| Message ID | 20210430121616.2295-13-brijesh.singh@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add AMD Secure Nested Paging (SEV-SNP) Guest Support | expand |
On Fri, Apr 30, 2021 at 07:16:08AM -0500, Brijesh Singh wrote: > diff --git a/arch/x86/include/asm/sev-common.h b/arch/x86/include/asm/sev-common.h > index 733fca403ae5..7487d4768ef0 100644 > --- a/arch/x86/include/asm/sev-common.h > +++ b/arch/x86/include/asm/sev-common.h > @@ -88,6 +88,18 @@ > #define GHCB_MSR_PSC_RSVD_MASK 0xfffffULL > #define GHCB_MSR_PSC_RESP_VAL(val) ((val) >> GHCB_MSR_PSC_ERROR_POS) > > +/* GHCB GPA Register */ > +#define GHCB_MSR_GPA_REG_REQ 0x012 > +#define GHCB_MSR_GPA_REG_VALUE_POS 12 > +#define GHCB_MSR_GPA_REG_VALUE_MASK 0xfffffffffffffULL GENMASK_ULL > +#define GHCB_MSR_GPA_REQ_VAL(v) \ > + (((v) << GHCB_MSR_GPA_REG_VALUE_POS) | GHCB_MSR_GPA_REG_REQ) > + > +#define GHCB_MSR_GPA_REG_RESP 0x013 > +#define GHCB_MSR_GPA_REG_RESP_VAL(v) ((v) >> GHCB_MSR_GPA_REG_VALUE_POS) > +#define GHCB_MSR_GPA_REG_ERROR 0xfffffffffffffULL > +#define GHCB_MSR_GPA_INVALID ~0ULL Ditto. > + > /* SNP Page State Change NAE event */ > #define VMGEXIT_PSC_MAX_ENTRY 253 > #define VMGEXIT_PSC_INVALID_HEADER 0x100000001 > diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c > index 085d3d724bc8..140c5bc07fc2 100644 > --- a/arch/x86/kernel/sev-shared.c > +++ b/arch/x86/kernel/sev-shared.c > @@ -81,6 +81,22 @@ static bool ghcb_get_hv_features(void) > return true; > } > > +static void snp_register_ghcb(unsigned long paddr) > +{ > + unsigned long pfn = paddr >> PAGE_SHIFT; > + u64 val; > + > + sev_es_wr_ghcb_msr(GHCB_MSR_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_GPA_REG_RESP) || > + (GHCB_MSR_GPA_REG_RESP_VAL(val) != pfn)) > + sev_es_terminate(1, GHCB_TERM_REGISTER); Nice, special termination reasons which say why the guest terminates, cool! :-)
diff --git a/arch/x86/boot/compressed/sev.c b/arch/x86/boot/compressed/sev.c index 4f215d0c9f76..07b9529d7d95 100644 --- a/arch/x86/boot/compressed/sev.c +++ b/arch/x86/boot/compressed/sev.c @@ -206,6 +206,10 @@ static bool early_setup_sev_es(void) /* Initialize lookup tables for the instruction decoder */ inat_init_tables(); + /* SEV-SNP guest requires the GHCB GPA must be registered */ + if (sev_snp_enabled()) + snp_register_ghcb(__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 733fca403ae5..7487d4768ef0 100644 --- a/arch/x86/include/asm/sev-common.h +++ b/arch/x86/include/asm/sev-common.h @@ -88,6 +88,18 @@ #define GHCB_MSR_PSC_RSVD_MASK 0xfffffULL #define GHCB_MSR_PSC_RESP_VAL(val) ((val) >> GHCB_MSR_PSC_ERROR_POS) +/* GHCB GPA Register */ +#define GHCB_MSR_GPA_REG_REQ 0x012 +#define GHCB_MSR_GPA_REG_VALUE_POS 12 +#define GHCB_MSR_GPA_REG_VALUE_MASK 0xfffffffffffffULL +#define GHCB_MSR_GPA_REQ_VAL(v) \ + (((v) << GHCB_MSR_GPA_REG_VALUE_POS) | GHCB_MSR_GPA_REG_REQ) + +#define GHCB_MSR_GPA_REG_RESP 0x013 +#define GHCB_MSR_GPA_REG_RESP_VAL(v) ((v) >> GHCB_MSR_GPA_REG_VALUE_POS) +#define GHCB_MSR_GPA_REG_ERROR 0xfffffffffffffULL +#define GHCB_MSR_GPA_INVALID ~0ULL + /* SNP Page State Change NAE event */ #define VMGEXIT_PSC_MAX_ENTRY 253 #define VMGEXIT_PSC_INVALID_HEADER 0x100000001 diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 085d3d724bc8..140c5bc07fc2 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -81,6 +81,22 @@ static bool ghcb_get_hv_features(void) return true; } +static void snp_register_ghcb(unsigned long paddr) +{ + unsigned long pfn = paddr >> PAGE_SHIFT; + u64 val; + + sev_es_wr_ghcb_msr(GHCB_MSR_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_GPA_REG_RESP) || + (GHCB_MSR_GPA_REG_RESP_VAL(val) != pfn)) + sev_es_terminate(1, GHCB_TERM_REGISTER); +} + static bool sev_es_negotiate_protocol(void) { u64 val;
The SEV-SNP guest is required to perform GHCB GPA registration. 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. If hypervisor can not work with the guest provided GPA then terminate the guest boot. Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> --- arch/x86/boot/compressed/sev.c | 4 ++++ arch/x86/include/asm/sev-common.h | 12 ++++++++++++ arch/x86/kernel/sev-shared.c | 16 ++++++++++++++++ 3 files changed, 32 insertions(+)