From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:41959) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fVdya-0007N9-6Y for qemu-devel@nongnu.org; Wed, 20 Jun 2018 10:20:48 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fVdyV-00033w-8v for qemu-devel@nongnu.org; Wed, 20 Jun 2018 10:20:48 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:37344 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fVdyV-00033q-1t for qemu-devel@nongnu.org; Wed, 20 Jun 2018 10:20:43 -0400 References: <20180615222855.44421-1-mst@redhat.com> <20180615222855.44421-2-mst@redhat.com> <20180619233509-mutt-send-email-mst@kernel.org> From: Paolo Bonzini Message-ID: <75758aed-81ab-d320-595d-3c7832faa8d8@redhat.com> Date: Wed, 20 Jun 2018 16:20:40 +0200 MIME-Version: 1.0 In-Reply-To: <20180619233509-mutt-send-email-mst@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 1/2] kvm: support -dedicated cpu-pm=on|off List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, Richard Henderson , Eduardo Habkost , Marcelo Tosatti , kvm@vger.kernel.org On 19/06/2018 22:43, Michael S. Tsirkin wrote: > >> 2) Maybe -hostresource? > > Is ability to cause high latency for other threads really a resource? The "resource" here is host CPU time. In general, a vCPU with KVM_CPU_X86_DISABLE_EXITS will use more host CPU time and block overcommitting, just like mlock does for memory. Paolo > The issues in question: > 1. a malicious guest can cause high latency for others sharing the host cpu. > 2. to host scheduler cpu looks busier than it really is.