Re: [Qemu-devel] [PATCH v2 1/3] vfio/display: add edid support.

[Alex Williamson]

On Wed, 20 Feb 2019 09:47:51 +0100
Gerd Hoffmann <address@hidden> wrote:

> This patch adds EDID support to the vfio display (aka vgpu) code.
> When supported by the mdev driver qemu will generate a EDID blob
> and pass it on using the new vfio edid region.  The EDID blob will
> be updated on UI changes (i.e. window resize), so the guest can
> adapt.

What are the requirements to enable this resizing feature?  I grabbed
the gvt-next-2019-02-01 branch and my ever expanding qemu:commandline
now looks like this:

  <qemu:commandline>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.x-igd-opregion=on'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.ramfb=on'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.driver=vfio-pci-nohotplug'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.xres=1600'/>
    <qemu:arg value='-set'/>
    <qemu:arg value='device.hostdev0.yres=900'/>
  </qemu:commandline>

Other relevant sections:

    <graphics type='spice'>
      <listen type='none'/>
      <gl enable='yes' rendernode='/dev/dri/by-path/pci-0000:00:02.0-render'/>
    </graphics>
    <video>
      <model type='none'/>
      <alias name='video0'/>
    </video>
    <hostdev mode='subsystem' type='mdev' managed='no' model='vfio-pci' 
display='on'>
      <source>
        <address uuid='0b2d768f-95ac-4c7e-a20e-dc002b7381fd'/>
      </source>
      <alias name='hostdev0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' 
function='0x0'/>
    </hostdev>

The 1600x900 is used, which is great, but neither virt-manager nor
virt-viewer are giving me any automatic resizing as this seems to
suggest it should.

One nit and one bug below.  Thanks,

Alex

> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  include/hw/vfio/vfio-common.h |   3 +
>  hw/vfio/display.c             | 127 
> ++++++++++++++++++++++++++++++++++++++++++
>  hw/vfio/trace-events          |   7 +++
>  3 files changed, 137 insertions(+)
> 
> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h
> index 7624c9f511..5f7f709b95 100644
> --- a/include/hw/vfio/vfio-common.h
> +++ b/include/hw/vfio/vfio-common.h
> @@ -148,6 +148,9 @@ typedef struct VFIODMABuf {
>  typedef struct VFIODisplay {
>      QemuConsole *con;
>      RAMFBState *ramfb;
> +    struct vfio_region_info *edid_info;
> +    struct vfio_region_gfx_edid *edid_regs;
> +    uint8_t *edid_blob;
>      struct {
>          VFIORegion buffer;
>          DisplaySurface *surface;
> diff --git a/hw/vfio/display.c b/hw/vfio/display.c
> index dead30e626..ed2eb19ea3 100644
> --- a/hw/vfio/display.c
> +++ b/hw/vfio/display.c
> @@ -15,15 +15,139 @@
>  #include <sys/ioctl.h>
>  
>  #include "sysemu/sysemu.h"
> +#include "hw/display/edid.h"
>  #include "ui/console.h"
>  #include "qapi/error.h"
>  #include "pci.h"
> +#include "trace.h"
>  
>  #ifndef DRM_PLANE_TYPE_PRIMARY
>  # define DRM_PLANE_TYPE_PRIMARY 1
>  # define DRM_PLANE_TYPE_CURSOR  2
>  #endif
>  
> +#define pread_field(_fd, _reg, _ptr, _fld)                              \
> +    if (sizeof(_ptr->_fld) !=                                           \
> +        pread(_fd, &(_ptr->_fld), sizeof(_ptr->_fld),                   \
> +              _reg->offset + offsetof(typeof(*_ptr), _fld)))            \
> +        goto err;
> +#define pwrite_field(_fd, _reg, _ptr, _fld)                             \
> +    if (sizeof(_ptr->_fld) !=                                           \
> +        pwrite(_fd, &(_ptr->_fld), sizeof(_ptr->_fld),                  \
> +               _reg->offset + offsetof(typeof(*_ptr), _fld)))           \
> +        goto err;
> +
> +
> +static void vfio_display_edid_update(VFIOPCIDevice *vdev, bool enabled,
> +                                     int prefx, int prefy)
> +{
> +    VFIODisplay *dpy = vdev->dpy;
> +    int fd = vdev->vbasedev.fd;
> +    qemu_edid_info edid = {
> +        .maxx  = dpy->edid_regs->max_xres,
> +        .maxy  = dpy->edid_regs->max_yres,
> +        .prefx = prefx,
> +        .prefy = prefy,
> +    };
> +
> +    dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_DOWN;
> +    pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state);
> +    trace_vfio_display_edid_link_down();
> +
> +    if (!enabled) {
> +        return;
> +    }
> +
> +    if (edid.maxx && edid.prefx > edid.maxx) {
> +        edid.prefx = edid.maxx;
> +    }
> +    if (edid.maxy && edid.prefy > edid.maxy) {
> +        edid.prefy = edid.maxy;
> +    }
> +    qemu_edid_generate(dpy->edid_blob,
> +                       dpy->edid_regs->edid_max_size,
> +                       &edid);
> +    trace_vfio_display_edid_update(edid.prefx, edid.prefy);
> +
> +    dpy->edid_regs->edid_size = qemu_edid_size(dpy->edid_blob);
> +    pwrite_field(fd, dpy->edid_info, dpy->edid_regs, edid_size);
> +    if (pwrite(fd, dpy->edid_blob, dpy->edid_regs->edid_size,
> +               dpy->edid_info->offset + dpy->edid_regs->edid_offset)
> +        != dpy->edid_regs->edid_size) {
> +        goto err;
> +    }
> +
> +    dpy->edid_regs->link_state = VFIO_DEVICE_GFX_LINK_STATE_UP;
> +    pwrite_field(fd, dpy->edid_info, dpy->edid_regs, link_state);
> +    trace_vfio_display_edid_link_up();
> +    return;
> +
> +err:
> +    trace_vfio_display_edid_write_error();
> +    return;

nit, no unwind and only one call point, could probably do without the
goto.

