Re: [PATCH v2 3/3] KVM: Non-atomic interrupt injection
On 07/21/2010 07:27 PM, Marcelo Tosatti wrote:
Also should undo vmx.rmode.* ?
Elaborate?
Undo vmx.rmode assignments on cancel_injection.
Hm. Doesn't vmx_complete_interrupts() have to do that anyway if an
injection fails?
Ah:
vmx_vcpu_run()
{
...
vmx->idt_vectoring_info = vmcs_read32(IDT_VECTORING_INFO_FIELD);
if (vmx->rmode.irq.pending)
fixup_rmode_irq(vmx);
...
vmx_complete_interrupts(vmx);
So I'll just move that bit into vmx_complete_interrupts. Good catch.
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Re: [PATCH v2 3/3] KVM: Non-atomic interrupt injection
On Wed, Jul 21, 2010 at 08:37:26AM +0300, Avi Kivity wrote:
> On 07/21/2010 03:55 AM, Marcelo Tosatti wrote:
> >
> >>--- a/arch/x86/kvm/x86.c
> >>+++ b/arch/x86/kvm/x86.c
> >>@@ -4709,6 +4709,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> >>if (unlikely(r))
> >>goto out;
> >>
> >>+ inject_pending_event(vcpu);
> >>+
> >>+ /* enable NMI/IRQ window open exits if needed */
> >>+ if (vcpu->arch.nmi_pending)
> >>+ kvm_x86_ops->enable_nmi_window(vcpu);
> >>+ else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> >>+ kvm_x86_ops->enable_irq_window(vcpu);
> >>+
> >>+ if (kvm_lapic_enabled(vcpu)) {
> >>+ update_cr8_intercept(vcpu);
> >>+ kvm_lapic_sync_to_vapic(vcpu);
> >>+ }
> >>+
> >>preempt_disable();
> >>
> >>kvm_x86_ops->prepare_guest_switch(vcpu);
> >>@@ -4727,23 +4740,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> >>smp_wmb();
> >>local_irq_enable();
> >>preempt_enable();
> >>+ kvm_x86_ops->cancel_injection(vcpu);
> >>r = 1;
> >>goto out;
> >>}
> >>
> >>- inject_pending_event(vcpu);
> >>-
> >>- /* enable NMI/IRQ window open exits if needed */
> >>- if (vcpu->arch.nmi_pending)
> >>- kvm_x86_ops->enable_nmi_window(vcpu);
> >>- else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> >>- kvm_x86_ops->enable_irq_window(vcpu);
> >>-
> >>- if (kvm_lapic_enabled(vcpu)) {
> >>- update_cr8_intercept(vcpu);
> >>- kvm_lapic_sync_to_vapic(vcpu);
> >>- }
> >>-
> >>srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
> >>
> >>kvm_guest_enter();
> >This breaks
> >
> >int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
> >{
> > struct kvm_lapic *apic = vcpu->arch.apic;
> > int highest_irr;
> >
> > /* This may race with setting of irr in __apic_accept_irq() and
> > * value returned may be wrong, but kvm_vcpu_kick() in
> > * __apic_accept_irq
> > * will cause vmexit immediately and the value will be
> > * recalculated
> > * on the next vmentry.
> > */
> >
> >(also valid for nmi_pending and PIC). Can't simply move
> >atomic_set(guest_mode, 1) in preemptible section as that would make it
> >possible for kvm_vcpu_kick to IPI stale vcpu->cpu.
>
> Right. Can fix by adding a kvm_make_request() to force the retry loop.
>
> >Also should undo vmx.rmode.* ?
>
> Elaborate?
Undo vmx.rmode assignments on cancel_injection.
