tree a59e85a1e9a7ed208704f811e978b7342a63e185
parent 0614cb82ca27bdffb83864e693fc29e29182667b
author Jan Kiszka <jan.kiszka@siemens.com> 1338992922 +0200
committer Avi Kivity <avi@redhat.com> 1339413503 +0300

kvm: i8254: Fix conversion of in-kernel to userspace state

Due to a offset between the clock used to generate the in-kernel
count_load_time (CLOCK_MONOTONIC) and the clock used for processing this
in userspace (vm_clock), reading back the output of PIT channel 2 via
port 0x61 was broken. One use cases that suffered from it was the CPU
frequency calibration of SeaBIOS, which also affected IDE/AHCI timeouts.

This fixes it by calibrating the offset between both clocks on
kvm_pit_get and adjusting the kernel value before saving it in the
userspace state. As the calibration only works while the vm_clock is
running, we cache the in-kernel state across stopped phases.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Avi Kivity <avi@redhat.com>