> +}
> +
> +static int vfio_display_edid_ui_info(void *opaque, uint32_t idx,
> +                                     QemuUIInfo *info)
> +{
> +    VFIOPCIDevice *vdev = opaque;
> +    VFIODisplay *dpy = vdev->dpy;
> +
> +    if (!dpy->edid_regs) {
> +        return 0;
> +    }
> +
> +    if (info->width && info->height) {
> +        vfio_display_edid_update(vdev, true, info->width, info->height);
> +    } else {
> +        vfio_display_edid_update(vdev, false, 0, 0);
> +    }
> +
> +    return 0;
> +}
> +
> +static void vfio_display_edid_init(VFIOPCIDevice *vdev)
> +{
> +    VFIODisplay *dpy = vdev->dpy;
> +    int fd = vdev->vbasedev.fd;
> +    int ret;
> +
> +    ret = vfio_get_dev_region_info(&vdev->vbasedev,
> +                                   VFIO_REGION_TYPE_GFX,
> +                                   VFIO_REGION_SUBTYPE_GFX_EDID,
> +                                   &dpy->edid_info);
> +    if (ret) {
> +        return;
> +    }
> +
> +    trace_vfio_display_edid_available();
> +    dpy->edid_regs = g_new0(struct vfio_region_gfx_edid, 1);
> +    pread_field(fd, dpy->edid_info, dpy->edid_regs, edid_offset);
> +    pread_field(fd, dpy->edid_info, dpy->edid_regs, edid_max_size);
> +    pread_field(fd, dpy->edid_info, dpy->edid_regs, max_xres);
> +    pread_field(fd, dpy->edid_info, dpy->edid_regs, max_yres);
> +    dpy->edid_blob = g_malloc0(dpy->edid_regs->edid_max_size);
> +
> +    vfio_display_edid_update(vdev, true, 0, 0);
> +    return;
> +
> +err:
> +    fprintf(stderr, "%s: Oops, pread error\n", __func__);
> +    g_free(dpy->edid_regs);
> +    dpy->edid_regs = NULL;
> +    return;

This code is unreachable.

> +}
> +
> +static void vfio_display_edid_exit(VFIODisplay *dpy)
> +{
> +    if (!dpy->edid_regs) {
> +        return;
> +    }
> +
> +    g_free(dpy->edid_regs);
> +    g_free(dpy->edid_blob);
> +}
> +
>  static void vfio_display_update_cursor(VFIODMABuf *dmabuf,
>                                         struct vfio_device_gfx_plane_info 
> *plane)
>  {
> @@ -171,6 +295,7 @@ static void vfio_display_dmabuf_update(void *opaque)
>  
>  static const GraphicHwOps vfio_display_dmabuf_ops = {
>      .gfx_update = vfio_display_dmabuf_update,
> +    .ui_info    = vfio_display_edid_ui_info,
>  };
>  
>  static int vfio_display_dmabuf_init(VFIOPCIDevice *vdev, Error **errp)
> @@ -187,6 +312,7 @@ static int vfio_display_dmabuf_init(VFIOPCIDevice *vdev, 
> Error **errp)
>      if (vdev->enable_ramfb) {
>          vdev->dpy->ramfb = ramfb_setup(errp);
>      }
> +    vfio_display_edid_init(vdev);
>      return 0;
>  }
>  
> @@ -366,5 +492,6 @@ void vfio_display_finalize(VFIOPCIDevice *vdev)
>      graphic_console_close(vdev->dpy->con);
>      vfio_display_dmabuf_exit(vdev->dpy);
>      vfio_display_region_exit(vdev->dpy);
> +    vfio_display_edid_exit(vdev->dpy);
>      g_free(vdev->dpy);
>  }
> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events
> index f41ca96160..28d445caaf 100644
> --- a/hw/vfio/trace-events
> +++ b/hw/vfio/trace-events
> @@ -131,3 +131,10 @@ vfio_prereg_unregister(uint64_t va, uint64_t size, int 
> ret) "va=0x%"PRIx64" size
>  vfio_spapr_create_window(int ps, uint64_t ws, uint64_t off) "pageshift=0x%x 
> winsize=0x%"PRIx64" offset=0x%"PRIx64
>  vfio_spapr_remove_window(uint64_t off) "offset=0x%"PRIx64
>  vfio_spapr_group_attach(int groupfd, int tablefd) "Attached groupfd %d to 
> liobn fd %d"
> +
> +# hw/vfio/display.c
> +vfio_display_edid_available(void) ""
> +vfio_display_edid_link_up(void) ""
> +vfio_display_edid_link_down(void) ""
> +vfio_display_edid_update(uint32_t prefx, uint32_t prefy) "%dx%d"
> +vfio_display_edid_write_error(void) ""