* [PATCH] x86: let userspace inject interrupts into the local APIC
@ 2013-03-19 15:51 Paolo Bonzini
2013-03-19 18:13 ` Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2013-03-19 15:51 UTC (permalink / raw)
To: linux-kernel; +Cc: kvm
There is no way for userspace to inject interrupts into a VCPU's
local APIC, which is important in order to inject INITs coming from
the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
local APIC is used, so we can repurpose it. The shorthand destination
field must contain APIC_DEST_SELF, which has a double effect: first,
the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
enough; second, it ensures that the valid range of the irq field is
distinct in the userspace-APIC and kernel-APIC cases.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
Documentation/virtual/kvm/api.txt | 13 ++++++++++---
arch/x86/kvm/lapic.c | 20 +++++++++++++++-----
arch/x86/kvm/lapic.h | 1 +
arch/x86/kvm/x86.c | 6 +++---
4 files changed, 29 insertions(+), 11 deletions(-)
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index 4237c27..a69706b 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -396,8 +396,8 @@ Type: vcpu ioctl
Parameters: struct kvm_interrupt (in)
Returns: 0 on success, -1 on error
-Queues a hardware interrupt vector to be injected. This is only
-useful if in-kernel local APIC or equivalent is not used.
+Queues a hardware interrupt vector to be injected into either the VCPU
+or into the in-kernel local APIC or equivalent (if in use).
/* for KVM_INTERRUPT */
struct kvm_interrupt {
@@ -407,7 +407,14 @@ struct kvm_interrupt {
X86:
-Note 'irq' is an interrupt vector, not an interrupt pin or line.
+If the in-kernel local APIC is enabled, 'irq' is sent to the local APIC
+as if it were written to the ICR register, except that it is not reflected
+into ICR if the guest reads it. The destination (bits 18 and 19) must be
+set to APIC_DEST_SELF.
+
+If the in-kernel local APIC is disabled, 'irq' is an interrupt vector (not
+an interrupt pin or line) that is injected synchronously into the VCPU.
+
PPC:
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index a8e9369..efb67f7 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -826,12 +826,9 @@ void kvm_apic_set_eoi_accelerated(struct kvm_vcpu *vcpu, int vector)
}
EXPORT_SYMBOL_GPL(kvm_apic_set_eoi_accelerated);
-static void apic_send_ipi(struct kvm_lapic *apic)
+static void apic_send_ipi(struct kvm_lapic *apic, u32 icr_low, u32 icr_high)
{
- u32 icr_low = kvm_apic_get_reg(apic, APIC_ICR);
- u32 icr_high = kvm_apic_get_reg(apic, APIC_ICR2);
struct kvm_lapic_irq irq;
-
irq.vector = icr_low & APIC_VECTOR_MASK;
irq.delivery_mode = icr_low & APIC_MODE_MASK;
irq.dest_mode = icr_low & APIC_DEST_MASK;
@@ -855,6 +852,16 @@ static void apic_send_ipi(struct kvm_lapic *apic)
kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
}
+int kvm_lapic_ioctl_interrupt(struct kvm_vcpu *vcpu, u32 value)
+{
+ if ((value & APIC_SHORT_MASK) != APIC_DEST_SELF)
+ return -EINVAL;
+
+ apic_send_ipi(vcpu->arch.apic, value, 0);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(kvm_lapic_ioctl_interrupt);
+
static u32 apic_get_tmcct(struct kvm_lapic *apic)
{
ktime_t remaining;
@@ -1155,7 +1162,10 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
case APIC_ICR:
/* No delay here, so we always clear the pending bit */
apic_set_reg(apic, APIC_ICR, val & ~(1 << 12));
- apic_send_ipi(apic);
+ apic_send_ipi(apic,
+ kvm_apic_get_reg(apic, APIC_ICR),
+ kvm_apic_get_reg(apic, APIC_ICR2));
+
break;
case APIC_ICR2:
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 2c721b9..0631b5c 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -49,6 +49,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu);
u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu);
void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8);
void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu);
+int kvm_lapic_ioctl_interrupt(struct kvm_vcpu *vcpu, u32 value);
void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value);
u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu);
void kvm_apic_set_version(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 3e0a8ba..ab4a401 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2703,11 +2703,11 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
struct kvm_interrupt *irq)
{
- if (irq->irq >= KVM_NR_INTERRUPTS)
- return -EINVAL;
if (irqchip_in_kernel(vcpu->kvm))
- return -ENXIO;
+ return kvm_lapic_ioctl_interrupt(vcpu, irq->irq);
+ if (irq->irq >= KVM_NR_INTERRUPTS)
+ return -EINVAL;
kvm_queue_interrupt(vcpu, irq->irq, false);
kvm_make_request(KVM_REQ_EVENT, vcpu);
--
1.8.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: let userspace inject interrupts into the local APIC
2013-03-19 15:51 [PATCH] x86: let userspace inject interrupts into the local APIC Paolo Bonzini
@ 2013-03-19 18:13 ` Gleb Natapov
2013-03-19 18:39 ` Paolo Bonzini
0 siblings, 1 reply; 6+ messages in thread
From: Gleb Natapov @ 2013-03-19 18:13 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm
On Tue, Mar 19, 2013 at 04:51:13PM +0100, Paolo Bonzini wrote:
> There is no way for userspace to inject interrupts into a VCPU's
> local APIC, which is important in order to inject INITs coming from
> the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
> local APIC is used, so we can repurpose it. The shorthand destination
> field must contain APIC_DEST_SELF, which has a double effect: first,
> the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
> enough; second, it ensures that the valid range of the irq field is
> distinct in the userspace-APIC and kernel-APIC cases.
