From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Wang Subject: Re: [PATCH net V2 4/4] vhost: log dirty page correctly Date: Fri, 14 Dec 2018 10:43:03 +0800 Message-ID: <519ee6f7-06fc-ad49-03da-c096aeb24ced@redhat.com> References: <20181212100819.21295-1-jasowang@redhat.com> <20181212100819.21295-5-jasowang@redhat.com> <20181212092435-mutt-send-email-mst@kernel.org> <0239c220-e7ca-c08f-be26-eb9be63fced3@redhat.com> <20181213092930-mutt-send-email-mst@kernel.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Cc: kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Jintack Lim To: "Michael S. Tsirkin" Return-path: In-Reply-To: <20181213092930-mutt-send-email-mst@kernel.org> Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 2018/12/13 下午10:31, Michael S. Tsirkin wrote: >> Just to make sure I understand this. It looks to me we should: >> >> - allow passing GIOVA->GPA through UAPI >> >> - cache GIOVA->GPA somewhere but still use GIOVA->HVA in device IOTLB for >> performance >> >> Is this what you suggest? >> >> Thanks > Not really. We already have GPA->HVA, so I suggested a flag to pass > GIOVA->GPA in the IOTLB. > > This has advantages for security since a single table needs > then to be validated to ensure guest does not corrupt > QEMU memory. > I wonder how much we can gain through this. Currently, qemu IOMMU gives GIOVA->GPA mapping, and qemu vhost code will translate GPA to HVA then pass GIOVA->HVA to vhost. It looks no difference to me. Thanks