lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Message-ID: <CAD=HUj6ZsZo_kxZazDDDUp61pEHupuf0Lf7WqkKBsMOA1CYcNQ@mail.gmail.com> Date: Fri, 15 Dec 2023 10:00:41 +0900 From: David Stevens <stevensd@...omium.org> To: David Hildenbrand <david@...hat.com> Cc: "Michael S . Tsirkin" <mst@...hat.com>, Jason Wang <jasowang@...hat.com>, virtualization@...ts.linux-foundation.org, linux-kernel@...r.kernel.org Subject: Re: [PATCH v2] virtio: Add support for no-reset virtio PCI PM On Thu, Dec 14, 2023 at 6:47 PM David Hildenbrand <david@...hat.com> 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 <stevensd@...omium.org> > > --- > > 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@...0 ~]# echo "s2idle" > /sys/power/mem_sleep > [root@...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
Powered by blists - more mailing lists