From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by ozlabs.org (Postfix) with ESMTP id 8E2B5B6F35 for ; Mon, 28 Jun 2010 18:13:08 +1000 (EST) Message-ID: <4C285991.1050303@redhat.com> Date: Mon, 28 Jun 2010 11:13:05 +0300 From: Avi Kivity MIME-Version: 1.0 To: Alexander Graf Subject: Re: [PATCH 26/26] KVM: PPC: Add Documentation about PV interface References: <1277508314-915-1-git-send-email-agraf@suse.de> <07C9A4B8-881A-438C-AA99-AEC23887C6B8@suse.de> <4C270876.2050806%40redhat.com> <1277709531_13308@mail4.comsite.net> <92F4A3F3-A89F-418D-BD4D-66E2489F2E42@suse.de> In-Reply-To: <92F4A3F3-A89F-418D-BD4D-66E2489F2E42@suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev , kvm-ppc@vger.kernel.org, Milton Miller , KVM list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 06/28/2010 10:49 AM, Alexander Graf wrote: > >> I don't believe we support the kernel actually doing a syscall to itself >> anymore, at least on powerpc. The callers call the underlying system >> call function, or kernel_thread. >> >> That said, I would suggest we allocate a syscall number for this, as it >> would document the usage. (In additon to 0..nr_syscalls - 1 we have >> 0x1ebe in use). >> > That's actually a pretty good idea. > Since the syscall register is not architectual (or rather it is architectural but Linux ignores it) I don't see the point. It would work for Linux but may alias some random parameter for a different guest. We need a reliable method of distinguishing between syscalls and hypercalls. Matching pc would work (but is defeated by inlining) so long as we find some other way of identifying the hc pc to the hypervisor. -- error compiling committee.c: too many arguments to function