Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753193AbbH3JMq (ORCPT ); Sun, 30 Aug 2015 05:12:46 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53058 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751701AbbH3JMo (ORCPT ); Sun, 30 Aug 2015 05:12:44 -0400 Date: Sun, 30 Aug 2015 12:12:41 +0300 From: "Michael S. Tsirkin" To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, Paolo Bonzini Subject: [PATCH RFC 0/3] kvm add ioeventfd pf capability Message-ID: <1440925898-23440-1-git-send-email-mst@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline X-Mutt-Fcc: =sent Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1056 Lines: 31 One of the reasons MMIO is slower than port IO is because it requires a page table lookup. For normal memory accesses, this is solved by using the TLB cache - but MMIO entries are either not present or reserved and so are never cached. To fix, allow installing an ioeventfd on top of a read only memory region, which allows the CPU to cache the translations. Warning: svm patch is untested. Michael S. Tsirkin (3): vmx: allow ioeventfd for EPT violations svm: allow ioeventfd for NPT page faults kvm: add KVM_CAP_IOEVENTFD_PF capability include/uapi/linux/kvm.h | 1 + arch/x86/kvm/svm.c | 5 +++++ arch/x86/kvm/vmx.c | 5 +++++ arch/x86/kvm/x86.c | 1 + Documentation/virtual/kvm/api.txt | 7 +++++++ 5 files changed, 19 insertions(+) -- MST -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/