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KVM: ioapic: extract body of kvm_ioapic_set_irq

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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>
This commit is contained in:
Paolo Bonzini 2014-03-18 12:00:14 +01:00
parent 0bc830b05c
commit 44847dea79
1 changed files with 50 additions and 24 deletions
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74
virt/kvm/ioapic.c
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@ -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;