2020-03-27 06:25:19

by Wanpeng Li

Subject: [PATCH 1/2] KVM: X86: Filter the broadcast dest for IPI fastpath

From: Wanpeng Li <[email protected]>

Except destination shorthand, a destination value 0xffffffff is used to
broadcast interrupts, let's also filter this for single target IPI fastpath.

Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/lapic.c | 3 ---
arch/x86/kvm/lapic.h | 3 +++
arch/x86/kvm/x86.c | 3 ++-
3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index a38f1a8..88929b1 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -59,9 +59,6 @@
#define MAX_APIC_VECTOR 256
#define APIC_VECTORS_PER_REG 32

-#define APIC_BROADCAST 0xFF
-#define X2APIC_BROADCAST 0xFFFFFFFFul
-
static bool lapic_timer_advance_dynamic __read_mostly;
#define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100 /* clock cycles */
#define LAPIC_TIMER_ADVANCE_ADJUST_MAX 10000 /* clock cycles */
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index bc76860..25b77a6 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -17,6 +17,9 @@
#define APIC_BUS_CYCLE_NS 1
#define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS)

+#define APIC_BROADCAST 0xFF
+#define X2APIC_BROADCAST 0xFFFFFFFFul
+
enum lapic_mode {
LAPIC_MODE_DISABLED = 0,
LAPIC_MODE_INVALID = X2APIC_ENABLE,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c4bb7d8..495709f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1559,7 +1559,8 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data

if (((data & APIC_SHORT_MASK) == APIC_DEST_NOSHORT) &&
((data & APIC_DEST_MASK) == APIC_DEST_PHYSICAL) &&
- ((data & APIC_MODE_MASK) == APIC_DM_FIXED)) {
+ ((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
+ ((u32)(data >> 32) != X2APIC_BROADCAST)) {

data &= ~(1 << 12);
kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));
--
2.7.4

2020-03-27 06:25:21

by Wanpeng Li

Subject: [PATCH 2/2] KVM: LAPIC: Don't need to clear IPI delivery status for x2apic

From: Wanpeng Li <[email protected]>

IPI delivery status field is not present for x2apic, don't need
to clear IPI delivery status for x2apic.

Signed-off-by: Wanpeng Li <[email protected]>
---
arch/x86/kvm/lapic.c | 3 ++-
arch/x86/kvm/x86.c | 1 -
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 88929b1..f6d69e2 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1942,7 +1942,8 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
}
case APIC_ICR:
/* No delay here, so we always clear the pending bit */
- val &= ~(1 << 12);
+ if (!apic_x2apic_mode(apic))
+ val &= ~(1 << 12);
kvm_apic_send_ipi(apic, val, kvm_lapic_get_reg(apic, APIC_ICR2));
kvm_lapic_set_reg(apic, APIC_ICR, val);
break;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 495709f..6ced0e1 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1562,7 +1562,6 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data
((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
((u32)(data >> 32) != X2APIC_BROADCAST)) {

- data &= ~(1 << 12);
kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));
kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR2, (u32)(data >> 32));
kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR, (u32)data);
--
2.7.4

2020-03-27 09:01:47

by Vitaly Kuznetsov

Subject: Re: [PATCH 1/2] KVM: X86: Filter the broadcast dest for IPI fastpath

Wanpeng Li <[email protected]> writes:

> From: Wanpeng Li <[email protected]>
>
> Except destination shorthand, a destination value 0xffffffff is used to
> broadcast interrupts, let's also filter this for single target IPI fastpath.
>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> arch/x86/kvm/lapic.c | 3 ---
> arch/x86/kvm/lapic.h | 3 +++
> arch/x86/kvm/x86.c | 3 ++-
> 3 files changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index a38f1a8..88929b1 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -59,9 +59,6 @@
> #define MAX_APIC_VECTOR 256
> #define APIC_VECTORS_PER_REG 32
>
> -#define APIC_BROADCAST 0xFF
> -#define X2APIC_BROADCAST 0xFFFFFFFFul
> -
> static bool lapic_timer_advance_dynamic __read_mostly;
> #define LAPIC_TIMER_ADVANCE_ADJUST_MIN 100 /* clock cycles */
> #define LAPIC_TIMER_ADVANCE_ADJUST_MAX 10000 /* clock cycles */
> diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
> index bc76860..25b77a6 100644
> --- a/arch/x86/kvm/lapic.h
> +++ b/arch/x86/kvm/lapic.h
> @@ -17,6 +17,9 @@
> #define APIC_BUS_CYCLE_NS 1
> #define APIC_BUS_FREQUENCY (1000000000ULL / APIC_BUS_CYCLE_NS)
>
> +#define APIC_BROADCAST 0xFF
> +#define X2APIC_BROADCAST 0xFFFFFFFFul
> +
> enum lapic_mode {
> LAPIC_MODE_DISABLED = 0,
> LAPIC_MODE_INVALID = X2APIC_ENABLE,
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index c4bb7d8..495709f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1559,7 +1559,8 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data
>
> if (((data & APIC_SHORT_MASK) == APIC_DEST_NOSHORT) &&
> ((data & APIC_DEST_MASK) == APIC_DEST_PHYSICAL) &&
> - ((data & APIC_MODE_MASK) == APIC_DM_FIXED)) {
> + ((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
> + ((u32)(data >> 32) != X2APIC_BROADCAST)) {
>
> data &= ~(1 << 12);
> kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));

