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Diffstat (limited to 'arch/x86/kvm/ioapic.c')
-rw-r--r--arch/x86/kvm/ioapic.c34
1 files changed, 25 insertions, 9 deletions
diff --git a/arch/x86/kvm/ioapic.c b/arch/x86/kvm/ioapic.c
index bdff437acbcb..4e822ad363f3 100644
--- a/arch/x86/kvm/ioapic.c
+++ b/arch/x86/kvm/ioapic.c
@@ -209,12 +209,12 @@ static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq,
old_irr = ioapic->irr;
ioapic->irr |= mask;
- if (edge)
+ if (edge) {
ioapic->irr_delivered &= ~mask;
- if ((edge && old_irr == ioapic->irr) ||
- (!edge && entry.fields.remote_irr)) {
- ret = 0;
- goto out;
+ if (old_irr == ioapic->irr) {
+ ret = 0;
+ goto out;
+ }
}
ret = ioapic_service(ioapic, irq, line_status);
@@ -257,8 +257,7 @@ void kvm_ioapic_scan_entry(struct kvm_vcpu *vcpu, ulong *ioapic_handled_vectors)
index == RTC_GSI) {
if (kvm_apic_match_dest(vcpu, NULL, 0,
e->fields.dest_id, e->fields.dest_mode) ||
- (e->fields.trig_mode == IOAPIC_EDGE_TRIG &&
- kvm_apic_pending_eoi(vcpu, e->fields.vector)))
+ kvm_apic_pending_eoi(vcpu, e->fields.vector))
__set_bit(e->fields.vector,
ioapic_handled_vectors);
}
@@ -277,6 +276,7 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
{
unsigned index;
bool mask_before, mask_after;
+ int old_remote_irr, old_delivery_status;
union kvm_ioapic_redirect_entry *e;
switch (ioapic->ioregsel) {
@@ -299,14 +299,28 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
return;
e = &ioapic->redirtbl[index];
mask_before = e->fields.mask;
+ /* Preserve read-only fields */
+ old_remote_irr = e->fields.remote_irr;
+ old_delivery_status = e->fields.delivery_status;
if (ioapic->ioregsel & 1) {
e->bits &= 0xffffffff;
e->bits |= (u64) val << 32;
} else {
e->bits &= ~0xffffffffULL;
e->bits |= (u32) val;
- e->fields.remote_irr = 0;
}
+ e->fields.remote_irr = old_remote_irr;
+ e->fields.delivery_status = old_delivery_status;
+
+ /*
+ * Some OSes (Linux, Xen) assume that Remote IRR bit will
+ * be cleared by IOAPIC hardware when the entry is configured
+ * as edge-triggered. This behavior is used to simulate an
+ * explicit EOI on IOAPICs that don't have the EOI register.
+ */
+ if (e->fields.trig_mode == IOAPIC_EDGE_TRIG)
+ e->fields.remote_irr = 0;
+
mask_after = e->fields.mask;
if (mask_before != mask_after)
kvm_fire_mask_notifiers(ioapic->kvm, KVM_IRQCHIP_IOAPIC, index, mask_after);
@@ -324,7 +338,9 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
struct kvm_lapic_irq irqe;
int ret;
- if (entry->fields.mask)
+ if (entry->fields.mask ||
+ (entry->fields.trig_mode == IOAPIC_LEVEL_TRIG &&
+ entry->fields.remote_irr))
return -1;
ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "