From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Date: Thu, 16 Apr 2009 08:59:15 +0000 Subject: Re: switching from KVM guest to the host .... TLBs not present? Message-Id: <49E6F363.3040908@redhat.com> List-Id: References: <49DE0856.8010700@sgi.com> In-Reply-To: <49DE0856.8010700@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ia64@vger.kernel.org Jes Sorensen wrote: > Avi Kivity wrote: >> Applied, but I note that entering the guest with any lock held is >> problematic, as the guest may spend an arbitrary amount of time in >> guest mode. Really, entering the guest is almost exactly like >> exiting to userspace. > > Hi Avi, > > I had a look at this and reworked the locking some, so we don't hold > the slots_lock when entering the guest. > > How does this look? Xiantao any thoughts of whether it's unsafe to call > kvm_vcpu_post_transition without holding that semaphore? I believe it > should be fine. > > I am still seeing issues where the host can get a lock timeout when > running large guests, but the situation seems to be better with this > patch applied. > It looks fine, though I'm hardly qualified to review ia64 code. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.