From: hexin hexin.op@gmail.com
[ Upstream commit 92c8026854c25093946e0d7fe536fd9eac440f06 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- 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 6cf00d9f512b7..a92c2868d9021 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -373,11 +373,20 @@ 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: