From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754199AbcKUOui (ORCPT ); Mon, 21 Nov 2016 09:50:38 -0500 Received: from mx1.redhat.com ([209.132.183.28]:50981 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753622AbcKUOuf (ORCPT ); Mon, 21 Nov 2016 09:50:35 -0500 Subject: Re: [PATCH v1 2/3] kvm: svm: Add kvm_fast_pio_in support To: Brijesh Singh , kvm@vger.kernel.org References: <147916172660.16347.15695649975899246333.stgit@brijesh-build-machine> <147916175150.16347.2494044229416144843.stgit@brijesh-build-machine> Cc: Thomas.Lendacky@amd.com, rkrcmar@redhat.com, joro@8bytes.org, x86@kernel.org, linux-kernel@vger.kernel.org, mingo@redhat.com, hpa@zytor.com, tglx@linutronix.de, bp@suse.de From: Paolo Bonzini Message-ID: <63d4112c-71c4-9d6f-60dc-c5a71c03df7a@redhat.com> Date: Mon, 21 Nov 2016 15:50:29 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <147916175150.16347.2494044229416144843.stgit@brijesh-build-machine> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Mon, 21 Nov 2016 14:50:35 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/11/2016 23:15, Brijesh Singh wrote: > + /* For size less than 4 we merge, else we zero extend */ > + val = (size < 4) ? kvm_register_read(vcpu, VCPU_REGS_RAX) : 0; Are you sure it shouldn't always zero extend the high 32-bits? So "val" should be declared as u32. Paolo > + ret = emulator_pio_in_emulated(&vcpu->arch.emulate_ctxt, size, port, > + &val, 1); > + if (ret) { > + kvm_register_write(vcpu, VCPU_REGS_RAX, val); > + return ret; > + }