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authorGleb Natapov <gleb@redhat.com>2009-07-05 18:48:11 +0300
committerAvi Kivity <avi@redhat.com>2009-08-09 11:45:49 +0300
commitb4a2f5e723e4f7df46731106faf9e2405673c073 (patch)
tree98766bcb94182957b27b9bdd371c742d927da951 /virt
parent53a27b39ff4d2492f84b1fdc2f0047175f0b0b93 (diff)
downloadlinux-linaro-stable-b4a2f5e723e4f7df46731106faf9e2405673c073.tar.gz
KVM: Avoid redelivery of edge interrupt before next edge
The check for an edge is broken in current ioapic code. ioapic->irr is cleared on each edge interrupt by ioapic_service() and this makes old_irr != ioapic->irr condition in kvm_ioapic_set_irq() to be always true. The patch fixes the code to properly recognise edge. Some HW emulation calls set_irq() without level change. If each such call is propagated to an OS it may confuse a device driver. This is the case with keyboard device emulation and Windows XP x64 installer on SMP VM. Each keystroke produce two interrupts (down/up) one interrupt is submitted to CPU0 and another to CPU1. This confuses Windows somehow and it ignores keystrokes. Signed-off-by: Gleb Natapov <gleb@redhat.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/ioapic.c10
1 files changed, 5 insertions, 5 deletions
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 1eddae94bab3..1150c6d5c7b8 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -95,8 +95,6 @@ static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
pent->fields.remote_irr = 1;
}
- if (!pent->fields.trig_mode)
- ioapic->irr &= ~(1 << idx);
return injected;
}
@@ -136,7 +134,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
mask_after = ioapic->redirtbl[index].fields.mask;
if (mask_before != mask_after)
kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
- if (ioapic->irr & (1 << index))
+ if (ioapic->redirtbl[index].fields.trig_mode == IOAPIC_LEVEL_TRIG
+ && ioapic->irr & (1 << index))
ioapic_service(ioapic, index);
break;
}
@@ -184,9 +183,10 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
if (!level)
ioapic->irr &= ~mask;
else {
+ int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
ioapic->irr |= mask;
- if ((!entry.fields.trig_mode && old_irr != ioapic->irr)
- || !entry.fields.remote_irr)
+ if ((edge && old_irr != ioapic->irr) ||
+ (!edge && !entry.fields.remote_irr))
ret = ioapic_service(ioapic, irq);
}
}