Reviewed-by: Vitaly Kuznetsov <[email protected]>

--
Vitaly

2020-03-27 09:08:40

by Vitaly Kuznetsov

Subject: Re: [PATCH 2/2] KVM: LAPIC: Don't need to clear IPI delivery status for x2apic

Wanpeng Li <[email protected]> writes:

> From: Wanpeng Li <[email protected]>
>
> IPI delivery status field is not present for x2apic, don't need
> to clear IPI delivery status for x2apic.
>
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> arch/x86/kvm/lapic.c | 3 ++-
> arch/x86/kvm/x86.c | 1 -
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index 88929b1..f6d69e2 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -1942,7 +1942,8 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
> }
> case APIC_ICR:
> /* No delay here, so we always clear the pending bit */

'Always' in the comment above now reads a bit odd, I'd suggest modifying
it to 'Immediately clear Delivery Status field in xAPIC mode' - or just
drop it altogeter.

> - val &= ~(1 << 12);
> + if (!apic_x2apic_mode(apic))
> + val &= ~(1 << 12);
> kvm_apic_send_ipi(apic, val, kvm_lapic_get_reg(apic, APIC_ICR2));
> kvm_lapic_set_reg(apic, APIC_ICR, val);
> break;
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index 495709f..6ced0e1 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -1562,7 +1562,6 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data
> ((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
> ((u32)(data >> 32) != X2APIC_BROADCAST)) {
>
> - data &= ~(1 << 12);
> kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));
> kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR2, (u32)(data >> 32));
> kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR, (u32)data);

Reviewed-by: Vitaly Kuznetsov <[email protected]>

--
Vitaly

2020-03-27 09:27:52

by Wanpeng Li

Subject: Re: [PATCH 2/2] KVM: LAPIC: Don't need to clear IPI delivery status for x2apic

On Fri, 27 Mar 2020 at 17:07, Vitaly Kuznetsov <[email protected]> wrote:
>
> Wanpeng Li <[email protected]> writes:
>
> > From: Wanpeng Li <[email protected]>
> >
> > IPI delivery status field is not present for x2apic, don't need
> > to clear IPI delivery status for x2apic.
> >
> > Signed-off-by: Wanpeng Li <[email protected]>
> > ---
> > arch/x86/kvm/lapic.c | 3 ++-
> > arch/x86/kvm/x86.c | 1 -
> > 2 files changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> > index 88929b1..f6d69e2 100644
> > --- a/arch/x86/kvm/lapic.c
> > +++ b/arch/x86/kvm/lapic.c
> > @@ -1942,7 +1942,8 @@ int kvm_lapic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
> > }
> > case APIC_ICR:
> > /* No delay here, so we always clear the pending bit */
>
> 'Always' in the comment above now reads a bit odd, I'd suggest modifying
> it to 'Immediately clear Delivery Status field in xAPIC mode' - or just
> drop it altogeter.

Thank you for your review, I guess Paolo can do it when apply.

Wanpeng

>
> > - val &= ~(1 << 12);
> > + if (!apic_x2apic_mode(apic))
> > + val &= ~(1 << 12);
> > kvm_apic_send_ipi(apic, val, kvm_lapic_get_reg(apic, APIC_ICR2));
> > kvm_lapic_set_reg(apic, APIC_ICR, val);
> > break;
> > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> > index 495709f..6ced0e1 100644
> > --- a/arch/x86/kvm/x86.c
> > +++ b/arch/x86/kvm/x86.c
> > @@ -1562,7 +1562,6 @@ static int handle_fastpath_set_x2apic_icr_irqoff(struct kvm_vcpu *vcpu, u64 data
> > ((data & APIC_MODE_MASK) == APIC_DM_FIXED) &&
> > ((u32)(data >> 32) != X2APIC_BROADCAST)) {
> >
> > - data &= ~(1 << 12);
> > kvm_apic_send_ipi(vcpu->arch.apic, (u32)data, (u32)(data >> 32));
> > kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR2, (u32)(data >> 32));
> > kvm_lapic_set_reg(vcpu->arch.apic, APIC_ICR, (u32)data);
>
> Reviewed-by: Vitaly Kuznetsov <[email protected]>
>
> --
> Vitaly
>