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c51100f9e2
Implement the read_snapshot() callback for the Hyper-V TSC page clock- source. This returns the derived 10MHz reference time (for timekeeping) while also providing the raw TSC value that was used to compute it. When the TSC page is valid, hv_read_tsc_page_tsc() atomically captures both values from a single RDTSC inside the sequence-counter protected read. When the TSC page is invalid (sequence == 0), the hw_csid and hw_cycles are set to zero indicating no value is available. This enables ktime_get_snapshot_id() to provide the raw TSC to consumers like KVM's master clock when running nested guests under Hyper-V. Signed-off-by: David Woodhouse <dwmw@amazon.co.uk> Signed-off-by: Thomas Gleixner <tglx@kernel.org> Assisted-by: Kiro:claude-opus-4.6-1m Reviewed-by: Michael Kelley <mhklinux@outlook.com> Link: https://patch.msgid.link/20260604095755.64849-2-dwmw2@infradead.org
668 lines
18 KiB
668 lines
18 KiB