tree 5c84e0392454df650cb4ce25d6bfcb3bac843bc3
parent cb26b572dc39467ba0969d1a76c2f723d2d6a2a6
author Avi Kivity <avi@qumranet.com> 1168043798 -0800
committer Linus Torvalds <torvalds@woody.osdl.org> 1168070123 -0800

[PATCH] KVM: Prevent stale bits in cr0 and cr4

Hardware virtualization implementations allow the guests to freely change some
of the bits in cr0 and cr4, but trap when changing the other bits.  This is
useful to avoid excessive exits due to changing, for example, the ts flag.

It also means the kvm's copy of cr0 and cr4 may be stale with respect to these
bits.  most of the time this doesn't matter as these bits are not very
interesting.  Other times, however (for example when returning cr0 to
userspace), they are, so get the fresh contents of these bits from the guest
by means of a new arch operation.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>