From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754556AbeEHHzk (ORCPT ); Tue, 8 May 2018 03:55:40 -0400 Received: from mail-oi0-f68.google.com ([209.85.218.68]:32997 "EHLO mail-oi0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754269AbeEHHzi (ORCPT ); Tue, 8 May 2018 03:55:38 -0400 X-Google-Smtp-Source: AB8JxZrK3C/ri+GhUFeCWfeMa7r/P/n/tcglnpK4OOaD5NOVk4c7peOdx2CS9hDnMQlCSYqi7DbIfuDACec27EquQXM= MIME-Version: 1.0 In-Reply-To: <1523943962-25415-1-git-send-email-wanpengli@tencent.com> References: <1523943962-25415-1-git-send-email-wanpengli@tencent.com> From: Wanpeng Li Date: Tue, 8 May 2018 15:55:37 +0800 Message-ID: Subject: Re: [PATCH 0/3] KVM: VMX: Allow to disable ioport intercept per-VM by userspace To: LKML , kvm Cc: Paolo Bonzini , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= , Tim Shearer , Liran Alon Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from quoted-printable to 8bit by mail.home.local id w487tkcF028571 2018-04-17 13:45 GMT+08:00 Wanpeng Li : > Tim Shearer reported that "There is a guest which is running a packet > forwarding app based on the DPDK (dpdk.org). The packet receive routine > writes to 0xc070 using glibc's "outw_p" function which does an additional > write to I/O port 0x80. It does this write for every packet that's > received, causing a flood of KVM userspace context switches". He uses > mpstat to observe a CPU performing L2 packet forwarding on a pinned > guest vCPU, the guest time is 95 percent when allowing I/O port 0x80 > bypass, however, it is 65.78 percent when I/O port 0x80 bypss is > disabled. > > This patchset introduces per-VM I/O permission bitmaps, the userspace > can disable the ioport intercept when they are more concern the > performance than the security. > > Cc: Paolo Bonzini > Cc: Radim Krčmář > Cc: Tim Shearer > Cc: Liran Alon > Hi Paolo, Did you send the patch to glibc or the patchset still can be considered? Regards, Wanpeng Li > Wanpeng Li (3): > KVM: VMX: Introduce per-VM I/O permission bitmaps > KVM: X86: Allow userspace to disable ioport intercept > KVM: VMX: Allow I/O port 0x80 bypass when userspace prefer > > Documentation/virtual/kvm/api.txt | 11 +++++++++++ > arch/x86/include/asm/kvm_host.h | 2 ++ > arch/x86/kvm/vmx.c | 41 ++++++++++++++++++++++++++++++++++++--- > arch/x86/kvm/x86.c | 5 +++++ > include/uapi/linux/kvm.h | 1 + > 5 files changed, 57 insertions(+), 3 deletions(-) > > -- > 2.7.4 >