KVM: track pid for VCPU only on KVM_RUN ioctl

We currently track the pid of the task that runs the VCPU in vcpu_load.
If a yield to that VCPU is triggered while the PID of the wrong thread
is active, the wrong thread might receive a yield, but this will most
likely not help the executing thread at all.  Instead, if we only track
the pid on the KVM_RUN ioctl, there are two possibilities:

1) the thread that did a non-KVM_RUN ioctl is holding a mutex that
the VCPU thread is waiting for.  In this case, the VCPU thread is not
runnable, but we also do not do a wrong yield.

2) the thread that did a non-KVM_RUN ioctl is sleeping, or doing
something that does not block the VCPU thread.  In this case, the
VCPU thread can receive the directed yield correctly.

Signed-off-by: Christian Borntraeger <[email protected]>
CC: Rik van Riel <[email protected]>
CC: Raghavendra K T <[email protected]>
CC: Michael Mueller <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

0 files changed, 0 insertions, 0 deletions