On 09/07/2015 07:18 PM, Paolo Bonzini wrote:


+static int handle_pcommit(struct kvm_vcpu *vcpu)
+{
+       /* we never catch pcommit instruct for L1 guest. */
+       BUG();

Please WARN instead.


Okay.

+       return 1;
+}
+
  /*
   * The exit handlers return 1 if the exit was handled fully and guest 
execution
   * may resume.  Otherwise they set the kvm_run parameter to indicate what 
needs
@@ -7258,6 +7269,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct 
kvm_vcpu *vcpu) = {
        [EXIT_REASON_XSAVES]                  = handle_xsaves,
        [EXIT_REASON_XRSTORS]                 = handle_xrstors,
        [EXIT_REASON_PML_FULL]                = handle_pml_full,
+       [EXIT_REASON_PCOMMIT]                 = handle_pcommit,
  };

  static const int kvm_vmx_max_exit_handlers =
@@ -7559,6 +7571,8 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)
                 * the XSS exit bitmap in vmcs12.
                 */
                return nested_cpu_has2(vmcs12, SECONDARY_EXEC_XSAVES);
+       case EXIT_REASON_PCOMMIT:
+               return nested_cpu_has2(vmcs12, SECONDARY_EXEC_PCOMMIT);
        default:
                return true;
        }
@@ -8688,6 +8702,10 @@ static void vmx_cpuid_update(struct kvm_vcpu *vcpu)
                if (best)
                        best->ebx &= ~bit(X86_FEATURE_INVPCID);
        }
+
+       if (!guest_cpuid_has_pcommit(vcpu) && nested)
+               vmx->nested.nested_vmx_secondary_ctls_high &=
+                       ~SECONDARY_EXEC_PCOMMIT;

Why is this needed?


If pcommit is not allowed in L1 guest, L1 is not allowed to intercept pcommit
for L2.

BTW, the spec saied:

| IA32_VMX_PROCBASED_CTLS2[53] (which enumerates support for the 1-setting of 
“PCOMMIT exiting”) is
| always the same as CPUID.07H:EBX.PCOMMIT[bit 22]. Thus, software can set 
“PCOMMIT exiting” to 1
| if and only if the PCOMMIT instruction is enumerated via CPUID
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to