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KVM: nVMX: Validate EFER values for VM_ENTRY/EXIT_LOAD_IA32_EFER

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As we may emulate the loading of EFER on VM-entry and VM-exit, implement
the checks that VMX performs on the guest and host values on vmlaunch/
vmresume. Factor out kvm_valid_efer for this purpose which checks for
set reserved bits.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Jan Kiszka 2013-04-20 10:52:36 +02:00 committed by Gleb Natapov
parent ea8ceb8354
commit 384bb78327
3 changed files with 60 additions and 10 deletions
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1
arch/x86/include/asm/kvm_host.h
View File

@ -809,6 +809,7 @@ static inline int emulate_instruction(struct kvm_vcpu *vcpu,
}
void kvm_enable_efer_bits(u64);
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer);
int kvm_get_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *data);
int kvm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr);

40
arch/x86/kvm/vmx.c
View File

@ -7558,6 +7558,7 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
struct vcpu_vmx *vmx = to_vmx(vcpu);
int cpu;
struct loaded_vmcs *vmcs02;
bool ia32e;
if (!nested_vmx_check_permission(vcpu) ||
!nested_vmx_check_vmcs12(vcpu))
@ -7648,6 +7649,45 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch)
return 1;
}
/*
* If the “load IA32_EFER” VM-entry control is 1, the following checks
* are performed on the field for the IA32_EFER MSR:
* - Bits reserved in the IA32_EFER MSR must be 0.
* - Bit 10 (corresponding to IA32_EFER.LMA) must equal the value of
* the IA-32e mode guest VM-exit control. It must also be identical
* to bit 8 (LME) if bit 31 in the CR0 field (corresponding to
* CR0.PG) is 1.
*/
if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER) {
ia32e = (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) != 0;
if (!kvm_valid_efer(vcpu, vmcs12->guest_ia32_efer) ||
ia32e != !!(vmcs12->guest_ia32_efer & EFER_LMA) ||
((vmcs12->guest_cr0 & X86_CR0_PG) &&
ia32e != !!(vmcs12->guest_ia32_efer & EFER_LME))) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
return 1;
}
}
/*
* If the load IA32_EFER VM-exit control is 1, bits reserved in the
* IA32_EFER MSR must be 0 in the field for that register. In addition,
* the values of the LMA and LME bits in the field must each be that of
* the host address-space size VM-exit control.
*/
if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_EFER) {
ia32e = (vmcs12->vm_exit_controls &
VM_EXIT_HOST_ADDR_SPACE_SIZE) != 0;
if (!kvm_valid_efer(vcpu, vmcs12->host_ia32_efer) ||
ia32e != !!(vmcs12->host_ia32_efer & EFER_LMA) ||
ia32e != !!(vmcs12->host_ia32_efer & EFER_LME)) {
nested_vmx_entry_failure(vcpu, vmcs12,
EXIT_REASON_INVALID_STATE, ENTRY_FAIL_DEFAULT);
return 1;
}
}
/*
* We're finally done with prerequisite checking, and can start with
* the nested entry.

29
arch/x86/kvm/x86.c
View File

@ -845,23 +845,17 @@ static const u32 emulated_msrs[] = {
MSR_IA32_MCG_CTL,
};
static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
bool kvm_valid_efer(struct kvm_vcpu *vcpu, u64 efer)
{
u64 old_efer = vcpu->arch.efer;
if (efer & efer_reserved_bits)
return 1;
if (is_paging(vcpu)
&& (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
return 1;
return false;
if (efer & EFER_FFXSR) {
struct kvm_cpuid_entry2 *feat;
feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
if (!feat || !(feat->edx & bit(X86_FEATURE_FXSR_OPT)))
return 1;
return false;
}
if (efer & EFER_SVME) {
@ -869,9 +863,24 @@ static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
feat = kvm_find_cpuid_entry(vcpu, 0x80000001, 0);
if (!feat || !(feat->ecx & bit(X86_FEATURE_SVM)))
return 1;
return false;
}
return true;
}
EXPORT_SYMBOL_GPL(kvm_valid_efer);
static int set_efer(struct kvm_vcpu *vcpu, u64 efer)
{
u64 old_efer = vcpu->arch.efer;
if (!kvm_valid_efer(vcpu, efer))
return 1;
if (is_paging(vcpu)
&& (vcpu->arch.efer & EFER_LME) != (efer & EFER_LME))
return 1;
efer &= ~EFER_LMA;
efer |= vcpu->arch.efer & EFER_LMA;