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

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

[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.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 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

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

[Radim Krčmář]

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 <pbonzini@redhat.com>
> ---
>  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 <rkrcmar@redhat.com>

>  	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
> 

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

[Paolo Bonzini]

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