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From: Jason Wang <jasowang@redhat.com>
To: Andi Kleen <ak@linux.intel.com>, mst@redhat.com
Cc: virtualization@lists.linux-foundation.org, hch@lst.de,
	m.szyprowski@samsung.com, robin.murphy@arm.com,
	iommu@lists.linux-foundation.org, x86@kernel.org,
	sathyanarayanan.kuppuswamy@linux.intel.com, jpoimboe@redhat.com,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest
Date: Thu, 3 Jun 2021 11:02:21 +0800	[thread overview]
Message-ID: <9b10bb24-eb27-510e-cf0d-7818ab9166ef@redhat.com> (raw)
In-Reply-To: <5a2d0d70-fa6b-f08d-f222-5c00cf5f9d44@linux.intel.com>


在 2021/6/3 上午10:56, Andi Kleen 写道:
>
>>
>> I agree, but I want to know why indirect descriptor needs to be 
>> disabled. The table can't be wrote by the device since it's not 
>> coherent swiotlb mapping.
>
> I had all kinds of problems with uninitialized entries in the indirect 
> table. So I gave up on it and concluded it would be too difficult to 
> secure.
>
>
> -Andi
>
>

Ok, but what I meant is this, if we don't read from the descriptor ring, 
and validate all the other metadata supplied by the device (used id and 
len). Then there should be no way for the device to suppress the dma 
flags to write to the indirect descriptor table.

Or do you have an example how it can do that?

Thanks


WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com>
To: Andi Kleen <ak@linux.intel.com>, mst@redhat.com
Cc: x86@kernel.org, linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	iommu@lists.linux-foundation.org, jpoimboe@redhat.com,
	robin.murphy@arm.com, hch@lst.de
Subject: Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest
Date: Thu, 3 Jun 2021 11:02:21 +0800	[thread overview]
Message-ID: <9b10bb24-eb27-510e-cf0d-7818ab9166ef@redhat.com> (raw)
In-Reply-To: <5a2d0d70-fa6b-f08d-f222-5c00cf5f9d44@linux.intel.com>


在 2021/6/3 上午10:56, Andi Kleen 写道:
>
>>
>> I agree, but I want to know why indirect descriptor needs to be 
>> disabled. The table can't be wrote by the device since it's not 
>> coherent swiotlb mapping.
>
> I had all kinds of problems with uninitialized entries in the indirect 
> table. So I gave up on it and concluded it would be too difficult to 
> secure.
>
>
> -Andi
>
>

Ok, but what I meant is this, if we don't read from the descriptor ring, 
and validate all the other metadata supplied by the device (used id and 
len). Then there should be no way for the device to suppress the dma 
flags to write to the indirect descriptor table.

Or do you have an example how it can do that?

Thanks

_______________________________________________
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

WARNING: multiple messages have this Message-ID (diff)
From: Jason Wang <jasowang@redhat.com>
To: Andi Kleen <ak@linux.intel.com>, mst@redhat.com
Cc: sathyanarayanan.kuppuswamy@linux.intel.com, x86@kernel.org,
	linux-kernel@vger.kernel.org,
	virtualization@lists.linux-foundation.org,
	iommu@lists.linux-foundation.org, jpoimboe@redhat.com,
	robin.murphy@arm.com, hch@lst.de, m.szyprowski@samsung.com
Subject: Re: [PATCH v1 1/8] virtio: Force only split mode with protected guest
Date: Thu, 3 Jun 2021 11:02:21 +0800	[thread overview]
Message-ID: <9b10bb24-eb27-510e-cf0d-7818ab9166ef@redhat.com> (raw)
In-Reply-To: <5a2d0d70-fa6b-f08d-f222-5c00cf5f9d44@linux.intel.com>


在 2021/6/3 上午10:56, Andi Kleen 写道:
>
>>
>> I agree, but I want to know why indirect descriptor needs to be 
>> disabled. The table can't be wrote by the device since it's not 
>> coherent swiotlb mapping.
>
> I had all kinds of problems with uninitialized entries in the indirect 
> table. So I gave up on it and concluded it would be too difficult to 
> secure.
>
>
> -Andi
>
>

Ok, but what I meant is this, if we don't read from the descriptor ring, 
and validate all the other metadata supplied by the device (used id and 
len). Then there should be no way for the device to suppress the dma 
flags to write to the indirect descriptor table.

Or do you have an example how it can do that?

Thanks

_______________________________________________
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

  reply	other threads:[~2021-06-03  3:05 UTC|newest]

