[v5] vfio: Create dmabuf from multiple VFIO ranges and use it in virtio-gpu

[PATCH v5 09/12] vfio/device: Add a helper to lookup VFIODevice from memory region

Posted by Vivek Kasireddy 3 days, 22 hours ago

Instead of iterating over all QOM devices to find the VFIODevice
associated with a memory region, it is faster to just use the
vfio_device_list to lookup the VFIODevice.

Cc: Alex Williamson <alex@shazbot.org>
Cc: Cédric Le Goater <clg@redhat.com>
Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
---
 hw/vfio/device.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/hw/vfio/device.c b/hw/vfio/device.c
index 973fc35b59..ecb3581fcc 100644
--- a/hw/vfio/device.c
+++ b/hw/vfio/device.c
@@ -644,3 +644,26 @@ static VFIODeviceIOOps vfio_device_io_ops_ioctl = {
     .region_read = vfio_device_io_region_read,
     .region_write = vfio_device_io_region_write,
 };
+
+static bool vfio_device_lookup(struct iovec *iov, VFIODevice **vbasedevp,
+                               Error **errp)
+{
+    VFIODevice *vbasedev;
+    RAMBlock *first_rb;
+    ram_addr_t offset;
+
+    first_rb = qemu_ram_block_from_host(iov[0].iov_base, false, &offset);
+    if (!first_rb) {
+        error_setg(errp, "Could not find first ramblock\n");
+        return false;
+    }
+
+    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
+        if (vbasedev->dev == first_rb->mr->dev) {
+            *vbasedevp = vbasedev;
+            return true;
+        }
+    }
+    error_setg(errp, "No VFIO device found to create dmabuf from\n");
+    return false;
+}
-- 
2.50.1

Re: [PATCH v5 09/12] vfio/device: Add a helper to lookup VFIODevice from memory region

Posted by Cédric Le Goater 3 days, 16 hours ago

On 2/3/26 08:30, Vivek Kasireddy wrote:
> Instead of iterating over all QOM devices to find the VFIODevice
> associated with a memory region, it is faster to just use the
> vfio_device_list to lookup the VFIODevice.
> 
> Cc: Alex Williamson <alex@shazbot.org>
> Cc: Cédric Le Goater <clg@redhat.com>
> Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> ---
>   hw/vfio/device.c | 23 +++++++++++++++++++++++
>   1 file changed, 23 insertions(+)
> 
> diff --git a/hw/vfio/device.c b/hw/vfio/device.c
> index 973fc35b59..ecb3581fcc 100644
> --- a/hw/vfio/device.c
> +++ b/hw/vfio/device.c
> @@ -644,3 +644,26 @@ static VFIODeviceIOOps vfio_device_io_ops_ioctl = {
>       .region_read = vfio_device_io_region_read,
>       .region_write = vfio_device_io_region_write,
>   };
> +
> +static bool vfio_device_lookup(struct iovec *iov, VFIODevice **vbasedevp,
> +                               Error **errp)
> +{
> +    VFIODevice *vbasedev;
> +    RAMBlock *first_rb;
> +    ram_addr_t offset;
> +
> +    first_rb = qemu_ram_block_from_host(iov[0].iov_base, false, &offset);
> +    if (!first_rb) {
> +        error_setg(errp, "Could not find first ramblock\n");
> +        return false;
> +    }
> +
> +    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
> +        if (vbasedev->dev == first_rb->mr->dev) {
> +            *vbasedevp = vbasedev;
> +            return true;
> +        }
> +    }
> +    error_setg(errp, "No VFIO device found to create dmabuf from\n");
> +    return false;
> +}


This won't compile and break bisect. Please merge with the following patch.

Thanks,

C.

RE: [PATCH v5 09/12] vfio/device: Add a helper to lookup VFIODevice from memory region

Posted by Kasireddy, Vivek 3 days ago

Hi Cedric,

> Subject: Re: [PATCH v5 09/12] vfio/device: Add a helper to lookup
> VFIODevice from memory region
> 
> On 2/3/26 08:30, Vivek Kasireddy wrote:
> > Instead of iterating over all QOM devices to find the VFIODevice
> > associated with a memory region, it is faster to just use the
> > vfio_device_list to lookup the VFIODevice.
> >
> > Cc: Alex Williamson <alex@shazbot.org>
> > Cc: Cédric Le Goater <clg@redhat.com>
> > Signed-off-by: Vivek Kasireddy <vivek.kasireddy@intel.com>
> > ---
> >   hw/vfio/device.c | 23 +++++++++++++++++++++++
> >   1 file changed, 23 insertions(+)
> >
> > diff --git a/hw/vfio/device.c b/hw/vfio/device.c
> > index 973fc35b59..ecb3581fcc 100644
> > --- a/hw/vfio/device.c
> > +++ b/hw/vfio/device.c
> > @@ -644,3 +644,26 @@ static VFIODeviceIOOps
> vfio_device_io_ops_ioctl = {
> >       .region_read = vfio_device_io_region_read,
> >       .region_write = vfio_device_io_region_write,
> >   };
> > +
> > +static bool vfio_device_lookup(struct iovec *iov, VFIODevice
> **vbasedevp,
> > +                               Error **errp)
> > +{
> > +    VFIODevice *vbasedev;
> > +    RAMBlock *first_rb;
> > +    ram_addr_t offset;
> > +
> > +    first_rb = qemu_ram_block_from_host(iov[0].iov_base, false,
> &offset);
> > +    if (!first_rb) {
> > +        error_setg(errp, "Could not find first ramblock\n");
> > +        return false;
> > +    }
> > +
> > +    QLIST_FOREACH(vbasedev, &vfio_device_list, next) {
> > +        if (vbasedev->dev == first_rb->mr->dev) {
> > +            *vbasedevp = vbasedev;
> > +            return true;
> > +        }
> > +    }
> > +    error_setg(errp, "No VFIO device found to create dmabuf from\n");
> > +    return false;
> > +}
> 
> 
> This won't compile and break bisect. Please merge with the following
> patch.
Ok, I'll merge it with the next patch that adds vfio_device_create_dmabuf().

Thanks,
Vivek

> 
> Thanks,
> 
> C.