Kernel

[PATCH 10/18] Keep SMP VMs more in sync on unstable TSC
SMP VMs on machines with unstable TSC have their TSC offset adjusted by the local offset delta from last measurement. This does not take into account how long it has been since the measurement, leading to drift. Minimize the drift by accounting for any time difference the kernel has observed. Signed-off-by: Zac... 12 Jul 2010 22:56

[PATCH 09/18] Robust TSC compensation
Make the match of TSC find TSC writes that are close to each other instead of perfectly identical; this allows the compensator to also work in migration / suspend scenarios. Signed-off-by: Zachary Amsden <zamsden(a)redhat.com> --- arch/x86/kvm/x86.c | 14 ++++++++++---- 1 files changed, 10 insertions(+), 4 del... 12 Jul 2010 22:56

[PATCH 06/18] Unify TSC logic
Move the TSC control logic from the vendor backends into x86.c by adding adjust_tsc_offset to x86 ops. Now all TSC decisions can be done in one place. Also, rename some variable in the VCPU structure to more accurately reflect their actual content. Signed-off-by: Zachary Amsden <zamsden(a)redhat.com> --- arc... 12 Jul 2010 22:56

[PATCH 04/18] Make cpu_tsc_khz updates use local CPU
This simplifies much of the init code; we can now simply always call tsc_khz_changed, optionally passing it a new value, or letting it figure out the existing value (while interrupts are disabled, and thus, by inference from the rule, not raceful against CPU hotplug or frequency updates, which will issue IPIs to th... 12 Jul 2010 22:56

[PATCH 14/18] Fix a possible backwards warp of kvmclock
Kernel time, which advances in discrete steps may progress much slower than TSC. As a result, when kvmclock is adjusted to a new base, the apparent time to the guest, which runs at a much higher, nsec scaled rate based on the current TSC, may have already been observed to have a larger value (kernel_ns + scaled ts... 12 Jul 2010 22:56

[PATCH 11/18] Perform hardware_enable in CPU_STARTING callback
The CPU_STARTING callback was added upstream with the intention of being used for KVM, specifically for the hardware enablement that must be done before we can run in hardware virt. It had bugs on the x86_64 architecture at the time, where it was called after CPU_ONLINE. The arches have since merged and the bug i... 12 Jul 2010 22:56

KVM timekeeping fixes, V2
Discovered brammage in patches due to unresolved merge. Also, had to move 09/18 past 08/18 to resolve compile issue. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html ... 19 Jul 2010 04:50

[PATCH 15/18] Implement getnsboottime kernel API
Add a kernel call to get the number of nanoseconds since boot. This is generally useful enough to make it a generic call. Signed-off-by: Zachary Amsden <zamsden(a)redhat.com> --- include/linux/time.h | 1 + kernel/time/timekeeping.c | 27 +++++++++++++++++++++++++++ 2 files changed, 28 insertions(+), ... 12 Jul 2010 22:56

[PATCH 11/18] Perform hardware_enable in CPU_STARTING callback
The CPU_STARTING callback was added upstream with the intention of being used for KVM, specifically for the hardware enablement that must be done before we can run in hardware virt. It had bugs on the x86_64 architecture at the time, where it was called after CPU_ONLINE. The arches have since merged and the bug i... 12 Jul 2010 22:56

[PATCH 12/18] Add clock sync request to hardware enable
If there are active VCPUs which are marked as belonging to a particular hardware CPU, request a clock sync for them when enabling hardware; the TSC could be desynchronized on a newly arriving CPU, and we need to recompute guests system time relative to boot after a suspend event. This covers both cases. Note ... 12 Jul 2010 22:56