From: Christian Borntraeger Date: Tue, 5 Aug 2014 14:44:14 +0000 (+0200) Subject: KVM: track pid for VCPU only on KVM_RUN ioctl X-Git-Tag: omap-for-v3.20/drop-legacy-3517~40^2~20 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7a72f7a140bfd3a5dae73088947010bfdbcf6a40;p=pandora-kernel.git 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 CC: Rik van Riel CC: Raghavendra K T CC: Michael Mueller Signed-off-by: Paolo Bonzini --- Reading git-diff-tree failed