From mboxrd@z Thu Jan 1 00:00:00 1970 From: marc.zyngier@arm.com (Marc Zyngier) Date: Thu, 20 Sep 2012 16:02:48 +0200 Subject: [PATCH 01/10] ARM: KVM: Keep track of currently running vcpus In-Reply-To: <001401cd972e$f18cd1c0$d4a67540$@samsung.com> References: <20120915153657.21545.3972.stgit@ubuntu> <001401cd972e$f18cd1c0$d4a67540$@samsung.com> Message-ID: <13e04ac2694ba74a724c2c7a59344d2f@localhost> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 20 Sep 2012 21:53:33 +0900, Min-gyu Kim wrote: >> -----Original Message----- >> From: kvm-owner at vger.kernel.org [mailto:kvm-owner at vger.kernel.org] On >> Behalf Of Christoffer Dall >> Sent: Sunday, September 16, 2012 12:37 AM >> To: kvm at vger.kernel.org; linux-arm-kernel at lists.infradead.org; >> kvmarm at lists.cs.columbia.edu >> Subject: [PATCH 01/10] ARM: KVM: Keep track of currently running vcpus >> >> From: Marc Zyngier >> >> When an interrupt occurs for the guest, it is sometimes necessary to find >> out which vcpu was running at that point. >> >> Keep track of which vcpu is being tun in kvm_arch_vcpu_ioctl_run(), and >> allow the data to be retrived using either: >> - kvm_arm_get_running_vcpu(): returns the vcpu running at this point >> on the current CPU. Can only be used in a non-preemptable context. > > What's the purpose of kvm_arm_get_running_vcpu? > It seems to be enough to pass vcpu struct through function argument, > and there is no caller by now. This is also designed to be used in an interrupt handler, and is used by the (currently out of tree) perf code: https://lists.cs.columbia.edu/pipermail/kvmarm/2012-September/003192.html Basically, you need this infrastructure when handling interrupts. M. -- Fast, cheap, reliable. Pick two.