KVM: x86: some apic broadcast modes does not work

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."

In addition, the local-apic enables cluster mode broadcast. As Intel SDM
10.6.2.2 says: "Broadcast to all local APICs is achieved by setting all
destination bits to one." This patch enables cluster mode broadcast.

The fix tries to combine broadcast in different modes through a unified code.

One rare case occurs when the source of IPI has its APIC disabled.  In such
case, the source can still issue IPIs, but since the source is not obliged to
have the same LAPIC mode as the enabled ones, we cannot rely on it.
Since it is a rare case, it is unoptimized and done on the slow-path.

Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Reviewed-by: Wanpeng Li <wanpeng.li@linux.intel.com>
[As per Radim's review, use unsigned int for X2APIC_BROADCAST, return bool from
 kvm_apic_broadcast. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 25 insertions, 9 deletions

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6ed0c30d6a0c..dd7cfc6de4a3 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 b8345dd41b25..ee04adf6c73a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -68,6 +68,9 @@
 #define MAX_APIC_VECTOR			256
 #define APIC_VECTORS_PER_REG		32
 
+#define APIC_BROADCAST			0xFF
+#define X2APIC_BROADCAST		0xFFFFFFFFul
+
 #define VEC_POS(v) ((v) & (32 - 1))
 #define REG_POS(v) (((v) >> 5) << 4)
 
@@ -149,6 +152,7 @@ static void recalculate_apic_map(struct kvm *kvm)
 	new->cid_shift = 8;
 	new->cid_mask = 0;
 	new->lid_mask = 0xff;
+	new->broadcast = APIC_BROADCAST;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		struct kvm_lapic *apic = vcpu->arch.apic;
@@ -170,6 +174,7 @@ 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 = X2APIC_BROADCAST;
 		} else if (kvm_apic_sw_enabled(apic) &&
 				!new->cid_mask /* flat mode */ &&
 				kvm_apic_get_reg(apic, APIC_DFR) == APIC_DFR_CLUSTER) {
@@ -558,16 +563,25 @@ 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)
+static int kvm_apic_broadcast(struct kvm_lapic *apic, u32 dest)
+{
+	return dest == (apic_x2apic_mode(apic) ?
+			X2APIC_BROADCAST : APIC_BROADCAST);
+}
+
+int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u32 dest)
 {
-	return dest == 0xff || kvm_apic_id(apic) == dest;
+	return kvm_apic_id(apic) == dest || kvm_apic_broadcast(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 (kvm_apic_broadcast(apic, mda))
+		return 1;
+
 	if (apic_x2apic_mode(apic)) {
 		logical_id = kvm_apic_get_reg(apic, APIC_LDR);
 		return logical_id & mda;
@@ -595,7 +609,7 @@ 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 +671,11 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
 	if (!map)
 		goto out;
 
+	if (irq->dest_id == map->broadcast)
+		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 6a11845fd8b9..3fd6c22d187d 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);