Changes in virtio_rtc_driver.c

f088104d837a991c65e51fa30bb4196169b3244d - Merge drm/drm-next into drm-intel-gt-next

Tue, 16 Sep 2025 12:53:20 +0200

Merge drm/drm-next into drm-intel-gt-nextBackmerge in order to get the commit: 048832a3f400 ("drm/i915: Refactor shmem_pwrite() to use kiocb and write_iter")To drm-intel-gt-next as there are followup fixes to be applied.Signed-off-by: Joonas Lahtinen List of files: /linux/drivers/virtio/virtio_rtc_driver.c

ab93e0dd72c37d378dd936f031ffb83ff2bd87ce - Merge branch 'next' into for-linus

Wed, 06 Aug 2025 19:08:54 +0200

Merge branch 'next' into for-linusPrepare input updates for 6.17 merge window. List of files: /linux/drivers/virtio/virtio_rtc_driver.c

a7bee4e7f78089c101be2ad51f4b5ec64782053e - Merge tag 'ib-mfd-gpio-input-pwm-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into next

Mon, 04 Aug 2025 08:28:48 +0200

Merge tag 'ib-mfd-gpio-input-pwm-v6.17' of git://git.kernel.org/pub/scm/linux/kernel/git/lee/mfd into nextMerge an immutable branch between MFD, GPIO, Input and PWM to resolveconflicts for the merge window pull request. List of files: /linux/drivers/virtio/virtio_rtc_driver.c

74f1af95820fc2ee580a775a3a17c416db30b38c - Merge remote-tracking branch 'drm/drm-next' into msm-next

Sun, 29 Jun 2025 04:54:49 +0200

Merge remote-tracking branch 'drm/drm-next' into msm-nextBack-merge drm-next to (indirectly) get arm-smmu updates for makingstall-on-fault more reliable.Signed-off-by: Rob Clark List of files: /linux/drivers/virtio/virtio_rtc_driver.c

c598d5eb9fb331ba17bc9ad67ae9a2231ca5aca5 - Merge drm/drm-next into drm-misc-next

Wed, 11 Jun 2025 09:01:34 +0200

Merge drm/drm-next into drm-misc-nextBackmerging to forward to v6.16-rc1Signed-off-by: Thomas Zimmermann List of files: /linux/drivers/virtio/virtio_rtc_driver.c

86e2d052c2320bf12571a5d96b16c2745e1cfc5e - Merge drm/drm-next into drm-xe-next

Mon, 09 Jun 2025 18:26:55 +0200

Merge drm/drm-next into drm-xe-nextBackmerging to bring in 6.16Signed-off-by: Thomas Hellström List of files: /linux/drivers/virtio/virtio_rtc_driver.c

34c55367af96f62e89221444f04487440ebc6487 - Merge drm/drm-next into drm-intel-next

Mon, 09 Jun 2025 11:40:46 +0200

Merge drm/drm-next into drm-intel-nextSync to v6.16-rc1, among other things to get the fixed size GENMASK_U*()and BIT_U*() macros.Signed-off-by: Jani Nikula List of files: /linux/drivers/virtio/virtio_rtc_driver.c

8ca154e4910efff1b04e7750e007d75732c68323 - Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Thu, 29 May 2025 17:15:35 +0200

Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhostPull virtio updates from Michael Tsirkin: - A new virtio RTC driver - vhost scsi now logs write descriptors so migration works - Some hardening work in virtio core - An old spec compliance issue fixed in vhost net - A couple of cleanups, fixes in vringh, virtio-pci, vdpa* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost: virtio: reject shm region if length is zero virtio_rtc: Add RTC class driver virtio_rtc: Add Arm Generic Timer cross-timestamping virtio_rtc: Add PTP clocks virtio_rtc: Add module and driver core vringh: use bvec_kmap_local vhost: vringh: Use matching allocation type in resize_iovec() virtio-pci: Fix result size returned for the admin command completion vdpa/octeon_ep: Control PCI dev enabling manually vhost-scsi: log event queue write descriptors vhost-scsi: log control queue write descriptors vhost-scsi: log I/O queue write descriptors vhost-scsi: adjust vhost_scsi_get_desc() to log vring descriptors vhost: modify vhost_log_write() for broader users List of files: /linux/drivers/virtio/virtio_rtc_driver.c

