> -----Original Message----- > From: kvm-owner@xxxxxxxxxxxxxxx [mailto:kvm-owner@xxxxxxxxxxxxxxx] On > Behalf Of Gerd Hoffmann > Sent: Friday, September 7, 2018 10:05 PM > To: intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx; kvm@xxxxxxxxxxxxxxx; Kirti Wankhede > <kwankhede@xxxxxxxxxx>; Alex Williamson <alex.williamson@xxxxxxxxxx> > Subject: RfC: vfio: add vgpu edid support? > > Hi, > > I consider adding EDID support to qemu, for display configuration. > > qemu patches are here: > https://git.kraxel.org/cgit/qemu/log/?h=sirius/edid > > linux kernel patches are here: > https://git.kraxel.org/cgit/linux/log/?h=edid > > Current (experimental) patches have support for the stdvga and virtio-vga. > > I think it would be quite useful for vgpu too. Unlike emulated devices vgpu's do > not have a paravirtual display configuration path, because the standard way to > configure the display is to simply read the edid from the monitor. > > Intel has two hard-coded edid blobs for that (depending on vgpu type). > Not sure how nvidia handles this, but probably simliar. With qemu passing a > edid blob for the virtual display instead of using the hardcoded blob we could > make the display configuration much more flexible. Sounds interesting. People are asking us to add more display modes. With this proposal, we could provide any required mode in a flexible way. But the hard-coded resolution might still be needed. As it is used for vgpu resources allocation during vgpu creation before running a qemu. And a vgpu cannot support a resolution bigger than the one used for its resources allocation. So some logic might be needed to make sure to only allow qemu to pass an edid with a smaller resolution than the one (a.k.a the hard-coded resolution) used for populating the vgpu. Thanks. BR, Tina > > Ideally qemu would also be able to update the edid blob at any time, and the > vgpu will notify the guest about it (probably by emulating a monitor hotplug > event). The guest can react on qemu window resizing then and adapt > automatically, simliar to how it works with qxl and virtio-gpu. > > The guest and the vgpu should be able to handle "odd" non-standard display > resolutions like this (coming from random window resizing): > > Detailed mode: Clock 106.620 MHz, 477 mm x 330 mm > 1212 1515 1551 1636 hborder 0 > 840 844 848 869 vborder 0 > -hsync -vsync > VertFreq: 74 Hz, HorFreq: 65171 Hz > > RfC patch for the vfio interface is below. > > Comments? > > cheers, > Gerd > > =================== cut here =================== > > From 556299e8c6280b1c4061fdae15491a013c22be98 Mon Sep 17 00:00:00 > 2001 > From: Gerd Hoffmann <kraxel@xxxxxxxxxx> > Date: Thu, 6 Sep 2018 16:17:17 +0200 > Subject: [PATCH] [RfC] vfio: edid interface > > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> > --- > include/uapi/linux/vfio.h | 42 > ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 42 insertions(+) > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h index > 1aa7b82e81..9ac7dfb7c1 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -602,6 +602,48 @@ struct vfio_device_ioeventfd { > > #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + > 16) > > +/** > + * VFIO_DEVICE_GFX_EDID_CAPS - _IOW(VFIO_TYPE, VFIO_BASE + 17, > + * struct vfio_device_gfx_edid_caps) > + * > + * Get edid capabilities. > + * > + * Drivers must support either none or both GFX_EDID ioctls, > + * so the CAPS ioctl can also be used to probe for edid support. > + * > + * max_xres, max_yres - maximum display resolution supported. > + * value "0" means no restriction. > + * > + */ > +struct vfio_device_gfx_edid_caps { > + __u32 argsz; > + __u32 flags; > + /* out */ > + __u32 max_xres; > + __u32 max_yres; > +}; > + > +#define VFIO_DEVICE_GFX_EDID_CAPS _IO(VFIO_TYPE, VFIO_BASE + 17) > + > +/** > + * VFIO_DEVICE_GFX_EDID_SET - _IOW(VFIO_TYPE, VFIO_BASE + 18, > + * struct vfio_device_gfx_edid_set) > + * > + * Set edid blob. > + * > + * Should trigger monitor hotplug emulation, to notifiy the guest os > + * that the edid has changed. > + * > + */ > +struct vfio_device_gfx_edid_set { > + __u32 argsz; > + __u32 flags; > + /* in */ > + __u8 edid[256]; > +}; > + > +#define VFIO_DEVICE_GFX_EDID_SET _IO(VFIO_TYPE, VFIO_BASE + 18) > + > /* -------- API for Type1 VFIO IOMMU -------- */ > > /** > -- > 2.9.3
