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Date: Wed, 20 Jan 2016 09:42:56 +0800
From: Feng Wu <feng.wu@...el.com>
To: pbonzini@...hat.com, rkrcmar@...hat.com
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
Feng Wu <feng.wu@...el.com>
Subject: [PATCH v3 3/4] KVM: x86: Add lowest-priority support for vt-d posted-interrupts
Use vector-hashing to deliver lowest-priority interrupts for
VT-d posted-interrupts. This patch extends kvm_intr_is_single_vcpu()
to support lowest-priority handling.
Signed-off-by: Feng Wu <feng.wu@...el.com>
---
v3:
- Remove unnecessary check in fast irq delivery patch
- print a error message only once for each guest when we find hardware
disabled LAPIC during interrupt injection.
arch/x86/include/asm/kvm_host.h | 4 +--
arch/x86/kvm/irq_comm.c | 8 +++---
arch/x86/kvm/lapic.c | 59 +++++++++++++++++++++++++++++++++++------
arch/x86/kvm/lapic.h | 4 +--
arch/x86/kvm/vmx.c | 2 +-
5 files changed, 60 insertions(+), 17 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 5054810..ce5a2ea 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1316,8 +1316,8 @@ int x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa, u32 size);
bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu);
bool kvm_vcpu_is_bsp(struct kvm_vcpu *vcpu);
-bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
- struct kvm_vcpu **dest_vcpu);
+bool kvm_intr_can_posting(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu);
void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
struct kvm_lapic_irq *irq);
diff --git a/arch/x86/kvm/irq_comm.c b/arch/x86/kvm/irq_comm.c
index 062e907..75cd02b 100644
--- a/arch/x86/kvm/irq_comm.c
+++ b/arch/x86/kvm/irq_comm.c
@@ -300,13 +300,13 @@ out:
return r;
}
-bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
- struct kvm_vcpu **dest_vcpu)
+bool kvm_intr_can_posting(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu)
{
int i, r = 0;
struct kvm_vcpu *vcpu;
- if (kvm_intr_is_single_vcpu_fast(kvm, irq, dest_vcpu))
+ if (kvm_intr_can_posting_fast(kvm, irq, dest_vcpu))
return true;
kvm_for_each_vcpu(i, vcpu, kvm) {
@@ -325,7 +325,7 @@ bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
return r == 1;
}
-EXPORT_SYMBOL_GPL(kvm_intr_is_single_vcpu);
+EXPORT_SYMBOL_GPL(kvm_intr_can_posting);
#define IOAPIC_ROUTING_ENTRY(irq) \
{ .gsi = irq, .type = KVM_IRQ_ROUTING_IRQCHIP, \
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e1a449da..d22e87e 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -800,7 +800,22 @@ out:
return ret;
}
-bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
+/*
+ * This routine tries to handler interrupts in posted mode, here is how
+ * it deals with different cases:
+ * - For single-destination interrupts, handle it in posted mode
+ * - Else if vector hashing is enabled and it is a lowest-priority
+ * interrupt, handle it in posted mode and use the following mechanism
+ * to find the destinaiton vCPU.
+ * 1. For lowest-priority interrupts, store all the possible
+ * destination vCPUs in an array.
+ * 2. Use "guest vector % max number of destination vCPUs" to find
+ * the right destination vCPU in the array for the lowest-priority
+ * interrupt.
+ * - Otherwise, use remapped mode to inject the interrupt.
+ */
+
+bool kvm_intr_can_posting_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
struct kvm_vcpu **dest_vcpu)
{
struct kvm_apic_map *map;
@@ -841,16 +856,44 @@ bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
if (cid >= ARRAY_SIZE(map->logical_map))
goto out;
- for_each_set_bit(i, &bitmap, 16) {
- dst = map->logical_map[cid][i];
- if (++r == 2)
+ if (kvm_vector_hashing_enabled() &&
+ kvm_lowest_prio_delivery(irq)) {
+ int idx = 0;
+ unsigned int dest_vcpus = 0;
+
+ dest_vcpus = hweight16(bitmap);
+ if (dest_vcpus == 0)
goto out;
- }
- if (dst && kvm_apic_present(dst->vcpu))
+ idx = kvm_vector_2_index(irq->vector, dest_vcpus,
+ &bitmap, 16);
+
+ /*
+ * We may find a hardware disabled LAPIC here, if that
+ * is the case, print out a error message once for each
+ * guest and return
+ */
+ dst = map->logical_map[cid][idx-1];
+ if (!dst && (kvm->arch.disabled_lapic_found == 0)) {
+ kvm->arch.disabled_lapic_found = 1;
+ printk(KERN_ERR
+ "Disabled LAPIC found during irq injection\n");
+ goto out;
+ }
+
*dest_vcpu = dst->vcpu;
- else
- goto out;
+ } else {
+ for_each_set_bit(i, &bitmap, 16) {
+ dst = map->logical_map[cid][i];
+ if (++r == 2)
+ goto out;
+ }
+
+ if (dst && kvm_apic_present(dst->vcpu))
+ *dest_vcpu = dst->vcpu;
+ else
+ goto out;
+ }
}
ret = true;
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index d864601..6145939 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -173,8 +173,8 @@ bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
void wait_lapic_expire(struct kvm_vcpu *vcpu);
-bool kvm_intr_is_single_vcpu_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
- struct kvm_vcpu **dest_vcpu);
+bool kvm_intr_can_posting_fast(struct kvm *kvm, struct kvm_lapic_irq *irq,
+ struct kvm_vcpu **dest_vcpu);
int kvm_vector_2_index(u32 vector, u32 dest_vcpus,
const unsigned long *bitmap, u32 bitmap_size);
#endif
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 13d14d4..b909ea1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -10764,7 +10764,7 @@ static int vmx_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
*/
kvm_set_msi_irq(e, &irq);
- if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) {
+ if (!kvm_intr_can_posting(kvm, &irq, &vcpu)) {
/*
* Make sure the IRTE is in remapped mode if
* we don't handle it in posted mode.
--
2.1.0
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