From: Jason Gunthorpe <jgg@nvidia•com>
To: "Tian, Kevin" <kevin.tian@intel•com>
Cc: "Cao, Yahui" <yahui.cao@intel•com>,
"intel-wired-lan@lists•osuosl.org"
<intel-wired-lan@lists•osuosl.org>,
"kvm@vger•kernel.org" <kvm@vger•kernel.org>,
"netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"Liu, Lingyu" <lingyu.liu@intel•com>,
"Chittim, Madhu" <madhu.chittim@intel•com>,
"Samudrala, Sridhar" <sridhar.samudrala@intel•com>,
"alex.williamson@redhat•com" <alex.williamson@redhat•com>,
"yishaih@nvidia•com" <yishaih@nvidia•com>,
"shameerali.kolothum.thodi@huawei•com"
<shameerali.kolothum.thodi@huawei•com>,
"brett.creeley@amd•com" <brett.creeley@amd•com>,
"davem@davemloft•net" <davem@davemloft•net>,
"edumazet@google•com" <edumazet@google•com>,
"kuba@kernel•org" <kuba@kernel•org>,
"pabeni@redhat•com" <pabeni@redhat•com>
Subject: Re: [PATCH iwl-next v4 09/12] ice: Save and load TX Queue head
Date: Thu, 7 Dec 2023 10:48:07 -0400 [thread overview]
Message-ID: <20231207144807.GL2692119@nvidia.com> (raw)
In-Reply-To: <BN9PR11MB52766AECA2168F37AEF6995D8C8BA@BN9PR11MB5276.namprd11.prod.outlook.com>
On Thu, Dec 07, 2023 at 08:22:53AM +0000, Tian, Kevin wrote:
> > In virtual channel model, VF driver only send TX queue ring base and
> > length info to PF, while rest of the TX queue context are managed by PF.
> > TX queue length must be verified by PF during virtual channel message
> > processing. When PF uses dummy descriptors to advance TX head, it will
> > configure the TX ring base as the new address managed by PF itself. As a
> > result, all of the TX queue context is taken control of by PF and this
> > method won't generate any attacking vulnerability
>
> So basically the key points are:
>
> 1) TX queue head cannot be directly updated via VF mmio interface;
> 2) Using dummy descriptors to update TX queue head is possible but it
> must be done in PF's context;
> 3) FW provides a way to keep TX queue head intact when moving
> the TX queue ownership between VF and PF;
> 4) the TX queue context affected by the ownership change is largely
> initialized by the PF driver already, except ring base/size coming from
> virtual channel messages. This implies that a malicious guest VF driver
> cannot attack this small window though the tx head restore is done
> after all the VF state are restored;
> 5) and a missing point is that the temporary owner change doesn't
> expose the TX queue to the software stack on top of the PF driver
> otherwise that would be a severe issue.
This matches my impression of these patches. It is convoluted but the
explanation sounds find, and if Intel has done an internal security
review then I have no issue.
Jason
next prev parent reply other threads:[~2023-12-07 14:48 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-21 2:50 [PATCH iwl-next v4 00/12] Add E800 live migration driver Yahui Cao
2023-11-21 2:51 ` [PATCH iwl-next v4 01/12] ice: Add function to get RX queue context Yahui Cao
2023-12-08 22:01 ` Brett Creeley
2023-11-21 2:51 ` [PATCH iwl-next v4 02/12] ice: Add function to get and set TX " Yahui Cao
2023-12-08 22:14 ` Brett Creeley
2023-11-21 2:51 ` [PATCH iwl-next v4 03/12] ice: Introduce VF state ICE_VF_STATE_REPLAYING_VC for migration Yahui Cao
2023-12-08 22:28 ` Brett Creeley
2024-02-12 23:07 ` [Intel-wired-lan] " Jacob Keller
2023-11-21 2:51 ` [PATCH iwl-next v4 04/12] ice: Add fundamental migration init and exit function Yahui Cao
2023-11-21 2:51 ` [PATCH iwl-next v4 05/12] ice: Log virtual channel messages in PF Yahui Cao
2023-11-29 17:12 ` Simon Horman
2023-12-01 8:27 ` Cao, Yahui
2023-12-07 7:33 ` Tian, Kevin
2023-12-08 1:53 ` Brett Creeley
2023-11-21 2:51 ` [PATCH iwl-next v4 06/12] ice: Add device state save/load function for migration Yahui Cao
2023-12-07 7:39 ` Tian, Kevin
2023-11-21 2:51 ` [PATCH iwl-next v4 07/12] ice: Fix VSI id in virtual channel message " Yahui Cao
2023-12-07 7:42 ` Tian, Kevin
2023-11-21 2:51 ` [PATCH iwl-next v4 08/12] ice: Save and load RX Queue head Yahui Cao
2023-12-07 7:55 ` Tian, Kevin
2023-12-07 14:46 ` Jason Gunthorpe
2023-12-08 2:53 ` Tian, Kevin
2023-11-21 2:51 ` [PATCH iwl-next v4 09/12] ice: Save and load TX " Yahui Cao
2023-12-07 8:22 ` Tian, Kevin
2023-12-07 14:48 ` Jason Gunthorpe [this message]
2023-11-21 2:51 ` [PATCH iwl-next v4 10/12] ice: Add device suspend function for migration Yahui Cao
2023-11-21 2:51 ` [PATCH iwl-next v4 11/12] ice: Save and load mmio registers Yahui Cao
2023-11-21 2:51 ` [PATCH iwl-next v4 12/12] vfio/ice: Implement vfio_pci driver for E800 devices Yahui Cao
2023-12-07 22:43 ` Alex Williamson
2023-12-08 3:42 ` Tian, Kevin
2023-12-08 3:42 ` Tian, Kevin
2023-12-04 11:18 ` [PATCH iwl-next v4 00/12] Add E800 live migration driver Cao, Yahui
2024-01-18 22:09 ` Jacob Keller
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