From 4fa6b9c5dc4134bdeac341d731a87783cc11ca10 Mon Sep 17 00:00:00 2001
From: Avi Kivity <avi@qumranet.com>
Date: Tue, 17 Jun 2008 15:36:36 -0700
Subject: [PATCH] KVM: ioapic: fix lost interrupt when changing a device's irq
The ioapic acknowledge path translates interrupt vectors to irqs. It
currently uses a first match algorithm, stopping when it finds the first
redirection table entry containing the vector. That fails however if the
guest changes the irq to a different line, leaving the old redirection table
entry in place (though masked). Result is interrupts not making it to the
guest.
Fix by always scanning the entire redirection table.
Signed-off-by: Avi Kivity <avi@qumranet.com>
---
virt/kvm/ioapic.c | 31 +++++++++++--------------------
1 file changed, 11 insertions(+), 20 deletions(-)
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 98778cb69c6ef..1dcf9f3d11071 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -269,28 +269,9 @@ void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level)
}
}
-static int get_eoi_gsi(struct kvm_ioapic *ioapic, int vector)
+static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int gsi)
{
- int i;
-
- for (i = 0; i < IOAPIC_NUM_PINS; i++)
- if (ioapic->redirtbl[i].fields.vector == vector)
- return i;
- return -1;
-}
-
-void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)
-{
- struct kvm_ioapic *ioapic = kvm->arch.vioapic;
union ioapic_redir_entry *ent;
- int gsi;
-
- gsi = get_eoi_gsi(ioapic, vector);
- if (gsi == -1) {
- printk(KERN_WARNING "Can't find redir item for %d EOI\n",
- vector);
- return;
- }
ent = &ioapic->redirtbl[gsi];
ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
@@ -300,6 +281,16 @@ void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)
ioapic_deliver(ioapic, gsi);
}
+void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)
+{
+ struct kvm_ioapic *ioapic = kvm->arch.vioapic;
+ int i;
+
+ for (i = 0; i < IOAPIC_NUM_PINS; i++)
+ if (ioapic->redirtbl[i].fields.vector == vector)
+ __kvm_ioapic_update_eoi(ioapic, i);
+}
+
static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr)
{
struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;
--
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