Do not return true from kvm_apic_has_events, and consequently from
kvm_vcpu_has_events, if the vCPU is not going to process an INIT.
Signed-off-by: Paolo Bonzini <[email protected]>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/i8259.c | 2 +-
arch/x86/kvm/lapic.h | 2 +-
arch/x86/kvm/x86.c | 5 +++++
arch/x86/kvm/x86.h | 5 -----
5 files changed, 8 insertions(+), 7 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 293ff678fff5..1ce4ebc41118 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -2042,6 +2042,7 @@ void __user *__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_vcpu_latch_init(struct kvm_vcpu *vcpu);
bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
struct kvm_vcpu **dest_vcpu);
diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
index e1bb6218bb96..177555eea54e 100644
--- a/arch/x86/kvm/i8259.c
+++ b/arch/x86/kvm/i8259.c
@@ -29,9 +29,9 @@
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/bitops.h>
-#include "irq.h"
+#include <linux/kvm_host.h>
-#include <linux/kvm_host.h>
+#include "irq.h"
#include "trace.h"
#define pr_pic_unimpl(fmt, ...) \
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 117a46df5cc1..12577ddccdfc 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -225,7 +225,7 @@ static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
{
- return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events;
+ return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events && !kvm_vcpu_latch_init(vcpu);
}
static inline bool kvm_lowest_prio_delivery(struct kvm_lapic_irq *irq)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 0f9f24793b8a..5e9358ea112b 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12529,6 +12529,11 @@ static inline bool kvm_guest_apic_has_interrupt(struct kvm_vcpu *vcpu)
static_call(kvm_x86_guest_apic_has_interrupt)(vcpu));
}
+bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu)
+{
+ return is_smm(vcpu) || static_call(kvm_x86_apic_init_signal_blocked)(vcpu);
+}
+
static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
{
if (!list_empty_careful(&vcpu->async_pf.done))
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 1926d2cb8e79..c333e7cf933a 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -267,11 +267,6 @@ static inline bool kvm_check_has_quirk(struct kvm *kvm, u64 quirk)
return !(kvm->arch.disabled_quirks & quirk);
}
-static inline bool kvm_vcpu_latch_init(struct kvm_vcpu *vcpu)
-{
- return is_smm(vcpu) || static_call(kvm_x86_apic_init_signal_blocked)(vcpu);
-}
-
void kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip);
u64 get_kvmclock_ns(struct kvm *kvm);
--
2.31.1
On Thu, Aug 11, 2022, Paolo Bonzini wrote:
> Do not return true from kvm_apic_has_events, and consequently from
> kvm_vcpu_has_events, if the vCPU is not going to process an INIT.
>
> Signed-off-by: Paolo Bonzini <[email protected]>
> ---
> arch/x86/include/asm/kvm_host.h | 1 +
> arch/x86/kvm/i8259.c | 2 +-
> arch/x86/kvm/lapic.h | 2 +-
> arch/x86/kvm/x86.c | 5 +++++
> arch/x86/kvm/x86.h | 5 -----
> 5 files changed, 8 insertions(+), 7 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 293ff678fff5..1ce4ebc41118 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -2042,6 +2042,7 @@ void __user *__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_vcpu_latch_init(struct kvm_vcpu *vcpu);
>
> bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
> struct kvm_vcpu **dest_vcpu);
> diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> index e1bb6218bb96..177555eea54e 100644
> --- a/arch/x86/kvm/i8259.c
> +++ b/arch/x86/kvm/i8259.c
> @@ -29,9 +29,9 @@
> #include <linux/mm.h>
> #include <linux/slab.h>
> #include <linux/bitops.h>
> -#include "irq.h"
> +#include <linux/kvm_host.h>
>
> -#include <linux/kvm_host.h>
> +#include "irq.h"
> #include "trace.h"
>
> #define pr_pic_unimpl(fmt, ...) \
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index 117a46df5cc1..12577ddccdfc 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -225,7 +225,7 @@ static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
>
> static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
> {
> - return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events;
> + return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events && !kvm_vcpu_latch_init(vcpu);
Blech, the kvm_apic_has_events() name is awful (as is pending_events), e.g. it
really should be kvm_apic_has_pending_sipi_or_init().
To avoid the odd kvm_vcpu_latch_init() declaration and the long line above, what
if we open code this in kvm_vcpu_has_events() like we do for NMI, SMI, etc...?
And as follow-up, I would love to rename kvm_vcpu_latch_init() => kvm_vcpu_init_blocked(),
kvm_apic_has_events(), and pending_events.
E.g. for this patch just do:
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 9f11b505cbee..559900736a71 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -12533,7 +12533,8 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
if (!list_empty_careful(&vcpu->async_pf.done))
return true;
- if (kvm_apic_has_events(vcpu))
+ /* comment explaning that SIPIs are dropped in this case. */
+ if (kvm_apic_has_events(vcpu) && !kvm_vcpu_latch_init(vcpu))
return true;
if (vcpu->arch.pv.pv_unhalted)
On Wed, 2022-08-17 at 00:07 +0000, Sean Christopherson wrote:
> On Thu, Aug 11, 2022, Paolo Bonzini wrote:
> > Do not return true from kvm_apic_has_events, and consequently from
> > kvm_vcpu_has_events, if the vCPU is not going to process an INIT.
