From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Userspace hypercalls? Date: Thu, 30 Aug 2007 00:24:01 +0300 Message-ID: <46D5E3F1.2020609@qumranet.com> References: <1188228447.12698.8.camel@squirrel> <46D2F8FA.6050104@qumranet.com> <46D2FCE1.7020605@qumranet.com> <64F9B87B6B770947A9F8391472E032160D6558D8@ehost011-8.exch011.intermedia.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel To: Dor Laor Return-path: In-Reply-To: <64F9B87B6B770947A9F8391472E032160D6558D8-yEcIvxbTEBqsx+V+t5oei8rau4O3wl8o3fe8/T/H7NteoWH0uzbU5w@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Dor Laor wrote: >> >> Thinking a little more about this, it isn't about handling hypercalls >> > in > >> userspace, but about handling a virtio sync() in userspace. >> >> So how about having a KVM_HC_WAKE_CHANNEL hypercall (similar to Xen's >> event channel, but assymetric) that has a channel parameter. The >> > kernel > >> handler for that hypercall dispatches calls to either a kernel handler >> or a userspace handler. That means we don't need a separate ETH_SEND, >> ETH_RECEIVE, or BLOCK_SEND hypercalls. >> >> > > Some points: > - These were none receive/send/block_send hypercalls on the first place. > There were just register and notify hypercalls. > But they were ethernet/block/whatever specific. I'm proposing a single "wake this channel up" hypercall. > - The balloon code also uses hypercalls and let userspace handle them so > higher layer will allow the guest inflate/deflate actions. > That could be ported to virtio. It is actually advantageous to balloon asynchronously. -- Any sufficiently difficult bug is indistinguishable from a feature. ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/