AMD SEV introduces c-bit to page table entries. To work with AMD SEV: 1. c-bit should be set for new page table entries 2. address calculation should not use c-bit as part of address Signed-off-by: Zixuan Wang <zixuanwang@xxxxxxxxxx> --- lib/x86/amd_sev.c | 10 ++++++++++ lib/x86/amd_sev.h | 1 + lib/x86/asm/page.h | 27 ++++++++++++++++++++++++--- lib/x86/vm.c | 18 ++++++++++++++---- 4 files changed, 49 insertions(+), 7 deletions(-) diff --git a/lib/x86/amd_sev.c b/lib/x86/amd_sev.c index 5498ed6..f5e3585 100644 --- a/lib/x86/amd_sev.c +++ b/lib/x86/amd_sev.c @@ -75,3 +75,13 @@ unsigned long long get_amd_sev_c_bit_mask(void) return 0; } } + +unsigned long long get_amd_sev_addr_upperbound(void) +{ + if (amd_sev_enabled()) { + return amd_sev_c_bit_pos - 1; + } else { + /* Default memory upper bound */ + return PT_ADDR_UPPER_BOUND_DEFAULT; + } +} diff --git a/lib/x86/amd_sev.h b/lib/x86/amd_sev.h index 516d500..2780560 100644 --- a/lib/x86/amd_sev.h +++ b/lib/x86/amd_sev.h @@ -39,6 +39,7 @@ bool amd_sev_enabled(void); efi_status_t setup_amd_sev(void); unsigned long long get_amd_sev_c_bit_mask(void); +unsigned long long get_amd_sev_addr_upperbound(void); #endif /* TARGET_EFI */ diff --git a/lib/x86/asm/page.h b/lib/x86/asm/page.h index f6f740b..c25bc66 100644 --- a/lib/x86/asm/page.h +++ b/lib/x86/asm/page.h @@ -25,6 +25,12 @@ typedef unsigned long pgd_t; #define LARGE_PAGE_SIZE (1024 * PAGE_SIZE) #endif +#ifdef TARGET_EFI +/* lib/x86/amd_sev.c */ +extern unsigned long long get_amd_sev_c_bit_mask(void); +extern unsigned long long get_amd_sev_addr_upperbound(void); +#endif /* TARGET_EFI */ + #define PT_PRESENT_MASK (1ull << 0) #define PT_WRITABLE_MASK (1ull << 1) #define PT_USER_MASK (1ull << 2) @@ -33,10 +39,25 @@ typedef unsigned long pgd_t; #define PT_PAGE_SIZE_MASK (1ull << 7) #define PT_GLOBAL_MASK (1ull << 8) #define PT64_NX_MASK (1ull << 63) -#define PT_ADDR_MASK GENMASK_ULL(51, 12) -#define PDPTE64_PAGE_SIZE_MASK (1ull << 7) -#define PDPTE64_RSVD_MASK GENMASK_ULL(51, cpuid_maxphyaddr()) +/* + * Without AMD SEV, the default address upper bound is 51 (i.e., pte bit 51 and + * lower bits are addresses). But with AMD SEV enabled, the upper bound is one + * bit lower than the c-bit position. + */ +#define PT_ADDR_UPPER_BOUND_DEFAULT (51) + +#ifdef TARGET_EFI +#define PT_ADDR_UPPER_BOUND (get_amd_sev_addr_upperbound()) +#else +#define PT_ADDR_UPPER_BOUND (PT_ADDR_UPPER_BOUND_DEFAULT) +#endif /* TARGET_EFI */ + +#define PT_ADDR_LOWER_BOUND (PAGE_SHIFT) +#define PT_ADDR_MASK GENMASK_ULL(PT_ADDR_UPPER_BOUND, PT_ADDR_LOWER_BOUND) + +#define PDPTE64_PAGE_SIZE_MASK (1ull << 7) +#define PDPTE64_RSVD_MASK GENMASK_ULL(PT_ADDR_UPPER_BOUND, cpuid_maxphyaddr()) #define PT_AD_MASK (PT_ACCESSED_MASK | PT_DIRTY_MASK) diff --git a/lib/x86/vm.c b/lib/x86/vm.c index 5cd2ee4..0ebc860 100644 --- a/lib/x86/vm.c +++ b/lib/x86/vm.c @@ -26,6 +26,9 @@ pteval_t *install_pte(pgd_t *cr3, pt_page = 0; memset(new_pt, 0, PAGE_SIZE); pt[offset] = virt_to_phys(new_pt) | PT_PRESENT_MASK | PT_WRITABLE_MASK | pte_opt_mask; +#ifdef TARGET_EFI + pt[offset] |= get_amd_sev_c_bit_mask(); +#endif /* TARGET_EFI */ } pt = phys_to_virt(pt[offset] & PT_ADDR_MASK); } @@ -63,7 +66,7 @@ struct pte_search find_pte_level(pgd_t *cr3, void *virt, if (r.level == lowest_level) return r; - pt = phys_to_virt(pte & 0xffffffffff000ull); + pt = phys_to_virt(pte & PT_ADDR_MASK); } } @@ -94,13 +97,20 @@ pteval_t *get_pte_level(pgd_t *cr3, void *virt, int pte_level) pteval_t *install_large_page(pgd_t *cr3, phys_addr_t phys, void *virt) { - return install_pte(cr3, 2, virt, - phys | PT_PRESENT_MASK | PT_WRITABLE_MASK | pte_opt_mask | PT_PAGE_SIZE_MASK, 0); + phys_addr_t flags = PT_PRESENT_MASK | PT_WRITABLE_MASK | pte_opt_mask | PT_PAGE_SIZE_MASK; +#ifdef TARGET_EFI + flags |= get_amd_sev_c_bit_mask(); +#endif /* TARGET_EFI */ + return install_pte(cr3, 2, virt, phys | flags, 0); } pteval_t *install_page(pgd_t *cr3, phys_addr_t phys, void *virt) { - return install_pte(cr3, 1, virt, phys | PT_PRESENT_MASK | PT_WRITABLE_MASK | pte_opt_mask, 0); + phys_addr_t flags = PT_PRESENT_MASK | PT_WRITABLE_MASK | pte_opt_mask; +#ifdef TARGET_EFI + flags |= get_amd_sev_c_bit_mask(); +#endif /* TARGET_EFI */ + return install_pte(cr3, 1, virt, phys | flags, 0); } void install_pages(pgd_t *cr3, phys_addr_t phys, size_t len, void *virt) -- 2.33.0.259.gc128427fd7-goog