9d4f22fd563e0cd02e8448e84d057e7c0132a586 - virtio_rtc: Add RTC class driver

Fri, 09 May 2025 18:07:25 +0200

virtio_rtc: Add RTC class driverExpose the virtio-rtc UTC-like clock as an RTC clock to userspace - if itis present, and if it does not step on leap seconds. The RTC class enablesthe virtio-rtc device to resume the system from sleep states on RTC alarm.Support RTC alarm if the virtio-rtc alarm feature is present. Thevirtio-rtc device signals an alarm by marking an alarmq buffer as used.Peculiarities-------------A virtio-rtc clock is a bit special for an RTC clock in that- the clock may step (also backwards) autonomously at any time and- the device, and its notification mechanism, will be reset during boot or resume from sleep.The virtio-rtc device avoids that the driver might miss an alarm. Thedevice signals an alarm whenever the clock has reached or passed the alarmtime, and also when the device is reset (on boot or resume from sleep), ifthe alarm time is in the past.Open Issue----------The CLOCK_BOOTTIME_ALARM will use the RTC clock to wake up from sleep, andimplicitly assumes that no RTC clock steps will occur during sleep. The RTCclass driver does not know whether the current alarm is a real-time alarmor a boot-time alarm.Perhaps this might be handled by the driver also setting a virtio-rtcmonotonic alarm (which uses a clock similar to CLOCK_BOOTTIME_ALARM). Thevirtio-rtc monotonic alarm would just be used to wake up in case it was aCLOCK_BOOTTIME_ALARM alarm.Otherwise, the behavior should not differ from other RTC class drivers.Signed-off-by: Peter Hilber Acked-by: Alexandre Belloni Message-Id: <20250509160734.1772-5-quic_philber@quicinc.com>Signed-off-by: Michael S. Tsirkin List of files: /linux/drivers/virtio/virtio_rtc_driver.c

9a17125a18f9ae1e1233a8e2d919059445b9d6fd - virtio_rtc: Add PTP clocks

Fri, 09 May 2025 18:07:23 +0200

virtio_rtc: Add PTP clocksExpose the virtio_rtc clocks as PTP clocks to userspace, similar toptp_kvm. virtio_rtc can expose multiple clocks, e.g. a UTC clock and amonotonic clock.Userspace should distinguish different clocks through the name assigned bythe driver. In particular, UTC-like clocks can also be distinguished by ifand how leap seconds are smeared. udev rules such as the following can beused to get different symlinks for different clock types: SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 0/variant 0", SYMLINK += "ptp_virtio" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 1/variant 0", SYMLINK += "ptp_virtio_tai" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 2/variant 0", SYMLINK += "ptp_virtio_monotonic" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 3/variant 0", SYMLINK += "ptp_virtio_smear_unspecified" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 3/variant 1", SYMLINK += "ptp_virtio_smear_noon_linear" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 3/variant 2", SYMLINK += "ptp_virtio_smear_sls" SUBSYSTEM=="ptp", ATTR{clock_name}=="Virtio PTP type 4/variant 0", SYMLINK += "ptp_virtio_maybe_smeared"The preferred PTP clock reading method is ioctl PTP_SYS_OFFSET_PRECISE2,through the ptp_clock_info.getcrosststamp() op. For now,PTP_SYS_OFFSET_PRECISE2 will return -EOPNOTSUPP through a weak function.PTP_SYS_OFFSET_PRECISE2 requires cross-timestamping support for specificclocksources, which will be added in the following. If the clocksourcespecific code is enabled, check that the Virtio RTC device supports therespective HW counter before obtaining an actual cross-timestamp from theVirtio device.The Virtio RTC device response time may be higher than the timekeeperseqcount increment interval. Therefore, obtain the cross-timestamp beforecalling get_device_system_crosststamp().As a fallback, support the ioctl PTP_SYS_OFFSET_EXTENDED2 for allplatforms.Assume that concurrency issues during PTP clock removal are avoided by theposix_clock framework.Kconfig recursive dependencies prevent virtio_rtc from implicitly enablingPTP_1588_CLOCK, therefore just warn the user if PTP_1588_CLOCK is notavailable. Since virtio_rtc should in the future also expose clocks as RTCclass devices, do not depend VIRTIO_RTC on PTP_1588_CLOCK.Signed-off-by: Peter Hilber Message-Id: <20250509160734.1772-3-quic_philber@quicinc.com>Signed-off-by: Michael S. Tsirkin List of files: /linux/drivers/virtio/virtio_rtc_driver.c

0623c759276885c3ae88197ba6fb5c9c6ba8612f - virtio_rtc: Add module and driver core

Fri, 09 May 2025 18:07:22 +0200

virtio_rtc: Add module and driver coreAdd the virtio_rtc module and driver core. The virtio_rtc module implementsa driver compatible with the proposed Virtio RTC device specification.The Virtio RTC (Real Time Clock) device provides information about currenttime. The device can provide different clocks, e.g. for the UTC or TAI timestandards, or for physical time elapsed since some past epoch. The drivercan read the clocks with simple or more accurate methods.Implement the core, which interacts with the Virtio RTC device. Apart fromthis, the core does not expose functionality outside of the virtio_rtcmodule. Follow-up patches will expose PTP clocks and an RTC Class device.Provide synchronous messaging, which is enough for the expected timesynchronization use cases through PTP clocks (similar to ptp_kvm) or RTCClass device.Signed-off-by: Peter Hilber Message-Id: <20250509160734.1772-2-quic_philber@quicinc.com>Signed-off-by: Michael S. Tsirkin List of files: /linux/drivers/virtio/virtio_rtc_driver.c