diff options
| author | Brijesh Singh <brijesh.singh@amd.com> | 2022-02-09 21:10:10 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2022-04-06 14:14:24 +0300 |
| commit | 87294bdb7b4b73555b0fba45da1cdecdc6a0d5a8 (patch) | |
| tree | 1a9da8387cd9b30e1ac28ca1992f45659e6d467b /arch | |
| parent | 4f9c403e44e5e88feb27d5e617d1adc9cc7ef684 (diff) | |
| download | linux-87294bdb7b4b73555b0fba45da1cdecdc6a0d5a8.tar.xz | |
x86/compressed: Register GHCB memory when SEV-SNP is active
The SEV-SNP guest is required by the GHCB spec to register the GHCB's
Guest Physical Address (GPA). This is because the hypervisor may prefer
that a guest use a consistent and/or specific GPA for the GHCB associated
with a vCPU. For more information, see the GHCB specification section
"GHCB GPA Registration".
If hypervisor can not work with the guest provided GPA then terminate the
guest boot.
Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Venu Busireddy <venu.busireddy@oracle.com>
Link: https://lore.kernel.org/r/20220307213356.2797205-17-brijesh.singh@amd.com
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/boot/compressed/sev.c | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/sev-common.h | 13 | ||||
| -rw-r--r-- | arch/x86/kernel/sev-shared.c | 16 |
3 files changed, 33 insertions, 0 deletions
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 5f2c26860df7..f31b434e2ce4 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -175,6 +175,10 @@ static bool early_setup_ghcb(void) /* Initialize lookup tables for the instruction decoder */ inat_init_tables(); + /* SNP guest requires the GHCB GPA must be registered */ + if (sev_snp_enabled()) + snp_register_ghcb_early(__pa(&boot_ghcb_page)); + return true; } diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h index fe7fe16e5fd5..f077a6c95e67 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -57,6 +57,19 @@ #define GHCB_MSR_AP_RESET_HOLD_REQ 0x006 #define GHCB_MSR_AP_RESET_HOLD_RESP 0x007 +/* GHCB GPA Register */ +#define GHCB_MSR_REG_GPA_REQ 0x012 +#define GHCB_MSR_REG_GPA_REQ_VAL(v) \ + /* GHCBData[63:12] */ \ + (((u64)((v) & GENMASK_ULL(51, 0)) << 12) | \ + /* GHCBData[11:0] */ \ + GHCB_MSR_REG_GPA_REQ) + +#define GHCB_MSR_REG_GPA_RESP 0x013 +#define GHCB_MSR_REG_GPA_RESP_VAL(v) \ + /* GHCBData[63:12] */ \ + (((u64)(v) & GENMASK_ULL(63, 12)) >> 12) + /* * SNP Page State Change Operation * diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 4a876e684f67..e9ff13cd90b0 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -68,6 +68,22 @@ static u64 get_hv_features(void) return GHCB_MSR_HV_FT_RESP_VAL(val); } +static void __maybe_unused snp_register_ghcb_early(unsigned long paddr) +{ + unsigned long pfn = paddr >> PAGE_SHIFT; + u64 val; + + sev_es_wr_ghcb_msr(GHCB_MSR_REG_GPA_REQ_VAL(pfn)); + VMGEXIT(); + + val = sev_es_rd_ghcb_msr(); + + /* If the response GPA is not ours then abort the guest */ + if ((GHCB_RESP_CODE(val) != GHCB_MSR_REG_GPA_RESP) || + (GHCB_MSR_REG_GPA_RESP_VAL(val) != pfn)) + sev_es_terminate(SEV_TERM_SET_LINUX, GHCB_TERM_REGISTER); +} + static bool sev_es_negotiate_protocol(void) { u64 val; |