Revision 0cdd3d14
| ID | 0cdd3d14447da1a04e778c219c77db8b96f9cf33 |
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>
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