From mboxrd@z Thu Jan 1 00:00:00 1970 From: mark.rutland@arm.com (Mark Rutland) Date: Fri, 6 Nov 2015 11:59:16 +0000 Subject: [PATCH v11 5/5] xen/arm: account for stolen ticks In-Reply-To: <563C91FD.7060703@citrix.com> References: <1446737696-9749-5-git-send-email-stefano.stabellini@eu.citrix.com> <20151105165743.GG32247@leverpostej> <563C91FD.7060703@citrix.com> Message-ID: <20151106115916.GA23038@leverpostej> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Nov 06, 2015 at 11:41:49AM +0000, David Vrabel wrote: > On 06/11/15 11:39, Stefano Stabellini wrote: > > On Thu, 5 Nov 2015, Mark Rutland wrote: > >>> static void xen_percpu_init(void) > >>> { > >>> struct vcpu_register_vcpu_info info; > >>> @@ -104,6 +120,8 @@ static void xen_percpu_init(void) > >>> BUG_ON(err); > >>> per_cpu(xen_vcpu, cpu) = vcpup; > >>> > >>> + xen_setup_runstate_info(cpu); > >> > >> Does the runstate memory area get unregsitered when a kernel tears > >> things down, or is kexec somehow inhibited for xen guests? > >> > >> i couldn't spot either happening, but I may have missed it. > > > > I don't think that the runstate memory area needs to be unregistered for > > kexec, but I am not very knowledgeble on kexec and Xen, CC'ing Vitaly > > and David. > > There's a whole pile of other state needing to be reset for kexec (event > channels and grant tables for example). The guest needs to soft reset > itself (available in Xen 4.6) before kexec'ing another kernel. > > This soft reset would also including cleaning up this shared memory region. Ok. So we don't currently have the code kernel-side, but it looks like it would be relatively simple to add (having just spotted [1]), and everything should be ready on the Xen side.` Thanks, Mark. [1] https://lkml.org/lkml/2015/9/25/152