| commit | 960d355dc60d998dcd7b389b84ffefad9b612650 | |
| author | Jan Kiszka <jan.kiszka@siemens.com> | |
| Wed, 6 Jun 2012 14:28:42 +0000 (6 16:28 +0200) | ||
| committer | Marcelo Tosatti <mtosatti@redhat.com> | |
| Sat, 30 Jun 2012 02:02:10 +0000 (29 23:02 -0300) | ||
| tree | e756c8b0329b37ddd2e2043bc564ba1213173316 | treesnapshot (tar.gz zip) |
| parent | 15ecf28f39e2b6fba359ed094770c8fa4ad8dc60 | commitdiff |
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>
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>
| hw/kvm/i8254.c | diffblobblamehistory |