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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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
arch/x86/kvm/lapic.h
View File

@ -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 *vcpu);
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 kvm_vcpu *vcpu);
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

26
arch/x86/kvm/x86.c
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;