From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH v2 28/30] KVM: x86 emulator: restart string instruction without going back to a guest. Date: Mon, 15 Mar 2010 12:15:22 +0200 Message-ID: <4B9E08BA.7090303@redhat.com> References: <1268583675-3101-1-git-send-email-gleb@redhat.com> <1268583675-3101-29-git-send-email-gleb@redhat.com> <4B9D1545.2020902@redhat.com> <20100314180625.GB5406@redhat.com> <4B9DE55A.5070003@redhat.com> <20100315094447.GG4294@redhat.com> <4B9E0450.4090403@redhat.com> <20100315100756.GH4294@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:7346 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S936064Ab0COKPY (ORCPT ); Mon, 15 Mar 2010 06:15:24 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o2FAFNwb024972 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 15 Mar 2010 06:15:24 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o2FAFMD7002235 for ; Mon, 15 Mar 2010 06:15:23 -0400 In-Reply-To: <20100315100756.GH4294@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 03/15/2010 12:07 PM, Gleb Natapov wrote: > >> Or we can make the buffer larger for everyone (outside this patchset >> though). >> >> > I am not sure what do you mean here. INS read ahead and MMIO read cache are > different beasts. Former is needed to speed-up string pio reads, later > (not yet implemented) is needed to reread previous MMIO read results in > case instruction emulation is restarted due to need to exit to userspace. > MMIO read cache need to be invalidated on each iteration of string > instruction. > Instructions with multiple reads or writes need an mmio read/write buffer that can be replayed on re-execution. buffer != cache! A cache can be dropped (perhaps after flushing it to a backing store), but a buffer in general cannot. -- error compiling committee.c: too many arguments to function