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Re: [Qemu-devel] [RFC PATCH v2 7/7] vfio/pci: Find and expose Intel IGD
From: |
Alex Williamson |
Subject: |
Re: [Qemu-devel] [RFC PATCH v2 7/7] vfio/pci: Find and expose Intel IGD OpRegion |
Date: |
Wed, 03 Feb 2016 12:52:37 -0700 |
On Wed, 2016-02-03 at 10:29 +0100, Gerd Hoffmann wrote:
> On Di, 2016-02-02 at 13:09 -0700, Alex Williamson wrote:
> > This is provided via a device specific region, look for it on Intel
> > VGA class devices. Our default mechanism to expose this to the BIOS
> > is via fw_cfg where it's expected that the BIOS will copy the data
> > into a reserved RAM area and update the ASL Storage register to
> > reference the GPA of that buffer.
>
> > We also support directly mapping
> > the OpRegion through to the host in response to the ASL Storage
> > register write, which makes the data "live" and potentially provides
> > write access should the underlying vfio region support writes.
>
> This should better be splitted into a separate patch.
Ok. Perhaps I'll drop it for now and make the kernel-level vfio code
expose the OpRegion as read-only as a start. It's easy enough to dig
out of the mail archives and add back later if we want.
> > This
> > option is automatically enabled if we somehow don't support fw_cfg (is
> > this a good idea?).
>
> I think this can't happen. And even in case it can: we have bigger
> problems than the opregion then.
A few of the other fw_cfg_find() users seem to handle the error case,
which is why I ask. Thanks,
Alex
- [Qemu-devel] [RFC PATCH 0/7] vfio: capability chains, sparse mmap, device specific regions, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 1/7] vfio: Add sysfsdev property for pci & platform, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 2/7] vfio: Wrap VFIO_DEVICE_GET_REGION_INFO, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 3/7] vfio: Generalize region support, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 4/7] vfio/pci: Convert all MemoryRegion to dynamic alloc and consistent functions, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 5/7] linux-headers/vfio: Update for proposed capabilities list, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 6/7] vfio: Enable sparse mmap capability, Alex Williamson, 2016/02/01
- [Qemu-devel] [RFC PATCH 7/7] vfio/pci: Find and expose Intel IGD OpRegion, Alex Williamson, 2016/02/01