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 <[email protected]>
---
v1 -> v2:
- Check the No_Soft_Reset bit
drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
1 file changed, 33 insertions(+), 1 deletion(-)
diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
index c2524a7207cf..3a95ecaf12dc 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
--
2.43.0.472.g3155946c3a-goog
On Fri, Dec 8, 2023 at 3:09 PM David Stevens <[email protected]> wrote:
>
> 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 <[email protected]>
Acked-by: Jason Wang <[email protected]>
Thanks
> ---
> v1 -> v2:
> - Check the No_Soft_Reset bit
>
> drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index c2524a7207cf..3a95ecaf12dc 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
>
> --
> 2.43.0.472.g3155946c3a-goog
>
On Fri, Dec 08, 2023 at 04:07:54PM +0900, David Stevens wrote:
> 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 <[email protected]>
tagged, thanks!
I'm still debating with myself whether we can classify this
as a bugfix ... better not risk it I guess.
> ---
> v1 -> v2:
> - Check the No_Soft_Reset bit
>
> drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index c2524a7207cf..3a95ecaf12dc 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
>
> --
> 2.43.0.472.g3155946c3a-goog
On Tue, Dec 12, 2023 at 12:37 AM Michael S. Tsirkin <[email protected]> wrote:
>
> On Fri, Dec 08, 2023 at 04:07:54PM +0900, David Stevens wrote:
> > 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 <[email protected]>
>
> tagged, thanks!
> I'm still debating with myself whether we can classify this
> as a bugfix ... better not risk it I guess.
It might be suitable if there's a hypervisor that advertises
no_soft_reset (but it seems Qemu doesn't).
Thanks
>
> > ---
> > v1 -> v2:
> > - Check the No_Soft_Reset bit
> >
> > drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> > 1 file changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> > index c2524a7207cf..3a95ecaf12dc 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
> >
> > --
> > 2.43.0.472.g3155946c3a-goog
>
On Tue, Dec 12, 2023 at 11:01:53AM +0800, Jason Wang wrote:
> On Tue, Dec 12, 2023 at 12:37 AM Michael S. Tsirkin <[email protected]> wrote:
> >
> > On Fri, Dec 08, 2023 at 04:07:54PM +0900, David Stevens wrote:
> > > 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 <[email protected]>
> >
> > tagged, thanks!
> > I'm still debating with myself whether we can classify this
> > as a bugfix ... better not risk it I guess.
>
> It might be suitable if there's a hypervisor that advertises
> no_soft_reset (but it seems Qemu doesn't).
>
> Thanks
Yea... so a bugfix but no rush to merge it I think.
> >
> > > ---
> > > v1 -> v2:
> > > - Check the No_Soft_Reset bit
> > >
> > > drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> > > 1 file changed, 33 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> > > index c2524a7207cf..3a95ecaf12dc 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
> > >
> > > --
> > > 2.43.0.472.g3155946c3a-goog
> >
On 08.12.23 08:07, David Stevens wrote:
> 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 <[email protected]>
> ---
> v1 -> v2:
> - Check the No_Soft_Reset bit
>
> drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> 1 file changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> index c2524a7207cf..3a95ecaf12dc 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
>
Am I correct with my assumption that this will make s2idle work with virtio-mem-pci as well?
Right now, all suspending is disabled, but really only s4/hibernate is problematic.
[root@vm-0 ~]# echo "s2idle" > /sys/power/mem_sleep
[root@vm-0 ~]# echo "mem" > /sys/power/state
[ 101.822991] PM: suspend entry (s2idle)
[ 101.828978] Filesystems sync: 0.004 seconds
[ 101.831618] Freezing user space processes
[ 101.834569] Freezing user space processes completed (elapsed 0.001 seconds)
[ 101.836915] OOM killer disabled.
[ 101.838072] Freezing remaining freezable tasks
[ 101.841054] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[ 101.843538] printk: Suspending console(s) (use no_console_suspend to debug)
[ 101.957676] virtio_mem virtio0: save/restore not supported.
