From 2f5f8fb9de095e9b255a89269827f1761c714690 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Thu, 21 Aug 2025 14:38:41 -0700 Subject: [PATCH] KVM: SEV: Save the SEV policy if and only if LAUNCH_START succeeds Wait until LAUNCH_START fully succeeds to set a VM's SEV/SNP policy so that KVM doesn't keep a potentially stale policy. In practice, the issue is benign as the policy is only used to detect if the VMSA can be decrypted, and the VMSA only needs to be decrypted if LAUNCH_UPDATE and thus LAUNCH_START succeeded. Fixes: 962e2b6152ef ("KVM: SVM: Decrypt SEV VMSA in dump_vmcb() if debugging is enabled") Cc: Tom Lendacky Cc: Kim Phillips Reviewed-by: Tom Lendacky Link: https://lore.kernel.org/r/20250821213841.3462339-1-seanjc@google.com Signed-off-by: Sean Christopherson --- arch/x86/kvm/svm/sev.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c index 86fd270a1d6ed..a95b862afa239 100644 --- a/arch/x86/kvm/svm/sev.c +++ b/arch/x86/kvm/svm/sev.c @@ -583,8 +583,6 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) if (copy_from_user(¶ms, u64_to_user_ptr(argp->data), sizeof(params))) return -EFAULT; - sev->policy = params.policy; - memset(&start, 0, sizeof(start)); dh_blob = NULL; @@ -632,6 +630,7 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) goto e_free_session; } + sev->policy = params.policy; sev->handle = start.handle; sev->fd = argp->sev_fd; @@ -2205,8 +2204,6 @@ static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) start.desired_tsc_khz = kvm->arch.default_tsc_khz; } - sev->policy = params.policy; - sev->snp_context = snp_context_create(kvm, argp); if (!sev->snp_context) return -ENOTTY; @@ -2222,6 +2219,7 @@ static int snp_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp) goto e_free_context; } + sev->policy = params.policy; sev->fd = argp->sev_fd; rc = snp_bind_asid(kvm, &argp->error); if (rc) { -- 2.47.3