diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2015-01-20 15:54:52 -0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-01-20 20:38:39 +0100 |
| commit | 54750f2cf042c42b4223d67b1bd20138464bde0e (patch) | |
| tree | e7914883c6452ee68f2b8f7e583db12d2afbe955 /arch/x86/include/asm | |
| parent | 69b0049a89ad418cd68aa59e7f1e6619a04a4a6f (diff) | |
KVM: x86: workaround SuSE's 2.6.16 pvclock vs masterclock issue
SuSE's 2.6.16 kernel fails to boot if the delta between tsc_timestamp
and rdtsc is larger than a given threshold:
* If we get more than the below threshold into the future, we rerequest
* the real time from the host again which has only little offset then
* that we need to adjust using the TSC.
*
* For now that threshold is 1/5th of a jiffie. That should be good
* enough accuracy for completely broken systems, but also give us swing
* to not call out to the host all the time.
*/
#define PVCLOCK_DELTA_MAX ((1000000000ULL / HZ) / 5)
Disable masterclock support (which increases said delta) in case the
boot vcpu does not use MSR_KVM_SYSTEM_TIME_NEW.
Upstreams kernels which support pvclock vsyscalls (and therefore make
use of PVCLOCK_STABLE_BIT) use MSR_KVM_SYSTEM_TIME_NEW.
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/include/asm')
| -rw-r--r-- | arch/x86/include/asm/kvm_host.h | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index 97a5dd0222c..177b2f2ff9f 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -627,6 +627,8 @@ struct kvm_arch { #ifdef CONFIG_KVM_MMU_AUDIT int audit_point; #endif + + bool boot_vcpu_runs_old_kvmclock; }; struct kvm_vm_stat { |