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KVM: nVMX: Clean up handling of VMX-related MSRs 

This simplifies the code and also stops issuing warning about writing to
unhandled MSRs when VMX is disabled or the Feature Control MSR is
locked - we do handle them all according to the spec.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jan Kiszka 2014-01-04 18:47:22 +01:00 committed by Paolo Bonzini
parent 542060ea79
commit cae501397a
2 changed files with 24 additions and 56 deletions
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1
arch/x86/include/uapi/asm/msr-index.h
View File

@ -527,6 +527,7 @@
#define MSR_IA32_VMX_TRUE_PROCBASED_CTLS 0x0000048e
#define MSR_IA32_VMX_TRUE_EXIT_CTLS 0x0000048f
#define MSR_IA32_VMX_TRUE_ENTRY_CTLS 0x00000490
#define MSR_IA32_VMX_VMFUNC 0x00000491
/* VMX_BASIC bits and bitmasks */
#define VMX_BASIC_VMCS_SIZE_SHIFT 32

79
arch/x86/kvm/vmx.c
View File

@ -2361,32 +2361,10 @@ static inline u64 vmx_control_msr(u32 low, u32 high)
return low | ((u64)high << 32);
}
/*
* If we allow our guest to use VMX instructions (i.e., nested VMX), we should
* also let it use VMX-specific MSRs.
* vmx_get_vmx_msr() and vmx_set_vmx_msr() return 1 when we handled a
* VMX-specific MSR, or 0 when we haven't (and the caller should handle it
* like all other MSRs).
*/
/* Returns 0 on success, non-0 otherwise. */
static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
{
if (!nested_vmx_allowed(vcpu) && msr_index >= MSR_IA32_VMX_BASIC &&
msr_index <= MSR_IA32_VMX_TRUE_ENTRY_CTLS) {
/*
* According to the spec, processors which do not support VMX
* should throw a #GP(0) when VMX capability MSRs are read.
*/
kvm_queue_exception_e(vcpu, GP_VECTOR, 0);
return 1;
}
switch (msr_index) {
case MSR_IA32_FEATURE_CONTROL:
if (nested_vmx_allowed(vcpu)) {
*pdata = to_vmx(vcpu)->nested.msr_ia32_feature_control;
break;
}
return 0;
case MSR_IA32_VMX_BASIC:
/*
* This MSR reports some information about VMX support. We
@ -2453,38 +2431,9 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
*pdata = nested_vmx_ept_caps;
break;
default:
return 0;
}
return 1;
}
static void vmx_leave_nested(struct kvm_vcpu *vcpu);
static int vmx_set_vmx_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
u32 msr_index = msr_info->index;
u64 data = msr_info->data;
bool host_initialized = msr_info->host_initiated;
if (!nested_vmx_allowed(vcpu))
return 0;
if (msr_index == MSR_IA32_FEATURE_CONTROL) {
if (!host_initialized &&
to_vmx(vcpu)->nested.msr_ia32_feature_control
& FEATURE_CONTROL_LOCKED)
return 0;
to_vmx(vcpu)->nested.msr_ia32_feature_control = data;
if (host_initialized && data == 0)
vmx_leave_nested(vcpu);
return 1;
}
/*
* No need to treat VMX capability MSRs specially: If we don't handle
* them, handle_wrmsr will #GP(0), which is correct (they are readonly)
*/
return 0;
}
@ -2530,13 +2479,20 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
case MSR_IA32_SYSENTER_ESP:
data = vmcs_readl(GUEST_SYSENTER_ESP);
break;
case MSR_IA32_FEATURE_CONTROL:
if (!nested_vmx_allowed(vcpu))
return 1;
data = to_vmx(vcpu)->nested.msr_ia32_feature_control;
break;
case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
if (!nested_vmx_allowed(vcpu))
return 1;
return vmx_get_vmx_msr(vcpu, msr_index, pdata);
case MSR_TSC_AUX:
if (!to_vmx(vcpu)->rdtscp_enabled)
return 1;
/* Otherwise falls through */
default:
if (vmx_get_vmx_msr(vcpu, msr_index, pdata))
return 0;
msr = find_msr_entry(to_vmx(vcpu), msr_index);
if (msr) {
data = msr->data;
@ -2549,6 +2505,8 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata)
return 0;
}
static void vmx_leave_nested(struct kvm_vcpu *vcpu);
/*
* Writes msr value into into the appropriate "register".
* Returns 0 on success, non-0 otherwise.
@ -2603,6 +2561,17 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_TSC_ADJUST:
ret = kvm_set_msr_common(vcpu, msr_info);
break;
case MSR_IA32_FEATURE_CONTROL:
if (!nested_vmx_allowed(vcpu) ||
(to_vmx(vcpu)->nested.msr_ia32_feature_control &
FEATURE_CONTROL_LOCKED && !msr_info->host_initiated))
return 1;
vmx->nested.msr_ia32_feature_control = data;
if (msr_info->host_initiated && data == 0)
vmx_leave_nested(vcpu);
break;
case MSR_IA32_VMX_BASIC ... MSR_IA32_VMX_VMFUNC:
return 1; /* they are read-only */
case MSR_TSC_AUX:
if (!vmx->rdtscp_enabled)
return 1;
@ -2611,8 +2580,6 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
return 1;
/* Otherwise falls through */
default:
if (vmx_set_vmx_msr(vcpu, msr_info))
break;
msr = find_msr_entry(vmx, msr_index);
if (msr) {
msr->data = data;