2022-11-10 06:19:04

by Xianting Tian

Subject: [PATCH] virtio_pci: use PAGE_SIZE for pci vring align

As the comments of VIRTIO_PCI_VRING_ALIGN shows, we should use
PAGE_SZIE not the hard code 4096.

Signed-off-by: Xianting Tian <[email protected]>
---
include/uapi/linux/virtio_pci.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index f703afc7ad31..ed5f678c682b 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -90,7 +90,7 @@

/* The alignment to use between consumer and producer parts of vring.
* x86 pagesize again. */
-#define VIRTIO_PCI_VRING_ALIGN 4096
+#define VIRTIO_PCI_VRING_ALIGN PAGE_SIZE

#endif /* VIRTIO_PCI_NO_LEGACY */

--
2.17.1

2022-11-10 06:33:02

by Jason Wang

Subject: Re: [PATCH] virtio_pci: use PAGE_SIZE for pci vring align

On Thu, Nov 10, 2022 at 2:14 PM Xianting Tian
<[email protected]> wrote:
>
> As the comments of VIRTIO_PCI_VRING_ALIGN shows, we should use
> PAGE_SZIE not the hard code 4096.
>
> Signed-off-by: Xianting Tian <[email protected]>
> ---
> include/uapi/linux/virtio_pci.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index f703afc7ad31..ed5f678c682b 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -90,7 +90,7 @@
>
> /* The alignment to use between consumer and producer parts of vring.
> * x86 pagesize again. */

See the comment above, PAGE_SIZE varies among archs.

Thanks

> -#define VIRTIO_PCI_VRING_ALIGN 4096
> +#define VIRTIO_PCI_VRING_ALIGN PAGE_SIZE
>
> #endif /* VIRTIO_PCI_NO_LEGACY */
>
> --
> 2.17.1
>

2022-11-10 07:17:38

by Michael S. Tsirkin

Subject: Re: [PATCH] virtio_pci: use PAGE_SIZE for pci vring align

On Thu, Nov 10, 2022 at 02:11:11PM +0800, Xianting Tian wrote:
> As the comments of VIRTIO_PCI_VRING_ALIGN shows, we should use
> PAGE_SZIE not the hard code 4096.
>
> Signed-off-by: Xianting Tian <[email protected]>


where does it show this?
what is the problem you are trying to solve?
PAGE_SIZE is generally not valid in uapi

> ---
> include/uapi/linux/virtio_pci.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
> index f703afc7ad31..ed5f678c682b 100644
> --- a/include/uapi/linux/virtio_pci.h
> +++ b/include/uapi/linux/virtio_pci.h
> @@ -90,7 +90,7 @@
>
> /* The alignment to use between consumer and producer parts of vring.
> * x86 pagesize again. */
> -#define VIRTIO_PCI_VRING_ALIGN 4096
> +#define VIRTIO_PCI_VRING_ALIGN PAGE_SIZE
>
> #endif /* VIRTIO_PCI_NO_LEGACY */
>
> --
> 2.17.1