This creates a way to detect when kvm_set_irq(...,0) was run
twice with the same source id by returning 0 in this case.
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
This is on top of my bugfix patch. Uncompiled and untested. Alex, I
think something like this patch will make it possible for you to simply
do
if (kvm_set_irq(...., 0))
eventfd_signal()
without need for further tricks.
arch/x86/include/asm/kvm_host.h | 9 ++++-----
arch/x86/kvm/i8259.c | 11 +++++++----
virt/kvm/ioapic.c | 17 ++++++++++-------
3 files changed, 21 insertions(+), 16 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index fe6e9f1..6f5ed0a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -802,16 +802,15 @@ int kvm_read_guest_page_mmu(struct kvm_vcpu *vcpu, struct kvm_mmu *mmu,
void kvm_propagate_fault(struct kvm_vcpu *vcpu, struct x86_exception *fault);
bool kvm_require_cpl(struct kvm_vcpu *vcpu, int required_cpl);
-static inline int kvm_irq_line_state(unsigned long *irq_state,
+/* Tweak line state. Return true if state was changed. */
+static inline bool kvm_irq_line_state(unsigned long *irq_state,
int irq_source_id, int level)
{
/* Logical OR for level trig interrupt */
if (level)
- __set_bit(irq_source_id, irq_state);
+ return !__test_and_set_bit(irq_source_id, irq_state);
else
- __clear_bit(irq_source_id, irq_state);
-
- return !!(*irq_state);
+ return __test_and_clear_bit(irq_source_id, irq_state);
}
int kvm_pic_set_irq(struct kvm_pic *pic, int irq, int irq_source_id, int level);
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index 95b504b..44e3635 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -190,12 +190,15 @@ void kvm_pic_update_irq(struct kvm_pic *s)
int kvm_pic_set_irq(struct kvm_pic *s, int irq, int src_id, int l)
{
- int ret = -1;
- int level;
+ int ret, level;
pic_lock(s);
- if (irq >= 0 && irq < PIC_NUM_PINS) {
- level = kvm_irq_line_state(&s->irq_states[irq], src_id, l);
+ if (irq < 0 || irq >= PIC_NUM_PINS) {
+ ret = -1;
+ } else if (!kvm_irq_line_state(&s->irq_states[irq], src_id, l)) {
+ ret = 0;
+ } else {
+ level = !!s->irq_states[irq];
ret = pic_set_irq1(&s->pics[irq >> 3], irq & 7, level);
pic_update_irq(s);
trace_kvm_pic_set_irq(irq >> 3, irq & 7, s->pics[irq >> 3].elcr,
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 268b332..edc9445 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -196,18 +196,21 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int src_id, int l)
u32 old_irr;
u32 mask = 1 << irq;
union kvm_ioapic_redirect_entry entry;
- int ret = 1;
- int level;
+ int ret, level;
spin_lock(&ioapic->lock);
old_irr = ioapic->irr;
- if (irq >= 0 && irq < IOAPIC_NUM_PINS) {
+ if (irq < 0 || irq >= IOAPIC_NUM_PINS) {
+ ret = -1;
+ } else if (!kvm_irq_line_state(&ioapic->irq_states[irq], src_id, l)) {
+ ret = 0;
+ } else {
entry = ioapic->redirtbl[irq];
- level = kvm_irq_line_state(&ioapic->irq_states[irq], src_id, l);
- level ^= entry.fields.polarity;
- if (!level)
+ level = (!!ioapic->irq_states[irq]) ^ entry.fields.polarity;
+ if (!level) {
ioapic->irr &= ~mask;
- else {
+ ret = 1;
+ } else {
int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
ioapic->irr |= mask;
if ((edge && old_irr != ioapic->irr) ||
--
MST
--
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