Re: [PATCH v3 2/6] x86/msr: add VMX MSRs into struct msr_domain_policy

[Sergey Dyasli <sergey.dyasli@citrix.com>]

On Fri, 2017-10-13 at 16:16 +0100, Andrew Cooper wrote:
> On 13/10/17 13:35, Sergey Dyasli wrote:
> > @@ -210,6 +375,255 @@ struct msr_domain_policy
> >          bool available; /* This MSR is non-architectural */
> >          bool cpuid_faulting;
> >      } plaform_info;
> > +
> > +    /* 0x00000480  MSR_IA32_VMX_BASIC */
> > +    struct {
> > +        bool available;
> 
> We don't need available bits for any of these MSRs.  Their availability
> is cpuid->basic.vmx, and we don't want (let alone need) to duplicate
> information like this.

Andrew,

What do you think about the following way of checking the availability?

diff --git a/xen/arch/x86/msr.c b/xen/arch/x86/msr.c
index 2527fdd1d1..828f1bb503 100644
--- a/xen/arch/x86/msr.c
+++ b/xen/arch/x86/msr.c
@@ -33,6 +33,43 @@ struct msr_domain_policy __read_mostly     raw_msr_domain_policy,
 struct msr_vcpu_policy __read_mostly hvm_max_msr_vcpu_policy,
                        __read_mostly  pv_max_msr_vcpu_policy;
 
+bool msr_vmx_available(const struct domain *d, uint32_t msr)
+{
+    const struct msr_domain_policy *dp = d->arch.msr;
+    bool secondary_available;
+
+    if ( !nestedhvm_enabled(d) || !d->arch.cpuid->basic.vmx )
+        return false;
+
+    secondary_available =
+        dp->vmx_procbased_ctls.u.allowed_1.activate_secondary_controls;
+
+    switch (msr)
+    {
+    case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMCS_ENUM:
+        return true;
+
+    case MSR_IA32_VMX_PROCBASED_CTLS2:
+        return secondary_available;
+
+    case MSR_IA32_VMX_EPT_VPID_CAP:
+        return ( secondary_available &&
+                 (dp->vmx_procbased_ctls2.u.allowed_1.enable_ept ||
+                  dp->vmx_procbased_ctls2.u.allowed_1.enable_vpid) );
+
+    case MSR_IA32_VMX_TRUE_PINBASED_CTLS ... MSR_IA32_VMX_TRUE_ENTRY_CTLS:
+        return dp->vmx_basic.u.default1_zero;
+
+    case MSR_IA32_VMX_VMFUNC:
+        return ( secondary_available &&
+                 dp->vmx_procbased_ctls2.u.allowed_1.enable_vm_functions );
+
+    default: break;
+    }
+
+    return false;
+}
+
 static void __init calculate_raw_vmx_policy(struct msr_domain_policy *dp)
 {
     if ( !cpu_has_vmx )

-- 
Thanks,
Sergey
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