[RFC,v3,33/36] i386/tdx: Only configure MSR_IA32_UCODE_REV in kvm_init_msrs() for TDs

Commit Message

Xiaoyao Li March 17, 2022, 1:59 p.m. UTC

For TDs, only MSR_IA32_UCODE_REV in kvm_init_msrs() can be configured
by VMM, while the features enumerated/controlled by other MSRs except
MSR_IA32_UCODE_REV in kvm_init_msrs() are not under control of VMM.

Only configure MSR_IA32_UCODE_REV for TDs.

Signed-off-by: Xiaoyao Li <[e-mail]>
---
 target/i386/kvm/kvm.c | 44 ++++++++++++++++++++++---------------------
 1 file changed, 23 insertions(+), 21 deletions(-)

Comments

Isaku Yamahata March 18, 2022, 5:31 p.m. UTC | #1

On Thu, Mar 17, 2022 at 09:59:10PM +0800,
Xiaoyao Li <[e-mail]> wrote:

> For TDs, only MSR_IA32_UCODE_REV in kvm_init_msrs() can be configured
> by VMM, while the features enumerated/controlled by other MSRs except
> MSR_IA32_UCODE_REV in kvm_init_msrs() are not under control of VMM.
> 
> Only configure MSR_IA32_UCODE_REV for TDs.

non-TDs?

Xiaoyao Li March 21, 2022, 6:08 a.m. UTC | #2

On 3/19/2022 1:31 AM, Isaku Yamahata wrote:
> On Thu, Mar 17, 2022 at 09:59:10PM +0800,
> Xiaoyao Li <[e-mail]> wrote:
> 
>> For TDs, only MSR_IA32_UCODE_REV in kvm_init_msrs() can be configured
>> by VMM, while the features enumerated/controlled by other MSRs except
>> MSR_IA32_UCODE_REV in kvm_init_msrs() are not under control of VMM.
>>
>> Only configure MSR_IA32_UCODE_REV for TDs.
> 
> non-TDs?

No. It meant exactly TDs.

Only MSR_IA32_UCODE_REV is supported to be emulated by VMM for TDs.

Patch

diff --git a/target/i386/kvm/kvm.c b/target/i386/kvm/kvm.c
index f6024b723b70..480c05d6c969 100644
--- a/target/i386/kvm/kvm.c
+++ b/target/i386/kvm/kvm.c
@@ -3055,32 +3055,34 @@  static void kvm_init_msrs(X86CPU *cpu)
     CPUX86State *env = &cpu->env;
 
     kvm_msr_buf_reset(cpu);
-    if (has_msr_arch_capabs) {
-        kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,
-                          env->features[FEAT_ARCH_CAPABILITIES]);
-    }
-
-    if (has_msr_core_capabs) {
-        kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,
-                          env->features[FEAT_CORE_CAPABILITY]);
-    }
-
-    if (has_msr_perf_capabs && cpu->enable_pmu) {
-        kvm_msr_entry_add_perf(cpu, env->features);
+
+    if (!is_tdx_vm()) {
+        if (has_msr_arch_capabs) {
+            kvm_msr_entry_add(cpu, MSR_IA32_ARCH_CAPABILITIES,
+                                env->features[FEAT_ARCH_CAPABILITIES]);
+        }
+
+        if (has_msr_core_capabs) {
+            kvm_msr_entry_add(cpu, MSR_IA32_CORE_CAPABILITY,
+                                env->features[FEAT_CORE_CAPABILITY]);
+        }
+
+        if (has_msr_perf_capabs && cpu->enable_pmu) {
+            kvm_msr_entry_add_perf(cpu, env->features);
+        }
+
+        /*
+         * Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but
+         * all kernels with MSR features should have them.
+         */
+        if (kvm_feature_msrs && cpu_has_vmx(env)) {
+            kvm_msr_entry_add_vmx(cpu, env->features);
+        }
     }
 
     if (has_msr_ucode_rev) {
         kvm_msr_entry_add(cpu, MSR_IA32_UCODE_REV, cpu->ucode_rev);
     }
-
-    /*
-     * Older kernels do not include VMX MSRs in KVM_GET_MSR_INDEX_LIST, but
-     * all kernels with MSR features should have them.
-     */
-    if (kvm_feature_msrs && cpu_has_vmx(env)) {
-        kvm_msr_entry_add_vmx(cpu, env->features);
-    }
-
     assert(kvm_buf_set_msrs(cpu) == 0);
 }