Re: [PATCH 8/8] x86/hvm: Disallow access to unknown MSRs

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 17/08/2020 16:57, Roger Pau Monne wrote:
> From: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>
> Change the catch-all behavior for MSR not explicitly handled. Instead
> of allow full read-access to the MSR space and silently dropping
> writes return an exception when the MSR is not explicitly handled.
>
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

It occurs to me that this hunk should be folded.

diff --git a/xen/arch/x86/hvm/vmx/vmx.c b/xen/arch/x86/hvm/vmx/vmx.c
index 7b056ccc05..fdfce4f665 100644
--- a/xen/arch/x86/hvm/vmx/vmx.c
+++ b/xen/arch/x86/hvm/vmx/vmx.c
@@ -3294,11 +3294,6 @@ static int vmx_msr_write_intercept(unsigned int
msr, uint64_t msr_content)
         __vmwrite(GUEST_IA32_DEBUGCTL, msr_content);
         break;
 
-    case MSR_IA32_FEATURE_CONTROL:
-    case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
-        /* None of these MSRs are writeable. */
-        goto gp_fault;
-
     case MSR_IA32_MISC_ENABLE:
         /* Silently drop writes that don't change the reported value. */
         if ( vmx_msr_read_intercept(msr, &tmp) != X86EMUL_OKAY ||

now that the default: case does the right thing.

~Andrew