diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2022-02-24 19:56:01 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 14:24:53 +0300 |
| commit | dc3f3d2474b80eaee8be89f4c5eb344f10648f42 (patch) | |
| tree | 2c72a1701916d2288f5703f123a0f83c2761bc8f /arch/x86/mm | |
| parent | 9704c07bf9f7682a83aec4e66f2d9154dbd8577f (diff) | |
| download | linux-dc3f3d2474b80eaee8be89f4c5eb344f10648f42.tar.xz | |
x86/mm: Validate memory when changing the C-bit
Add the needed functionality to change pages state from shared
to private and vice-versa using the Page State Change VMGEXIT as
documented in the GHCB spec.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-22-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/mm')
| -rw-r--r-- | arch/x86/mm/mem_encrypt_amd.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/x86/mm/mem_encrypt_amd.c b/arch/x86/mm/mem_encrypt_amd.c index 8539dd6f24ff..d3c88d9ef8d6 100644 --- a/arch/x86/mm/mem_encrypt_amd.c +++ b/arch/x86/mm/mem_encrypt_amd.c @@ -316,11 +316,24 @@ static void enc_dec_hypercall(unsigned long vaddr, int npages, bool enc) static void amd_enc_status_change_prepare(unsigned long vaddr, int npages, bool enc) { + /* + * To maintain the security guarantees of SEV-SNP guests, make sure + * to invalidate the memory before encryption attribute is cleared. + */ + if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && !enc) + snp_set_memory_shared(vaddr, npages); } /* Return true unconditionally: return value doesn't matter for the SEV side */ static bool amd_enc_status_change_finish(unsigned long vaddr, int npages, bool enc) { + /* + * After memory is mapped encrypted in the page table, validate it + * so that it is consistent with the page table updates. + */ + if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP) && enc) + snp_set_memory_private(vaddr, npages); + if (!cc_platform_has(CC_ATTR_HOST_MEM_ENCRYPT)) enc_dec_hypercall(vaddr, npages, enc); |