Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934570Ab3FSJNG (ORCPT ); Wed, 19 Jun 2013 05:13:06 -0400 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:45906 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934321Ab3FSJJo (ORCPT ); Wed, 19 Jun 2013 05:09:44 -0400 From: Xiao Guangrong To: gleb@redhat.com Cc: avi.kivity@gmail.com, mtosatti@redhat.com, pbonzini@redhat.com, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Xiao Guangrong Subject: [PATCH 4/7] KVM: MMU: document mmio page fault Date: Wed, 19 Jun 2013 17:09:22 +0800 Message-Id: <1371632965-20077-5-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-Mailer: git-send-email 1.8.1.4 In-Reply-To: <1371632965-20077-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> References: <1371632965-20077-1-git-send-email-xiaoguangrong@linux.vnet.ibm.com> X-Content-Scanned: Fidelis XPS MAILER x-cbid: 13061909-5140-0000-0000-0000036649B9 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2047 Lines: 43 Document it to Documentation/virtual/kvm/mmu.txt Signed-off-by: Xiao Guangrong --- Documentation/virtual/kvm/mmu.txt | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/Documentation/virtual/kvm/mmu.txt b/Documentation/virtual/kvm/mmu.txt index 5a6b2e2..4fb442b 100644 --- a/Documentation/virtual/kvm/mmu.txt +++ b/Documentation/virtual/kvm/mmu.txt @@ -270,14 +270,21 @@ This is the most complicated event. The cause of a page fault can be: Handling a page fault is performed as follows: + - if the RSV bit of the error code is set, the page fault is caused by guest + accessing MMIO, walk shadow page table to get the last spte where the mmio + information is stored and cache the information to vcpu->arch.mmio_gva, + vcpu->arch.access and vcpu->arch.mmio_gfn then call the emulator to emulate + the instruction who will get the benefit from the cached mmio info - if needed, walk the guest page tables to determine the guest translation (gva->gpa or ngpa->gpa) - if permissions are insufficient, reflect the fault back to the guest - determine the host page - - if this is an mmio request, there is no host page; call the emulator - to emulate the instruction instead + - if this is an mmio request, there is no host page; cache the info to + vcpu->arch.mmio_gva, vcpu->arch.access and vcpu->arch.mmio_gfn - walk the shadow page table to find the spte for the translation, instantiating missing intermediate page tables as necessary + - If this is an mmio request, cache the mmio info to the spte and set some + reserved bits on the spte - try to unsynchronize the page - if successful, we can let the guest continue and modify the gpte - emulate the instruction -- 1.8.1.4 -- 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/