From: Jan Kiszka <jan.kis...@siemens.com>
Since the arrival of posted interrupt support we can no longer guarantee
that coalesced IRQs are always reported to the IRQ source. Moreover,
accumulated APIC timer events could cause a busy loop when a VCPU should
rather be halted. The consensus is to remove coalesced tracking from the
LAPIC.
Signed-off-by: Jan Kiszka <jan.kis...@siemens.com>
---
Not sure, though, if this is going too far or not far enough /wrt
removing return values from affected functions.
arch/x86/kvm/lapic.c | 62 ++++++++++++++++++-------------------------------
arch/x86/kvm/lapic.h | 9 ++++---
virt/kvm/ioapic.c | 23 +++++++++---------
virt/kvm/ioapic.h | 5 ++-
virt/kvm/irq_comm.c | 31 +++++++++++-------------
5 files changed, 56 insertions(+), 74 deletions(-)
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e29883c..7cfd35c 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -405,17 +405,17 @@ int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
return highest_irr;
}
-static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
- int vector, int level, int trig_mode,
- unsigned long *dest_map);
+static void __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
+ int vector, int level, int trig_mode,
+ unsigned long *dest_map);
-int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
- unsigned long *dest_map)
+void kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
+ unsigned long *dest_map)
{
struct kvm_lapic *apic = vcpu->arch.apic;
- return __apic_accept_irq(apic, irq->delivery_mode, irq->vector,
- irq->level, irq->trig_mode, dest_map);
+ __apic_accept_irq(apic, irq->delivery_mode, irq->vector,
+ irq->level, irq->trig_mode, dest_map);
}
static int pv_eoi_put_user(struct kvm_vcpu *vcpu, u8 val)
@@ -597,7 +597,8 @@ int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct
kvm_lapic *source,
}
bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
- struct kvm_lapic_irq *irq, int *r, unsigned long *dest_map)
+ struct kvm_lapic_irq *irq,
+ unsigned long *dest_map)
{
struct kvm_apic_map *map;
unsigned long bitmap = 1;
@@ -605,10 +606,8 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct
kvm_lapic *src,
int i;
bool ret = false;
- *r = -1;
-
if (irq->shorthand == APIC_DEST_SELF) {
- *r = kvm_apic_set_irq(src->vcpu, irq, dest_map);
+ kvm_apic_set_irq(src->vcpu, irq, dest_map);
return true;
}
@@ -651,9 +650,7 @@ bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct
kvm_lapic *src,
for_each_set_bit(i, &bitmap, 16) {
if (!dst[i])
continue;
- if (*r < 0)
- *r = 0;
- *r += kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
+ kvm_apic_set_irq(dst[i]->vcpu, irq, dest_map);
}
ret = true;
@@ -662,15 +659,11 @@ out:
return ret;
}
-/*
- * Add a pending IRQ into lapic.
- * Return 1 if successfully added and 0 if discarded.
- */
-static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
- int vector, int level, int trig_mode,
- unsigned long *dest_map)
+/* Set an IRQ pending in the lapic. */
+static void __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
+ int vector, int level, int trig_mode,
+ unsigned long *dest_map)
{
- int result = 0;
struct kvm_vcpu *vcpu = apic->vcpu;
switch (delivery_mode) {
@@ -684,13 +677,10 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int
delivery_mode,
if (dest_map)
__set_bit(vcpu->vcpu_id, dest_map);
- if (kvm_x86_ops->deliver_posted_interrupt) {
- result = 1;
+ if (kvm_x86_ops->deliver_posted_interrupt)
kvm_x86_ops->deliver_posted_interrupt(vcpu, vector);
- } else {
- result = !apic_test_and_set_irr(vector, apic);
-
- if (!result) {
+ else {
+ if (apic_test_and_set_irr(vector, apic)) {
if (trig_mode)
apic_debug("level trig mode repeatedly "
"for vector %d", vector);
@@ -702,7 +692,7 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int
delivery_mode,
}
out:
trace_kvm_apic_accept_irq(vcpu->vcpu_id, delivery_mode,
- trig_mode, vector, !result);
+ trig_mode, vector, false);
break;
case APIC_DM_REMRD:
@@ -714,14 +704,12 @@ out:
break;
case APIC_DM_NMI:
- result = 1;
kvm_inject_nmi(vcpu);
kvm_vcpu_kick(vcpu);
break;
case APIC_DM_INIT:
if (!trig_mode || level) {
- result = 1;
/* assumes that there are only KVM_APIC_INIT/SIPI */
apic->pending_events = (1UL << KVM_APIC_INIT);
/* make sure pending_events is visible before sending
@@ -738,7 +726,6 @@ out:
case APIC_DM_STARTUP:
apic_debug("SIPI to vcpu %d vector 0x%02x\n",
vcpu->vcpu_id, vector);
- result = 1;
apic->sipi_vector = vector;
/* make sure sipi_vector is visible for the receiver */
smp_wmb();
@@ -760,7 +747,6 @@ out:
delivery_mode);
break;
}
- return result;
}
int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2)
@@ -1470,7 +1456,7 @@ int apic_has_pending_timer(struct kvm_vcpu *vcpu)
return 0;
}
-int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type)
+void kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type)
{
u32 reg = kvm_apic_get_reg(apic, lvt_type);
int vector, mode, trig_mode;
@@ -1479,10 +1465,8 @@ int kvm_apic_local_deliver(struct kvm_lapic *apic, int
lvt_type)
vector = reg & APIC_VECTOR_MASK;
mode = reg & APIC_MODE_MASK;
trig_mode = reg & APIC_LVT_LEVEL_TRIGGER;
- return __apic_accept_irq(apic, mode, vector, 1, trig_mode,
- NULL);
+ __apic_accept_irq(apic, mode, vector, 1, trig_mode, NULL);
}
- return 0;
}
void kvm_apic_nmi_wd_deliver(struct kvm_vcpu *vcpu)
@@ -1608,8 +1592,8 @@ void kvm_inject_apic_timer_irqs(struct kvm_vcpu *vcpu)
return;
if (atomic_read(&apic->lapic_timer.pending) > 0) {
- if (kvm_apic_local_deliver(apic, APIC_LVTT))
- atomic_dec(&apic->lapic_timer.pending);
+ kvm_apic_local_deliver(apic, APIC_LVTT);
+ atomic_set(&apic->lapic_timer.pending, 0);
}
}
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index c730ac9..4d1b9eb 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -57,12 +57,13 @@ void kvm_apic_update_tmr(struct kvm_vcpu *vcpu, u32 *tmr);
void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest);
int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda);
-int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
- unsigned long *dest_map);
-int kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type);
+void kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
+ unsigned long *dest_map);
+void kvm_apic_local_deliver(struct kvm_lapic *apic, int lvt_type);
bool kvm_irq_delivery_to_apic_fast(struct kvm *kvm, struct kvm_lapic *src,
- struct kvm_lapic_irq *irq, int *r, unsigned long *dest_map);
+ struct kvm_lapic_irq *irq,
+ unsigned long *dest_map);
u64 kvm_get_apic_base(struct kvm_vcpu *vcpu);
void kvm_set_apic_base(struct kvm_vcpu *vcpu, u64 data);
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 2d68297..606e09b 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -50,8 +50,8 @@
#else
#define ioapic_debug(fmt, arg...)
