From: Jim Mattson <jmattson@xxxxxxxxxx>
commit 588716494258899389206fa50426e78cc9df89b9 upstream.
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@xxxxxxxxxx>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@xxxxxxxxxx>
[Check invalid bits even if msr_info->host_initiated. Reported by
Wanpeng Li. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: "Jitindar SIngh, Suraj" <surajjs@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/lapic.h | 14 ++++++++++++++
arch/x86/kvm/x86.c | 26 +++++++++++++++-----------
2 files changed, 29 insertions(+), 11 deletions(-)
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -16,6 +16,13 @@
#define APIC_BUS_CYCLE_NS 1
#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS)
+enum lapic_mode {
+ LAPIC_MODE_DISABLED = 0,
+ LAPIC_MODE_INVALID = X2APIC_ENABLE,
+ LAPIC_MODE_XAPIC = MSR_IA32_APICBASE_ENABLE,
+ LAPIC_MODE_X2APIC = MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE,
+};
+
struct kvm_timer {
struct hrtimer timer;
s64 period; /* unit: ns */
@@ -89,6 +96,7 @@ u64 kvm_get_apic_base(struct kvm_vcpu *v
int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s);
+enum lapic_mode kvm_get_apic_mode(struct kvm_vcpu *vcpu);
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);
u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
@@ -220,4 +228,10 @@ void kvm_lapic_switch_to_hv_timer(struct
void kvm_lapic_expired_hv_timer(struct kvm_vcpu *vcpu);
bool kvm_lapic_hv_timer_in_use(struct kvm_vcpu *vcpu);
void kvm_lapic_restart_hv_timer(struct kvm_vcpu *vcpu);
+
+static inline enum lapic_mode kvm_apic_mode(u64 apic_base)
+{
+ return apic_base & (MSR_IA32_APICBASE_ENABLE | X2APIC_ENABLE);
+}
+
#endif
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -306,23 +306,27 @@ u64 kvm_get_apic_base(struct kvm_vcpu *v
}
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;
