From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932600AbcIFGU2 (ORCPT ); Tue, 6 Sep 2016 02:20:28 -0400 Received: from mail-wm0-f50.google.com ([74.125.82.50]:35469 "EHLO mail-wm0-f50.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932183AbcIFGUZ (ORCPT ); Tue, 6 Sep 2016 02:20:25 -0400 Date: Tue, 6 Sep 2016 08:22:52 +0200 From: Christoffer Dall To: Punit Agrawal Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, kvmarm@lists.cs.columbia.edu, linux-arm-kernel@lists.infradead.org, Marc Zyngier , Steven Rostedt , Ingo Molnar , Will Deacon , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= Subject: Re: [RFC v2 PATCH 2/7] KVM: Track the pid of the VM process Message-ID: <20160906062252.GA30513@cbox> References: <1473093097-30932-1-git-send-email-punit.agrawal@arm.com> <1473093097-30932-3-git-send-email-punit.agrawal@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <1473093097-30932-3-git-send-email-punit.agrawal@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 05, 2016 at 05:31:32PM +0100, Punit Agrawal wrote: > Userspace tools such as perf can be used to profile individual > processes. > > Track the PID of the virtual machine process to match profiling requests > targeted at it. This can be used to take appropriate action to enable > the requested profiling operations for the VMs of interest. > > Signed-off-by: Punit Agrawal > Cc: Paolo Bonzini > Cc: "Radim Krčmář" > Cc: Christoffer Dall > Cc: Marc Zyngier > --- > include/linux/kvm_host.h | 1 + > virt/kvm/kvm_main.c | 2 ++ > 2 files changed, 3 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 9c28b4d..7c42c94 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -374,6 +374,7 @@ struct kvm_memslots { > struct kvm { > spinlock_t mmu_lock; > struct mutex slots_lock; > + struct pid *pid; > struct mm_struct *mm; /* userspace tied to this vm */ > struct kvm_memslots *memslots[KVM_ADDRESS_SPACE_NUM]; > struct srcu_struct srcu; > diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c > index 1950782..ab2535a 100644 > --- a/virt/kvm/kvm_main.c > +++ b/virt/kvm/kvm_main.c > @@ -613,6 +613,7 @@ static struct kvm *kvm_create_vm(unsigned long type) > spin_lock_init(&kvm->mmu_lock); > atomic_inc(¤t->mm->mm_count); > kvm->mm = current->mm; > + kvm->pid = get_task_pid(current, PIDTYPE_PID); How dooes this deal with threading? Is the idea that the user by specifying the main thread's pid will enable trapping for all vcpu threads belonging to that VM? > kvm_eventfd_init(kvm); > mutex_init(&kvm->lock); > mutex_init(&kvm->irq_lock); > @@ -712,6 +713,7 @@ static void kvm_destroy_vm(struct kvm *kvm) > int i; > struct mm_struct *mm = kvm->mm; > > + put_pid(kvm->pid); > kvm_destroy_vm_debugfs(kvm); > kvm_arch_sync_events(kvm); > spin_lock(&kvm_lock); > -- > 2.8.1 >