KVM: SEV: Handle unknown #VMGEXIT reasons in sev_handle_vmgexit()

Handle unknown #VMGEXIT reasons in sev_handle_vmgexit(), not in
sev_es_validate_vmgexit().  This makes it _much_ more obvious that KVM
simply funnels "legacy" exits to the standard SVM interception handlers,
and is the final preparatory change needed to reduce the scope of
sev_es_validate_vmgexit().

No functional change intended.

Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-ID: <20260501202250.2115252-23-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20260529183549.1104619-23-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 84421d9a116ba9ebe98eaba981b85292ebda070e..864d6aea544bbefab0014ad3606f0b252e358735 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -3414,9 +3414,6 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
 {
        struct vmcb_control_area *control = &svm->vmcb->control;
        struct kvm_vcpu *vcpu = &svm->vcpu;
-       u64 reason;
-
-       reason = GHCB_ERR_MISSING_INPUT;
 
        if (!kvm_ghcb_sw_exit_code_is_valid(svm) ||
            !kvm_ghcb_sw_exit_info_1_is_valid(svm) ||
@@ -3424,14 +3421,10 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
                goto vmgexit_err;
 
        switch (control->exit_code) {
-       case SVM_EXIT_READ_DR7:
-               break;
        case SVM_EXIT_WRITE_DR7:
                if (!kvm_ghcb_rax_is_valid(svm))
                        goto vmgexit_err;
                break;
-       case SVM_EXIT_RDTSC:
-               break;
        case SVM_EXIT_RDPMC:
                if (!kvm_ghcb_rcx_is_valid(svm))
                        goto vmgexit_err;
@@ -3444,8 +3437,6 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
                        if (!kvm_ghcb_xcr0_is_valid(svm))
                                goto vmgexit_err;
                break;
-       case SVM_EXIT_INVD:
-               break;
        case SVM_EXIT_IOIO:
                if (control->exit_info_1 & SVM_IOIO_STR_MASK) {
                        if (!kvm_ghcb_sw_scratch_is_valid(svm))
@@ -3470,10 +3461,6 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
                    !kvm_ghcb_cpl_is_valid(svm))
                        goto vmgexit_err;
                break;
-       case SVM_EXIT_RDTSCP:
-               break;
-       case SVM_EXIT_WBINVD:
-               break;
        case SVM_EXIT_MONITOR:
                if (!kvm_ghcb_rax_is_valid(svm) ||
                    !kvm_ghcb_rcx_is_valid(svm) ||
@@ -3495,23 +3482,12 @@ static int sev_es_validate_vmgexit(struct vcpu_svm *svm)
                        if (!kvm_ghcb_rax_is_valid(svm))
                                goto vmgexit_err;
                break;
-       case SVM_VMGEXIT_NMI_COMPLETE:
-       case SVM_VMGEXIT_AP_HLT_LOOP:
-       case SVM_VMGEXIT_AP_JUMP_TABLE:
-       case SVM_VMGEXIT_UNSUPPORTED_EVENT:
-       case SVM_VMGEXIT_HV_FEATURES:
-       case SVM_VMGEXIT_TERM_REQUEST:
-               break;
        case SVM_VMGEXIT_PSC:
                if (!kvm_ghcb_sw_scratch_is_valid(svm))
                        goto vmgexit_err;
                break;
-       case SVM_VMGEXIT_GUEST_REQUEST:
-       case SVM_VMGEXIT_EXT_GUEST_REQUEST:
-               break;
        default:
-               reason = GHCB_ERR_INVALID_EVENT;
-               goto vmgexit_err;
+               break;
        }
 
        return 0;
@@ -3521,16 +3497,10 @@ vmgexit_err:
         * Print the exit code even though it may not be marked valid as it
         * could help with debugging.
         */
-       if (reason == GHCB_ERR_INVALID_EVENT) {
-               vcpu_unimpl(vcpu, "vmgexit: exit code %#llx is not valid\n",
-                           control->exit_code);
-       } else {
-               vcpu_unimpl(vcpu, "vmgexit: exit code %#llx input is not valid\n",
-                           control->exit_code);
-               dump_ghcb(svm);
-       }
-
-       svm_vmgexit_bad_input(svm, reason);
+       vcpu_unimpl(vcpu, "vmgexit: exit code %#llx input is not valid\n",
+                   control->exit_code);
+       dump_ghcb(svm);
+       svm_vmgexit_bad_input(svm, GHCB_ERR_MISSING_INPUT);
 
        /* Resume the guest to "return" the error code. */
        return 1;
@@ -4547,6 +4517,25 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
        svm_vmgexit_success(svm, 0);
 
        switch (control->exit_code) {
+       case SVM_EXIT_IOIO:
+               if (!((control->exit_info_1 & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT))
+                       return 1;
+
+               fallthrough;
+       case SVM_EXIT_READ_DR7:
+       case SVM_EXIT_WRITE_DR7:
+       case SVM_EXIT_RDTSC:
+       case SVM_EXIT_RDTSCP:
+       case SVM_EXIT_RDPMC:
+       case SVM_EXIT_CPUID:
+       case SVM_EXIT_INVD:
+       case SVM_EXIT_MSR:
+       case SVM_EXIT_VMMCALL:
+       case SVM_EXIT_WBINVD:
+       case SVM_EXIT_MONITOR:
+       case SVM_EXIT_MWAIT:
+               ret = svm_invoke_exit_handler(vcpu, control->exit_code);
+               break;
        case SVM_VMGEXIT_MMIO_READ:
        case SVM_VMGEXIT_MMIO_WRITE: {
                bool is_write = control->exit_code == SVM_VMGEXIT_MMIO_WRITE;
@@ -4643,18 +4632,21 @@ int sev_handle_vmgexit(struct kvm_vcpu *vcpu)
                                                       control->exit_info_2);
                break;
        case SVM_VMGEXIT_UNSUPPORTED_EVENT:
+               /*
+                * Note, the _guest_ is reporting an unsupported #VC, i.e. this
+                * isn't the same thing as KVM getting an unsupported #VMGEXIT.
+                */
                vcpu_unimpl(vcpu,
                            "vmgexit: unsupported event - exit_info_1=%#llx, exit_info_2=%#llx\n",
                            control->exit_info_1, control->exit_info_2);
                ret = -EINVAL;
                break;
-       case SVM_EXIT_IOIO:
-               if (!((control->exit_info_1 & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT))
-                       return 1;
-
-               fallthrough;
        default:
-               ret = svm_invoke_exit_handler(vcpu, control->exit_code);
+               vcpu_unimpl(vcpu, "vmgexit: exit code %#llx is not valid\n",
+                           control->exit_code);
+               svm_vmgexit_bad_input(svm, GHCB_ERR_INVALID_EVENT);
+               ret = 1;
+               break;
        }
 
        return ret;