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authorGleb Natapov <gleb@redhat.com>2009-07-05 11:48:11 -0400
committerAvi Kivity <avi@redhat.com>2009-08-09 04:45:49 -0400
commitb4a2f5e723e4f7df46731106faf9e2405673c073 (patch)
tree98766bcb94182957b27b9bdd371c742d927da951 /virt
parent53a27b39ff4d2492f84b1fdc2f0047175f0b0b93 (diff)
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)
95 if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG) 95 if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
96 pent->fields.remote_irr = 1; 96 pent->fields.remote_irr = 1;
97 } 97 }
98 if (!pent->fields.trig_mode)
99 ioapic->irr &= ~(1 << idx);
100 98
101 return injected; 99 return injected;
102} 100}
@@ -136,7 +134,8 @@ static void ioapic_write_indirect(struct kvm_ioapic *ioapic, u32 val)
136 mask_after = ioapic->redirtbl[index].fields.mask; 134 mask_after = ioapic->redirtbl[index].fields.mask;
137 if (mask_before != mask_after) 135 if (mask_before != mask_after)
138 kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after); 136 kvm_fire_mask_notifiers(ioapic->kvm, index, mask_after);
139 if (ioapic->irr & (1 << index)) 137 if (ioapic->redirtbl[index].fields.trig_mode == IOAPIC_LEVEL_TRIG
138 && ioapic->irr & (1 << index))
140 ioapic_service(ioapic, index); 139 ioapic_service(ioapic, index);
141 break; 140 break;
142 } 141 }
@@ -184,9 +183,10 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
184 if (!level) 183 if (!level)
185 ioapic->irr &= ~mask; 184 ioapic->irr &= ~mask;
186 else { 185 else {
186 int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
187 ioapic->irr |= mask; 187 ioapic->irr |= mask;
188 if ((!entry.fields.trig_mode && old_irr != ioapic->irr) 188 if ((edge && old_irr != ioapic->irr) ||
189 || !entry.fields.remote_irr) 189 (!edge && !entry.fields.remote_irr))
190 ret = ioapic_service(ioapic, irq); 190 ret = ioapic_service(ioapic, irq);
191 } 191 }
192 } 192 }