| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Tom Lendacky | 2119 | 25.89% | 36 | 24.83% |
| Nikunj A. Dadhania | 1631 | 19.92% | 13 | 8.97% |
| Ard Biesheuvel | 1496 | 18.28% | 4 | 2.76% |
| Brijesh Singh | 1290 | 15.76% | 15 | 10.34% |
| Joerg Roedel | 353 | 4.31% | 19 | 13.10% |
| Ingo Molnar | 340 | 4.15% | 6 | 4.14% |
| Borislav Petkov | 230 | 2.81% | 9 | 6.21% |
| Michael Roth | 196 | 2.39% | 6 | 4.14% |
| Stefano Garzarella | 149 | 1.82% | 2 | 1.38% |
| Ashish Kalra | 137 | 1.67% | 3 | 2.07% |
| Dionna Glaze | 64 | 0.78% | 3 | 2.07% |
| Alexey Kardashevskiy | 49 | 0.60% | 1 | 0.69% |
| Kirill A. Shutemov | 19 | 0.23% | 3 | 2.07% |
| Peter Gonda | 18 | 0.22% | 2 | 1.38% |
| Kevin Loughlin | 13 | 0.16% | 1 | 0.69% |
| Dan J Williams | 12 | 0.15% | 1 | 0.69% |
| Li RongQing | 11 | 0.13% | 1 | 0.69% |
| Michael Sterritt | 7 | 0.09% | 1 | 0.69% |
| Martin Radev | 6 | 0.07% | 1 | 0.69% |
| Rick Edgecombe | 6 | 0.07% | 1 | 0.69% |
| Namhyung Kim | 6 | 0.07% | 1 | 0.69% |
| Song Liu | 6 | 0.07% | 1 | 0.69% |
| Thomas Gleixner | 6 | 0.07% | 4 | 2.76% |
| James Bottomley | 5 | 0.06% | 1 | 0.69% |
| Linus Torvalds | 4 | 0.05% | 1 | 0.69% |
| Dave Jones | 3 | 0.04% | 2 | 1.38% |
| Andrew Morton | 2 | 0.02% | 1 | 0.69% |
| Jack Steiner | 2 | 0.02% | 1 | 0.69% |
| Linus Torvalds (pre-git) | 2 | 0.02% | 1 | 0.69% |
| Ahmed S. Darwish | 1 | 0.01% | 1 | 0.69% |
| Jarkko Sakkinen | 1 | 0.01% | 1 | 0.69% |
| H. Peter Anvin | 1 | 0.01% | 1 | 0.69% |
| Haowen Bai | 1 | 0.01% | 1 | 0.69% |
| Total | 8186 | 145 |
// 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/sev-internal.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/api.h> #include <asm/cmdline.h> #include <asm/msr.h> /* 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 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 unsigned long snp_tsc_freq_khz __ro_after_init; DEFINE_PER_CPU(struct sev_es_runtime_data*, runtime_data); DEFINE_PER_CPU(struct sev_es_save_area *, sev_vmsa); /* * SVSM related information: * When running under an SVSM, the VMPL that Linux is executing at must be * non-zero. The VMPL is therefore used to indicate the presence of an SVSM. */ u8 snp_vmpl __ro_after_init; EXPORT_SYMBOL_GPL(snp_vmpl); static u64 __init get_snp_jump_table_addr(void) { struct snp_secrets_page *secrets; void __iomem *mem; u64 addr; mem = ioremap_encrypted(sev_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 inline void __pval_terminate(u64 pfn, bool action, unsigned int page_size, int ret, u64 svsm_ret) { WARN(1, "PVALIDATE failure: pfn: 0x%llx, action: %u, size: %u, ret: %d, svsm_ret: 0x%llx\n", pfn, action, page_size, ret, svsm_ret); sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_PVALIDATE); } static void svsm_pval_terminate(struct svsm_pvalidate_call *pc, int ret, u64 svsm_ret) { unsigned int page_size; bool action; u64 pfn; pfn = pc->entry[pc->cur_index].pfn; action = pc->entry[pc->cur_index].action; page_size = pc->entry[pc->cur_index].page_size; __pval_terminate(pfn, action, page_size, ret, svsm_ret); } static void pval_pages(struct snp_psc_desc *desc) { struct psc_entry *e; unsigned long vaddr; unsigned int size; unsigned int i; bool validate; u64 pfn; int rc; for (i = 0; i <= desc->hdr.end_entry; i++) { e = &desc->entries[i]; pfn = e->gfn; vaddr = (unsigned long)pfn_to_kaddr(pfn); size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K; validate = e->operation == SNP_PAGE_STATE_PRIVATE; rc = pvalidate(vaddr, size, validate); if (!rc) continue; if (rc == PVALIDATE_FAIL_SIZEMISMATCH && size == RMP_PG_SIZE_2M) { unsigned long vaddr_end = vaddr + PMD_SIZE; for (; vaddr < vaddr_end; vaddr += PAGE_SIZE, pfn++) { rc = pvalidate(vaddr, RMP_PG_SIZE_4K, validate); if (rc) __pval_terminate(pfn, validate, RMP_PG_SIZE_4K, rc, 0); } } else { __pval_terminate(pfn, validate, size, rc, 0); } } } static u64 svsm_build_ca_from_pfn_range(u64 pfn, u64 pfn_end, bool action, struct svsm_pvalidate_call *pc) { struct svsm_pvalidate_entry *pe; /* Nothing in the CA yet */ pc->num_entries = 0; pc->cur_index = 0; pe = &pc->entry[0]; while (pfn < pfn_end) { pe->page_size = RMP_PG_SIZE_4K; pe->action = action; pe->ignore_cf = 0; pe->pfn = pfn; pe++; pfn++; pc->num_entries++; if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT) break; } return pfn; } static int svsm_build_ca_from_psc_desc(struct snp_psc_desc *desc, unsigned int desc_entry, struct svsm_pvalidate_call *pc) { struct svsm_pvalidate_entry *pe; struct psc_entry *e; /* Nothing in the CA yet */ pc->num_entries = 0; pc->cur_index = 0; pe = &pc->entry[0]; e = &desc->entries[desc_entry]; while (desc_entry <= desc->hdr.end_entry) { pe->page_size = e->pagesize ? RMP_PG_SIZE_2M : RMP_PG_SIZE_4K; pe->action = e->operation == SNP_PAGE_STATE_PRIVATE; pe->ignore_cf = 0; pe->pfn = e->gfn; pe++; e++; desc_entry++; pc->num_entries++; if (pc->num_entries == SVSM_PVALIDATE_MAX_COUNT) break; } return desc_entry; } static void svsm_pval_pages(struct snp_psc_desc *desc) { struct svsm_pvalidate_entry pv_4k[VMGEXIT_PSC_MAX_ENTRY]; unsigned int i, pv_4k_count = 0; struct svsm_pvalidate_call *pc; struct svsm_call call = {}; unsigned long flags; bool action; u64 pc_pa; 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(); /* * The SVSM calling area (CA) can support processing 510 entries at a * time. Loop through the Page State Change descriptor until the CA is * full or the last entry in the descriptor is reached, at which time * the SVSM is invoked. This repeats until all entries in the descriptor * are processed. */ call.caa = svsm_get_caa(); pc = (struct svsm_pvalidate_call *)call.caa->svsm_buffer; pc_pa = svsm_get_caa_pa() + offsetof(struct svsm_ca, svsm_buffer); /* Protocol 0, Call ID 1 */ call.rax = SVSM_CORE_CALL(SVSM_CORE_PVALIDATE); call.rcx = pc_pa; for (i = 0; i <= desc->hdr.end_entry;) { i = svsm_build_ca_from_psc_desc(desc, i, pc); do { ret = svsm_perform_call_protocol(&call); if (!ret) continue; /* * Check if the entry failed because of an RMP mismatch (a * PVALIDATE at 2M was requested, but the page is mapped in * the RMP as 4K). */ if (call.rax_out == SVSM_PVALIDATE_FAIL_SIZEMISMATCH && pc->entry[pc->cur_index].page_size == RMP_PG_SIZE_2M) { /* Save this entry for post-processing at 4K */ pv_4k[pv_4k_count++] = pc->entry[pc->cur_index]; /* Skip to the next one unless at the end of the list */ pc->cur_index++; if (pc->cur_index < pc->num_entries) ret = -EAGAIN; else ret = 0; } } while (ret == -EAGAIN); if (ret) svsm_pval_terminate(pc, ret, call.rax_out); } /* Process any entries that failed to be validated at 2M and validate them at 4K */ for (i = 0; i < pv_4k_count; i++) { u64 pfn, pfn_end; action = pv_4k[i].action; pfn = pv_4k[i].pfn; pfn_end = pfn + 512; while (pfn < pfn_end) { pfn = svsm_build_ca_from_pfn_range(pfn, pfn_end, action, pc); ret = svsm_perform_call_protocol(&call); if (ret) svsm_pval_terminate(pc, ret, call.rax_out); } } native_local_irq_restore(flags); } static void pvalidate_pages(struct snp_psc_desc *desc) { if (snp_vmpl) svsm_pval_pages(desc); else pval_pages(desc); } static int vmgexit_psc(struct ghcb *ghcb, struct snp_psc_desc *desc) { int cur_entry, end_entry, ret = 0; struct snp_psc_desc *data; struct es_em_ctxt ctxt; vc_ghcb_invalidate(ghcb); /* Copy the input desc into GHCB shared buffer */ data = (struct snp_psc_desc *)ghcb->shared_buffer; memcpy(ghcb->shared_buffer, desc, min_t(int, GHCB_SHARED_BUF_SIZE, sizeof(*desc))); /* * As per the GHCB specification, the hypervisor can resume the guest * before processing all the entries. Check whether all the entries * are processed. If not, then keep retrying. Note, the hypervisor * will update the data memory directly to indicate the status, so * reference the data->hdr everywhere. * * The strategy here is to wait for the hypervisor to change the page * state in the RMP table before guest accesses the memory pages. If the * page state change was not successful, then later memory access will * result in a crash. */ cur_entry = data->hdr.cur_entry; end_entry = data->hdr.end_entry; while (data->hdr.cur_entry <= data->hdr.end_entry) { ghcb_set_sw_scratch(ghcb, (u64)__pa(data)); /* This will advance the shared buffer data points to. */ ret = sev_es_ghcb_hv_call(ghcb, &ctxt, SVM_VMGEXIT_PSC, 