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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>,
	virtualization <virtualization@lists.linux-foundation.org>,
	"Eli Cohen" <eli@mellanox.com>, "Eric Blake" <eblake@redhat.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Cindy Lu" <lulu@redhat.com>,
	"Fangyi (Eric)" <eric.fangyi@huawei.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	yebiaoxiang@huawei.com, "Eugenio Pérez" <eperezma@redhat.com>,
	Liuxiangdong <liuxiangdong5@huawei.com>,
	"Laurent Vivier" <lvivier@redhat.com>,
	"Parav Pandit" <parav@mellanox.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Gautam Dawar" <gdawar@xilinx.com>,
	"Xiao W Wang" <xiao.w.wang@intel.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Harpreet Singh Anand" <hanand@xilinx.com>,
	Lingshan <lingshan.zhu@intel.com>
Subject: Re: [PATCH v5 00/15] vDPA shadow virtqueue
Date: Tue, 8 Mar 2022 05:48:20 -0500	[thread overview]
Message-ID: <20220308054623-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CACGkMEsPBDM8ko1qgnCR1DcofPNJJo3S2j3pOJHk4xaSGQimcQ@mail.gmail.com>

On Tue, Mar 08, 2022 at 04:20:53PM +0800, Jason Wang wrote:
> > Not by itself but I'm not sure we can guarantee guest will not
> > attempt to use the IOVA addresses we are reserving down
> > the road.
> 
> The IOVA is allocated via the listeners and stored in the iova tree
> per GPA range as IOVA->(GPA)->HVA.Guests will only see GPA, Qemu
> virtio core see GPA to HVA mapping. And we do a reverse lookup to find
> the HVA->IOVA we allocated previously.  So we have double check here:
> 
> 1) Qemu memory core to make sure the GPA that guest uses is valid
> 2) the IOVA tree that guarantees there will be no HVA beyond what
> guest can see is used
> 
> So technically, there's no way for the guest to use the IOVA address
> allocated for the shadow virtqueue.
> 
> Thanks

I mean, IOVA is programmed in the host hardware to translate to HPA, right?

-- 
MST

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WARNING: multiple messages have this Message-ID (diff)
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jason Wang <jasowang@redhat.com>
Cc: qemu-devel <qemu-devel@nongnu.org>,
	"Peter Xu" <peterx@redhat.com>,
	virtualization <virtualization@lists.linux-foundation.org>,
	"Eli Cohen" <eli@mellanox.com>, "Eric Blake" <eblake@redhat.com>,
	"Eduardo Habkost" <ehabkost@redhat.com>,
	"Cindy Lu" <lulu@redhat.com>,
	"Fangyi (Eric)" <eric.fangyi@huawei.com>,
	"Markus Armbruster" <armbru@redhat.com>,
	yebiaoxiang@huawei.com, "Eugenio Pérez" <eperezma@redhat.com>,
	Liuxiangdong <liuxiangdong5@huawei.com>,
	"Stefano Garzarella" <sgarzare@redhat.com>,
	"Laurent Vivier" <lvivier@redhat.com>,
	"Parav Pandit" <parav@mellanox.com>,
	"Richard Henderson" <richard.henderson@linaro.org>,
	"Gautam Dawar" <gdawar@xilinx.com>,
	"Xiao W Wang" <xiao.w.wang@intel.com>,
	"Stefan Hajnoczi" <stefanha@redhat.com>,
	"Juan Quintela" <quintela@redhat.com>,
	"Harpreet Singh Anand" <hanand@xilinx.com>,
	Lingshan <lingshan.zhu@intel.com>
Subject: Re: [PATCH v5 00/15] vDPA shadow virtqueue
Date: Tue, 8 Mar 2022 05:48:20 -0500	[thread overview]
Message-ID: <20220308054623-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <CACGkMEsPBDM8ko1qgnCR1DcofPNJJo3S2j3pOJHk4xaSGQimcQ@mail.gmail.com>

On Tue, Mar 08, 2022 at 04:20:53PM +0800, Jason Wang wrote:
> > Not by itself but I'm not sure we can guarantee guest will not
> > attempt to use the IOVA addresses we are reserving down
> > the road.
> 
> The IOVA is allocated via the listeners and stored in the iova tree
> per GPA range as IOVA->(GPA)->HVA.Guests will only see GPA, Qemu
> virtio core see GPA to HVA mapping. And we do a reverse lookup to find
> the HVA->IOVA we allocated previously.  So we have double check here:
> 
> 1) Qemu memory core to make sure the GPA that guest uses is valid
> 2) the IOVA tree that guarantees there will be no HVA beyond what
> guest can see is used
> 
> So technically, there's no way for the guest to use the IOVA address
> allocated for the shadow virtqueue.
> 
> Thanks

I mean, IOVA is programmed in the host hardware to translate to HPA, right?

