[v2,3/7] KVM: irqchip: convey devid to kvm_set_msi
diff mbox

Message ID 1436430137-24205-4-git-send-email-eric.auger@linaro.org
State New
Headers show

Commit Message

Eric Auger July 9, 2015, 8:22 a.m. UTC
on ARM, a devid field is populated in kvm_msi struct in case the
flag is set to KVM_MSI_VALID_DEVID. Let's populate the corresponding
kvm_kernel_irq_routing_entry devid field and set the msi type to
KVM_IRQ_ROUTING_EXTENDED_MSI.

Signed-off-by: Eric Auger <eric.auger@linaro.org>
---
 virt/kvm/irqchip.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

Comments

Andre Przywara July 10, 2015, 11:15 p.m. UTC | #1
On 09/07/15 09:22, Eric Auger wrote:
> on ARM, a devid field is populated in kvm_msi struct in case the
> flag is set to KVM_MSI_VALID_DEVID. Let's populate the corresponding
> kvm_kernel_irq_routing_entry devid field and set the msi type to
> KVM_IRQ_ROUTING_EXTENDED_MSI.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> ---
>  virt/kvm/irqchip.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
> index 21c1424..e678f8a 100644
> --- a/virt/kvm/irqchip.c
> +++ b/virt/kvm/irqchip.c
> @@ -72,9 +72,17 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
>  {
>  	struct kvm_kernel_irq_routing_entry route;
>  
> -	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
> +	if (!irqchip_in_kernel(kvm))
>  		return -EINVAL;
>  
> +	if (msi->flags & KVM_MSI_VALID_DEVID) {
> +		route.devid = msi->devid;
> +		route.type = KVM_IRQ_ROUTING_EXTENDED_MSI;
> +	} else if (!msi->flags)
> +		return -EINVAL;

I think we get away without using the extended type on the kernel side.
Within the kernel we don't have an ABI that we have to stick to forever,
so we can simplify things by re-using the existing type (no need to
check for both MSI types later).
So we always set the device ID, the only code that looks at it later is
the ITS emulation anyway, any other code path simply ignores that.

To be honest I am not 100% sure that is actually better, but I had
hacked it in a way where I didn't need it.
Also have a look at the other comments in the following patches for
clarification.

Cheers,
Andre.


> +
> +	/* historically the route.type was not set */
> +
>  	route.msi.address_lo = msi->address_lo;
>  	route.msi.address_hi = msi->address_hi;
>  	route.msi.data = msi->data;
> 

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Pavel Fedin July 17, 2015, 7:27 a.m. UTC | #2
> -----Original Message-----
> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Eric Auger
> Sent: Thursday, July 09, 2015 11:22 AM
> To: eric.auger@st.com; eric.auger@linaro.org; linux-arm-kernel@lists.infradead.org;
> marc.zyngier@arm.com; christoffer.dall@linaro.org; kvmarm@lists.cs.columbia.edu;
> kvm@vger.kernel.org
> Cc: patches@linaro.org; andre.przywara@arm.com; p.fedin@samsung.com; pbonzini@redhat.com
> Subject: [PATCH v2 3/7] KVM: irqchip: convey devid to kvm_set_msi
> 
> on ARM, a devid field is populated in kvm_msi struct in case the
> flag is set to KVM_MSI_VALID_DEVID. Let's populate the corresponding
> kvm_kernel_irq_routing_entry devid field and set the msi type to
> KVM_IRQ_ROUTING_EXTENDED_MSI.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> ---
>  virt/kvm/irqchip.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
> index 21c1424..e678f8a 100644
> --- a/virt/kvm/irqchip.c
> +++ b/virt/kvm/irqchip.c
> @@ -72,9 +72,17 @@ int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
>  {
>  	struct kvm_kernel_irq_routing_entry route;
> 
> -	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
> +	if (!irqchip_in_kernel(kvm))
>  		return -EINVAL;
> 
> +	if (msi->flags & KVM_MSI_VALID_DEVID) {
> +		route.devid = msi->devid;
> +		route.type = KVM_IRQ_ROUTING_EXTENDED_MSI;
> +	} else if (!msi->flags)
> +		return -EINVAL;

 Did you mean "if (msg->flags)" here (inverted condition)?

> +
> +	/* historically the route.type was not set */
> +
>  	route.msi.address_lo = msi->address_lo;
>  	route.msi.address_hi = msi->address_hi;
>  	route.msi.data = msi->data;
> --
> 1.9.1

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia

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Paolo Bonzini July 17, 2015, 10:09 a.m. UTC | #3
On 17/07/2015 09:27, Pavel Fedin wrote:
>> > +	} else if (!msi->flags)
>> > +		return -EINVAL;
>  Did you mean "if (msg->flags)" here (inverted condition)?

Indeed, and also you need { } around the return for the QEMU coding
standard.

Paolo

>> > +
>> > +	/* historically the route.type was not set */
>> > +
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Pavel Fedin July 17, 2015, 10:21 a.m. UTC | #4
Hello!

> >> > +	} else if (!msi->flags)
> >> > +		return -EINVAL;
> >  Did you mean "if (msg->flags)" here (inverted condition)?
> 
> Indeed, and also you need { } around the return for the QEMU coding
> standard.

 It's kernel and not qemu :)

Kind regards,
Pavel Fedin
Expert Engineer
Samsung Electronics Research center Russia

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Eric Auger July 18, 2015, 6:39 p.m. UTC | #5
On 07/17/2015 12:21 PM, Pavel Fedin wrote:
>  Hello!
> 
>>>>> +	} else if (!msi->flags)
>>>>> +		return -EINVAL;
>>>  Did you mean "if (msg->flags)" here (inverted condition)?
Yes thanks for spotting this.

Thanks

Eric
>>
>> Indeed, and also you need { } around the return for the QEMU coding
>> standard.
> 
>  It's kernel and not qemu :)
> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 

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Patch
diff mbox

diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 21c1424..e678f8a 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -72,9 +72,17 @@  int kvm_send_userspace_msi(struct kvm *kvm, struct kvm_msi *msi)
 {
 	struct kvm_kernel_irq_routing_entry route;
 
-	if (!irqchip_in_kernel(kvm) || msi->flags != 0)
+	if (!irqchip_in_kernel(kvm))
 		return -EINVAL;
 
+	if (msi->flags & KVM_MSI_VALID_DEVID) {
+		route.devid = msi->devid;
+		route.type = KVM_IRQ_ROUTING_EXTENDED_MSI;
+	} else if (!msi->flags)
+		return -EINVAL;
+
+	/* historically the route.type was not set */
+
 	route.msi.address_lo = msi->address_lo;
 	route.msi.address_hi = msi->address_hi;
 	route.msi.data = msi->data;