0, 0); /* * Page State Change VMGEXIT can pass error code through * exit_info_2. */ if (WARN(ret || ghcb->save.sw_exit_info_2, "SNP: PSC failed ret=%d exit_info_2=%llx\n", ret, ghcb->save.sw_exit_info_2)) { ret = 1; goto out; } /* Verify that reserved bit is not set */ if (WARN(data->hdr.reserved, "Reserved bit is set in the PSC header\n")) { ret = 1; goto out; } /* * Sanity check that entry processing is not going backwards. * This will happen only if hypervisor is tricking us. */ if (WARN(data->hdr.end_entry > end_entry || cur_entry > data->hdr.cur_entry, "SNP: PSC processing going backward, end_entry %d (got %d) cur_entry %d (got %d)\n", end_entry, data->hdr.end_entry, cur_entry, data->hdr.cur_entry)) { ret = 1; goto out; } } out: return ret; } 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, unsigned int cpu) { struct sev_es_save_area *cur_vmsa, *vmsa; struct svsm_ca *caa; u8 sipi_vector; int 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; 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; } 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; } /* * 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; } /** * snp_svsm_vtpm_probe() - Probe if SVSM provides a vTPM device * * Check that there is SVSM and that it supports at least TPM_SEND_COMMAND * which is the only request used so far. * * Return: true if the platform provides a vTPM SVSM device, false otherwise. */ static bool snp_svsm_vtpm_probe(void) { struct svsm_call call = {}; /* The vTPM device is available only if a SVSM is present */ if (!snp_vmpl) return false; call.caa = svsm_get_caa(); call.rax = SVSM_VTPM_CALL(SVSM_VTPM_QUERY); if (svsm_perform_call_protocol(&call)) return false; /* Check platform commands contains TPM_SEND_COMMAND - platform command 8 */ return call.rcx_out & BIT_ULL(8); } /** * snp_svsm_vtpm_send_command() - Execute a vTPM operation on SVSM * @buffer: A buffer used to both send the command and receive the response. * * Execute a SVSM_VTPM_CMD call as defined by * "Secure VM Service Module for SEV-SNP Guests" Publication # 58019 Revision: 1.00 * * All command request/response buffers have a common structure as specified by * the following table: * Byte Size In/Out Description * Offset (Bytes) * 0x000 4 In Platform command * Out Platform command response size * * Each command can build upon this common request/response structure to create * a structure specific to the command. See include/linux/tpm_svsm.h for more * details. * * Return: 0 on success, -errno on failure */ int snp_svsm_vtpm_send_command(u8 *buffer) { struct svsm_call call = {}; call.caa = svsm_get_caa(); call.rax = SVSM_VTPM_CALL(SVSM_VTPM_CMD); call.rcx = __pa(buffer); return svsm_perform_call_protocol(&call); } EXPORT_SYMBOL_GPL(snp_svsm_vtpm_send_command); static struct platform_device sev_guest_device = { .name = "sev-guest", .id = -1, }; static struct platform_device tpm_svsm_device = { .name = "tpm-svsm", .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; if (snp_svsm_vtpm_probe() && platform_device_register(&tpm_svsm_device)) return -ENODEV; pr_info("SNP guest platform devices 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(sev_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) { struct snp_secrets_page *secrets; unsigned long tsc_freq_mhz; void *mem; if (!cc_platform_has(CC_ATTR_GUEST_SNP_SECURE_TSC)) return; mem = early_memremap_encrypted(sev_secrets_pa, PAGE_SIZE); if (!mem) { pr_err("Unable to get TSC_FACTOR: failed to map the SNP secrets page.\n"); sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_SECURE_TSC); } secrets = (__force struct snp_secrets_page *)mem; setup_force_cpu_cap(X86_FEATURE_TSC_KNOWN_FREQ); rdmsrq(MSR_AMD64_GUEST_TSC_FREQ, tsc_freq_mhz); /* Extract the GUEST TSC MHZ from BIT[17:0], rest is reserved space */ tsc_freq_mhz &= GENMASK_ULL(17, 0); snp_tsc_freq_khz = SNP_SCALE_TSC_FREQ(tsc_freq_mhz * 1000, secrets->tsc_factor); x86_platform.calibrate_cpu = securetsc_get_tsc_khz; x86_platform.calibrate_tsc = securetsc_get_tsc_khz; early_memunmap(mem, PAGE_SIZE); }
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