>
Init coming from triggering INIT# line should not be modeled as INIT coming from
APIC. In fact INIT cannot be send using SELF shorthand. If APIC code
will be fixed to check for that this code will break.
> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> ---
> Documentation/virtual/kvm/api.txt | 13 ++++++++++---
> arch/x86/kvm/lapic.c | 20 +++++++++++++++-----
> arch/x86/kvm/lapic.h | 1 +
> arch/x86/kvm/x86.c | 6 +++---
> 4 files changed, 29 insertions(+), 11 deletions(-)
>
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 4237c27..a69706b 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -396,8 +396,8 @@ Type: vcpu ioctl
> Parameters: struct kvm_interrupt (in)
> Returns: 0 on success, -1 on error
>
> -Queues a hardware interrupt vector to be injected. This is only
> -useful if in-kernel local APIC or equivalent is not used.
> +Queues a hardware interrupt vector to be injected into either the VCPU
> +or into the in-kernel local APIC or equivalent (if in use).
>
> /* for KVM_INTERRUPT */
> struct kvm_interrupt {
> @@ -407,7 +407,14 @@ struct kvm_interrupt {
>
> X86:
>
> -Note 'irq' is an interrupt vector, not an interrupt pin or line.
> +If the in-kernel local APIC is enabled, 'irq' is sent to the local APIC
> +as if it were written to the ICR register, except that it is not reflected
> +into ICR if the guest reads it. The destination (bits 18 and 19) must be
> +set to APIC_DEST_SELF.
> +
> +If the in-kernel local APIC is disabled, 'irq' is an interrupt vector (not
> +an interrupt pin or line) that is injected synchronously into the VCPU.
> +
>
> PPC:
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index a8e9369..efb67f7 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -826,12 +826,9 @@ void kvm_apic_set_eoi_accelerated(struct kvm_vcpu *vcpu, int vector)
> }
> EXPORT_SYMBOL_GPL(kvm_apic_set_eoi_accelerated);
>
> -static void apic_send_ipi(struct kvm_lapic *apic)
> +static void apic_send_ipi(struct kvm_lapic *apic, u32 icr_low, u32 icr_high)
> {
> - u32 icr_low = kvm_apic_get_reg(apic, APIC_ICR);
> - u32 icr_high = kvm_apic_get_reg(apic, APIC_ICR2);
> struct kvm_lapic_irq irq;
> -
> irq.vector = icr_low & APIC_VECTOR_MASK;
> irq.delivery_mode = icr_low & APIC_MODE_MASK;
> irq.dest_mode = icr_low & APIC_DEST_MASK;
> @@ -855,6 +852,16 @@ static void apic_send_ipi(struct kvm_lapic *apic)
> kvm_irq_delivery_to_apic(apic->vcpu->kvm, apic, &irq);
> }
>
> +int kvm_lapic_ioctl_interrupt(struct kvm_vcpu *vcpu, u32 value)
> +{
> + if ((value & APIC_SHORT_MASK) != APIC_DEST_SELF)
> + return -EINVAL;
> +
> + apic_send_ipi(vcpu->arch.apic, value, 0);
> + return 0;
> +}
> +EXPORT_SYMBOL_GPL(kvm_lapic_ioctl_interrupt);
> +
> static u32 apic_get_tmcct(struct kvm_lapic *apic)
> {
> ktime_t remaining;
> @@ -1155,7 +1162,10 @@ static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
> case APIC_ICR:
> /* No delay here, so we always clear the pending bit */
> apic_set_reg(apic, APIC_ICR, val & ~(1 << 12));
> - apic_send_ipi(apic);
> + apic_send_ipi(apic,
> + kvm_apic_get_reg(apic, APIC_ICR),
> + kvm_apic_get_reg(apic, APIC_ICR2));
> +
> break;
>
> case APIC_ICR2:
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 2c721b9..0631b5c 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -49,6 +49,7 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu);
> u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu);
> void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8);
> void kvm_lapic_set_eoi(struct kvm_vcpu *vcpu);
> +int kvm_lapic_ioctl_interrupt(struct kvm_vcpu *vcpu, u32 value);
