From: hexin <hexin.op@gmail.com>
To: Alex Williamson <alex.williamson@redhat.com>,
kvm@vger.kernel.org, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org
Cc: hexin <hexin15@baidu.com>, Liu Qi <liuqi16@baidu.com>,
Zhang Yu <zhangyu31@baidu.com>
Subject: [PATCH v3] vfio_pci: Restore original state on release
Date: Thu, 22 Aug 2019 11:35:19 +0800 [thread overview]
Message-ID: <1566444919-3331-1-git-send-email-hexin15@baidu.com> (raw)
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(-)
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:
--
1.8.3.1
next reply other threads:[~2019-08-22 3:35 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-22 3:35 hexin [this message]
2019-08-23 20:45 ` [PATCH v3] vfio_pci: Restore original state on release Alex Williamson
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