summaryrefslogtreecommitdiff
path: root/drivers/virtio
diff options
context:
space:
mode:
authorDavid Stevens <stevensd@chromium.org>2023-12-08 10:07:54 +0300
committerMichael S. Tsirkin <mst@redhat.com>2023-12-28 00:10:38 +0300
commitdff4fa0e57856045359440d05af9e9b7f7048f52 (patch)
tree9a5c7aa416b31d43a874fd907be621c1dc582dd1 /drivers/virtio
parentd2c4f1928a3f7f4a1f28a0cfc022e8a145ce6903 (diff)
downloadlinux-dff4fa0e57856045359440d05af9e9b7f7048f52.tar.xz
virtio: Add support for no-reset virtio PCI PM
If a virtio_pci_device supports native PCI power management and has the No_Soft_Reset bit set, then skip resetting and reinitializing the device when suspending and restoring the device. This allows system-wide low power states like s2idle to be used in systems with stateful virtio devices that can't simply be re-initialized (e.g. virtio-fs). Signed-off-by: David Stevens <stevensd@chromium.org> Message-Id: <20231208070754.3132339-1-stevensd@chromium.org> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_pci_common.c34
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index 7a5593997e0e..1d21d1a1b3f5 100644
--- a/drivers/virtio/virtio_pci_common.c
+++ b/drivers/virtio/virtio_pci_common.c
@@ -492,8 +492,40 @@ static int virtio_pci_restore(struct device *dev)
return virtio_device_restore(&vp_dev->vdev);
}
+static bool vp_supports_pm_no_reset(struct device *dev)
+{
+ struct pci_dev *pci_dev = to_pci_dev(dev);
+ u16 pmcsr;
+
+ if (!pci_dev->pm_cap)
+ return false;
+
+ pci_read_config_word(pci_dev, pci_dev->pm_cap + PCI_PM_CTRL, &pmcsr);
+ if (PCI_POSSIBLE_ERROR(pmcsr)) {
+ dev_err(dev, "Unable to query pmcsr");
+ return false;
+ }
+
+ return pmcsr & PCI_PM_CTRL_NO_SOFT_RESET;
+}
+
+static int virtio_pci_suspend(struct device *dev)
+{
+ return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_freeze(dev);
+}
+
+static int virtio_pci_resume(struct device *dev)
+{
+ return vp_supports_pm_no_reset(dev) ? 0 : virtio_pci_restore(dev);
+}
+
static const struct dev_pm_ops virtio_pci_pm_ops = {
- SET_SYSTEM_SLEEP_PM_OPS(virtio_pci_freeze, virtio_pci_restore)
+ .suspend = virtio_pci_suspend,
+ .resume = virtio_pci_resume,
+ .freeze = virtio_pci_freeze,
+ .thaw = virtio_pci_restore,
+ .poweroff = virtio_pci_freeze,
+ .restore = virtio_pci_restore,
};
#endif