KVM: x86: fix mixed APIC mode broadcast

Broadcast allowed only one global APIC mode, but mixed modes are
theoretically possible.  x2APIC IPI doesn't mean 0xff as broadcast,
the rest does.

x2APIC broadcasts are accepted by xAPIC.  If we take SDM to be logical,
even addreses beginning with 0xff should be accepted, but real hardware
disagrees.  This patch aims for simple code by considering most of real
behavior as undefined.

Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-3-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 8d92e3bab11880f9ded9c7401c786d7ea2e4c5ee..5b1bc97a258a59619a2423f898939681c7130553 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -552,7 +552,7 @@ 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, broadcast;
+       u32 cid_shift, cid_mask, lid_mask;
        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 69569744745d47634e537e4fa4025c20c4f18742..d45f00ba74402213d57bc89e97efeb6a926722ec 100644 (file)
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -151,7 +151,6 @@ 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;
@@ -163,7 +162,6 @@ static void recalculate_apic_map(struct kvm *kvm)
                        new->ldr_bits = 32;
                        new->cid_shift = 16;
                        new->cid_mask = new->lid_mask = 0xffff;
-                       new->broadcast = X2APIC_BROADCAST;
                } else if (kvm_apic_get_reg(apic, APIC_LDR)) {
                        if (kvm_apic_get_reg(apic, APIC_DFR) ==
                                                        APIC_DFR_CLUSTER) {
@@ -690,6 +688,7 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
        struct kvm_lapic **dst;
        int i;
        bool ret = false;
+       bool x2apic_ipi = src && apic_x2apic_mode(src);
 
        *r = -1;
 
@@ -701,15 +700,15 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
        if (irq->shorthand)
                return false;
 
+       if (irq->dest_id == (x2apic_ipi ? X2APIC_BROADCAST : APIC_BROADCAST))
+               return false;
+
        rcu_read_lock();
        map = rcu_dereference(kvm->arch.apic_map);
 
        if (!map)
                goto out;
 
-       if (irq->dest_id == map->broadcast)
-               goto out;
-
        ret = true;
 
        if (irq->dest_mode == APIC_DEST_PHYSICAL) {