diff options
| author | Brijesh Singh | 2022-02-09 12:10:05 -0600 |
|---|---|---|
| committer | Borislav Petkov | 2022-04-06 13:10:18 +0200 |
| commit | 2ea29c5abbc27147c2d9e2ab5e05436aca706b65 (patch) | |
| tree | 157a8406acede39e6fad1c07b13589bc85648bdf /arch/x86 | |
| parent | 6c0f74d678c94060932683738b3e227995b363d3 (diff) | |
x86/sev: Save the negotiated GHCB version
The SEV-ES guest calls sev_es_negotiate_protocol() to negotiate the GHCB
protocol version before establishing the GHCB. Cache the negotiated GHCB
version so that it can be used later.
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/20220307213356.2797205-12-brijesh.singh@amd.com
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/sev.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/sev-shared.c | 17 |
2 files changed, 15 insertions, 4 deletions
diff --git a/arch/x86/include/asm/sev.h b/arch/x86/include/asm/sev.h index ec060c433589..9b9c190e8c3b 100644 --- a/arch/x86/include/asm/sev.h +++ b/arch/x86/include/asm/sev.h @@ -12,7 +12,7 @@ #include <asm/insn.h> #include <asm/sev-common.h> -#define GHCB_PROTO_OUR 0x0001UL +#define GHCB_PROTOCOL_MIN 1ULL #define GHCB_PROTOCOL_MAX 1ULL #define GHCB_DEFAULT_USAGE 0ULL diff --git a/arch/x86/kernel/sev-shared.c b/arch/x86/kernel/sev-shared.c index 2abf8a7d75e5..91105f5a02a8 100644 --- a/arch/x86/kernel/sev-shared.c +++ b/arch/x86/kernel/sev-shared.c @@ -14,6 +14,15 @@ #define has_cpuflag(f) boot_cpu_has(f) #endif +/* + * Since feature negotiation related variables are set early in the boot + * process they must reside in the .data section so as not to be zeroed + * out when the .bss section is later cleared. + * + * GHCB protocol version negotiated with the hypervisor. + */ +static u16 ghcb_version __ro_after_init; + static bool __init sev_es_check_cpu_features(void) { if (!has_cpuflag(X86_FEATURE_RDRAND)) { @@ -51,10 +60,12 @@ static bool sev_es_negotiate_protocol(void) if (GHCB_MSR_INFO(val) != GHCB_MSR_SEV_INFO_RESP) return false; - if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTO_OUR || - GHCB_MSR_PROTO_MIN(val) > GHCB_PROTO_OUR) + if (GHCB_MSR_PROTO_MAX(val) < GHCB_PROTOCOL_MIN || + GHCB_MSR_PROTO_MIN(val) > GHCB_PROTOCOL_MAX) return false; + ghcb_version = min_t(size_t, GHCB_MSR_PROTO_MAX(val), GHCB_PROTOCOL_MAX); + return true; } @@ -127,7 +138,7 @@ enum es_result sev_es_ghcb_hv_call(struct ghcb *ghcb, bool set_ghcb_msr, u64 exit_info_1, u64 exit_info_2) { /* Fill in protocol and format specifiers */ - ghcb->protocol_version = GHCB_PROTOCOL_MAX; + ghcb->protocol_version = ghcb_version; ghcb->ghcb_usage = GHCB_DEFAULT_USAGE; ghcb_set_sw_exit_code(ghcb, exit_code); |