From: Jim Mattson jmattson@google.com
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@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 Cc: "Jitindar SIngh, Suraj" surajjs@amazon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- 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;