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authorhexin <hexin.op@gmail.com>2019-08-22 06:35:19 +0300
committerAlex Williamson <alex.williamson@redhat.com>2019-08-22 23:53:06 +0300
commit92c8026854c25093946e0d7fe536fd9eac440f06 (patch)
treefa9d8837d81f953490b0047049fa491ae636b010 /drivers/vfio
parentd1abaeb3be7b5fa6d7a1fbbd2e14e3310005c4c1 (diff)
downloadlinux-92c8026854c25093946e0d7fe536fd9eac440f06.tar.xz
vfio_pci: Restore original state on release
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> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 703948c9fbe1..02206162eaa9 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: