From: Gleb Natapov <[email protected]> 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 <[email protected]> Signed-off-by: Avi Kivity <[email protected]> diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c index 124ecf7..8a9c6cc 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; } @@ -186,9 +185,10 @@ 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); } } -- To unsubscribe from this list: send the line "unsubscribe kvm-commits" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
