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drm/hyperv: Fix device removal on Gen1 VMs

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The Hyper-V DRM driver tries to free MMIO region on removing
the device regardless of VM type, while Gen1 VMs don't use MMIO
and hence causing the kernel to crash on a NULL pointer dereference.

Fix this by making deallocating MMIO only on Gen2 machines and implement
removal for Gen1

Fixes: 76c56a5aff ("drm/hyperv: Add DRM driver for hyperv synthetic video device")

Signed-off-by: Mohammed Gamal <mgamal@redhat.com>
Reviewed-by: Deepak Rawat <drawat.floss@gmail.com>
Signed-off-by: Deepak Rawat <drawat.floss@gmail.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211119112900.300537-1-mgamal@redhat.com
This commit is contained in:
Mohammed Gamal
2021-11-19 12:29:00 +01:00
committed by Deepak Rawat
parent b4a6aaeaf4
commit e048834c20
1 changed files with 18 additions and 1 deletions
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19
drivers/gpu/drm/hyperv/hyperv_drm_drv.c
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@@ -225,12 +225,29 @@ static int hyperv_vmbus_remove(struct hv_device *hdev)
{
struct drm_device *dev = hv_get_drvdata(hdev);
struct hyperv_drm_device *hv = to_hv(dev);
struct pci_dev *pdev;
drm_dev_unplug(dev);
drm_atomic_helper_shutdown(dev);
vmbus_close(hdev->channel);
hv_set_drvdata(hdev, NULL);
vmbus_free_mmio(hv->mem->start, hv->fb_size);
/*
* Free allocated MMIO memory only on Gen2 VMs.
* On Gen1 VMs, release the PCI device
*/
if (efi_enabled(EFI_BOOT)) {
vmbus_free_mmio(hv->mem->start, hv->fb_size);
} else {
pdev = pci_get_device(PCI_VENDOR_ID_MICROSOFT,
PCI_DEVICE_ID_HYPERV_VIDEO, NULL);
if (!pdev) {
drm_err(dev, "Unable to find PCI Hyper-V video\n");
return -ENODEV;
}
pci_release_region(pdev, 0);
pci_dev_put(pdev);
}
return 0;
}