-- 
MST



  parent reply	other threads:[~2022-03-08 10:48 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-07 15:33 [PATCH v5 00/15] vDPA shadow virtqueue Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 01/15] vhost: Add VhostShadowVirtqueue Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 02/15] vhost: Add Shadow VirtQueue kick forwarding capabilities Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 03/15] vhost: Add Shadow VirtQueue call " Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 04/15] vhost: Add vhost_svq_valid_features to shadow vq Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 05/15] virtio: Add vhost_svq_get_vring_addr Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 06/15] vdpa: adapt vhost_ops callbacks to svq Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 07/15] vhost: Shadow virtqueue buffers forwarding Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 08/15] util: Add iova_tree_alloc_map Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 09/15] util: add iova_tree_find_iova Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 10/15] vhost: Add VhostIOVATree Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 11/15] vdpa: Add custom IOTLB translations to SVQ Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 12/15] vdpa: Adapt vhost_vdpa_get_vring_base " Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 13/15] vdpa: Never set log_base addr if SVQ is enabled Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 14/15] vdpa: Expose VHOST_F_LOG_ALL on SVQ Eugenio Pérez
2022-03-07 15:33 ` [PATCH v5 15/15] vdpa: Add x-svq to NetdevVhostVDPAOptions Eugenio Pérez
2022-03-08  7:11   ` Michael S. Tsirkin
2022-03-08  7:11     ` Michael S. Tsirkin
2022-03-08  7:32     ` Eugenio Perez Martin
2022-03-08  7:33       ` Eugenio Perez Martin
2022-03-08  8:02       ` Michael S. Tsirkin
2022-03-08  8:02         ` Michael S. Tsirkin
2022-03-08  8:24         ` Eugenio Perez Martin
2022-03-08 12:31           ` Michael S. Tsirkin
2022-03-08 12:31             ` Michael S. Tsirkin
2022-03-08  9:29   ` Markus Armbruster
2022-03-08  6:03 ` [PATCH v5 00/15] vDPA shadow virtqueue Jason Wang
2022-03-08  6:03   ` Jason Wang
2022-03-08  7:11   ` Michael S. Tsirkin
2022-03-08  7:11     ` Michael S. Tsirkin
2022-03-08  7:14     ` Jason Wang
2022-03-08  7:14       ` Jason Wang
2022-03-08  7:27       ` Michael S. Tsirkin
2022-03-08  7:27         ` Michael S. Tsirkin
2022-03-08  7:34         ` Jason Wang
2022-03-08  7:34           ` Jason Wang
2022-03-08  7:55           ` Michael S. Tsirkin
2022-03-08  7:55             ` Michael S. Tsirkin
2022-03-08  8:15             ` Eugenio Perez Martin
2022-03-08  8:19               ` Michael S. Tsirkin
2022-03-08  8:19                 ` Michael S. Tsirkin
2022-03-08  8:20             ` Jason Wang
2022-03-08  8:20               ` Jason Wang
2022-03-08 10:46               ` Michael S. Tsirkin
2022-03-08 10:46                 ` Michael S. Tsirkin
2022-03-08 13:23                 ` Jason Wang
2022-03-08 13:23                   ` Jason Wang
2022-03-08 10:48               ` Michael S. Tsirkin [this message]
2022-03-08 10:48                 ` Michael S. Tsirkin
2022-03-08 11:37                 ` Eugenio Perez Martin
2022-03-08 12:16                   ` Michael S. Tsirkin
2022-03-08 12:16                     ` Michael S. Tsirkin
2022-03-08 13:56                     ` Eugenio Perez Martin
2022-03-09  3:38                     ` Jason Wang
2022-03-09  3:38                       ` Jason Wang
2022-03-09  7:30                       ` Michael S. Tsirkin
2022-03-09  7:30                         ` Michael S. Tsirkin
2022-03-09  7:45                         ` Jason Wang
2022-03-09  7:45                           ` Jason Wang
2022-03-08  7:49         ` Eugenio Perez Martin

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