diff options
| author | David Stevens <stevensd@chromium.org> | 2023-12-08 16:07:54 +0900 |
|---|---|---|
| committer | Michael S. Tsirkin <mst@redhat.com> | 2023-12-27 16:10:38 -0500 |
| commit | dff4fa0e57856045359440d05af9e9b7f7048f52 (patch) | |
| tree | 9a5c7aa416b31d43a874fd907be621c1dc582dd1 /drivers/virtio | |
| parent | d2c4f1928a3f7f4a1f28a0cfc022e8a145ce6903 (diff) | |
| download | linux-dff4fa0e57856045359440d05af9e9b7f7048f52.tar.gz | |
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.c | 34 |
1 files changed, 33 insertions, 1 deletions
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c index 7a5593997e0ef..1d21d1a1b3f55 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 |