> void kvm_lapic_set_base(struct kvm_vcpu *vcpu, u64 value);
> u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu);
> void kvm_apic_set_version(struct kvm_vcpu *vcpu);
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 3e0a8ba..ab4a401 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -2703,11 +2703,11 @@ static int kvm_vcpu_ioctl_set_lapic(struct kvm_vcpu *vcpu,
> static int kvm_vcpu_ioctl_interrupt(struct kvm_vcpu *vcpu,
> struct kvm_interrupt *irq)
> {
> - if (irq->irq >= KVM_NR_INTERRUPTS)
> - return -EINVAL;
> if (irqchip_in_kernel(vcpu->kvm))
> - return -ENXIO;
> + return kvm_lapic_ioctl_interrupt(vcpu, irq->irq);
>
> + if (irq->irq >= KVM_NR_INTERRUPTS)
> + return -EINVAL;
> kvm_queue_interrupt(vcpu, irq->irq, false);
> kvm_make_request(KVM_REQ_EVENT, vcpu);
>
> --
> 1.8.1.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: let userspace inject interrupts into the local APIC
2013-03-19 18:13 ` Gleb Natapov
@ 2013-03-19 18:39 ` Paolo Bonzini
2013-03-19 18:50 ` Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2013-03-19 18:39 UTC (permalink / raw)
To: Gleb Natapov; +Cc: linux-kernel, kvm
Il 19/03/2013 19:13, Gleb Natapov ha scritto:
>> > There is no way for userspace to inject interrupts into a VCPU's
>> > local APIC, which is important in order to inject INITs coming from
>> > the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
>> > local APIC is used, so we can repurpose it. The shorthand destination
>> > field must contain APIC_DEST_SELF, which has a double effect: first,
>> > the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
>> > enough; second, it ensures that the valid range of the irq field is
>> > distinct in the userspace-APIC and kernel-APIC cases.
>> >
> Init coming from triggering INIT# line should not be modeled as INIT coming from
> APIC.
Then Jan's patch was wrong, and INIT should not have been an apic event
(perhaps SIPI should).
> In fact INIT cannot be send using SELF shorthand.
Where does the SDM say that?
Paolo
> If APIC code will be fixed to check for that this code will break.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: let userspace inject interrupts into the local APIC
2013-03-19 18:39 ` Paolo Bonzini
@ 2013-03-19 18:50 ` Gleb Natapov
2013-03-19 20:22 ` Paolo Bonzini
0 siblings, 1 reply; 6+ messages in thread
From: Gleb Natapov @ 2013-03-19 18:50 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm
On Tue, Mar 19, 2013 at 07:39:24PM +0100, Paolo Bonzini wrote:
> Il 19/03/2013 19:13, Gleb Natapov ha scritto:
> >> > There is no way for userspace to inject interrupts into a VCPU's
> >> > local APIC, which is important in order to inject INITs coming from
> >> > the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
> >> > local APIC is used, so we can repurpose it. The shorthand destination
> >> > field must contain APIC_DEST_SELF, which has a double effect: first,
> >> > the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
> >> > enough; second, it ensures that the valid range of the irq field is
> >> > distinct in the userspace-APIC and kernel-APIC cases.
> >> >
> > Init coming from triggering INIT# line should not be modeled as INIT coming from
> > APIC.
>
> Then Jan's patch was wrong, and INIT should not have been an apic event
> (perhaps SIPI should).
>
If it goes through APIC it is. Also the problem with reusing KVM_INTERRUPT is
that it is synchronous interface but INIT# is asynchronous. Shouldn't be a big
deal though.
> > In fact INIT cannot be send using SELF shorthand.
>
> Where does the SDM say that?
>
Table 10-3.
