Skip to content

Commit

Permalink
KVM: x86: use hardware-compatible format for APIC ID register
Browse files Browse the repository at this point in the history 
We currently always shift APIC ID as if APIC was in xAPIC mode.
x2APIC mode wants to use more bits and storing a hardware-compabible
value is the the sanest option.

KVM API to set the lapic expects that bottom 8 bits of APIC ID are in
top 8 bits of APIC_ID register, so the register needs to be shifted in
x2APIC mode.

Signed-off-by: Radim Krčmář <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
  • Loading branch information
@rkrcmar @bonzini
rkrcmar authored and bonzini committed Jul 14, 2016
1 parent 3159d36 commit a92e254
Show file tree
Hide file tree
Showing 3 changed files with 52 additions and 22 deletions.
52 changes: 37 additions & 15 deletions arch/x86/kvm/lapic.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -227,7 +227,7 @@ static inline void apic_set_spiv(struct kvm_lapic *apic, u32 val)
}
}

static inline void kvm_apic_set_id(struct kvm_lapic *apic, u8 id)
static inline void kvm_apic_set_xapic_id(struct kvm_lapic *apic, u8 id)
{
kvm_lapic_set_reg(apic, APIC_ID, id << 24);
recalculate_apic_map(apic->vcpu->kvm);
Expand All @@ -239,11 +239,11 @@ static inline void kvm_apic_set_ldr(struct kvm_lapic *apic, u32 id)
recalculate_apic_map(apic->vcpu->kvm);
}

static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u8 id)
static inline void kvm_apic_set_x2apic_id(struct kvm_lapic *apic, u32 id)
{
u32 ldr = ((id >> 4) << 16) | (1 << (id & 0xf));

kvm_lapic_set_reg(apic, APIC_ID, id << 24);
kvm_lapic_set_reg(apic, APIC_ID, id);
kvm_lapic_set_reg(apic, APIC_LDR, ldr);
recalculate_apic_map(apic->vcpu->kvm);
}
Expand Down Expand Up @@ -1102,12 +1102,6 @@ static u32 __apic_read(struct kvm_lapic *apic, unsigned int offset)
return 0;

switch (offset) {
case APIC_ID:
if (apic_x2apic_mode(apic))
val = kvm_apic_id(apic);
else
val = kvm_apic_id(apic) << 24;
break;
case APIC_ARBPRI:
apic_debug("Access APIC ARBPRI register which is for P6\n");
break;
Expand Down Expand Up @@ -1465,7 +1459,7 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
switch (reg) {
case APIC_ID: /* Local APIC ID */
if (!apic_x2apic_mode(apic))
kvm_apic_set_id(apic, val >> 24);
kvm_apic_set_xapic_id(apic, val >> 24);
else
ret = 1;
break;
Expand Down Expand Up @@ -1769,7 +1763,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event)
hrtimer_cancel(&apic->lapic_timer.timer);

if (!init_event)
kvm_apic_set_id(apic, vcpu->vcpu_id);
kvm_apic_set_xapic_id(apic, vcpu->vcpu_id);
kvm_apic_set_version(apic->vcpu);

for (i = 0; i < KVM_APIC_LVT_NUM; i++)
Expand Down Expand Up @@ -1990,17 +1984,43 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu)
return vector;
}

void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
struct kvm_lapic_state *s)
static int kvm_apic_state_fixup(struct kvm_vcpu *vcpu,
struct kvm_lapic_state *s, bool set)
{
if (apic_x2apic_mode(vcpu->arch.apic)) {
u32 *id = (u32 *)(s->regs + APIC_ID);

if (set)
*id >>= 24;
else
*id <<= 24;
}

return 0;
}

int kvm_apic_get_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
{
memcpy(s->regs, vcpu->arch.apic->regs, sizeof(*s));
return kvm_apic_state_fixup(vcpu, s, false);
}

int kvm_apic_set_state(struct kvm_vcpu *vcpu, struct kvm_lapic_state *s)
{
struct kvm_lapic *apic = vcpu->arch.apic;
int r;


kvm_lapic_set_base(vcpu, vcpu->arch.apic_base);
/* set SPIV separately to get count of SW disabled APICs right */
apic_set_spiv(apic, *((u32 *)(s->regs + APIC_SPIV)));

r = kvm_apic_state_fixup(vcpu, s, true);
if (r)
return r;
memcpy(vcpu->arch.apic->regs, s->regs, sizeof *s);
/* call kvm_apic_set_id() to put apic into apic_map */
kvm_apic_set_id(apic, kvm_apic_id(apic));

recalculate_apic_map(vcpu->kvm);
kvm_apic_set_version(vcpu);

apic_update_ppr(apic);
Expand All @@ -2026,6 +2046,8 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
kvm_rtc_eoi_tracking_restore_one(vcpu);

vcpu->arch.apic_arb_prio = 0;

return 0;
}

void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
Expand Down
12 changes: 9 additions & 3 deletions arch/x86/kvm/lapic.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -81,8 +81,8 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,

u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
int kvm_set_apic_base(struct kvm_vcpu *vcpu, struct msr_data *msr_info);
void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
struct kvm_lapic_state *s);
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);
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu);

u64 kvm_get_lapic_tscdeadline_msr(struct kvm_vcpu *vcpu);
Expand Down Expand Up @@ -202,7 +202,13 @@ static inline int kvm_lapic_latched_init(struct kvm_vcpu *vcpu)

static inline u32 kvm_apic_id(struct kvm_lapic *apic)
{
return (kvm_lapic_get_reg(apic, APIC_ID) >> 24) & 0xff;
/* To avoid a race between apic_base and following APIC_ID update when
* switching to x2apic_mode, the x2apic mode returns initial x2apic id.
*/
if (apic_x2apic_mode(apic))
return apic->vcpu->vcpu_id;

return kvm_lapic_get_reg(apic, APIC_ID) >> 24;
}

bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
Expand Down
10 changes: 6 additions & 4 deletions arch/x86/kvm/x86.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -2779,15 +2779,17 @@ static int kvm_vcpu_ioctl_get_lapic(struct kvm_vcpu *vcpu,
if (vcpu->arch.apicv_active)
kvm_x86_ops->sync_pir_to_irr(vcpu);

memcpy(s->regs, vcpu->arch.apic->regs, sizeof *s);

return 0;
return kvm_apic_get_state(vcpu, s);
}

static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
struct kvm_lapic_state *s)
{
kvm_apic_post_state_restore(vcpu, s);
int r;

r = kvm_apic_set_state(vcpu, s);
if (r)
return r;
update_cr8_intercept(vcpu);

return 0;
Expand Down

0 comments on commit a92e254

Please sign in to comment.