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Subject[PATCH v3 0/3] Drivers: hv: Avoid allocating MMIO from framebuffer region for other passed through PCI devices
Date
Changes since v2:
- Add Michael's R-b tags to PATCHes1-3 and Bjorn's A-b tag to PATCH1.
- Commit messages tweaks [Michael].

Passed through PCI device sometimes misbehave on Gen1 VMs when Hyper-V
DRM driver is also loaded. Looking at IOMEM assignment, we can see e.g.

$ cat /proc/iomem
...
f8000000-fffbffff : PCI Bus 0000:00
f8000000-fbffffff : 0000:00:08.0
f8000000-f8001fff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe
...
fe0000000-fffffffff : PCI Bus 0000:00
fe0000000-fe07fffff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe
fe0000000-fe07fffff : 2ba2:00:02.0
fe0000000-fe07fffff : mlx4_core

the interesting part is the 'f8000000' region as it is actually the
VM's framebuffer:

$ lspci -v
...
0000:00:08.0 VGA compatible controller: Microsoft Corporation Hyper-V virtual VGA (prog-if 00 [VGA controller])
Flags: bus master, fast devsel, latency 0, IRQ 11
Memory at f8000000 (32-bit, non-prefetchable) [size=64M]
...

Recently merged commit a0ab5abced55 ("drm/hyperv : Removing the restruction of
VRAM allocation with PCI bar size") improved the situation as resources,
reserved through vmbus_allocate_mmio() can't be allocated twice:

...
f8000000-fffbffff : PCI Bus 0000:00
f8000000-fbffffff : 0000:00:08.0
f8000000-f8001fff : bb8c4f33-2ba2-4808-9f7f-02f3b4da22fe
f8100000-f88fffff : 5620e0c7-8062-4dce-aeb7-520c7ef76171
...

Always reserve FB region on Gen1 VMs (PATCH2) and make sure we never allocate
anything besides framebuffer from there (PATCH3).

Vitaly Kuznetsov (3):
PCI: Move PCI_VENDOR_ID_MICROSOFT/PCI_DEVICE_ID_HYPERV_VIDEO
definitions to pci_ids.h
Drivers: hv: Always reserve framebuffer region for Gen1 VMs
Drivers: hv: Never allocate anything besides framebuffer from
framebuffer memory region

drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 3 -
drivers/hv/vmbus_drv.c | 56 ++++++++++++++-----
.../net/ethernet/microsoft/mana/gdma_main.c | 4 --
drivers/video/fbdev/hyperv_fb.c | 4 --
include/linux/pci_ids.h | 3 +
5 files changed, 44 insertions(+), 26 deletions(-)

--
2.37.1

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