diff options
| author | Ard Biesheuvel <ardb@kernel.org> | 2025-08-28 12:22:13 +0200 |
|---|---|---|
| committer | Borislav Petkov (AMD) <bp@alien8.de> | 2025-09-03 17:59:09 +0200 |
| commit | 68a501d7fd82454525797971c6a0005ceeb93153 (patch) | |
| tree | 9e651d1c7cc81a43061e1fa3beff38de67ed7089 | |
| parent | c54604fb7f2522fec5b97e86103ec49e539e80fe (diff) | |
x86/boot: Drop redundant RMPADJUST in SEV SVSM presence check
snp_vmpl will be assigned a non-zero value when executing at a VMPL other than
0, and this is inferred from a call to RMPADJUST, which only works when
running at VMPL0.
This means that testing snp_vmpl is sufficient, and there is no need to
perform the same check again.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Link: https://lore.kernel.org/20250828102202.1849035-34-ardb+git@google.com
| -rw-r--r-- | arch/x86/boot/compressed/sev.c | 20 |
1 files changed, 3 insertions, 17 deletions
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 4873469b2a39..26aa389f802d 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -406,30 +406,16 @@ void sev_enable(struct boot_params *bp) */ if (sev_status & MSR_AMD64_SEV_SNP_ENABLED) { u64 hv_features; - int ret; hv_features = get_hv_features(); if (!(hv_features & GHCB_HV_FT_SNP)) sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); /* - * Enforce running at VMPL0 or with an SVSM. - * - * Use RMPADJUST (see the rmpadjust() function for a description of - * what the instruction does) to update the VMPL1 permissions of a - * page. If the guest is running at VMPL0, this will succeed. If the - * guest is running at any other VMPL, this will fail. Linux SNP guests - * only ever run at a single VMPL level so permission mask changes of a - * lesser-privileged VMPL are a don't-care. + * Running at VMPL0 is required unless an SVSM is present and + * the hypervisor supports the required SVSM GHCB events. */ - ret = rmpadjust((unsigned long)&boot_ghcb_page, RMP_PG_SIZE_4K, 1); - - /* - * Running at VMPL0 is not required if an SVSM is present and the hypervisor - * supports the required SVSM GHCB events. - */ - if (ret && - !(snp_vmpl && (hv_features & GHCB_HV_FT_SNP_MULTI_VMPL))) + if (snp_vmpl && !(hv_features & GHCB_HV_FT_SNP_MULTI_VMPL)) sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_NOT_VMPL0); } |