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Re: [PATCH v2 3/3] KVM: Non-atomic interrupt injection
On 07/21/2010 03:55 AM, Marcelo Tosatti wrote:
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4709,6 +4709,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (unlikely(r))
goto out;
+ inject_pending_event(vcpu);
+
+ /* enable NMI/IRQ window open exits if needed */
+ if (vcpu->arch.nmi_pending)
+ kvm_x86_ops->enable_nmi_window(vcpu);
+ else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+ kvm_x86_ops->enable_irq_window(vcpu);
+
+ if (kvm_lapic_enabled(vcpu)) {
+ update_cr8_intercept(vcpu);
+ kvm_lapic_sync_to_vapic(vcpu);
+ }
+
preempt_disable();
kvm_x86_ops->prepare_guest_switch(vcpu);
@@ -4727,23 +4740,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
smp_wmb();
local_irq_enable();
preempt_enable();
+ kvm_x86_ops->cancel_injection(vcpu);
r = 1;
goto out;
}
- inject_pending_event(vcpu);
-
- /* enable NMI/IRQ window open exits if needed */
- if (vcpu->arch.nmi_pending)
- kvm_x86_ops->enable_nmi_window(vcpu);
- else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
- kvm_x86_ops->enable_irq_window(vcpu);
-
- if (kvm_lapic_enabled(vcpu)) {
- update_cr8_intercept(vcpu);
- kvm_lapic_sync_to_vapic(vcpu);
- }
-
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
kvm_guest_enter();
This breaks
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;
/* This may race with setting of irr in __apic_accept_irq() and
* value returned may be wrong, but kvm_vcpu_kick() in
* __apic_accept_irq
* will cause vmexit immediately and the value will be
* recalculated
* on the next vmentry.
*/
(also valid for nmi_pending and PIC). Can't simply move
atomic_set(guest_mode, 1) in preemptible section as that would make it
possible for kvm_vcpu_kick to IPI stale vcpu->cpu.
Right. Can fix by adding a kvm_make_request() to force the retry loop.
Also should undo vmx.rmode.* ?
Elaborate?
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
--
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Re: [PATCH v2 3/3] KVM: Non-atomic interrupt injection
On Tue, Jul 20, 2010 at 04:17:07PM +0300, Avi Kivity wrote:
> Change the interrupt injection code to work from preemptible, interrupts
> enabled context. This works by adding a ->cancel_injection() operation
> that undoes an injection in case we were not able to actually enter the guest
> (this condition could never happen with atomic injection).
>
> Signed-off-by: Avi Kivity
> ---
> arch/x86/include/asm/kvm_host.h |1 +
> arch/x86/kvm/svm.c | 12
> arch/x86/kvm/vmx.c | 11 +++
> arch/x86/kvm/x86.c | 27 ++-
> 4 files changed, 38 insertions(+), 13 deletions(-)
>
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -4709,6 +4709,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> if (unlikely(r))
> goto out;
>
> + inject_pending_event(vcpu);
> +
> + /* enable NMI/IRQ window open exits if needed */
> + if (vcpu->arch.nmi_pending)
> + kvm_x86_ops->enable_nmi_window(vcpu);
> + else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> + kvm_x86_ops->enable_irq_window(vcpu);
> +
> + if (kvm_lapic_enabled(vcpu)) {
> + update_cr8_intercept(vcpu);
> + kvm_lapic_sync_to_vapic(vcpu);
> + }
> +
> preempt_disable();
>
> kvm_x86_ops->prepare_guest_switch(vcpu);
> @@ -4727,23 +4740,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
> smp_wmb();
> local_irq_enable();
> preempt_enable();
> + kvm_x86_ops->cancel_injection(vcpu);
> r = 1;
> goto out;
> }
>
> - inject_pending_event(vcpu);
> -
> - /* enable NMI/IRQ window open exits if needed */
> - if (vcpu->arch.nmi_pending)
> - kvm_x86_ops->enable_nmi_window(vcpu);
> - else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
> - kvm_x86_ops->enable_irq_window(vcpu);
> -
> - if (kvm_lapic_enabled(vcpu)) {
> - update_cr8_intercept(vcpu);
> - kvm_lapic_sync_to_vapic(vcpu);
> - }
> -
> srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
>
> kvm_guest_enter();
This breaks
int kvm_lapic_find_highest_irr(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;
int highest_irr;
/* This may race with setting of irr in __apic_accept_irq() and
* value returned may be wrong, but kvm_vcpu_kick() in
* __apic_accept_irq
* will cause vmexit immediately and the value will be
* recalculated
* on the next vmentry.
*/
(also valid for nmi_pending and PIC). Can't simply move
atomic_set(guest_mode, 1) in preemptible section as that would make it
possible for kvm_vcpu_kick to IPI stale vcpu->cpu.
Also should undo vmx.rmode.* ?
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the body of a message to majord...@vger.kernel.org
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[PATCH v2 3/3] KVM: Non-atomic interrupt injection
Change the interrupt injection code to work from preemptible, interrupts
enabled context. This works by adding a ->cancel_injection() operation
that undoes an injection in case we were not able to actually enter the guest
(this condition could never happen with atomic injection).