[ 101.957683] virtio-pci 0000:00:02.0: PM: pci_pm_suspend(): virtio_pci_freeze+0x0/0x50 returns -1
[ 101.957702] virtio-pci 0000:00:02.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x170 returns -1
[ 101.957718] virtio-pci 0000:00:02.0: PM: failed to suspend async: error -1
--
Cheers,
David / dhildenb
On Thu, Dec 14, 2023 at 6:47 PM David Hildenbrand <[email protected]> wrote:
>
> On 08.12.23 08:07, David Stevens wrote:
> > 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 <[email protected]>
> > ---
> > v1 -> v2:
> > - Check the No_Soft_Reset bit
> >
> > drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
> > 1 file changed, 33 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
> > index c2524a7207cf..3a95ecaf12dc 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
> >
>
> Am I correct with my assumption that this will make s2idle work with virtio-mem-pci as well?
>
> Right now, all suspending is disabled, but really only s4/hibernate is problematic.
>
> [root@vm-0 ~]# echo "s2idle" > /sys/power/mem_sleep
> [root@vm-0 ~]# echo "mem" > /sys/power/state
> [ 101.822991] PM: suspend entry (s2idle)
> [ 101.828978] Filesystems sync: 0.004 seconds
> [ 101.831618] Freezing user space processes
> [ 101.834569] Freezing user space processes completed (elapsed 0.001 seconds)
> [ 101.836915] OOM killer disabled.
> [ 101.838072] Freezing remaining freezable tasks
> [ 101.841054] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
> [ 101.843538] printk: Suspending console(s) (use no_console_suspend to debug)
> [ 101.957676] virtio_mem virtio0: save/restore not supported.
> [ 101.957683] virtio-pci 0000:00:02.0: PM: pci_pm_suspend(): virtio_pci_freeze+0x0/0x50 returns -1
> [ 101.957702] virtio-pci 0000:00:02.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x170 returns -1
> [ 101.957718] virtio-pci 0000:00:02.0: PM: failed to suspend async: error -1
QEMU's virtio-pci devices don't advertise no_soft_reset, so this patch
won't affect vanilla QEMU. But if you add PCI_PM_CTRL_NO_SOFT_RESET to
the capability, then it should work. I'm working with crosvm, which
doesn't have virtio-mem implemented, but this patch makes virtio-fs
work with no extra kernel changes.
-David
On 15.12.23 02:00, David Stevens wrote:
> On Thu, Dec 14, 2023 at 6:47 PM David Hildenbrand <[email protected]> wrote:
>>
>> On 08.12.23 08:07, David Stevens wrote:
>>> 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 <[email protected]>
>>> ---
>>> v1 -> v2:
>>> - Check the No_Soft_Reset bit
>>>
>>> drivers/virtio/virtio_pci_common.c | 34 +++++++++++++++++++++++++++++-
>>> 1 file changed, 33 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/virtio/virtio_pci_common.c b/drivers/virtio/virtio_pci_common.c
>>> index c2524a7207cf..3a95ecaf12dc 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
>>>
>>
>> Am I correct with my assumption that this will make s2idle work with virtio-mem-pci as well?
>>
>> Right now, all suspending is disabled, but really only s4/hibernate is problematic.
>>
>> [root@vm-0 ~]# echo "s2idle" > /sys/power/mem_sleep
>> [root@vm-0 ~]# echo "mem" > /sys/power/state
>> [ 101.822991] PM: suspend entry (s2idle)
>> [ 101.828978] Filesystems sync: 0.004 seconds
>> [ 101.831618] Freezing user space processes
>> [ 101.834569] Freezing user space processes completed (elapsed 0.001 seconds)
>> [ 101.836915] OOM killer disabled.
>> [ 101.838072] Freezing remaining freezable tasks
>> [ 101.841054] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
>> [ 101.843538] printk: Suspending console(s) (use no_console_suspend to debug)
>> [ 101.957676] virtio_mem virtio0: save/restore not supported.
>> [ 101.957683] virtio-pci 0000:00:02.0: PM: pci_pm_suspend(): virtio_pci_freeze+0x0/0x50 returns -1
>> [ 101.957702] virtio-pci 0000:00:02.0: PM: dpm_run_callback(): pci_pm_suspend+0x0/0x170 returns -1
>> [ 101.957718] virtio-pci 0000:00:02.0: PM: failed to suspend async: error -1
>
> QEMU's virtio-pci devices don't advertise no_soft_reset, so this patch
> won't affect vanilla QEMU. But if you add PCI_PM_CTRL_NO_SOFT_RESET to
> the capability, then it should work. I'm working with crosvm, which
> doesn't have virtio-mem implemented, but this patch makes virtio-fs
> work with no extra kernel changes.
Thanks for the explanation, makes sense to me.
--
Cheers,
David / dhildenb