and verify that its a non-zero */ seqno = snp_get_msg_seqno(mdesc); if (!seqno) return -EIO; /* Clear shared memory's response for the host to populate. */ memset(mdesc->response, 0, sizeof(struct snp_guest_msg)); /* Encrypt the userspace provided payload in mdesc->secret_request. */ rc = enc_payload(mdesc, seqno, req); if (rc) return rc; /* * Write the fully encrypted request to the shared unencrypted * request page. */ memcpy(mdesc->request, &mdesc->secret_request, sizeof(mdesc->secret_request)); /* Initialize the input address for guest request */ req->input.req_gpa = __pa(mdesc->request); req->input.resp_gpa = __pa(mdesc->response); req->input.data_gpa = req->certs_data ? __pa(req->certs_data) : 0; rc = __handle_guest_request(mdesc, req, rio); if (rc) { if (rc == -EIO && rio->exitinfo2 == SNP_GUEST_VMM_ERR(SNP_GUEST_VMM_ERR_INVALID_LEN)) return rc; pr_alert("Detected error from ASP request. rc: %d, exitinfo2: 0x%llx\n", rc, rio->exitinfo2); snp_disable_vmpck(mdesc); return rc; } rc = verify_and_dec_payload(mdesc, req); if (rc) { pr_alert("Detected unexpected decode failure from ASP. rc: %d\n", rc); snp_disable_vmpck(mdesc); return rc; } return 0; } EXPORT_SYMBOL_GPL(snp_send_guest_request); static int __init snp_get_tsc_info(void) { struct snp_guest_request_ioctl *rio; struct snp_tsc_info_resp *tsc_resp; struct snp_tsc_info_req *tsc_req; struct snp_msg_desc *mdesc; struct snp_guest_req *req; int rc = -ENOMEM; tsc_req = kzalloc(sizeof(*tsc_req), GFP_KERNEL); if (!tsc_req) return rc; /* * The intermediate response buffer is used while decrypting the * response payload. Make sure that it has enough space to cover * the authtag. */ tsc_resp = kzalloc(sizeof(*tsc_resp) + AUTHTAG_LEN, GFP_KERNEL); if (!tsc_resp) goto e_free_tsc_req; req = kzalloc(sizeof(*req), GFP_KERNEL); if (!req) goto e_free_tsc_resp; rio = kzalloc(sizeof(*rio), GFP_KERNEL); if (!rio) goto e_free_req; mdesc = snp_msg_alloc(); if (IS_ERR_OR_NULL(mdesc)) goto e_free_rio; rc = snp_msg_init(mdesc, snp_vmpl); if (rc) goto e_free_mdesc; req->msg_version = MSG_HDR_VER; req->msg_type = SNP_MSG_TSC_INFO_REQ; req->vmpck_id = snp_vmpl; req->req_buf = tsc_req; req->req_sz = sizeof(*tsc_req); req->resp_buf = (void *)tsc_resp; req->resp_sz = sizeof(*tsc_resp) + AUTHTAG_LEN; req->exit_code = SVM_VMGEXIT_GUEST_REQUEST; rc = snp_send_guest_request(mdesc, req, rio); if (rc) goto e_request; pr_debug("%s: response status 0x%x scale 0x%llx offset 0x%llx factor 0x%x\n", __func__, tsc_resp->status, tsc_resp->tsc_scale, tsc_resp->tsc_offset, tsc_resp->tsc_factor); if (!tsc_resp->status) { snp_tsc_scale = tsc_resp->tsc_scale; snp_tsc_offset = tsc_resp->tsc_offset; } else { pr_err("Failed to get TSC info, response status 0x%x\n", tsc_resp->status); rc = -EIO; } e_request: /* The response buffer contains sensitive data, explicitly clear it. */ memzero_explicit(tsc_resp, sizeof(*tsc_resp) + AUTHTAG_LEN); e_free_mdesc: snp_msg_free(mdesc); e_free_rio: kfree(rio); e_free_req: kfree(req); e_free_tsc_resp: kfree(tsc_resp); e_free_tsc_req: kfree(tsc_req); return rc; } void __init snp_secure_tsc_prepare(void) { if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) return; if (snp_get_tsc_info()) { pr_alert("Unable to retrieve Secure TSC info from ASP\n"); sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC); } pr_debug("SecureTSC enabled"); } static unsigned long securetsc_get_tsc_khz(void) { return snp_tsc_freq_khz; } void __init snp_secure_tsc_init(void) { unsigned long long tsc_freq_mhz; if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) return; setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); rdmsrl(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); snp_tsc_freq_khz = (unsigned long)(tsc_freq_mhz * 1000); x86_platform.calibrate_cpu = securetsc_get_tsc_khz; x86_platform.calibrate_tsc = securetsc_get_tsc_khz; }
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