diff options
| author | Corvin Köhne <corvin.koehne@gmail.com> | 2024-08-28 15:43:25 +0200 |
|---|---|---|
| committer | Cédric Le Goater <clg@redhat.com> | 2024-09-17 10:37:55 +0200 |
| commit | 11b5ce95beecfd51d1b17858d23fe9cbb0b5783f (patch) | |
| tree | a7be64c87337857854662332f97650f18baae4fe /hw/vfio/pci.h | |
| parent | 7bafcd17672934284d59b82a2e2a876566c3f6f9 (diff) | |
vfio/igd: add new bar0 quirk to emulate BDSM mirror
The BDSM register is mirrored into MMIO space at least for gen 11 and
later devices. Unfortunately, the Windows driver reads the register
value from MMIO space instead of PCI config space for those devices [1].
Therefore, we either have to keep a 1:1 mapping for the host and guest
address or we have to emulate the MMIO register too. Using the igd in
legacy mode is already hard due to it's many constraints. Keeping a 1:1
mapping may not work in all cases and makes it even harder to use. An
MMIO emulation has to trap the whole MMIO page. This makes accesses to
this page slower compared to using second level address translation.
Nevertheless, it doesn't have any constraints and I haven't noticed any
performance degradation yet making it a better solution.
[1] https://github.com/projectacrn/acrn-hypervisor/blob/5c351bee0f6ae46250eefc07f44b4a31e770f3cf/devicemodel/hw/pci/passthrough.c#L650-L653
Signed-off-by: Corvin Köhne <c.koehne@beckhoff.com>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'hw/vfio/pci.h')
| -rw-r--r-- | hw/vfio/pci.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/hw/vfio/pci.h b/hw/vfio/pci.h index bf67df2fbc..5ad090a229 100644 --- a/hw/vfio/pci.h +++ b/hw/vfio/pci.h @@ -215,6 +215,7 @@ void vfio_setup_resetfn_quirk(VFIOPCIDevice *vdev); bool vfio_add_virt_caps(VFIOPCIDevice *vdev, Error **errp); void vfio_quirk_reset(VFIOPCIDevice *vdev); VFIOQuirk *vfio_quirk_alloc(int nr_mem); +void vfio_probe_igd_bar0_quirk(VFIOPCIDevice *vdev, int nr); void vfio_probe_igd_bar4_quirk(VFIOPCIDevice *vdev, int nr); extern const PropertyInfo qdev_prop_nv_gpudirect_clique; |