From: Peter Xu <peterx@redhat.com>
To: Justin He <Justin.He@arm.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Cornelia Huck <cohuck@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [PATCH] vfio iommu type1: Bypass the vma permission check in vfio_pin_pages_remote()
Date: Wed, 25 Nov 2020 10:57:11 -0500 [thread overview]
Message-ID: <20201125155711.GA6489@xz-x1> (raw)
In-Reply-To: <AM6PR08MB32245E7F990955395B44CE6BF7FA0@AM6PR08MB3224.eurprd08.prod.outlook.com>
On Wed, Nov 25, 2020 at 01:05:25AM +0000, Justin He wrote:
> > I'd appreciate if you could explain why vfio needs to dma map some
> > PROT_NONE
>
> Virtiofs will map a PROT_NONE cache window region firstly, then remap the sub
> region of that cache window with read or write permission. I guess this might
> be an security concern. Just CC virtiofs expert Stefan to answer it more accurately.
Yep. Since my previous sentence was cut off, I'll rephrase: I was thinking
whether qemu can do vfio maps only until it remaps the PROT_NONE regions into
PROT_READ|PROT_WRITE ones, rather than trying to map dma pages upon PROT_NONE.
Thanks,
--
Peter Xu
next prev parent reply other threads:[~2020-11-25 15:57 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-19 14:27 [PATCH] vfio iommu type1: Bypass the vma permission check in vfio_pin_pages_remote() Jia He
2020-11-19 17:05 ` Alex Williamson
2020-11-23 2:37 ` Justin He
2020-11-24 17:07 ` Alex Williamson
2020-11-24 18:12 ` Peter Xu
2020-11-25 1:05 ` Justin He
2020-11-25 15:57 ` Peter Xu [this message]
2020-12-02 14:33 ` Stefan Hajnoczi
2020-12-02 15:45 ` Peter Xu
2020-12-03 11:20 ` Stefan Hajnoczi
2020-12-03 15:43 ` Peter Xu
2020-12-03 15:55 ` Alex Williamson
2020-12-03 16:01 ` David Hildenbrand
2020-12-07 14:48 ` Stefan Hajnoczi
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