KVM does not deliver x2APIC broadcast messages with physical mode. Intel SDM
(10.12.9 ICR Operation in x2APIC Mode) states: "A destination ID value of
FFFF_FFFFH is used for broadcast of interrupts in both logical destination and
physical destination modes."
The fix tries to combine broadcast in different modes. Broadcast can be done
in the fast-path if the delivery-mode is logical and there is only a single
cluster. Otherwise, do it slowly.
Signed-off-by: Nadav Amit <namit@xxxxxxxxxxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +-
arch/x86/kvm/lapic.c | 22 ++++++++++++++++------
arch/x86/kvm/lapic.h | 4 ++--
virt/kvm/ioapic.h | 2 +-
4 files changed, 20 insertions(+), 10 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 7d603a7..6f2be83 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -542,7 +542,7 @@ struct kvm_apic_map {
struct rcu_head rcu;
u8 ldr_bits;
/* fields bellow are used to decode ldr values in different modes */
- u32 cid_shift, cid_mask, lid_mask;
+ u32 cid_shift, cid_mask, lid_mask, broadcast;
struct kvm_lapic *phys_map[256];
/* first index is cluster id second is cpu id in a cluster */
struct kvm_lapic *logical_map[16][16];
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index b8345dd..16404cd 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -149,6 +149,7 @@ static void recalculate_apic_map(struct kvm *kvm)
new->cid_shift = 8;
new->cid_mask = 0;
new->lid_mask = 0xff;
+ new->broadcast = 0xff;
kvm_for_each_vcpu(i, vcpu, kvm) {
struct kvm_lapic *apic = vcpu->arch.apic;
@@ -170,6 +171,7 @@ static void recalculate_apic_map(struct kvm *kvm)
new->cid_shift = 16;
new->cid_mask = (1 << KVM_X2APIC_CID_BITS) - 1;
new->lid_mask = 0xffff;
+ new->broadcast = (u32)-1;
} else if (kvm_apic_sw_enabled(apic) &&
!new->cid_mask /* flat mode */ &&
kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER) {
@@ -558,17 +560,21 @@ static void apic_set_tpr(struct kvm_lapic *apic, u32 tpr)
apic_update_ppr(apic);
}
-int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest)
+int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 dest)
{
- return dest == 0xff || kvm_apic_id(apic) == dest;
+ u32 broadcast = apic_x2apic_mode(apic) ? (u32)-1 : 0xff;
+
+ return (dest == broadcast || kvm_apic_id(apic) == dest);
}
-int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
+int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda)
{
int result = 0;
u32 logical_id;
if (apic_x2apic_mode(apic)) {
+ if (mda == (u32)-1)
+ return 1; /* x2apic broadcast */
logical_id = kvm_apic_get_reg(apic, APIC_LDR);
return logical_id & mda;
}
@@ -595,7 +601,7 @@ int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda)
}
int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
- int short_hand, int dest, int dest_mode)
+ int short_hand, unsigned int dest, int dest_mode)
{
int result = 0;
struct kvm_lapic *target = vcpu->arch.apic;
@@ -657,9 +663,13 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
if (!map)
goto out;
+ /* broadcast on physical or multiple clusters is done slowly */
+ if (irq->dest_id == map->broadcast &&
+ (irq->dest_mode == 0 || map->cid_mask != 0))
+ goto out;
+
if (irq->dest_mode == 0) { /* physical mode */
- if (irq->delivery_mode == APIC_DM_LOWEST ||
- irq->dest_id == 0xff)
+ if (irq->delivery_mode == APIC_DM_LOWEST)
goto out;
dst = &map->phys_map[irq->dest_id & 0xff];
} else {
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 6a11845..3fd6c22 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -55,8 +55,8 @@ void kvm_apic_set_version(struct kvm_vcpu *vcpu);
void kvm_apic_update_tmr(struct kvm_vcpu *vcpu, u32 *tmr);
void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
-int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest);
-int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda);
+int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 dest);
+int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u32 mda);
int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
unsigned long *dest_map);
int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type);
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index e23b706..31725a3 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -83,7 +83,7 @@ static inline struct kvm_ioapic *ioapic_irqchip(struct kvm *kvm)
void kvm_rtc_eoi_tracking_restore_one(struct kvm_vcpu *vcpu);
int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
- int short_hand, int dest, int dest_mode);
+ int short_hand, unsigned int dest, int dest_mode);
int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2);
void kvm_ioapic_update_eoi(struct kvm_vcpu *vcpu, int vector,
int trigger_mode);
--
1.9.1
--
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