On 2/20/24 03:32, Xiaoyao Li wrote:
diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index 11b8177eff..c8f6c0b531 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -2296,6 +2296,7 @@ void kvm_arch_do_init_vcpu(X86CPU *cpu)
static int kvm_get_supported_feature_msrs(KVMState *s)
{
int ret = 0;
+ int i;
if (kvm_feature_msrs != NULL) {
return 0;
@@ -2330,6 +2331,19 @@ static int
kvm_get_supported_feature_msrs(KVMState *s)
return ret;
}
+ /*
+ * Compatibility fix:
+ * Older Linux kernels(<5.3) include the
MSR_IA32_VMX_PROCBASED_CTLS2
we can be more accurate, that kernel version 4.17 to 5.2, reports
MSR_IA32_VMX_PROCBASED_CTLS2 in KVM_GET_MSR_FEATURE_INDEX_LIST but not
KVM_GET_MSR_INDEX_LIST.
Yeah, I'll add this more precise comment to the next patch.
+ * only in feature msr list, but not in regular msr list. This
lead to
+ * an issue in older kernel versions where QEMU, through the
regular
+ * MSR list check, assumes the kernel doesn't maintain this msr,
+ * resulting in incorrect settings by QEMU for this msr.
+ */
+ for (i = 0; i < kvm_feature_msrs->nmsrs; i++) {
+ if (kvm_feature_msrs->indices[i] ==
MSR_IA32_VMX_PROCBASED_CTLS2) {
+ has_msr_vmx_procbased_ctls2 = true;
+ }
+ }
I'm wondering should we move all the initialization of has_msr_*, that
associated with feature MSRs, to here. e.g., has_msr_arch_capabs,
has_msr_vmx_vmfunc,...
I believe this is a more elegant way to fix the issue, which will be
reflected in my next patch.
