From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56619) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f1D4a-0003Al-6W for qemu-devel@nongnu.org; Wed, 28 Mar 2018 11:33:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f1D4X-0007dM-2x for qemu-devel@nongnu.org; Wed, 28 Mar 2018 11:33:12 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:57192 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f1D4W-0007cj-W4 for qemu-devel@nongnu.org; Wed, 28 Mar 2018 11:33:09 -0400 Date: Wed, 28 Mar 2018 18:33:01 +0300 From: "Michael S. Tsirkin" Message-ID: <20180328183159-mutt-send-email-mst@kernel.org> References: <20180319071537.28649-1-tiwei.bie@intel.com> <20180322181952-mutt-send-email-mst@kernel.org> <20180328122407.gc6yba26gijlm5g6@debian> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180328122407.gc6yba26gijlm5g6@debian> Subject: Re: [Qemu-devel] [PATCH v2 0/6] Extend vhost-user to support VFIO based accelerators List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Tiwei Bie Cc: qemu-devel@nongnu.org, virtio-dev@lists.oasis-open.org, alex.williamson@redhat.com, jasowang@redhat.com, pbonzini@redhat.com, stefanha@redhat.com, cunming.liang@intel.com, dan.daly@intel.com, jianfeng.tan@intel.com, zhihong.wang@intel.com, xiao.w.wang@intel.com On Wed, Mar 28, 2018 at 08:24:07PM +0800, Tiwei Bie wrote: > > > Update notes > > > ============ > > > > > > IOMMU feature bit check is removed in this version, because: > > > > > > The IOMMU feature is negotiable, when an accelerator is used and > > > it doesn't support virtual IOMMU, its driver just won't provide > > > this feature bit when vhost library querying its features. And if > > > it supports the virtual IOMMU, its driver can provide this feature > > > bit. It's not reasonable to add this limitation in this patch set. > > > > Fair enough. Still: > > Can hardware on intel platforms actually support IOTLB requests? > > Don't you need to add support for vIOMMU shadowing instead? > > > > For the hardware I have, I guess they can't for now. So VFIO in QEMU has support for vIOMMU shadowing. Can you use that somehow? Ability to run dpdk within guest seems important. -- MST