Signed-off-by: Avi Kivity
---
arch/x86/include/asm/kvm_host.h |1 +
arch/x86/kvm/svm.c | 12
arch/x86/kvm/vmx.c | 11 +++
arch/x86/kvm/x86.c | 27 ++-
4 files changed, 38 insertions(+), 13 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 502e53f..5dd797c 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -505,6 +505,7 @@ struct kvm_x86_ops {
void (*queue_exception)(struct kvm_vcpu *vcpu, unsigned nr,
bool has_error_code, u32 error_code,
bool reinject);
+ void (*cancel_injection)(struct kvm_vcpu *vcpu);
int (*interrupt_allowed)(struct kvm_vcpu *vcpu);
int (*nmi_allowed)(struct kvm_vcpu *vcpu);
bool (*get_nmi_mask)(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 56c9b6b..46d068e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3135,6 +3135,17 @@ static void svm_complete_interrupts(struct vcpu_svm *svm)
}
}
+static void svm_cancel_injection(struct kvm_vcpu *vcpu)
+{
+ struct vcpu_svm *svm = to_svm(vcpu);
+ struct vmcb_control_area *control = &svm->vmcb->control;
+
+ control->exit_int_info = control->event_inj;
+ control->exit_int_info_err = control->event_inj_err;
+ control->event_inj = 0;
+ svm_complete_interrupts(svm);
+}
+
#ifdef CONFIG_X86_64
#define R "r"
#else
@@ -3493,6 +3504,7 @@ static struct kvm_x86_ops svm_x86_ops = {
.set_irq = svm_set_irq,
.set_nmi = svm_inject_nmi,
.queue_exception = svm_queue_exception,
+ .cancel_injection = svm_cancel_injection,
.interrupt_allowed = svm_interrupt_allowed,
.nmi_allowed = svm_nmi_allowed,
.get_nmi_mask = svm_get_nmi_mask,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 53b6fc0..72381b7 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -3906,6 +3906,16 @@ static void vmx_complete_interrupts(struct vcpu_vmx *vmx)
IDT_VECTORING_ERROR_CODE);
}
+static void vmx_cancel_injection(struct kvm_vcpu *vcpu)
+{
+ __vmx_complete_interrupts(to_vmx(vcpu),
+ vmcs_read32(VM_ENTRY_INTR_INFO_FIELD),
+ VM_ENTRY_INSTRUCTION_LEN,
+ VM_ENTRY_EXCEPTION_ERROR_CODE);
+
+ vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, 0);
+}
+
/*
* Failure to inject an interrupt should give us the information
* in IDT_VECTORING_INFO_FIELD. However, if the failure occurs
@@ -4360,6 +4370,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
.set_irq = vmx_inject_irq,
.set_nmi = vmx_inject_nmi,
.queue_exception = vmx_queue_exception,
+ .cancel_injection = vmx_cancel_injection,
.interrupt_allowed = vmx_interrupt_allowed,
.nmi_allowed = vmx_nmi_allowed,
.get_nmi_mask = vmx_get_nmi_mask,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 84bfb51..1040d3f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4709,6 +4709,19 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
if (unlikely(r))
goto out;
+ inject_pending_event(vcpu);
+
+ /* enable NMI/IRQ window open exits if needed */
+ if (vcpu->arch.nmi_pending)
+ kvm_x86_ops->enable_nmi_window(vcpu);
+ else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+ kvm_x86_ops->enable_irq_window(vcpu);
+
+ if (kvm_lapic_enabled(vcpu)) {
+ update_cr8_intercept(vcpu);
+ kvm_lapic_sync_to_vapic(vcpu);
+ }
+
preempt_disable();
kvm_x86_ops->prepare_guest_switch(vcpu);
@@ -4727,23 +4740,11 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
smp_wmb();
local_irq_enable();
preempt_enable();
+ kvm_x86_ops->cancel_injection(vcpu);
r = 1;
goto out;
}
- inject_pending_event(vcpu);
-
- /* enable NMI/IRQ window open exits if needed */
- if (vcpu->arch.nmi_pending)
- kvm_x86_ops->enable_nmi_window(vcpu);
- else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
- kvm_x86_ops->enable_irq_window(vcpu);
-
- if (kvm_lapic_enabled(vcpu)) {
- update_cr8_intercept(vcpu);
- kvm_lapic_sync_to_vapic(vcpu);
- }
-
srcu_read_unlock(&vcpu->kvm->srcu, vcpu->srcu_idx);
kvm_guest_enter();
--
1.7.1
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