#endif
-static int ioapic_deliver(struct kvm_ioapic *vioapic, int irq,
- bool line_status);
+static void ioapic_deliver(struct kvm_ioapic *vioapic, int irq,
+ bool line_status);
static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
unsigned long addr,
@@ -172,9 +172,10 @@ static int ioapic_service(struct kvm_ioapic *ioapic,
unsigned int idx,
pent = &ioapic->redirtbl[idx];
if (!pent->fields.mask) {
- injected = ioapic_deliver(ioapic, idx, line_status);
- if (injected && pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
+ ioapic_deliver(ioapic, idx, line_status);
+ if (pent->fields.trig_mode == IOAPIC_LEVEL_TRIG)
pent->fields.remote_irr = 1;
+ injected = 1;
}
return injected;
@@ -282,11 +283,11 @@ static void ioapic_write_indirect(struct kvm_ioapic
*ioapic, u32 val)
}
}
-static int ioapic_deliver(struct kvm_ioapic *ioapic, int irq, bool line_status)
+static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq,
+ bool line_status)
{
union kvm_ioapic_redirect_entry *entry = &ioapic->redirtbl[irq];
struct kvm_lapic_irq irqe;
- int ret;
ioapic_debug("dest=%x dest_mode=%x delivery_mode=%x "
"vector=%x trig_mode=%x\n",
@@ -304,13 +305,11 @@ static int ioapic_deliver(struct kvm_ioapic *ioapic, int
irq, bool line_status)
if (irq == RTC_GSI && line_status) {
BUG_ON(ioapic->rtc_status.pending_eoi != 0);
- ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
- ioapic->rtc_status.dest_map);
- ioapic->rtc_status.pending_eoi = ret;
+ kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe,
+ ioapic->rtc_status.dest_map);
+ ioapic->rtc_status.pending_eoi++;
} else
- ret = kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
-
- return ret;
+ kvm_irq_delivery_to_apic(ioapic->kvm, NULL, &irqe, NULL);
}
int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index 615d8c9..639fe9c 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -92,8 +92,9 @@ int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq,
int irq_source_id,
int level, bool line_status);
void kvm_ioapic_clear_all(struct kvm_ioapic *ioapic, int irq_source_id);
void kvm_ioapic_reset(struct kvm_ioapic *ioapic);
-int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
- struct kvm_lapic_irq *irq, unsigned long *dest_map);
+void kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
+ struct kvm_lapic_irq *irq,
+ unsigned long *dest_map);
int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state);
void kvm_vcpu_request_scan_ioapic(struct kvm *kvm);
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 25ab480..58d4538 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -65,10 +65,11 @@ inline static bool kvm_is_dm_lowest_prio(struct
kvm_lapic_irq *irq)
#endif
}
-int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
- struct kvm_lapic_irq *irq, unsigned long *dest_map)
+void kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
+ struct kvm_lapic_irq *irq,
+ unsigned long *dest_map)
{
- int i, r = -1;
+ int i;
struct kvm_vcpu *vcpu, *lowest = NULL;
if (irq->dest_mode == 0 && irq->dest_id == 0xff &&
@@ -77,8 +78,8 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct
kvm_lapic *src,
irq->delivery_mode = APIC_DM_FIXED;
}
- if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, &r, dest_map))
- return r;
+ if (kvm_irq_delivery_to_apic_fast(kvm, src, irq, dest_map))
+ return;
kvm_for_each_vcpu(i, vcpu, kvm) {
if (!kvm_apic_present(vcpu))
@@ -88,11 +89,9 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct
kvm_lapic *src,
irq->dest_id, irq->dest_mode))
continue;
- if (!kvm_is_dm_lowest_prio(irq)) {
- if (r < 0)
- r = 0;
- r += kvm_apic_set_irq(vcpu, irq, dest_map);
- } else if (kvm_lapic_enabled(vcpu)) {
+ if (!kvm_is_dm_lowest_prio(irq))
+ kvm_apic_set_irq(vcpu, irq, dest_map);
+ else if (kvm_lapic_enabled(vcpu)) {
if (!lowest)
lowest = vcpu;
else if (kvm_apic_compare_prio(vcpu, lowest) < 0)
@@ -101,9 +100,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct
kvm_lapic *src,
}
if (lowest)
- r = kvm_apic_set_irq(lowest, irq, dest_map);
-
- return r;
+ kvm_apic_set_irq(lowest, irq, dest_map);
}
static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
@@ -133,7 +130,8 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
kvm_set_msi_irq(e, &irq);
- return kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
+ kvm_irq_delivery_to_apic(kvm, NULL, &irq, NULL);
+ return 1;
}
@@ -141,12 +139,11 @@ static int kvm_set_msi_inatomic(struct
kvm_kernel_irq_routing_entry *e,
struct kvm *kvm)
{
struct kvm_lapic_irq irq;
- int r;
kvm_set_msi_irq(e, &irq);
- if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, &r, NULL))
- return r;
+ if (kvm_irq_delivery_to_apic_fast(kvm, NULL, &irq, NULL))
+ return 1;
else
return -EWOULDBLOCK;
}
--
1.7.3.4
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