| Message ID | 1566444919-3331-1-git-send-email-hexin15@baidu.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] vfio_pci: Restore original state on release | expand |
On Thu, 22 Aug 2019 11:35:19 +0800 hexin <hexin.op@gmail.com> wrote: > vfio_pci_enable() saves the device's initial configuration information > with the intent that it is restored in vfio_pci_disable(). However, > the commit referenced in Fixes: below replaced the call to > __pci_reset_function_locked(), which is not wrapped in a state save > and restore, with pci_try_reset_function(), which overwrites the > restored device state with the current state before applying it to the > device. Reinstate use of __pci_reset_function_locked() to return to > the desired behavior. > > Fixes: 890ed578df82 ("vfio-pci: Use pci "try" reset interface") > Signed-off-by: hexin <hexin15@baidu.com> > Signed-off-by: Liu Qi <liuqi16@baidu.com> > Signed-off-by: Zhang Yu <zhangyu31@baidu.com> > --- Applied to vfio next branch for v5.4. Thanks, Alex > v2->v3: > - change commit log > v1->v2: > - add fixes tag > - add comment to warn > > [1] https://lore.kernel.org/linux-pci/1565926427-21675-1-git-send-email-hexin15@baidu.com > [2] https://lore.kernel.org/linux-pci/1566042663-16694-1-git-send-email-hexin15@baidu.com > > drivers/vfio/pci/vfio_pci.c | 17 +++++++++++++---- > 1 file changed, 13 insertions(+), 4 deletions(-) > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > index 703948c..0220616 100644 > --- a/drivers/vfio/pci/vfio_pci.c > +++ b/drivers/vfio/pci/vfio_pci.c > @@ -438,11 +438,20 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) > pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE); > > /* > - * Try to reset the device. The success of this is dependent on > - * being able to lock the device, which is not always possible. > + * Try to get the locks ourselves to prevent a deadlock. The > + * success of this is dependent on being able to lock the device, > + * which is not always possible. > + * We can not use the "try" reset interface here, which will > + * overwrite the previously restored configuration information. > */ > - if (vdev->reset_works && !pci_try_reset_function(pdev)) > - vdev->needs_reset = false; > + if (vdev->reset_works && pci_cfg_access_trylock(pdev)) { > + if (device_trylock(&pdev->dev)) { > + if (!__pci_reset_function_locked(pdev)) > + vdev->needs_reset = false; > + device_unlock(&pdev->dev); > + } > + pci_cfg_access_unlock(pdev); > + } > > pci_restore_state(pdev); > out:
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index 703948c..0220616 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -438,11 +438,20 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev) pci_write_config_word(pdev, PCI_COMMAND, PCI_COMMAND_INTX_DISABLE); /* - * Try to reset the device. The success of this is dependent on - * being able to lock the device, which is not always possible. + * Try to get the locks ourselves to prevent a deadlock. The + * success of this is dependent on being able to lock the device, + * which is not always possible. + * We can not use the "try" reset interface here, which will + * overwrite the previously restored configuration information. */ - if (vdev->reset_works && !pci_try_reset_function(pdev)) - vdev->needs_reset = false; + if (vdev->reset_works && pci_cfg_access_trylock(pdev)) { + if (device_trylock(&pdev->dev)) { + if (!__pci_reset_function_locked(pdev)) + vdev->needs_reset = false; + device_unlock(&pdev->dev); + } + pci_cfg_access_unlock(pdev); + } pci_restore_state(pdev); out:
vfio_pci_enable() saves the device's initial configuration information with the intent that it is restored in vfio_pci_disable(). However, the commit referenced in Fixes: below replaced the call to __pci_reset_function_locked(), which is not wrapped in a state save and restore, with pci_try_reset_function(), which overwrites the restored device state with the current state before applying it to the device. Reinstate use of __pci_reset_function_locked() to return to the desired behavior. Fixes: 890ed578df82 ("vfio-pci: Use pci "try" reset interface") Signed-off-by: hexin <hexin15@baidu.com> Signed-off-by: Liu Qi <liuqi16@baidu.com> Signed-off-by: Zhang Yu <zhangyu31@baidu.com> --- v2->v3: - change commit log v1->v2: - add fixes tag - add comment to warn [1] https://lore.kernel.org/linux-pci/1565926427-21675-1-git-send-email-hexin15@baidu.com [2] https://lore.kernel.org/linux-pci/1566042663-16694-1-git-send-email-hexin15@baidu.com drivers/vfio/pci/vfio_pci.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-)