diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2022-02-09 12:10:06 -0600 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 13:10:23 +0200 |
| commit | cbd3d4f7c4e5a93edae68e5142a269368fde77d6 (patch) | |
| tree | 4c7df4cd0f61c1781905d4294a7cb9bd8d51579d /arch/x86/kernel/sev.c | |
| parent | 2ea29c5abbc27147c2d9e2ab5e05436aca706b65 (diff) | |
x86/sev: Check SEV-SNP features support
Version 2 of the GHCB specification added the advertisement of features
that are supported by the hypervisor. If the hypervisor supports SEV-SNP
then it must set the SEV-SNP features bit to indicate that the base
functionality is supported.
Check that feature bit while establishing the GHCB; if failed, terminate
the guest.
Version 2 of the GHCB specification adds several new Non-Automatic Exits
(NAEs), most of them are optional except the hypervisor feature. Now
that the hypervisor feature NAE is implemented, bump the GHCB maximum
supported protocol version.
While at it, move the GHCB protocol negotiation check from the #VC
exception handler to sev_enable() so that all feature detection happens
before the first #VC exception.
While at it, document why the GHCB page cannot be setup from
load_stage2_idt().
[ bp: Massage commit message. ]
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220307213356.2797205-13-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86/kernel/sev.c')
| -rw-r--r-- | arch/x86/kernel/sev.c | 14 |
1 files changed, 14 insertions, 0 deletions
diff --git a/arch/x86/kernel/sev.c b/arch/x86/kernel/sev.c index 19ad09712902..cb20fb0c608e 100644 --- a/arch/x86/kernel/sev.c +++ b/arch/x86/kernel/sev.c @@ -43,6 +43,9 @@ static struct ghcb boot_ghcb_page __bss_decrypted __aligned(PAGE_SIZE); */ static struct ghcb __initdata *boot_ghcb; +/* Bitmap of SEV features supported by the hypervisor */ +static u64 sev_hv_features __ro_after_init; + /* #VC handler runtime per-CPU data */ struct sev_es_runtime_data { struct ghcb ghcb_page; @@ -766,6 +769,17 @@ void __init sev_es_init_vc_handling(void) if (!sev_es_check_cpu_features()) panic("SEV-ES CPU Features missing"); + /* + * SNP is supported in v2 of the GHCB spec which mandates support for HV + * features. + */ + if (cc_platform_has(CC_ATTR_GUEST_SEV_SNP)) { + sev_hv_features = get_hv_features(); + + if (!(sev_hv_features & GHCB_HV_FT_SNP)) + sev_es_terminate(SEV_TERM_SET_GEN, GHCB_SNP_UNSUPPORTED); + } + /* Enable SEV-ES special handling */ static_branch_enable(&sev_es_enable_key); |