diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 5535edc6e8d71..6a6db7cd97cb3 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -452,6 +452,7 @@ #define X86_FEATURE_SME_COHERENT (19*32+10) /* AMD hardware-enforced cache coherency */ #define X86_FEATURE_DEBUG_SWAP (19*32+14) /* "debug_swap" AMD SEV-ES full debug state swap support */ #define X86_FEATURE_RMPREAD (19*32+21) /* RMPREAD instruction */ +#define X86_FEATURE_SEGMENTED_RMP (19*32+23) /* Segmented RMP support */ #define X86_FEATURE_SVSM (19*32+28) /* "svsm" SVSM present */ /* AMD-defined Extended Feature 2 EAX, CPUID level 0x80000021 (EAX), word 20 */ diff --git a/arch/x86/include/asm/msr-index.h b/arch/x86/include/asm/msr-index.h index 3ae84c3b8e6db..3f3e2bc99162c 100644 --- a/arch/x86/include/asm/msr-index.h +++ b/arch/x86/include/asm/msr-index.h @@ -644,6 +644,7 @@ #define MSR_AMD64_IBS_REG_COUNT_MAX 8 /* includes MSR_AMD64_IBSBRTARGET */ #define MSR_AMD64_SVM_AVIC_DOORBELL 0xc001011b #define MSR_AMD64_VM_PAGE_FLUSH 0xc001011e +#define MSR_AMD64_VIRT_SPEC_CTRL 0xc001011f #define MSR_AMD64_SEV_ES_GHCB 0xc0010130 #define MSR_AMD64_SEV 0xc0010131 #define MSR_AMD64_SEV_ENABLED_BIT 0 @@ -682,11 +683,12 @@ #define MSR_AMD64_SNP_SMT_PROT BIT_ULL(MSR_AMD64_SNP_SMT_PROT_BIT) #define MSR_AMD64_SNP_RESV_BIT 18 #define MSR_AMD64_SNP_RESERVED_MASK GENMASK_ULL(63, MSR_AMD64_SNP_RESV_BIT) - -#define MSR_AMD64_VIRT_SPEC_CTRL 0xc001011f - #define MSR_AMD64_RMP_BASE 0xc0010132 #define MSR_AMD64_RMP_END 0xc0010133 +#define MSR_AMD64_RMP_CFG 0xc0010136 +#define MSR_AMD64_SEG_RMP_ENABLED_BIT 0 +#define MSR_AMD64_SEG_RMP_ENABLED BIT_ULL(MSR_AMD64_SEG_RMP_ENABLED_BIT) +#define MSR_AMD64_RMP_SEGMENT_SHIFT(x) (((x) & GENMASK_ULL(13, 8)) >> 8) #define MSR_SVSM_CAA 0xc001f000 diff --git a/arch/x86/virt/svm/sev.c b/arch/x86/virt/svm/sev.c index e50b71c67fabc..1dcc027ec77e7 100644 --- a/arch/x86/virt/svm/sev.c +++ b/arch/x86/virt/svm/sev.c @@ -100,6 +100,10 @@ struct rmp_segment_desc { * a specific portion of memory. There can be up to 512 8-byte entries, * one pages worth. */ +#define RST_ENTRY_MAPPED_SIZE(x) ((x) & GENMASK_ULL(19, 0)) +#define RST_ENTRY_SEGMENT_BASE(x) ((x) & GENMASK_ULL(51, 20)) + +#define RST_SIZE SZ_4K static struct rmp_segment_desc **rmp_segment_table __ro_after_init; static unsigned int rst_max_index __ro_after_init = 512; @@ -110,6 +114,8 @@ static u64 rmp_segment_mask; #define RST_ENTRY_INDEX(x) ((x) >> rmp_segment_shift) #define RMP_ENTRY_INDEX(x) ((u64)(PHYS_PFN((x) & rmp_segment_mask))) +static u64 rmp_cfg; + /* 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) @@ -198,12 +204,62 @@ static void __init __snp_fixup_e820_tables(u64 pa) } } -void __init snp_fixup_e820_tables(void) +static void __init fixup_e820_tables_for_segmented_rmp(void) +{ + u64 pa, *rst, size, mapped_size; + unsigned int i; + + __snp_fixup_e820_tables(probed_rmp_base); + + pa = probed_rmp_base + RMPTABLE_CPU_BOOKKEEPING_SZ; + + __snp_fixup_e820_tables(pa + RST_SIZE); + + rst = early_memremap(pa, RST_SIZE); + if (!rst) + return; + + for (i = 0; i < rst_max_index; i++) { + pa = RST_ENTRY_SEGMENT_BASE(rst[i]); + mapped_size = RST_ENTRY_MAPPED_SIZE(rst[i]); + if (!mapped_size) + continue; + + __snp_fixup_e820_tables(pa); + + /* + * Mapped size in GB. Mapped size is allowed to exceed + * the segment coverage size, but gets reduced to the + * segment coverage size. + */ + mapped_size <<= 30; + if (mapped_size > rmp_segment_size) + mapped_size = rmp_segment_size; + + /* Calculate the RMP segment size (16 bytes/page mapped) */ + size = PHYS_PFN(mapped_size) << 4; + + __snp_fixup_e820_tables(pa + size); + } + + early_memunmap(rst, RST_SIZE); +} + +static void __init fixup_e820_tables_for_contiguous_rmp(void) { __snp_fixup_e820_tables(probed_rmp_base); __snp_fixup_e820_tables(probed_rmp_base + probed_rmp_size); } +void __init snp_fixup_e820_tables(void) +{ + if (rmp_cfg & MSR_AMD64_SEG_RMP_ENABLED) { + fixup_e820_tables_for_segmented_rmp(); + } else { + fixup_e820_tables_for_contiguous_rmp(); + } +} + static bool __init clear_rmptable_bookkeeping(void) { void *bk; @@ -307,29 +363,17 @@ static bool __init alloc_rmp_segment_table(void) return true; } -/* - * 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) +static bool __init setup_contiguous_rmptable(void) { - u64 max_rmp_pfn, calc_rmp_sz, rmptable_segment, rmptable_size, rmp_end, val; - unsigned int i; - - if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) - return 0; - - if (!amd_iommu_snp_en) - goto nosnp; + u64 max_rmp_pfn, calc_rmp_sz, rmptable_segment, rmptable_size, rmp_end; if (!probed_rmp_size) - goto nosnp; + return false; rmp_end = probed_rmp_base + probed_rmp_size - 1; /* - * Calculate the amount the memory that must be reserved by the BIOS to + * Calculate the amount of memory that must be reserved by the BIOS to * address the whole RAM, including the bookkeeping area. The RMP itself * must also be covered. */ @@ -341,11 +385,11 @@ static int __init snp_rmptable_init(void) 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; + return false; } if (!alloc_rmp_segment_table()) - goto nosnp; + return false; /* Map only the RMP entries */ rmptable_segment = probed_rmp_base + RMPTABLE_CPU_BOOKKEEPING_SZ; @@ -353,9 +397,128 @@ static int __init snp_rmptable_init(void) if (!alloc_rmp_segment_desc(rmptable_segment, rmptable_size, 0)) { free_rmp_segment_table(); - goto nosnp; + return false; } + return true; +} + +static bool __init setup_segmented_rmptable(void) +{ + u64 rst_pa, *rst, pa, ram_pa_end, ram_pa_max; + unsigned int i, max_index; + + if (!probed_rmp_base) + return false; + + if (!alloc_rmp_segment_table()) + return false; + + rst_pa = probed_rmp_base + RMPTABLE_CPU_BOOKKEEPING_SZ; + rst = memremap(rst_pa, RST_SIZE, MEMREMAP_WB); + if (!rst) { + pr_err("Failed to map RMP segment table addr 0x%llx\n", rst_pa); + goto e_free; + } + + pr_info("Segmented RMP using %lluGB segments\n", rmp_segment_size >> 30); + + ram_pa_max = max_pfn << PAGE_SHIFT; + + max_index = 0; + ram_pa_end = 0; + for (i = 0; i < rst_max_index; i++) { + u64 rmp_segment, rmp_size, mapped_size; + + mapped_size = RST_ENTRY_MAPPED_SIZE(rst[i]); + if (!mapped_size) + continue; + + max_index = i; + + /* + * Mapped size in GB. Mapped size is allowed to exceed the + * segment coverage size, but gets reduced to the segment + * coverage size. + */ + mapped_size <<= 30; + if (mapped_size > rmp_segment_size) { + pr_info("RMP segment %u mapped size (0x%llx) reduced to 0x%llx\n", + i, mapped_size, rmp_segment_size); + mapped_size = rmp_segment_size; + } + + rmp_segment = RST_ENTRY_SEGMENT_BASE(rst[i]); + + /* Calculate the RMP segment size (16 bytes/page mapped) */ + rmp_size = PHYS_PFN(mapped_size) << 4; + + pa = (u64)i << rmp_segment_shift; + + /* + * Some