Virtualization - May 2013 - [PATCH] virtio_pci: fix macro exported in uapi

macro VIRTIO_PCI_CONFIG except in the unlikely event userspace
actually has a structure with a field named msix_enabled.
Get the msix_enabled by value instead, to make it useful
for userspace.

Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
 drivers/virtio/virtio_pci.c     | 8 ++++----
 include/uapi/linux/virtio_pci.h | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index a7ce730..1bb6ff3 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -132,8 +132,8 @@ static void vp_get(struct virtio_device *vdev, unsigned
offset,
 		   void *buf, unsigned len)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	void __iomem *ioaddr = vp_dev->ioaddr +
-				VIRTIO_PCI_CONFIG(vp_dev) + offset;
+	void __iomem *ioaddr = vp_dev->ioaddr + offset +
+				VIRTIO_PCI_CONFIG(vp_dev->msix_enabled);
 	u8 *ptr = buf;
 	int i;
 
@@ -147,8 +147,8 @@ static void vp_set(struct virtio_device *vdev, unsigned
offset,
 		   const void *buf, unsigned len)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
-	void __iomem *ioaddr = vp_dev->ioaddr +
-				VIRTIO_PCI_CONFIG(vp_dev) + offset;
+	void __iomem *ioaddr = vp_dev->ioaddr + offset +
+				VIRTIO_PCI_CONFIG(vp_dev->msix_enabled);
 	const u8 *ptr = buf;
 	int i;
 
diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h
index ea66f3f..610c6c6 100644
--- a/include/uapi/linux/virtio_pci.h
+++ b/include/uapi/linux/virtio_pci.h
@@ -80,7 +80,7 @@
 
 /* The remaining space is defined by each driver as the per-driver
  * configuration space */
-#define VIRTIO_PCI_CONFIG(dev)		((dev)->msix_enabled ? 24 : 20)
+#define VIRTIO_PCI_CONFIG(msix_enabled)	((msix_enabled) ? 24 : 20)
 
 /* Virtio ABI version, this must match exactly */
 #define VIRTIO_PCI_ABI_VERSION		0
-- 
MST

"Michael S. Tsirkin" <mst at redhat.com>
writes:
> macro VIRTIO_PCI_CONFIG except in the unlikely event userspace
> actually has a structure with a field named msix_enabled.
> Get the msix_enabled by value instead, to make it useful
> for userspace.
>
> Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Macro still isn't usable, because userspace can't know whether it's
the
new or old.

We need to either remove it from UAPI, or rename it to
VIRTIO_PCI_CONFIG_OFF.

Cheers,
Rusty.

Rusty Russell <rusty at rustcorp.com.au> wrote:
> Macro still isn't usable, because userspace can't know whether
it's the
> new or old.
> 
> We need to either remove it from UAPI, or rename it to
> VIRTIO_PCI_CONFIG_OFF.
Surely, if userspace is using it as is, you can't remove it, rename it or
alter it?

David