From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 3/3] KVM: x86 emulator: fuzz tester Date: Mon, 29 Aug 2011 15:42:41 +0300 Message-ID: <4E5B8941.9040807@redhat.com> References: <1314020469-30882-1-git-send-email-avi@redhat.com> <1314020469-30882-4-git-send-email-avi@redhat.com> <20110825162753.GA6617@amt.cnet> <4E569CD4.6010101@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: lmr@redhat.com, kvm@vger.kernel.org To: Marcelo Tosatti Return-path: Received: from mx1.redhat.com ([209.132.183.28]:3243 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751037Ab1H2Mmo (ORCPT ); Mon, 29 Aug 2011 08:42:44 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id p7TCghFs010616 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 29 Aug 2011 08:42:43 -0400 In-Reply-To: <4E569CD4.6010101@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 08/25/2011 10:04 PM, Avi Kivity wrote: > >> Also fuzzing from an actual guest is useful to test the real backend >> functions. What problem did you encounter? The new testsuite scheme >> seems a good fit for that (with the exception of being locked to 32-bit >> mode). > > Mostly that I forgot it exists. Other issues are that it's harder to > force random values through it - though I could allocate a couple GB > and fill it with random values. We also lose the ability to test > inputs to callbacks (not that I do much of that here). Further issues would be: - much slower - heavyweight exit on every insn, KVM_SET_SREGS, etc. - need to set up GDT/LDT, I guess we can do this once and fill it with random entries - much more care in setting up registers so we can get a context that runs - need to figure out where %rip EA is so we can put insn there, hope it doesn't conflict with other code So it will probably work, but the result will be of lower quality. -- error compiling committee.c: too many arguments to function