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Date: Wed, 3 Apr 2024 11:57:50 +0200
From: Stefano Garzarella <sgarzare@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: linux-kernel@vger.kernel.org, 
	Arnaldo Carvalho de Melo <acme@kernel.org>, Namhyung Kim <namhyung@kernel.org>, 
	Zhu Lingshan <lingshan.zhu@intel.com>, Jason Wang <jasowang@redhat.com>, 
	Eugenio =?utf-8?B?UMOpcmV6?= <eperezma@redhat.com>, kvm@vger.kernel.org, virtualization@lists.linux.dev, 
	netdev@vger.kernel.org, Adrian Hunter <adrian.hunter@intel.com>, 
	Ian Rogers <irogers@google.com>, Jiri Olsa <jolsa@kernel.org>, 
	Kan Liang <kan.liang@linux.intel.com>
Subject: Re: [PATCH] vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE
Message-ID: <qxnpqulknydwdaqn2uangg6ke6pzeo46us2xnqw37ll6m4te5m@ounccq6x7sto>
References: <41c1c5489688abe5bfef9f7cf15584e3fb872ac5.1712092759.git.mst@redhat.com>
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On Tue, Apr 02, 2024 at 05:21:39PM -0400, Michael S. Tsirkin wrote:
>VDPA_GET_VRING_SIZE by mistake uses the already occupied
>ioctl # 0x80 and we never noticed - it happens to work
>because the direction and size are different, but confuses
>tools such as perf which like to look at just the number,
>and breaks the extra robustness of the ioctl numbering macros.
>
>To fix, sort the entries and renumber the ioctl - not too late
>since it wasn't in any released kernels yet.
>
>Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
>Reported-by: Namhyung Kim <namhyung@kernel.org>
>Fixes: 1496c47065f9 ("vhost-vdpa: uapi to support reporting per vq size")
>Cc: "Zhu Lingshan" <lingshan.zhu@intel.com>
>Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
>---
>
>Build tested only - userspace patches using this will have to adjust.
>I will merge this in a week or so unless I hear otherwise,
>and afterwards perf can update there header.

Fortunately, we haven't released any kernels with this yet, right?
(other than v6.9-rc*)

LGTM:

Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>

>
> include/uapi/linux/vhost.h | 15 ++++++++-------
> 1 file changed, 8 insertions(+), 7 deletions(-)
>
>diff --git a/include/uapi/linux/vhost.h b/include/uapi/linux/vhost.h
>index bea697390613..b95dd84eef2d 100644
>--- a/include/uapi/linux/vhost.h
>+++ b/include/uapi/linux/vhost.h
>@@ -179,12 +179,6 @@
> /* Get the config size */
> #define VHOST_VDPA_GET_CONFIG_SIZE	_IOR(VHOST_VIRTIO, 0x79, __u32)
>
>-/* Get the count of all virtqueues */
>-#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)
>-
>-/* Get the number of virtqueue groups. */
>-#define VHOST_VDPA_GET_GROUP_NUM	_IOR(VHOST_VIRTIO, 0x81, __u32)
>-
> /* Get the number of address spaces. */
> #define VHOST_VDPA_GET_AS_NUM		_IOR(VHOST_VIRTIO, 0x7A, unsigned int)
>
>@@ -228,10 +222,17 @@
> #define VHOST_VDPA_GET_VRING_DESC_GROUP	_IOWR(VHOST_VIRTIO, 0x7F,	\
> 					      struct vhost_vring_state)
>
>+
>+/* Get the count of all virtqueues */
>+#define VHOST_VDPA_GET_VQS_COUNT	_IOR(VHOST_VIRTIO, 0x80, __u32)
>+
>+/* Get the number of virtqueue groups. */
>+#define VHOST_VDPA_GET_GROUP_NUM	_IOR(VHOST_VIRTIO, 0x81, __u32)
>+
> /* Get the queue size of a specific virtqueue.
>  * userspace set the vring index in vhost_vring_state.index
>  * kernel set the queue size in vhost_vring_state.num
>  */
>-#define VHOST_VDPA_GET_VRING_SIZE	_IOWR(VHOST_VIRTIO, 0x80,	\
>+#define VHOST_VDPA_GET_VRING_SIZE	_IOWR(VHOST_VIRTIO, 0x82,	\
> 					      struct vhost_vring_state)
> #endif
>-- 
>MST
>
>