On 18/09/2015 17:54, Radim Krčmář wrote: > This patch series will be disabling PVCLOCK_COUNTS_FROM_ZERO flag and is > RFC because I haven't explored many potential problems or tested it. > > [1/2] uses a different algorithm in the guest to start counting from 0. > [2/2] stops exposing PVCLOCK_COUNTS_FROM_ZERO in the hypervisor. > > A viable alternative would be to implement opt-in features in kvm clock. > > And because we probably only broke one old user (the infamous SLES 10), a > workaround like this is also possible: (but I'd rather not do that) Thanks, applying 2/2 for 4.4 and 1/2 for 4.3. Paolo > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index a60bdbccff51..ae9049248aaf 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -2007,7 +2007,8 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info) > > ka->boot_vcpu_runs_old_kvmclock = tmp; > > - ka->kvmclock_offset = -get_kernel_ns(); > + if (!ka->boot_vcpu_runs_old_kvmclock) > + ka->kvmclock_offset = -get_kernel_ns(); > } > > vcpu->arch.time = data; > > > Radim Krčmář (2): > x86: kvmclock: abolish PVCLOCK_COUNTS_FROM_ZERO > Revert "KVM: x86: zero kvmclock_offset when vcpu0 initializes kvmclock > system MSR" > > arch/x86/include/asm/pvclock-abi.h | 1 + > arch/x86/kernel/kvmclock.c | 46 +++++++++++++++++++++++++++++--------- > arch/x86/kvm/x86.c | 4 ---- > 3 files changed, 36 insertions(+), 15 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
