kvm: vmx: Introduce lapic_mode enumeration

The local APIC can be in one of three modes: disabled, xAPIC or
x2APIC. (A fourth mode, "invalid," is included for completeness.)

Using the new enumeration can make some of the APIC mode logic easier
to read. In kvm_set_apic_base, for instance, it is clear that one
cannot transition directly from x2APIC mode to xAPIC mode or directly
from APIC disabled to x2APIC mode.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
[Check invalid bits even if msr_info->host_initiated.  Reported by
 Wanpeng Li. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Jim Mattson
2018-05-09 16:56:04 -04:00
committed by Paolo Bonzini
parent ceef7d10df
commit 5887164942
2 changed files with 29 additions and 11 deletions

View File

@@ -318,23 +318,27 @@ u64 kvm_get_apic_base(struct kvm_vcpu *vcpu)
}
EXPORT_SYMBOL_GPL(kvm_get_apic_base);
enum lapic_mode kvm_get_apic_mode(struct kvm_vcpu *vcpu)
{
return kvm_apic_mode(kvm_get_apic_base(vcpu));
}
EXPORT_SYMBOL_GPL(kvm_get_apic_mode);
int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
{
u64 old_state = vcpu->arch.apic_base &
(MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE);
u64 new_state = msr_info->data &
(MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE);
enum lapic_mode old_mode = kvm_get_apic_mode(vcpu);
enum lapic_mode new_mode = kvm_apic_mode(msr_info->data);
u64 reserved_bits = ((~0ULL) << cpuid_maxphyaddr(vcpu)) | 0x2ff |
(guest_cpuid_has(vcpu, X86_FEATURE_X2APIC) ? 0 : X2APIC_ENABLE);
if ((msr_info->data & reserved_bits) || new_state == X2APIC_ENABLE)
return 1;
if (!msr_info->host_initiated &&
((new_state == MSR_IA32_APICBASE_ENABLE &&
old_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE)) ||
(new_state == (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE) &&
old_state == 0)))
if ((msr_info->data & reserved_bits) != 0 || new_mode == LAPIC_MODE_INVALID)
return 1;
if (!msr_info->host_initiated) {
if (old_mode == LAPIC_MODE_X2APIC && new_mode == LAPIC_MODE_XAPIC)
return 1;
if (old_mode == LAPIC_MODE_DISABLED && new_mode == LAPIC_MODE_X2APIC)
return 1;
}
kvm_lapic_set_base(vcpu, msr_info->data);
return 0;