| Message ID | 20211119112900.300537-1-mgamal@redhat.com |
|---|---|
| State | New |
| Headers | show |
| Series |
"drm/hyperv: Fix device removal on Gen1 VMs"
( rev:
1
)
in
DRI devel |
diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c index cd818a629183..9f923beb7d8d 100644 --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c @@ -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; }
Thanks for the patch. Reviewed-by: Deepak Rawat <drawat.floss@gmail.com> I will push this to drm-fixes, let me know otherwise. Deepak On Fri, 2021-11-19 at 12:29 +0100, Mohammed Gamal wrote: > 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: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic > video device") > > Signed-off-by: Mohammed Gamal <mgamal@redhat.com> > --- > drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 19 ++++++++++++++++++- > 1 file changed, 18 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c > b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c > index cd818a629183..9f923beb7d8d 100644 > --- a/drivers/gpu/drm/hyperv/hyperv_drm_drv.c > +++ b/drivers/gpu/drm/hyperv/hyperv_drm_drv.c > @@ -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; > }
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: 76c56a5affeb ("drm/hyperv: Add DRM driver for hyperv synthetic video device") Signed-off-by: Mohammed Gamal <mgamal@redhat.com> --- drivers/gpu/drm/hyperv/hyperv_drm_drv.c | 19 ++++++++++++++++++- 1 file changed, 18 insertions(+), 1 deletion(-)