2015-04-21 17:01:41

by Paolo Bonzini

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Subject: [PATCH] KVM: x86: tweak types of fields in kvm_lapic_irq

Change to u16 if they only contain data in the low 16 bits.

Change the level field to bool, since we assign 1 sometimes, but
just mask icr_low with APIC_INT_ASSERT in apic_send_ipi.

Signed-off-by: Paolo Bonzini <[email protected]>
---
arch/x86/include/asm/kvm_host.h | 8 ++++----
arch/x86/kvm/lapic.c | 2 +-
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3a19e30f0be0..dc83b43d0850 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -689,10 +689,10 @@ struct msr_data {

struct kvm_lapic_irq {
u32 vector;
- u32 delivery_mode;
- u32 dest_mode;
- u32 level;
- u32 trig_mode;
+ u16 delivery_mode;
+ u16 dest_mode;
+ bool level;
+ u16 trig_mode;
u32 shorthand;
u32 dest_id;
};
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index abf165330881..ba585d0c42c5 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -914,7 +914,7 @@ static void apic_send_ipi(struct kvm_lapic *apic)
irq.vector = icr_low & APIC_VECTOR_MASK;
irq.delivery_mode = icr_low & APIC_MODE_MASK;
irq.dest_mode = icr_low & APIC_DEST_MASK;
- irq.level = icr_low & APIC_INT_ASSERT;
+ irq.level = (icr_low & APIC_INT_ASSERT) != 0;
irq.trig_mode = icr_low & APIC_INT_LEVELTRIG;
irq.shorthand = icr_low & APIC_SHORT_MASK;
if (apic_x2apic_mode(apic))
--
1.8.3.1


2015-04-22 09:35:49

by Radim Krčmář

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Subject: Re: [PATCH] KVM: x86: tweak types of fields in kvm_lapic_irq

2015-04-21 19:01+0200, Paolo Bonzini:
> Change to u16 if they only contain data in the low 16 bits.
>
> Change the level field to bool, since we assign 1 sometimes, but
> just mask icr_low with APIC_INT_ASSERT in apic_send_ipi.

Would be more consistent to change that assignment instead ...
If we dropped the idea that struct kvm_lapic_irq fields can be bitORed
to get the ICR, we could also easily change trig_mode/dest_mode to bool
level_trig/logical_dest. (I can do a followup patch.)

> Signed-off-by: Paolo Bonzini <[email protected]>
> ---
> arch/x86/include/asm/kvm_host.h | 8 ++++----
> arch/x86/kvm/lapic.c | 2 +-
> 2 files changed, 5 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 3a19e30f0be0..dc83b43d0850 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -689,10 +689,10 @@ struct msr_data {
>
> struct kvm_lapic_irq {
> u32 vector;

Vector can be u8.

> - u32 delivery_mode;
> - u32 dest_mode;
> - u32 level;
> - u32 trig_mode;
> + u16 delivery_mode;
> + u16 dest_mode;
> + bool level;
> + u16 trig_mode;

I'd prefer to have the u8 vector as well, but it works,
Reviewed-by: Radim Krčmář <[email protected]>

> u32 shorthand;
> u32 dest_id;
> };
> diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
> index abf165330881..ba585d0c42c5 100644
> --- a/arch/x86/kvm/lapic.c
> +++ b/arch/x86/kvm/lapic.c
> @@ -914,7 +914,7 @@ static void apic_send_ipi(struct kvm_lapic *apic)
> irq.vector = icr_low & APIC_VECTOR_MASK;
> irq.delivery_mode = icr_low & APIC_MODE_MASK;
> irq.dest_mode = icr_low & APIC_DEST_MASK;
> - irq.level = icr_low & APIC_INT_ASSERT;
> + irq.level = (icr_low & APIC_INT_ASSERT) != 0;
> irq.trig_mode = icr_low & APIC_INT_LEVELTRIG;
> irq.shorthand = icr_low & APIC_SHORT_MASK;
> if (apic_x2apic_mode(apic))
> --
> 1.8.3.1
>

2015-04-22 10:28:02

by Paolo Bonzini

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Subject: Re: [PATCH] KVM: x86: tweak types of fields in kvm_lapic_irq



On 22/04/2015 11:35, Radim Krčmář wrote:
> > Change the level field to bool, since we assign 1 sometimes, but
> > just mask icr_low with APIC_INT_ASSERT in apic_send_-ipi.
>
> Would be more consistent to change that assignment instead ...
> If we dropped the idea that struct kvm_lapic_irq fields can be bitORed
> to get the ICR, we could also easily change trig_mode/dest_mode to bool
> level_trig/logical_dest. (I can do a followup patch.)

Right, I thought of both. However, level is something that has an
obviously understandable meaning as a bool, while trig_mode/dest_mode as
you said have to be renamed as well.

You're right on the u8 type for vector, too. But I probably will end up
not committing this patch at all...

Paolo