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SEV-ES: vmm(4): Handle MSR gexit
Hi,
next bit, MSR related GEXIT:
Fill in the actual handler for MSR related VMGEXIT: The SEV-ES
guest sends vmm(4) A, C and D GPRs for wrmsr; and C for rdmsr. For
wrmsr vmm(4) returns nothing to the guest; for rdmsr the 64bit
result is split into EAX and EDX.
As with "normal" SVM_VMEXIT_MSR, svm_handle_msr() does the actual
work.
Take care,
HJ.
--------------------------------------------------------------------------
commit e16349e4d36f0efa87400ce304f4bc77a5cb2987
Author: Hans-Joerg Hoexer <hshoexer@genua.de>
Date: Thu Jan 16 14:10:04 2025 +0100
vmm(4): Handle MSR gexit
Fill in the actual handler for MSR related VMGEXIT: The SEV-ES
guest sends vmm(4) A, C and D GPRs for wrmsr; and C for rdmsr. For
wrmsr vmm(4) returns nothing to the guest; for rdmsr the 64bit
result is split into EAX and EDX.
As with "normal" SVM_VMEXIT_MSR, svm_handle_msr() does the actual
work.
diff --git a/sys/arch/amd64/amd64/vmm_machdep.c b/sys/arch/amd64/amd64/vmm_machdep.c
index c6bba94700a..9bcf3f3fffe 100644
--- a/sys/arch/amd64/amd64/vmm_machdep.c
+++ b/sys/arch/amd64/amd64/vmm_machdep.c
@@ -4382,6 +4382,17 @@ svm_gexit_sync_host(struct vcpu *vcpu)
ghcb_valbm_set(expected_bm, GHCB_RAX);
ghcb_valbm_set(expected_bm, GHCB_RCX);
break;
+ case SVM_VMEXIT_MSR:
+ if (ghcb->v_sw_exitinfo1 == 1) {
+ /* WRMSR */
+ ghcb_valbm_set(expected_bm, GHCB_RAX);
+ ghcb_valbm_set(expected_bm, GHCB_RCX);
+ ghcb_valbm_set(expected_bm, GHCB_RDX);
+ } else {
+ /* RDMSR */
+ ghcb_valbm_set(expected_bm, GHCB_RCX);
+ }
+ break;
default:
return (EINVAL);
}
@@ -4438,6 +4449,15 @@ svm_gexit_sync_guest(struct vcpu *vcpu)
ghcb_valbm_set(valid_bm, GHCB_RCX);
ghcb_valbm_set(valid_bm, GHCB_RDX);
break;
+ case SVM_VMEXIT_MSR:
+ if (svm_sw_exitinfo1 == 1) {
+ /* WRMSR -- nothing to return */
+ } else {
+ /* RDMSR */
+ ghcb_valbm_set(valid_bm, GHCB_RAX);
+ ghcb_valbm_set(valid_bm, GHCB_RDX);
+ }
+ break;
default:
return (EINVAL);
}
@@ -4503,6 +4523,11 @@ svm_handle_gexit(struct vcpu *vcpu)
vcpu->vc_gueststate.vg_rax = vmcb->v_rax;
syncout = 1;
break;
+ case SVM_VMEXIT_MSR:
+ error = svm_handle_msr(vcpu);
+ vmcb->v_rip = vcpu->vc_gueststate.vg_rip;
+ syncout = 1;
+ break;
default:
DPRINTF("%s: unknown exit 0x%llx\n", __func__,
vmcb->v_exitcode);
SEV-ES: vmm(4): Handle MSR gexit