Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
Brijesh Singh | 1334 | 72.78% | 6 | 26.09% |
Ashish Kalra | 245 | 13.37% | 3 | 13.04% |
Michael Roth | 174 | 9.49% | 1 | 4.35% |
Tom Lendacky | 40 | 2.18% | 2 | 8.70% |
Borislav Petkov | 23 | 1.25% | 2 | 8.70% |
zhong jiang | 4 | 0.22% | 1 | 4.35% |
Andrew Lutomirski | 4 | 0.22% | 2 | 8.70% |
Konrad Rzeszutek Wilk | 2 | 0.11% | 1 | 4.35% |
Peter Zijlstra | 2 | 0.11% | 1 | 4.35% |
Suravee Suthikulpanit | 2 | 0.11% | 1 | 4.35% |
Andi Kleen | 1 | 0.05% | 1 | 4.35% |
Thomas Gleixner | 1 | 0.05% | 1 | 4.35% |
Yinghai Lu | 1 | 0.05% | 1 | 4.35% |
Total | 1833 | 23 |
// SPDX-License-Identifier: GPL-2.0-only /* * AMD SVM-SEV Host Support. * * Copyright (C) 2023 Advanced Micro Devices, Inc. * * Author: Ashish Kalra <ashish.kalra@amd.com> * */ #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/iommu.h> #include <linux/amd-iommu.h> #include <asm/sev.h> #include <asm/processor.h> #include <asm/setup.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> #include <asm/iommu.h> /* * The RMP entry format is not architectural. The format is defined in PPR * Family 19h Model 01h, Rev B1 processor. */ struct rmpentry { union { struct { u64 assigned : 1, pagesize : 1, immutable : 1, rsvd1 : 9, gpa : 39, asid : 10, vmsa : 1, validated : 1, rsvd2 : 1; }; u64 lo; }; u64 hi; } __packed; /* * The first 16KB from the RMP_BASE is used by the processor for the * bookkeeping, the range needs to be added during the RMP entry lookup. */ #define RMPTABLE_CPU_BOOKKEEPING_SZ 0x4000 /* Mask to apply to a PFN to get the first PFN of a 2MB page */ #define PFN_PMD_MASK GENMASK_ULL(63, PMD_SHIFT - PAGE_SHIFT) static u64 probed_rmp_base, probed_rmp_size; static struct rmpentry *rmptable __ro_after_init; static u64 rmptable_max_pfn __ro_after_init; static LIST_HEAD(snp_leaked_pages_list); static DEFINE_SPINLOCK(snp_leaked_pages_list_lock); static unsigned long snp_nr_leaked_pages; #undef pr_fmt #define pr_fmt(fmt) "SEV-SNP: " fmt static int __mfd_enable(unsigned int cpu) { u64 val; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return 0; rdmsrl(MSR_AMD64_SYSCFG, val); val |= MSR_AMD64_SYSCFG_MFDM; wrmsrl(MSR_AMD64_SYSCFG, val); return 0; } static __init void mfd_enable(void *arg) { __mfd_enable(smp_processor_id()); } static int __snp_enable(unsigned int cpu) { u64 val; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return 0; rdmsrl(MSR_AMD64_SYSCFG, val); val |= MSR_AMD64_SYSCFG_SNP_EN; val |= MSR_AMD64_SYSCFG_SNP_VMPL_EN; wrmsrl(MSR_AMD64_SYSCFG, val); return 0; } static __init void snp_enable(void *arg) { __snp_enable(smp_processor_id()); } #define RMP_ADDR_MASK GENMASK_ULL(51, 13) bool snp_probe_rmptable_info(void) { u64 rmp_sz, rmp_base, rmp_end; rdmsrl(MSR_AMD64_RMP_BASE, rmp_base); rdmsrl(MSR_AMD64_RMP_END, rmp_end); if (!(rmp_base & RMP_ADDR_MASK) || !(rmp_end & RMP_ADDR_MASK)) { pr_err("Memory for the RMP table has not been reserved by BIOS\n"); return false; } if (rmp_base > rmp_end) { pr_err("RMP configuration not valid: base=%#llx, end=%#llx\n", rmp_base, rmp_end); return false; } rmp_sz = rmp_end - rmp_base + 1; probed_rmp_base = rmp_base; probed_rmp_size = rmp_sz; pr_info("RMP table physical range [0x%016llx - 0x%016llx]\n", rmp_base, rmp_end); return true; } static void __init __snp_fixup_e820_tables(u64 pa) { if (IS_ALIGNED(pa, PMD_SIZE)) return; /* * Handle cases where the RMP table placement by the BIOS is not * 2M aligned and the kexec kernel could try to allocate * from within that chunk which then causes a fatal RMP fault. * * The e820_table needs to be updated as it is converted to * kernel memory resources and used by KEXEC_FILE_LOAD syscall * to load kexec segments. * * The e820_table_firmware needs to be updated as it is exposed * to sysfs and used by the KEXEC_LOAD syscall to load kexec * segments. * * The e820_table_kexec needs to be updated as it passed to * the kexec-ed kernel. */ pa = ALIGN_DOWN(pa, PMD_SIZE); if (e820__mapped_any(pa, pa + PMD_SIZE, E820_TYPE_RAM)) { pr_info("Reserving start/end of RMP table on a 2MB boundary [0x%016llx]\n", pa); e820__range_update(pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED); e820__range_update_table(e820_table_kexec, pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED); e820__range_update_table(e820_table_firmware, pa, PMD_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED); } } void __init snp_fixup_e820_tables(void) { __snp_fixup_e820_tables(probed_rmp_base); __snp_fixup_e820_tables(probed_rmp_base + probed_rmp_size); } /* * Do the necessary preparations which are verified by the firmware as * described in the SNP_INIT_EX firmware command description in the SNP * firmware ABI spec. */ static int __init snp_rmptable_init(void) { u64 max_rmp_pfn, calc_rmp_sz, rmptable_size, rmp_end, val; void *rmptable_start; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return 0; if (!amd_iommu_snp_en) goto nosnp; if (!probed_rmp_size) goto nosnp; rmp_end = probed_rmp_base + probed_rmp_size - 1; /* * Calculate the amount the memory that must be reserved by the BIOS to * address the whole RAM, including the bookkeeping area. The RMP itself * must also be covered. */ max_rmp_pfn = max_pfn; if (PFN_UP(rmp_end) > max_pfn) max_rmp_pfn = PFN_UP(rmp_end); calc_rmp_sz = (max_rmp_pfn << 4) + RMPTABLE_CPU_BOOKKEEPING_SZ; if (calc_rmp_sz > probed_rmp_size) { pr_err("Memory reserved for the RMP table does not cover full system RAM (expected 0x%llx got 0x%llx)\n", calc_rmp_sz, probed_rmp_size); goto nosnp; } rmptable_start = memremap(probed_rmp_base, probed_rmp_size, MEMREMAP_WB); if (!rmptable_start) { pr_err("Failed to map RMP table\n"); goto nosnp; } /* * Check if SEV-SNP is already enabled, this can happen in case of * kexec boot. */ rdmsrl(MSR_AMD64_SYSCFG, val); if (val & MSR_AMD64_SYSCFG_SNP_EN) goto skip_enable; memset(rmptable_start, 0, probed_rmp_size); /* Flush the caches to ensure that data is written before SNP is enabled. */ wbinvd_on_all_cpus(); /* MtrrFixDramModEn must be enabled on all the CPUs prior to enabling SNP. */ on_each_cpu(mfd_enable, NULL, 1); on_each_cpu(snp_enable, NULL, 1); skip_enable: rmptable_start += RMPTABLE_CPU_BOOKKEEPING_SZ; rmptable_size = probed_rmp_size - RMPTABLE_CPU_BOOKKEEPING_SZ; rmptable = (struct rmpentry *)rmptable_start; rmptable_max_pfn = rmptable_size / sizeof(struct rmpentry) - 1; cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/rmptable_init:online", __snp_enable, NULL); /* * Setting crash_kexec_post_notifiers to 'true' to ensure that SNP panic * notifier is invoked to do SNP IOMMU shutdown before kdump. */ crash_kexec_post_notifiers = true; return 0; nosnp: cc_platform_clear(CC_ATTR_HOST_SEV_SNP); return -ENOSYS; } /* * This must be called after the IOMMU has been initialized. */ device_initcall(snp_rmptable_init); static struct rmpentry *get_rmpentry(u64 pfn) { if (WARN_ON_ONCE(pfn > rmptable_max_pfn)) return ERR_PTR(-EFAULT); return &rmptable[pfn]; } static struct rmpentry *__snp_lookup_rmpentry(u64 pfn, int *level) { struct rmpentry *large_entry, *entry; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return ERR_PTR(-ENODEV); entry = get_rmpentry(pfn); if (IS_ERR(entry)) return entry; /* * Find the authoritative RMP entry for a PFN. This can be either a 4K * RMP entry or a special large RMP entry that is authoritative for a * whole 2M area. */ large_entry = get_rmpentry(pfn & PFN_PMD_MASK); if (IS_ERR(large_entry)) return large_entry; *level = RMP_TO_PG_LEVEL(large_entry->pagesize); return entry; } int snp_lookup_rmpentry(u64 pfn, bool *assigned, int *level) { struct rmpentry *e; e = __snp_lookup_rmpentry(pfn, level); if (IS_ERR(e)) return PTR_ERR(e); *assigned = !!e->assigned; return 0; } EXPORT_SYMBOL_GPL(snp_lookup_rmpentry); /* * Dump the raw RMP entry for a particular PFN. These bits are documented in the * PPR for a particular CPU model and provide useful information about how a * particular PFN is being utilized by the kernel/firmware at the time certain * unexpected events occur, such as RMP faults. */ static void dump_rmpentry(u64 pfn) { u64 pfn_i, pfn_end; struct rmpentry *e; int level; e = __snp_lookup_rmpentry(pfn, &level); if (IS_ERR(e)) { pr_err("Failed to read RMP entry for PFN 0x%llx, error %ld\n", pfn, PTR_ERR(e)); return; } if (e->assigned) { pr_info("PFN 0x%llx, RMP entry: [0x%016llx - 0x%016llx]\n", pfn, e->lo, e->hi); return; } /* * If the RMP entry for a particular PFN is not in an assigned state, * then it is sometimes useful to get an idea of whether or not any RMP * entries for other PFNs within the same 2MB region are assigned, since * those too can affect the ability to access a particular PFN in * certain situations, such as when the PFN is being accessed via a 2MB * mapping in the host page table. */ pfn_i = ALIGN_DOWN(pfn, PTRS_PER_PMD); pfn_end = pfn_i + PTRS_PER_PMD; pr_info("PFN 0x%llx unassigned, dumping non-zero entries in 2M PFN region: [0x%llx - 0x%llx]\n", pfn, pfn_i, pfn_end); while (pfn_i < pfn_end) { e = __snp_lookup_rmpentry(pfn_i, &level); if (IS_ERR(e)) { pr_err("Error %ld reading RMP entry for PFN 0x%llx\n", PTR_ERR(e), pfn_i); pfn_i++; continue; } if (e->lo || e->hi) pr_info("PFN: 0x%llx, [0x%016llx - 0x%016llx]\n", pfn_i, e->lo, e->hi); pfn_i++; } } void snp_dump_hva_rmpentry(unsigned long hva) { unsigned long paddr; unsigned int level; pgd_t *pgd; pte_t *pte; pgd = __va(read_cr3_pa()); pgd += pgd_index(hva); pte = lookup_address_in_pgd(pgd, hva, &level); if (!pte) { pr_err("Can't dump RMP entry for HVA %lx: no PTE/PFN found\n", hva); return; } paddr = PFN_PHYS(pte_pfn(*pte)) | (hva & ~page_level_mask(level)); dump_rmpentry(PHYS_PFN(paddr)); } /* * PSMASH a 2MB aligned page into 4K pages in the RMP table while preserving the * Validated bit. */ int psmash(u64 pfn) { unsigned long paddr = pfn << PAGE_SHIFT; int ret; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return -ENODEV; if (!pfn_valid(pfn)) return -EINVAL; /* Binutils version 2.36 supports the PSMASH mnemonic. */ asm volatile(".byte 0xF3, 0x0F, 0x01, 0xFF" : "=a" (ret) : "a" (paddr) : "memory", "cc"); return ret; } EXPORT_SYMBOL_GPL(psmash); /* * If the kernel uses a 2MB or larger directmap mapping to write to an address, * and that mapping contains any 4KB pages that are set to private in the RMP * table, an RMP #PF will trigger and cause a host crash. Hypervisor code that * owns the PFNs being transitioned will never attempt such a write, but other * kernel tasks writing to other PFNs in the range may trigger these checks * inadvertently due a large directmap mapping that happens to overlap such a * PFN. * * Prevent this by splitting any 2MB+ mappings that might end up containing a * mix of private/shared PFNs as a result of a subsequent RMPUPDATE for the * PFN/rmp_level passed in. * * Note that there is no attempt here to scan all the RMP entries for the 2MB * physical range, since it would only be worthwhile in determining if a * subsequent RMPUPDATE for a 4KB PFN would result in all the entries being of * the same shared/private state, thus avoiding the need to split the mapping. * But that would mean the entries are currently in a mixed state, and so the * mapping would have already been split as a result of prior transitions. * And since the 4K split is only done if the mapping is 2MB+, and there isn't * currently a mechanism in place to restore 2MB+ mappings, such a check would * not provide any usable benefit. * * More specifics on how these checks are carried out can be found in APM * Volume 2, "RMP and VMPL Access Checks". */ static int adjust_direct_map(u64 pfn, int rmp_level) { unsigned long vaddr; unsigned int level; int npages, ret; pte_t *pte; /* * pfn_to_kaddr() will return a vaddr only within the direct * map range. */ vaddr = (unsigned long)pfn_to_kaddr(pfn); /* Only 4KB/2MB RMP entries are supported by current hardware. */ if (WARN_ON_ONCE(rmp_level > PG_LEVEL_2M)) return -EINVAL; if (!pfn_valid(pfn)) return -EINVAL; if (rmp_level == PG_LEVEL_2M && (!IS_ALIGNED(pfn, PTRS_PER_PMD) || !pfn_valid(pfn + PTRS_PER_PMD - 1))) return -EINVAL; /* * If an entire 2MB physical range is being transitioned, then there is * no risk of RMP #PFs due to write accesses from overlapping mappings, * since even accesses from 1GB mappings will be treated as 2MB accesses * as far as RMP table checks are concerned. */ if (rmp_level == PG_LEVEL_2M) return 0; pte = lookup_address(vaddr, &level); if (!pte || pte_none(*pte)) return 0; if (level == PG_LEVEL_4K) return 0; npages = page_level_size(rmp_level) / PAGE_SIZE; ret = set_memory_4k(vaddr, npages); if (ret) pr_warn("Failed to split direct map for PFN 0x%llx, ret: %d\n", pfn, ret); return ret; } /* * It is expected that those operations are seldom enough so that no mutual * exclusion of updaters is needed and thus the overlap error condition below * should happen very rarely and would get resolved relatively quickly by * the firmware. * * If not, one could consider introducing a mutex or so here to sync concurrent * RMP updates and thus diminish the amount of cases where firmware needs to * lock 2M ranges to protect against concurrent updates. * * The optimal solution would be range locking to avoid locking disjoint * regions unnecessarily but there's no support for that yet. */ static int rmpupdate(u64 pfn, struct rmp_state *state) { unsigned long paddr = pfn << PAGE_SHIFT; int ret, level; if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) return -ENODEV; level = RMP_TO_PG_LEVEL(state->pagesize); if (adjust_direct_map(pfn, level)) return -EFAULT; do { /* Binutils version 2.36 supports the RMPUPDATE mnemonic. */ asm volatile(".byte 0xF2, 0x0F, 0x01, 0xFE" : "=a" (ret) : "a" (paddr), "c" ((unsigned long)state) : "memory", "cc"); } while (ret == RMPUPDATE_FAIL_OVERLAP); if (ret) { pr_err("RMPUPDATE failed for PFN %llx, pg_level: %d, ret: %d\n", pfn, level, ret); dump_rmpentry(pfn); dump_stack(); return -EFAULT; } return 0; } /* Transition a page to guest-owned/private state in the RMP table. */ int rmp_make_private(u64 pfn, u64 gpa, enum pg_level level, u32 asid, bool immutable) { struct rmp_state state; memset(&state, 0, sizeof(state)); state.assigned = 1; state.asid = asid; state.immutable = immutable; state.gpa = gpa; state.pagesize = PG_LEVEL_TO_RMP(level); return rmpupdate(pfn, &state); } EXPORT_SYMBOL_GPL(rmp_make_private); /* Transition a page to hypervisor-owned/shared state in the RMP table. */ int rmp_make_shared(u64 pfn, enum pg_level level) { struct rmp_state state; memset(&state, 0, sizeof(state)); state.pagesize = PG_LEVEL_TO_RMP(level); return rmpupdate(pfn, &state); } EXPORT_SYMBOL_GPL(rmp_make_shared); void snp_leak_pages(u64 pfn, unsigned int npages) { struct page *page = pfn_to_page(pfn); pr_warn("Leaking PFN range 0x%llx-0x%llx\n", pfn, pfn + npages); spin_lock(&snp_leaked_pages_list_lock); while (npages--) { /* * Reuse the page's buddy list for chaining into the leaked * pages list. This page should not be on a free list currently * and is also unsafe to be added to a free list. */ if (likely(!PageCompound(page)) || /* * Skip inserting tail pages of compound page as * page->buddy_list of tail pages is not usable. */ (PageHead(page) && compound_nr(page) <= npages)) list_add_tail(&page->buddy_list, &snp_leaked_pages_list); dump_rmpentry(pfn); snp_nr_leaked_pages++; pfn++; page++; } spin_unlock(&snp_leaked_pages_list_lock); } EXPORT_SYMBOL_GPL(snp_leak_pages); void kdump_sev_callback(void) { /* * Do wbinvd() on remote CPUs when SNP is enabled in order to * safely do SNP_SHUTDOWN on the local CPU. */ if (cc_platform_has(CC_ATTR_HOST_SEV_SNP)) wbinvd(); }
Information contained on this website is for historical information purposes only and does not indicate or represent copyright ownership.
Created with Cregit http://github.com/cregit/cregit
Version 2.0-RC1