From: Dave Hansen <dave.hansen@intel.com>
To: Christian Borntraeger <borntraeger@de.ibm.com>,
Ulrich Weigand <uweigand@de.ibm.com>
Cc: Claudio Imbrenda <imbrenda@linux.ibm.com>,
viro@zeniv.linux.org.uk, david@redhat.com,
akpm@linux-foundation.org, aarcange@redhat.com,
linux-mm@kvack.org, frankja@linux.ibm.com, sfr@canb.auug.org.au,
jhubbard@nvidia.com, linux-kernel@vger.kernel.org,
linux-s390@vger.kernel.org, jack@suse.cz, kirill@shutemov.name,
peterz@infradead.org, sean.j.christopherson@intel.com,
Ulrich.Weigand@de.ibm.com
Subject: Re: [PATCH v2 1/1] fs/splice: add missing callback for inaccessible pages
Date: Tue, 5 May 2020 07:34:39 -0700 [thread overview]
Message-ID: <fcc9adea-598f-f882-c3e3-09d190cd5d52@intel.com> (raw)
In-Reply-To: <da6bc7cb-ef13-08cd-f162-663b4a66043b@de.ibm.com>
On 5/5/20 7:31 AM, Christian Borntraeger wrote:
>> So, the requirements are:
>>
>> 1. Allow host-side DMA and CPU access to shared pages
>> 2. Stop host-side DMA and CPU access to encrypted pages
>> 3. Allow pages to be converted between the states at the request of the
>> guest
>>
>> Stopping the DMA is pretty easy, even across the gazillions of drivers
>> in the tree because even random ethernet drivers do stuff like:
>>
>> txdr->buffer_info[i].dma =
>> dma_map_single(&pdev->dev, skb->data, skb->len,
>> DMA_TO_DEVICE);
>>
>> So the DMA can be stopped at the mapping layer. It's a *LOT* easier to
>> catch there since the IOMMUs already provide isolation between the I/O
>> and CPU address spaces.
> And your problem is that the guest could convert this after the dma_map?
> So you looked into our code if this would help?
Yep, it seemed like a close-enough problem.
next prev parent reply other threads:[~2020-05-05 14:35 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 14:38 Claudio Imbrenda
2020-04-30 20:04 ` Christian Borntraeger
2020-04-30 22:06 ` Dave Hansen
2020-04-30 22:20 ` Dave Hansen
2020-05-01 7:18 ` Christian Borntraeger
2020-05-01 16:32 ` Dave Hansen
2020-05-04 13:41 ` Ulrich Weigand
2020-05-05 12:34 ` Dave Hansen
2020-05-05 13:55 ` Ulrich Weigand
2020-05-05 14:01 ` Christian Borntraeger
2020-05-05 14:03 ` Christian Borntraeger
2020-05-05 14:33 ` Ulrich Weigand
2020-05-05 14:49 ` Christian Borntraeger
2020-05-05 14:57 ` Dave Hansen
2020-05-05 14:00 ` Christian Borntraeger
2020-05-05 14:24 ` Dave Hansen
2020-05-05 14:31 ` Christian Borntraeger
2020-05-05 14:34 ` Dave Hansen [this message]
2020-05-05 14:39 ` Christian Borntraeger
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