From: "Radim Krčmář" <rkrcmar@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
Steve Rutherford <srutherford@google.com>
Subject: [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI
Date: Thu, 8 Oct 2015 20:30:00 +0200 [thread overview]
Message-ID: <1444329000-8723-1-git-send-email-rkrcmar@redhat.com> (raw)
On real hardware, edge-triggered interrupts don't set a bit in TMR,
which means that IOAPIC isn't notified on EOI. Do the same here.
Staying in guest/kernel mode after edge EOI is what we want for most
devices. If some bugs could be nicely worked around with edge EOI
notifications, we should invest in a better interface.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
---
Completely untested.
arch/x86/kvm/irq_comm.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index c89228980230..8f4499c7ffc1 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -389,13 +389,15 @@ void kvm_scan_ioapic_routes(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
for (i = 0; i < nr_ioapic_pins; ++i) {
hlist_for_each_entry(entry, &table->map[i], link) {
u32 dest_id, dest_mode;
+ bool level;
if (entry->type != KVM_IRQ_ROUTING_MSI)
continue;
dest_id = (entry->msi.address_lo >> 12) & 0xff;
dest_mode = (entry->msi.address_lo >> 2) & 0x1;
- if (kvm_apic_match_dest(vcpu, NULL, 0, dest_id,
- dest_mode)) {
+ level = entry->msi.data & MSI_DATA_TRIGGER_LEVEL;
+ if (level && kvm_apic_match_dest(vcpu, NULL, 0,
+ dest_id, dest_mode)) {
u32 vector = entry->msi.data & 0xff;
__set_bit(vector,
--
2.5.3
next reply other threads:[~2015-10-08 18:30 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-08 18:30 Radim Krčmář [this message]
2015-10-08 18:34 ` [PATCH] KVM: x86: don't notify userspace IOAPIC on edge EOI Radim Krčmář
2015-10-09 11:03 ` Paolo Bonzini
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