> >
> > Signed-off-by: Paolo Bonzini <[email protected]>
> > ---
> > arch/x86/include/asm/kvm_host.h | 1 +
> > arch/x86/kvm/i8259.c | 2 +-
> > arch/x86/kvm/lapic.h | 2 +-
> > arch/x86/kvm/x86.c | 5 +++++
> > arch/x86/kvm/x86.h | 5 -----
> > 5 files changed, 8 insertions(+), 7 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> > index 293ff678fff5..1ce4ebc41118 100644
> > --- a/arch/x86/include/asm/kvm_host.h
> > +++ b/arch/x86/include/asm/kvm_host.h
> > @@ -2042,6 +2042,7 @@ void __user *__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_vcpu_latch_init(struct kvm_vcpu *vcpu);
> >
> > bool kvm_intr_is_single_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
> > struct kvm_vcpu **dest_vcpu);
> > diff --git a/arch/x86/kvm/i8259.c b/arch/x86/kvm/i8259.c
> > index e1bb6218bb96..177555eea54e 100644
> > --- a/arch/x86/kvm/i8259.c
> > +++ b/arch/x86/kvm/i8259.c
> > @@ -29,9 +29,9 @@
> > #include <linux/mm.h>
> > #include <linux/slab.h>
> > #include <linux/bitops.h>
> > -#include "irq.h"
> > +#include <linux/kvm_host.h>
> >
> > -#include <linux/kvm_host.h>
> > +#include "irq.h"
> > #include "trace.h"
> >
> > #define pr_pic_unimpl(fmt, ...) \
> > diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> > index 117a46df5cc1..12577ddccdfc 100644
> > --- a/arch/x86/kvm/lapic.h
> > +++ b/arch/x86/kvm/lapic.h
> > @@ -225,7 +225,7 @@ static inline bool kvm_vcpu_apicv_active(struct kvm_vcpu *vcpu)
> >
> > static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
> > {
> > - return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events;
> > + return lapic_in_kernel(vcpu) && vcpu->arch.apic->pending_events && !kvm_vcpu_latch_init(vcpu);
>
> Blech, the kvm_apic_has_events() name is awful (as is pending_events), e.g. it
> really should be kvm_apic_has_pending_sipi_or_init().
110% agree.
>
> To avoid the odd kvm_vcpu_latch_init() declaration and the long line above, what
> if we open code this in kvm_vcpu_has_events() like we do for NMI, SMI, etc...?
>
> And as follow-up, I would love to rename kvm_vcpu_latch_init() => kvm_vcpu_init_blocked(),
> kvm_apic_has_events(), and pending_events.
>
> E.g. for this patch just do:
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 9f11b505cbee..559900736a71 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -12533,7 +12533,8 @@ static inline bool kvm_vcpu_has_events(struct kvm_vcpu *vcpu)
> if (!list_empty_careful(&vcpu->async_pf.done))
> return true;
>
> - if (kvm_apic_has_events(vcpu))
> + /* comment explaning that SIPIs are dropped in this case. */
> + if (kvm_apic_has_events(vcpu) && !kvm_vcpu_latch_init(vcpu))
> return true;
I personally don't know if I prefer this or the original patch.
>
> if (vcpu->arch.pv.pv_unhalted)
>
While reviwing this, I noticed that we have this code:
static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
/*
* TODO: Last condition latch INIT signals on vCPU when
* vCPU is in guest-mode and vmcb12 defines intercept on INIT.
* To properly emulate the INIT intercept,
* svm_check_nested_events() should call nested_svm_vmexit()
* if an INIT signal is pending.
*/
return !gif_set(svm) ||
(vmcb_is_intercept(&svm->vmcb->control, INTERCEPT_INIT));
}
Is this workaround still needed? svm_check_nested_events does check the apic's INIT/SIPI status.
Currently the '.apic_init_signal_blocked' is called from kvm_vcpu_latch_init which itself is
currently called from kvm_vcpu_latch_init which happens after we would vmexit if INIT is intercepted by nested
hypervisor.
Best regards,
Maxim Levitsky
On 8/17/22 16:11, Maxim Levitsky wrote:
>
> While reviwing this, I noticed that we have this code:
>
>
> static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu)
> {
> struct vcpu_svm *svm = to_svm(vcpu);
>
> /*
> * TODO: Last condition latch INIT signals on vCPU when
> * vCPU is in guest-mode and vmcb12 defines intercept on INIT.
> * To properly emulate the INIT intercept,
> * svm_check_nested_events() should call nested_svm_vmexit()
> * if an INIT signal is pending.
> */
> return !gif_set(svm) ||
> (vmcb_is_intercept(&svm->vmcb->control, INTERCEPT_INIT));
> }
>
> Is this workaround still needed? svm_check_nested_events does check
> the apic's INIT/SIPI status.
>
> Currently the '.apic_init_signal_blocked' is called from
> kvm_vcpu_latch_init which itself is currently called from
> kvm_vcpu_latch_init which happens after we would vmexit if INIT is
> intercepted by nested hypervisor.
No, it shouldn't be needed anymore.
Paolo