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| author |   Zachary Amsden <zamsden@redhat.com> | 2010-08-19 22:07:30 -1000 |
|---|---|---|
| committer |   Avi Kivity <avi@redhat.com> | 2010-10-24 10:51:24 +0200 |
| commit | 1d5f066e0b63271b67eac6d3752f8aa96adcbddb (patch) | |
| tree | b3ba7c2783edbc6d9e6658d91e991913ba264684 /include | |
| parent | x86: pvclock: Move scale_delta into common header (diff) | |
| download | linux-dev-1d5f066e0b63271b67eac6d3752f8aa96adcbddb.tar.xz linux-dev-1d5f066e0b63271b67eac6d3752f8aa96adcbddb.zip | |
KVM: x86: 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 tsc) than the value to which we are
setting it (kernel_ns + 0).
We must instead compute the clock as potentially observed by the guest
for kernel_ns to make sure it does not go backwards.
Signed-off-by: Zachary Amsden <zamsden@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'include')
0 files changed, 0 insertions, 0 deletions