On 10/07/20 22:07, Oliver Upton wrote: > From: Peter Hornyack <peterhornyack@xxxxxxxxxx> > > The KVM_SET_MSR vcpu ioctl has some temporal and value-based heuristics > for determining when userspace is attempting to synchronize TSCs. > Instead of guessing at userspace's intentions in the kernel, directly > expose control of the TSC offset field to userspace such that userspace > may deliberately synchronize the guest TSCs. > > Note that TSC offset support is mandatory for KVM on both SVM and VMX. > > Reviewed-by: Jim Mattson <jmattson@xxxxxxxxxx> > Signed-off-by: Peter Hornyack <peterhornyack@xxxxxxxxxx> > Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx> > --- > Documentation/virt/kvm/api.rst | 27 +++++++++++++++++++++++++++ > arch/x86/kvm/x86.c | 28 ++++++++++++++++++++++++++++ > include/uapi/linux/kvm.h | 5 +++++ > 3 files changed, 60 insertions(+) Needless to say, a patch that comes with tests starts on the fast lane. But I have a fundamental question that isn't answered by either the test or the documentation: how should KVM_SET_TSC_OFFSET be used _in practice_ by a VMM? Thanks, Paolo