segments may be for MMIO mapped above system RAM. These + * segments are used for Trusted I/O. + */ + if (pa < ram_pa_max) + ram_pa_end = pa + mapped_size; + + if (!alloc_rmp_segment_desc(rmp_segment, rmp_size, pa)) + goto e_unmap; + + pr_info("RMP segment %u physical address [0x%llx - 0x%llx] covering [0x%llx - 0x%llx]\n", + i, rmp_segment, rmp_segment + rmp_size - 1, pa, pa + mapped_size - 1); + } + + if (ram_pa_max > ram_pa_end) { + pr_err("Segmented RMP does not cover full system RAM (expected 0x%llx got 0x%llx)\n", + ram_pa_max, ram_pa_end); + goto e_unmap; + } + + /* Adjust the maximum index based on the found segments */ + rst_max_index = max_index + 1; + + memunmap(rst); + + return true; + +e_unmap: + memunmap(rst); + +e_free: + free_rmp_segment_table(); + + return false; +} + +static bool __init setup_rmptable(void) +{ + if (rmp_cfg & MSR_AMD64_SEG_RMP_ENABLED) { + return setup_segmented_rmptable(); + } else { + return setup_contiguous_rmptable(); + } +} + +/* + * 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) +{ + unsigned int i; + u64 val; + + if (!cc_platform_has(CC_ATTR_HOST_SEV_SNP)) + return 0; + + if (!amd_iommu_snp_en) + goto nosnp; + + if (!setup_rmptable()) + goto nosnp; + /* * Check if SEV-SNP is already enabled, this can happen in case of * kexec boot. @@ -419,7 +582,7 @@ static void set_rmp_segment_info(unsigned int segment_shift) #define RMP_ADDR_MASK GENMASK_ULL(51, 13) -bool snp_probe_rmptable_info(void) +static bool probe_contiguous_rmptable_info(void) { u64 rmp_sz, rmp_base, rmp_end; @@ -452,6 +615,61 @@ bool snp_probe_rmptable_info(void) return true; } +static bool probe_segmented_rmptable_info(void) +{ + unsigned int eax, ebx, segment_shift, segment_shift_min, segment_shift_max; + u64 rmp_base, rmp_end; + + rdmsrl(MSR_AMD64_RMP_BASE, rmp_base); + if (!(rmp_base & RMP_ADDR_MASK)) { + pr_err("Memory for the RMP table has not been reserved by BIOS\n"); + return false; + } + + rdmsrl(MSR_AMD64_RMP_END, rmp_end); + WARN_ONCE(rmp_end & RMP_ADDR_MASK, + "Segmented RMP enabled but RMP_END MSR is non-zero\n"); + + /* Obtain the min and max supported RMP segment size */ + eax = cpuid_eax(0x80000025); + segment_shift_min = eax & GENMASK(5, 0); + segment_shift_max = (eax & GENMASK(11, 6)) >> 6; + + /* Verify the segment size is within the supported limits */ + segment_shift = MSR_AMD64_RMP_SEGMENT_SHIFT(rmp_cfg); + if (segment_shift > segment_shift_max || segment_shift < segment_shift_min) { + pr_err("RMP segment size (%u) is not within advertised bounds (min=%u, max=%u)\n", + segment_shift, segment_shift_min, segment_shift_max); + return false; + } + + /* Override the max supported RST index if a hardware limit exists */ + ebx = cpuid_ebx(0x80000025); + if (ebx & BIT(10)) + rst_max_index = ebx & GENMASK(9, 0); + + set_rmp_segment_info(segment_shift); + + probed_rmp_base = rmp_base; + probed_rmp_size = 0; + + pr_info("Segmented RMP base table physical range [0x%016llx - 0x%016llx]\n", + rmp_base, rmp_base + RMPTABLE_CPU_BOOKKEEPING_SZ + RST_SIZE); + + return true; +} + +bool snp_probe_rmptable_info(void) +{ + if (cpu_feature_enabled(X86_FEATURE_SEGMENTED_RMP)) + rdmsrl(MSR_AMD64_RMP_CFG, rmp_cfg); + + if (rmp_cfg & MSR_AMD64_SEG_RMP_ENABLED) + return probe_segmented_rmptable_info(); + else + return probe_contiguous_rmptable_info(); +} + /* * About the array_index_nospec() usage below: *