Thread overview: 116+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-03  0:41 Virtio hardening for TDX Andi Kleen
2021-06-03  0:41 ` Andi Kleen
2021-06-03  0:41 ` Andi Kleen
2021-06-03  0:41 ` [PATCH v1 1/8] virtio: Force only split mode with protected guest Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  1:36   ` Jason Wang
2021-06-03  1:36     ` Jason Wang
2021-06-03  1:36     ` Jason Wang
2021-06-03  1:48     ` Andi Kleen
2021-06-03  1:48       ` Andi Kleen
2021-06-03  1:48       ` Andi Kleen
2021-06-03  2:32       ` Jason Wang
2021-06-03  2:32         ` Jason Wang
2021-06-03  2:32         ` Jason Wang
2021-06-03  2:56         ` Andi Kleen
2021-06-03  2:56           ` Andi Kleen
2021-06-03  2:56           ` Andi Kleen
2021-06-03  3:02           ` Jason Wang [this message]
2021-06-03  3:02             ` Jason Wang
2021-06-03  3:02             ` Jason Wang
2021-06-03 13:55             ` Andi Kleen
2021-06-03 13:55               ` Andi Kleen
2021-06-03 13:55               ` Andi Kleen
2021-06-04  2:29               ` Jason Wang
2021-06-04  2:29                 ` Jason Wang
2021-06-04  2:29                 ` Jason Wang
2021-06-03 17:33   ` Andy Lutomirski
2021-06-03 17:33     ` Andy Lutomirski
2021-06-03 17:33     ` Andy Lutomirski
2021-06-03 18:00     ` Andi Kleen
2021-06-03 18:00       ` Andi Kleen
2021-06-03 18:00       ` Andi Kleen
2021-06-03 19:31       ` Andy Lutomirski
2021-06-03 19:31         ` Andy Lutomirski
2021-06-03 19:31         ` Andy Lutomirski
2021-06-03 19:53         ` Andi Kleen
2021-06-03 19:53           ` Andi Kleen
2021-06-03 19:53           ` Andi Kleen
2021-06-03 22:17           ` Andy Lutomirski
2021-06-03 22:17             ` Andy Lutomirski
2021-06-03 22:17             ` Andy Lutomirski
2021-06-03 23:32             ` Andi Kleen
2021-06-03 23:32               ` Andi Kleen
2021-06-03 23:32               ` Andi Kleen
2021-06-04  1:46               ` Andy Lutomirski
2021-06-04  1:46                 ` Andy Lutomirski
2021-06-04  1:46                 ` Andy Lutomirski
2021-06-04  1:54                 ` Andi Kleen
2021-06-04  1:54                   ` Andi Kleen
2021-06-04  1:54                   ` Andi Kleen
2021-06-04  1:22         ` Jason Wang
2021-06-04  1:22           ` Jason Wang
2021-06-04  1:22           ` Jason Wang
2021-06-04  1:29       ` Jason Wang
2021-06-04  1:29         ` Jason Wang
2021-06-04  1:29         ` Jason Wang
2021-06-04  2:20     ` Jason Wang
2021-06-04  2:20       ` Jason Wang
2021-06-04  2:20       ` Jason Wang
2021-06-03  0:41 ` [PATCH v1 2/8] virtio: Add boundary checks to virtio ring Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  2:14   ` Jason Wang
2021-06-03  2:14     ` Jason Wang
2021-06-03  2:14     ` Jason Wang
2021-06-03  2:18     ` Andi Kleen
2021-06-03  2:18       ` Andi Kleen
2021-06-03  2:18       ` Andi Kleen
2021-06-03  2:36       ` Jason Wang
2021-06-03  2:36         ` Jason Wang
2021-06-03  2:36         ` Jason Wang
2021-06-03  0:41 ` [PATCH v1 3/8] virtio: Harden split buffer detachment Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  2:29   ` Jason Wang
2021-06-03  2:29     ` Jason Wang
2021-06-03  2:29     ` Jason Wang
2021-06-03  0:41 ` [PATCH v1 4/8] x86/tdx: Add arch_has_restricted_memory_access for TDX Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  4:02   ` Kuppuswamy, Sathyanarayanan
2021-06-03  4:02     ` Kuppuswamy, Sathyanarayanan
2021-06-03  0:41 ` [PATCH v1 5/8] dma: Use size for swiotlb boundary checks Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  1:48   ` Konrad Rzeszutek Wilk
2021-06-03  1:48     ` Konrad Rzeszutek Wilk
2021-06-03  1:48     ` Konrad Rzeszutek Wilk
2021-06-03  2:03     ` Andi Kleen
2021-06-03  2:03       ` Andi Kleen
2021-06-03  2:03       ` Andi Kleen
2021-06-03  9:09   ` Robin Murphy
2021-06-03  9:09     ` Robin Murphy
2021-06-03  9:09     ` Robin Murphy
2021-06-03  0:41 ` [PATCH v1 6/8] dma: Add return value to dma_unmap_page Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  9:08   ` Robin Murphy
2021-06-03  9:08     ` Robin Murphy
2021-06-03  9:08     ` Robin Murphy
2021-06-03 12:36     ` Andi Kleen
2021-06-03 12:36       ` Andi Kleen
2021-06-03 12:36       ` Andi Kleen
2021-06-03  0:41 ` [PATCH v1 7/8] virtio: Abort IO when descriptor points outside forced swiotlb Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41 ` [PATCH v1 8/8] virtio: Error out on endless free lists Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  0:41   ` Andi Kleen
2021-06-03  1:34 ` Virtio hardening for TDX Jason Wang
2021-06-03  1:34   ` Jason Wang
2021-06-03  1:34   ` Jason Wang
2021-06-03  1:56   ` Andi Kleen
2021-06-03  1:56     ` Andi Kleen
2021-06-03  1:56     ` Andi Kleen

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