On incompatible firmware versions, SEV-SNP support is pulled and the setup is not performed. However, the platform and subsequently the KVM capability may continue to advertise support for it. Disable support for SEV-SNP if the FW version validation fails.
Fixes: 1dfe571c12cf ("KVM: SEV: Add initial SEV-SNP support") Suggested-by: Sean Christopherson seanjc@google.com Reviewed-by: Nikunj A Dadhania nikunj@amd.com Tested-by: Srikanth Aithal sraithal@amd.com Signed-off-by: Pratik R. Sampat prsampat@amd.com --- v5..v6:
* Collected tags from Nikunj and Srikanth. --- arch/x86/kvm/svm/sev.c | 4 +++- drivers/crypto/ccp/sev-dev.c | 6 ++++++ include/linux/psp-sev.h | 3 +++ 3 files changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 0f04f365885c..b709c2f0945c 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -3040,7 +3040,9 @@ void __init sev_hardware_setup(void) sev_es_asid_count = min_sev_asid - 1; WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV_ES, sev_es_asid_count)); sev_es_supported = true; - sev_snp_supported = sev_snp_enabled && cc_platform_has(CC_ATTR_HOST_SEV_SNP); + sev_snp_supported = (sev_snp_enabled && + cc_platform_has(CC_ATTR_HOST_SEV_SNP) && + snp_fw_valid());
out: if (boot_cpu_has(X86_FEATURE_SEV)) diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c index af018afd9cd7..b45cd60c19b0 100644 --- a/drivers/crypto/ccp/sev-dev.c +++ b/drivers/crypto/ccp/sev-dev.c @@ -122,6 +122,12 @@ static inline bool sev_version_greater_or_equal(u8 maj, u8 min) return false; }
+bool snp_fw_valid(void) +{ + return sev_version_greater_or_equal(SNP_MIN_API_MAJOR, SNP_MIN_API_MINOR); +} +EXPORT_SYMBOL_GPL(snp_fw_valid); + static void sev_irq_handler(int irq, void *data, unsigned int status) { struct sev_device *sev = data; diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h index 903ddfea8585..e841a8fbbb15 100644 --- a/include/linux/psp-sev.h +++ b/include/linux/psp-sev.h @@ -945,6 +945,7 @@ int sev_do_cmd(int cmd, void *data, int *psp_ret); void *psp_copy_user_blob(u64 uaddr, u32 len); void *snp_alloc_firmware_page(gfp_t mask); void snp_free_firmware_page(void *addr); +bool snp_fw_valid(void);
#else /* !CONFIG_CRYPTO_DEV_SP_PSP */
@@ -979,6 +980,8 @@ static inline void *snp_alloc_firmware_page(gfp_t mask)
static inline void snp_free_firmware_page(void *addr) { }
+static inline bool snp_fw_valid(void) { return false; } + #endif /* CONFIG_CRYPTO_DEV_SP_PSP */
#endif /* __PSP_SEV_H__ */