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: let userspace inject interrupts into the local APIC
2013-03-19 18:50 ` Gleb Natapov
@ 2013-03-19 20:22 ` Paolo Bonzini
2013-03-20 10:56 ` Gleb Natapov
0 siblings, 1 reply; 6+ messages in thread
From: Paolo Bonzini @ 2013-03-19 20:22 UTC (permalink / raw)
To: Gleb Natapov; +Cc: linux-kernel, kvm
Il 19/03/2013 19:50, Gleb Natapov ha scritto:
> On Tue, Mar 19, 2013 at 07:39:24PM +0100, Paolo Bonzini wrote:
>> Il 19/03/2013 19:13, Gleb Natapov ha scritto:
>>>>> There is no way for userspace to inject interrupts into a VCPU's
>>>>> local APIC, which is important in order to inject INITs coming from
>>>>> the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
>>>>> local APIC is used, so we can repurpose it. The shorthand destination
>>>>> field must contain APIC_DEST_SELF, which has a double effect: first,
>>>>> the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
>>>>> enough; second, it ensures that the valid range of the irq field is
>>>>> distinct in the userspace-APIC and kernel-APIC cases.
>>>>>
>>> Init coming from triggering INIT# line should not be modeled as INIT coming from
>>> APIC.
>>
>> Then Jan's patch was wrong, and INIT should not have been an apic event
>> (perhaps SIPI should).
>>
> If it goes through APIC it is.
Ok, I'll extract KVM_APIC_INIT handling into a separate function and
call it synchronously from KVM_INTERRUPT, with irq = -1
(KVM_INTERRUPT_INIT, similar to PPC's values of irq).
KVM_INTERRUPT_INIT will be accessible even with in-kernel irqchip.
>>> In fact INIT cannot be send using SELF shorthand.
>>
>> Where does the SDM say that?
>>
> Table 10-3.
Yeah, table 10-6 and 10-7 here.
Paolo
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] x86: let userspace inject interrupts into the local APIC
2013-03-19 20:22 ` Paolo Bonzini
@ 2013-03-20 10:56 ` Gleb Natapov
0 siblings, 0 replies; 6+ messages in thread
From: Gleb Natapov @ 2013-03-20 10:56 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: linux-kernel, kvm
On Tue, Mar 19, 2013 at 09:22:33PM +0100, Paolo Bonzini wrote:
> Il 19/03/2013 19:50, Gleb Natapov ha scritto:
> > On Tue, Mar 19, 2013 at 07:39:24PM +0100, Paolo Bonzini wrote:
> >> Il 19/03/2013 19:13, Gleb Natapov ha scritto:
> >>>>> There is no way for userspace to inject interrupts into a VCPU's
> >>>>> local APIC, which is important in order to inject INITs coming from
> >>>>> the chipset. KVM_INTERRUPT is currently disabled when the in-kernel
> >>>>> local APIC is used, so we can repurpose it. The shorthand destination
> >>>>> field must contain APIC_DEST_SELF, which has a double effect: first,
> >>>>> the ICR2 register is not used and the 32-bit field of KVM_INTERRUPT is
> >>>>> enough; second, it ensures that the valid range of the irq field is
> >>>>> distinct in the userspace-APIC and kernel-APIC cases.
> >>>>>
> >>> Init coming from triggering INIT# line should not be modeled as INIT coming from
> >>> APIC.
> >>
> >> Then Jan's patch was wrong, and INIT should not have been an apic event
> >> (perhaps SIPI should).
> >>
> > If it goes through APIC it is.
>
> Ok, I'll extract KVM_APIC_INIT handling into a separate function and
> call it synchronously from KVM_INTERRUPT, with irq = -1
> (KVM_INTERRUPT_INIT, similar to PPC's values of irq).
> KVM_INTERRUPT_INIT will be accessible even with in-kernel irqchip.
>
Why should it be accessible with in-kernel irqchip? The only valid value
for mp_state is RUNNING with userspace irqchip. We even validate it in
kvm_arch_vcpu_ioctl_set_mpstate() now.
> >>> In fact INIT cannot be send using SELF shorthand.
> >>
> >> Where does the SDM say that?
> >>
> > Table 10-3.
>
> Yeah, table 10-6 and 10-7 here.
>
Hmm, somebody needs to update SDM. Mine is from January 2013.
--
Gleb.
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2013-03-20 10:57 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2013-03-19 15:51 [PATCH] x86: let userspace inject interrupts into the local APIC Paolo Bonzini
2013-03-19 18:13 ` Gleb Natapov
2013-03-19 18:39 ` Paolo Bonzini
2013-03-19 18:50 ` Gleb Natapov
2013-03-19 20:22 ` Paolo Bonzini
2013-03-20 10:56 ` Gleb Natapov
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