From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zachary Amsden Subject: Re: [PATCH: kvm 3/5] Fix hotadd of CPUs for KVM. Date: Sun, 27 Sep 2009 15:39:51 -1000 Message-ID: <4AC013E7.1030508@redhat.com> References: <20090924151049.GB14102@amt.cnet> <1253839640-12695-1-git-send-email-zamsden@redhat.com> <1253839640-12695-2-git-send-email-zamsden@redhat.com> <1253839640-12695-3-git-send-email-zamsden@redhat.com> <1253839640-12695-4-git-send-email-zamsden@redhat.com> <4ABF27C8.2000406@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Marcelo Tosatti To: Avi Kivity Return-path: In-Reply-To: <4ABF27C8.2000406@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: kvm.vger.kernel.org On 09/26/2009 10:52 PM, Avi Kivity wrote: > On 09/25/2009 03:47 AM, Zachary Amsden wrote: >> >> --- a/virt/kvm/kvm_main.c >> +++ b/virt/kvm/kvm_main.c >> @@ -1716,9 +1716,6 @@ static int kvm_cpu_hotplug(struct >> notifier_block *notifier, unsigned long val, >> { >> int cpu = (long)v; >> >> - if (!kvm_usage_count) >> - return NOTIFY_OK; >> - > > Why? You'll now do hardware_enable() even if kvm is not in use. Because otherwise you'll never allocate and hardware_enable_all will fail: Switch to broadcast mode on CPU1 svm_hardware_enable: svm_data is NULL on 1 kvm: enabling virtualization on CPU1 failed qemu-system-x86[8698]: segfault at 20 ip 00000000004db22f sp 00007fff0a3b4560 error 6 in qemu-system-x86_64[400000+21f000] Perhaps I can make this work better by putting the allocation within hardware_enable_all. Zach