[Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts

Alistair Francis posted 6 patches 6 years, 11 months ago
There is a newer version of this series
[Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Alistair Francis 6 years, 11 months ago
Increase the number of interrupts to match the HiFive Unleashed board.

Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
---
 include/hw/riscv/virt.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
index 91163d6cbf..7cb2742070 100644
--- a/include/hw/riscv/virt.h
+++ b/include/hw/riscv/virt.h
@@ -45,7 +45,7 @@ enum {
     UART0_IRQ = 10,
     VIRTIO_IRQ = 1, /* 1 to 8 */
     VIRTIO_COUNT = 8,
-    VIRTIO_NDEV = 10
+    VIRTIO_NDEV = 0x35
 };
 
 enum {
-- 
2.19.1


Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Logan Gunthorpe 6 years, 11 months ago

On 2018-11-21 10:02 a.m., Alistair Francis wrote:
> Increase the number of interrupts to match the HiFive Unleashed board.
> 
> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> ---
>  include/hw/riscv/virt.h | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
> index 91163d6cbf..7cb2742070 100644
> --- a/include/hw/riscv/virt.h
> +++ b/include/hw/riscv/virt.h
> @@ -45,7 +45,7 @@ enum {
>      UART0_IRQ = 10,
>      VIRTIO_IRQ = 1, /* 1 to 8 */
>      VIRTIO_COUNT = 8,
> -    VIRTIO_NDEV = 10
> +    VIRTIO_NDEV = 0x35

Why 0x35? Based on the PCI patch we are using only 36 interrupts, not 53...

Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Alistair Francis 6 years, 11 months ago
On Wed, Nov 21, 2018 at 9:58 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>
>
>
> On 2018-11-21 10:02 a.m., Alistair Francis wrote:
> > Increase the number of interrupts to match the HiFive Unleashed board.
> >
> > Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> > ---
> >  include/hw/riscv/virt.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
> > index 91163d6cbf..7cb2742070 100644
> > --- a/include/hw/riscv/virt.h
> > +++ b/include/hw/riscv/virt.h
> > @@ -45,7 +45,7 @@ enum {
> >      UART0_IRQ = 10,
> >      VIRTIO_IRQ = 1, /* 1 to 8 */
> >      VIRTIO_COUNT = 8,
> > -    VIRTIO_NDEV = 10
> > +    VIRTIO_NDEV = 0x35
>
> Why 0x35? Based on the PCI patch we are using only 36 interrupts, not 53...

This is just for future proofing. There is no reason to set the number
lower then the number of interrupts we have, now hopefully this won't
keep churning every time we add a device.

Alistair

>
> Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Logan Gunthorpe 6 years, 11 months ago

On 2018-11-21 11:17 a.m., Alistair Francis wrote:
> On Wed, Nov 21, 2018 at 9:58 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>>
>>
>>
>> On 2018-11-21 10:02 a.m., Alistair Francis wrote:
>>> Increase the number of interrupts to match the HiFive Unleashed board.
>>>
>>> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
>>> ---
>>>  include/hw/riscv/virt.h | 2 +-
>>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
>>> index 91163d6cbf..7cb2742070 100644
>>> --- a/include/hw/riscv/virt.h
>>> +++ b/include/hw/riscv/virt.h
>>> @@ -45,7 +45,7 @@ enum {
>>>      UART0_IRQ = 10,
>>>      VIRTIO_IRQ = 1, /* 1 to 8 */
>>>      VIRTIO_COUNT = 8,
>>> -    VIRTIO_NDEV = 10
>>> +    VIRTIO_NDEV = 0x35
>>
>> Why 0x35? Based on the PCI patch we are using only 36 interrupts, not 53...
> 
> This is just for future proofing. There is no reason to set the number
> lower then the number of interrupts we have, now hopefully this won't
> keep churning every time we add a device.

Makes sense. Still 53 is an odd number.

Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Alistair Francis 6 years, 11 months ago
On Wed, Nov 21, 2018 at 10:45 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>
>
>
> On 2018-11-21 11:17 a.m., Alistair Francis wrote:
> > On Wed, Nov 21, 2018 at 9:58 AM Logan Gunthorpe <logang@deltatee.com> wrote:
> >>
> >>
> >>
> >> On 2018-11-21 10:02 a.m., Alistair Francis wrote:
> >>> Increase the number of interrupts to match the HiFive Unleashed board.
> >>>
> >>> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
> >>> ---
> >>>  include/hw/riscv/virt.h | 2 +-
> >>>  1 file changed, 1 insertion(+), 1 deletion(-)
> >>>
> >>> diff --git a/include/hw/riscv/virt.h b/include/hw/riscv/virt.h
> >>> index 91163d6cbf..7cb2742070 100644
> >>> --- a/include/hw/riscv/virt.h
> >>> +++ b/include/hw/riscv/virt.h
> >>> @@ -45,7 +45,7 @@ enum {
> >>>      UART0_IRQ = 10,
> >>>      VIRTIO_IRQ = 1, /* 1 to 8 */
> >>>      VIRTIO_COUNT = 8,
> >>> -    VIRTIO_NDEV = 10
> >>> +    VIRTIO_NDEV = 0x35
> >>
> >> Why 0x35? Based on the PCI patch we are using only 36 interrupts, not 53...
> >
> > This is just for future proofing. There is no reason to set the number
> > lower then the number of interrupts we have, now hopefully this won't
> > keep churning every time we add a device.
>
> Makes sense. Still 53 is an odd number.

Agreed. It's the same number as the last interrupt in the QEMU SiFive
U machine. So that is where it came from.

Alistair

>
> Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Logan Gunthorpe 6 years, 11 months ago

On 2018-11-21 11:49 a.m., Alistair Francis wrote:
> Agreed. It's the same number as the last interrupt in the QEMU SiFive
> U machine. So that is where it came from.

Ok, can we have a comment for that?

Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Alistair Francis 6 years, 11 months ago
On Wed, Nov 21, 2018 at 10:56 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>
>
>
> On 2018-11-21 11:49 a.m., Alistair Francis wrote:
> > Agreed. It's the same number as the last interrupt in the QEMU SiFive
> > U machine. So that is where it came from.
>
> Ok, can we have a comment for that?

I don't think we really need a comment. It's just a made up number. It
just has to be higher then the actual number of used interrupts. It
can be changed in the future if required.

Alistair

>
> Logan

Re: [Qemu-devel] [PATCH for-3.2 v7 1/6] hw/riscv/virt: Increase the number of interrupts
Posted by Logan Gunthorpe 6 years, 11 months ago

On 2018-11-21 11:59 a.m., Alistair Francis wrote:
> On Wed, Nov 21, 2018 at 10:56 AM Logan Gunthorpe <logang@deltatee.com> wrote:
>>
>>
>>
>> On 2018-11-21 11:49 a.m., Alistair Francis wrote:
>>> Agreed. It's the same number as the last interrupt in the QEMU SiFive
>>> U machine. So that is where it came from.
>>
>> Ok, can we have a comment for that?
> 
> I don't think we really need a comment. It's just a made up number. It
> just has to be higher then the actual number of used interrupts. It
> can be changed in the future if required.

If it's confusing to me it'll be confusing to others reading it. At
least put something in the commit log describing the choice of number
and why it's not important...

Logan