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authorPaolo Bonzini <pbonzini@redhat.com>2014-03-18 12:00:14 +0100
committerPaolo Bonzini <pbonzini@redhat.com>2014-03-21 10:20:16 +0100
commit44847dea79751e95665a439f8c63a65e51da8e1f (patch)
tree1329f713872d1034bfb2c1b80d483ffa0e72777c /virt
parent0bc830b05c667218d703f2026ec866c49df974fc (diff)
downloadkernel-44847dea79751e95665a439f8c63a65e51da8e1f.tar.gz
KVM: ioapic: extract body of kvm_ioapic_set_irq
We will reuse it to process a nonzero IRR that is passed to KVM_SET_IRQCHIP. Reviewed-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/ioapic.c74
1 files changed, 50 insertions, 24 deletions
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 25e16a6898ed..270f7fe73f39 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -163,6 +163,55 @@ static bool rtc_irq_check_coalesced(struct kvm_ioapic *ioapic)
return false;
}
+static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq,
+ int irq_level, bool line_status)
+{
+ union kvm_ioapic_redirect_entry entry;
+ u32 mask = 1 << irq;
+ u32 old_irr;
+ int edge, ret;
+
+ entry = ioapic->redirtbl[irq];
+ edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
+
+ if (!irq_level) {
+ ioapic->irr &= ~mask;
+ ret = 1;
+ goto out;
+ }
+
+ /*
+ * Return 0 for coalesced interrupts; for edge-triggered interrupts,
+ * this only happens if a previous edge has not been delivered due
+ * do masking. For level interrupts, the remote_irr field tells
+ * us if the interrupt is waiting for an EOI.
+ *
+ * RTC is special: it is edge-triggered, but userspace likes to know
+ * if it has been already ack-ed via EOI because coalesced RTC
+ * interrupts lead to time drift in Windows guests. So we track
+ * EOI manually for the RTC interrupt.
+ */
+ if (irq == RTC_GSI && line_status &&
+ rtc_irq_check_coalesced(ioapic)) {
+ ret = 0;
+ goto out;
+ }
+
+ old_irr = ioapic->irr;
+ ioapic->irr |= mask;
+ if ((edge && old_irr == ioapic->irr) ||
+ (!edge && entry.fields.remote_irr)) {
+ ret = 0;
+ goto out;
+ }
+
+ ret = ioapic_service(ioapic, irq, line_status);
+
+out:
+ trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
+ return ret;
+}
+
static void update_handled_vectors(struct kvm_ioapic *ioapic)
{
DECLARE_BITMAP(handled_vectors, 256);
@@ -308,38 +357,15 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status)
int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
int level, bool line_status)
{
- u32 old_irr;
- u32 mask = 1 << irq;
- union kvm_ioapic_redirect_entry entry;
int ret, irq_level;
BUG_ON(irq < 0 || irq >= IOAPIC_NUM_PINS);
spin_lock(&ioapic->lock);
- old_irr = ioapic->irr;
irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq],
irq_source_id, level);
- entry = ioapic->redirtbl[irq];
- if (!irq_level) {
- ioapic->irr &= ~mask;
- ret = 1;
- } else {
- int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
+ ret = ioapic_set_irq(ioapic, irq, irq_level, line_status);
- if (irq == RTC_GSI && line_status &&
- rtc_irq_check_coalesced(ioapic)) {
- ret = 0; /* coalesced */
- goto out;
- }
- ioapic->irr |= mask;
- if ((edge && old_irr != ioapic->irr) ||
- (!edge && !entry.fields.remote_irr))
- ret = ioapic_service(ioapic, irq, line_status);
- else
- ret = 0; /* report coalesced interrupt */
- }
-out:
- trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
spin_unlock(&ioapic->lock);
return ret;