diff options
| author | John Allen <john.allen@amd.com> | 2025-09-24 20:08:52 +0000 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-10-30 17:47:49 +0100 |
| commit | 92ad6505a4b5e28afcc8cf5f4dd3fd137e58026b (patch) | |
| tree | afcda7e4adc0f2c335145f4df1fed7312b93e153 | |
| parent | 9249bcdea0c6db4f450a9267aa6da5b4dd4153ca (diff) | |
x86/sev: Include XSS value in GHCB CPUID request
When a guest issues a CPUID instruction for Fn0000000D_x01, the hypervisor may
be intercepting the CPUID instruction and need to access the guest XSS value.
For SEV-ES, the XSS value is encrypted and needs to be included in the GHCB to
be visible to the hypervisor.
Signed-off-by: John Allen <john.allen@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Link: https://patch.msgid.link/all/20250924200852.4452-3-john.allen@amd.com/
| -rw-r--r-- | arch/x86/coco/sev/vc-shared.c | 11 | ||||
| -rw-r--r-- | arch/x86/include/asm/svm.h | 1 |
2 files changed, 12 insertions, 0 deletions
diff --git a/arch/x86/coco/sev/vc-shared.c b/arch/x86/coco/sev/vc-shared.c index 9b01c9ad81be..e2ac95de4611 100644 --- a/arch/x86/coco/sev/vc-shared.c +++ b/arch/x86/coco/sev/vc-shared.c @@ -1,5 +1,9 @@ // SPDX-License-Identifier: GPL-2.0 +#ifndef __BOOT_COMPRESSED +#define has_cpuflag(f) boot_cpu_has(f) +#endif + static enum es_result vc_check_opcode_bytes(struct es_em_ctxt *ctxt, unsigned long exit_code) { @@ -546,6 +550,13 @@ static enum es_result vc_handle_cpuid(struct ghcb *ghcb, /* xgetbv will cause #GP - use reset value for xcr0 */ ghcb_set_xcr0(ghcb, 1); + if (has_cpuflag(X86_FEATURE_SHSTK) && regs->ax == 0xd && regs->cx == 1) { + struct msr m; + + raw_rdmsr(MSR_IA32_XSS, &m); + ghcb_set_xss(ghcb, m.q); + } + ret = sev_es_ghcb_hv_call(ghcb, ctxt, SVM_EXIT_CPUID, 0, 0); if (ret != ES_OK) return ret; diff --git a/arch/x86/include/asm/svm.h b/arch/x86/include/asm/svm.h index 17f6c3fedeee..0581c477d466 100644 --- a/arch/x86/include/asm/svm.h +++ b/arch/x86/include/asm/svm.h @@ -701,5 +701,6 @@ DEFINE_GHCB_ACCESSORS(sw_exit_info_1) DEFINE_GHCB_ACCESSORS(sw_exit_info_2) DEFINE_GHCB_ACCESSORS(sw_scratch) DEFINE_GHCB_ACCESSORS(xcr0) +DEFINE_GHCB_ACCESSORS(xss) #endif |