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Tsirkin" To: Peter Hilber Cc: virtio-comment@lists.linux.dev, Cornelia Huck , Parav Pandit , Jason Wang , David Woodhouse , "Ridoux, Julien" , Trilok Soni , Matias Ezequiel Vara Larsen Subject: Re: [PATCH v8 0/4] virtio-rtc: Add device specification Message-ID: <20250416114208-mutt-send-email-mst@kernel.org> References: <20250306095112.1293-1-quic_philber@quicinc.com> Precedence: bulk X-Mailing-List: virtio-comment@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20250306095112.1293-1-quic_philber@quicinc.com> X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: r6GIVzQSYxWo5_eKg2n0fR6VyIBgB_kAiHvksP4W-xY_1744818209 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Good work. I sent some comments but they are pretty minor. Thanks! On Thu, Mar 06, 2025 at 10:51:08AM +0100, Peter Hilber wrote: > This iteration of the spec should address multiple review findings from > Matias Ezequiel Vara Larsen. > > Summary > ------- > > The RTC (Real Time Clock) device provides information about current > time. The device can provide different clocks, for the UTC or TAI time > standards, or for physical time elapsed since some past epoch. For UTC > clocks, the device can also indicate how leap seconds are handled. The > driver can read the clocks with simple or more accurate methods. > Optionally, the driver can set an alarm. A bit more text on the motivation, when to do you intend to use this device, would be good. > Changelog > --------- > v8: > > - Explicitly describe alarm enabled status, where relevant (Matias Ezequiel > Vara Larsen). > > - Reword multiple sentences and requirements (Matias Ezequiel Vara Larsen). > > - Drop unnecessary or redundant requirements (Matias Ezequiel Vara Larsen). > > - Change word order from "field X" to "the X field" (Matias Ezequiel Vara > Larsen). > > - Change word order from "flag X" to "the X flag" or "X". > > - Move requirements to serve alarm expiration events before requirements > about stopping to serve (Matias Ezequiel Vara Larsen). > > v7: > > - Remove leap second and performance indications from struct > virtio_rtc_resp_read_cross. Remove backing definitions. > > - Move wording change which was mistakenly placed in last patch to first > patch. > > v6: > > - Make leap second status information optional if the clock smears (or > might smear) leap seconds. > > - Do not use union for leap second indication. > > - Improve wording. > > - Refer to the new POSIX.1-2024 for UTC epoch definition. > > v5: > > - Change structure and wording to support adding shared memory like > vmclock [2]. > > - Add dedicated clock types for UTC leap second smearing (David > Woodhouse). > > - Extend leap second indications. > > - Replace VIRTIO_RTC_SUBTYPE_ by VIRTIO_RTC_SMEAR_. > > - For Arm Generic Timer, only support Virtual Count Register (David > Woodhouse). > > - Rename MONO clock to MONOTONIC clock. > > - Harmonize bit widths with vmclock [2]. > > - Change formatting. > > v4: > > - Distinguish UTC clocks with and without leap smearing (David > Woodhouse). > > - Add UTC leap second and TAI offset indication (David Woodhouse). > > - Add clock performance information (David Woodhouse). > > - Drop distinction of Arm Generic Timer virtual and physical counter. > > - Change requirements so that driver can reset alarm to clean slate, and > document how driver can achieve this (Cornelia Hell, Jason Wang). > > - Device should assume that driver reads clock from first vCPU (David > Woodhouse). > > - Driver should read clock to confirm that alarm has expired. > > - Require driver to set unused flags to zero. > > - Require device to support all expressible alarm times. > > - Formatting and wording improvements. > > v3: > > - Address comments from Parav Pandit. > > - Add an optional alarm feature. > > - Various other changes. > > v2: > > - Address comments from Cornelia Huck. > > [1] https://lore.kernel.org/lkml/61364452-bdf5-4bd8-adb1-a9e6236c9d26@opensynergy.com/ > [2] https://lore.kernel.org/lkml/20240708092924.1473461-1-dwmw2@infradead.org/ > [3] https://lore.kernel.org/all/78969a39b51ec00e85551b752767be65f6794b46.camel@infradead.org/ > [4] https://lore.kernel.org/lkml/20241219204208.3160-1-quic_philber@quicinc.com/ > > > Peter Hilber (4): > virtio-rtc: Add initial device specification > virtio-rtc: Add initial normative statements > virtio-rtc: Add alarm feature > virtio-rtc: Add normative statements for alarm feature > > conformance.tex | 2 + > content.tex | 3 +- > device-types/rtc/description.tex | 1100 +++++++++++++++++++++++ > device-types/rtc/device-conformance.tex | 13 + > device-types/rtc/driver-conformance.tex | 11 + > introduction.tex | 6 + > 6 files changed, 1134 insertions(+), 1 deletion(-) > create mode 100644 device-types/rtc/description.tex > create mode 100644 device-types/rtc/device-conformance.tex > create mode 100644 device-types/rtc/driver-conformance.tex > > > base-commit: 124fcd0e97f209aab19639e7369116d99ede22a2 > -- > 2.43.0 >