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authorTom Lendacky <thomas.lendacky@amd.com>2025-10-27 14:33:52 -0500
committerSean Christopherson <seanjc@google.com>2025-11-14 10:30:12 -0800
commit275d6d1189e6d5f8e7c1da43ffd4b09d7089f174 (patch)
tree155cb15af4b8265e63a4956bff1969ccb4f107f8
parent7a61d61396b97fd6bb9b9bde321c68513034ad11 (diff)
KVM: SEV: Add known supported SEV-SNP policy bits
Add to the known supported SEV-SNP policy bits that don't require any implementation support from KVM in order to successfully use them. At this time, this includes: - CXL_ALLOW - MEM_AES_256_XTS - RAPL_DIS - CIPHERTEXT_HIDING_DRAM - PAGE_SWAP_DISABLE Arguably, RAPL_DIS and CIPHERTEXT_HIDING_DRAM require KVM and the CCP driver to enable these features in order for the setting of the policy bits to be successfully handled. But, a guest owner may not wish their guest to run on a system that doesn't provide support for those features, so allowing the specification of these bits accomplishes that. Whether or not the bit is supported by SEV firmware, a system that doesn't support these features will either fail during the KVM validation of supported policy bits before issuing the LAUNCH_START or fail during the LAUNCH_START. Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com> Link: https://patch.msgid.link/ec040de9864099cf592a97c201dc4cc110b2b0cf.1761593632.git.thomas.lendacky@amd.com Signed-off-by: Sean Christopherson <seanjc@google.com>
-rw-r--r--arch/x86/kvm/svm/sev.c22
1 files changed, 16 insertions, 6 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index a425674fe993..f59c65abe3cf 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -65,12 +65,22 @@ module_param_named(ciphertext_hiding_asids, nr_ciphertext_hiding_asids, uint, 04
#define AP_RESET_HOLD_NAE_EVENT 1
#define AP_RESET_HOLD_MSR_PROTO 2
-#define KVM_SNP_POLICY_MASK_VALID (SNP_POLICY_MASK_API_MINOR | \
- SNP_POLICY_MASK_API_MAJOR | \
- SNP_POLICY_MASK_SMT | \
- SNP_POLICY_MASK_RSVD_MBO | \
- SNP_POLICY_MASK_DEBUG | \
- SNP_POLICY_MASK_SINGLE_SOCKET)
+/*
+ * SEV-SNP policy bits that can be supported by KVM. These include policy bits
+ * that have implementation support within KVM or policy bits that do not
+ * require implementation support within KVM to enforce the policy.
+ */
+#define KVM_SNP_POLICY_MASK_VALID (SNP_POLICY_MASK_API_MINOR | \
+ SNP_POLICY_MASK_API_MAJOR | \
+ SNP_POLICY_MASK_SMT | \
+ SNP_POLICY_MASK_RSVD_MBO | \
+ SNP_POLICY_MASK_DEBUG | \
+ SNP_POLICY_MASK_SINGLE_SOCKET | \
+ SNP_POLICY_MASK_CXL_ALLOW | \
+ SNP_POLICY_MASK_MEM_AES_256_XTS | \
+ SNP_POLICY_MASK_RAPL_DIS | \
+ SNP_POLICY_MASK_CIPHERTEXT_HIDING_DRAM | \
+ SNP_POLICY_MASK_PAGE_SWAP_DISABLE)
static u64 snp_supported_policy_bits __ro_after_init;