From 220c8ed536491315b4040d820328b8dfd60d67a7 Mon Sep 17 00:00:00 2001 From: "Gabriel L. Somlo" Date: Fri, 28 Feb 2014 13:57:19 -0500 Subject: qemu: x86: ignore ioapic polarity Both QEMU and KVM have already accumulated a significant number of optimizations based on the hard-coded assumption that ioapic polarity will always use the ActiveHigh convention, where the logical and physical states of level-triggered irq lines always match (i.e., active(asserted) == high == 1, inactive == low == 0). QEMU guests are expected to follow directions given via ACPI and configure the ioapic with polarity 0 (ActiveHigh). However, even when misbehaving guests (e.g. OS X <= 10.9) set the ioapic polarity to 1 (ActiveLow), QEMU will still use the ActiveHigh signaling convention when interfacing with the emulated ioapic. This patch modifies the emulated ioapic to completely ignore polarity as set by the guest OS, enabling misbehaving guests to work alongside those which comply with the ActiveHigh polarity specified by QEMU's ACPI tables. Signed-off-by: Gabriel L. Somlo Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/intc/ioapic.c | 3 --- 1 file changed, 3 deletions(-) (limited to 'hw') diff --git a/hw/intc/ioapic.c b/hw/intc/ioapic.c index 652dd47a1c..b527932382 100644 --- a/hw/intc/ioapic.c +++ b/hw/intc/ioapic.c @@ -93,9 +93,6 @@ static void ioapic_set_irq(void *opaque, int vector, int level) uint32_t mask = 1 << vector; uint64_t entry = s->ioredtbl[vector]; - if (entry & (1 << IOAPIC_LVT_POLARITY_SHIFT)) { - level = !level; - } if (((entry >> IOAPIC_LVT_TRIGGER_MODE_SHIFT) & 1) == IOAPIC_TRIGGER_LEVEL) { /* level triggered */ -- cgit v1.2.1