On Wed, Feb 10, 2021 at 07:39:08PM +0900, Hikaru Nishida wrote: > From: Hikaru Nishida <hikal...@chromium.org> > > This adds a sysfs interface /sys/kernel/boottime_adj to enable advancing > CLOCK_BOOTTIME from the userspace without actual susupend/resume cycles. > > This gives a way to mitigate CLOCK_BOOTTIME divergence between guest > and host on virtualized environments after suspend/resume cycles on > the host. > > We observed an issue of a guest application that expects there is a gap > between CLOCK_BOOTTIME and CLOCK_MONOTONIC after the device is suspended > to detect whether the device went into suspend or not. > Since the guest is paused instead of being actually suspended during the > host's suspension, guest kernel doesn't advance CLOCK_BOOTTIME correctly > and there is no way to correct that. > > To solve the problem, this change introduces a way to modify a gap > between those clocks and align the timer behavior to host's one. > > Signed-off-by: Hikaru Nishida <hikal...@chromium.org> > --- > > drivers/virt/Kconfig | 9 ++++++ > drivers/virt/Makefile | 1 + > drivers/virt/boottime_adj.c | 57 +++++++++++++++++++++++++++++++++++++ > 3 files changed, 67 insertions(+) > create mode 100644 drivers/virt/boottime_adj.c
No Documentation/ABI/ update for your new sysfs file? Please fix...
