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From: Jason Gunthorpe <jgg@ziepe.ca>
To: Peter Xu <peterx@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	cohuck@redhat.com, cai@lca.pw
Subject: Re: [PATCH v3 3/3] vfio-pci: Invalidate mmaps and block MMIO access on disabled memory
Date: Mon, 25 May 2020 09:26:07 -0300	[thread overview]
Message-ID: <20200525122607.GC744@ziepe.ca> (raw)
In-Reply-To: <20200523235257.GC939059@xz-x1>

On Sat, May 23, 2020 at 07:52:57PM -0400, Peter Xu wrote:

> For what I understand now, IMHO we should still need all those handlings of
> FAULT_FLAG_RETRY_NOWAIT like in the initial version.  E.g., IIUC KVM gup will
> try with FOLL_NOWAIT when async is allowed, before the complete slow path.  I'm
> not sure what would be the side effect of that if fault() blocked it.  E.g.,
> the caller could be in an atomic context.

AFAICT FAULT_FLAG_RETRY_NOWAIT only impacts what happens when
VM_FAULT_RETRY is returned, which this doesn't do?

It is not a generic 'do not sleep'

Do you know different?

Jason

  parent reply	other threads:[~2020-05-25 12:26 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-22 19:17 [PATCH v3 0/3] vfio-pci: Block user access to disabled device MMIO Alex Williamson
2020-05-22 19:17 ` [PATCH v3 1/3] vfio/type1: Support faulting PFNMAP vmas Alex Williamson
2020-05-22 19:17 ` [PATCH v3 2/3] vfio-pci: Fault mmaps to enable vma tracking Alex Williamson
2020-05-22 19:17 ` [PATCH v3 3/3] vfio-pci: Invalidate mmaps and block MMIO access on disabled memory Alex Williamson
2020-05-23 19:34   ` Peter Xu
2020-05-23 23:06     ` Alex Williamson
2020-05-23 23:52       ` Peter Xu
2020-05-24  0:02         ` Peter Xu
2020-05-25 12:26         ` Jason Gunthorpe [this message]
2020-05-25 14:28           ` Peter Xu
2020-05-25 14:46             ` Jason Gunthorpe
2020-05-25 15:11               ` Peter Xu
2020-05-25 16:56                 ` Jason Gunthorpe
2020-05-25 20:56                   ` John Hubbard
2020-05-26  0:37                     ` Jason Gunthorpe
2020-05-26  0:46                       ` John Hubbard
2020-05-26 13:49                       ` Peter Xu
2020-05-26 14:32                         ` Alex Williamson
2020-05-26 14:46                           ` Peter Xu
2020-05-26 15:53                           ` Jason Gunthorpe
2020-05-26 15:57                             ` Alex Williamson
2020-05-22 22:08 ` [PATCH v3 0/3] vfio-pci: Block user access to disabled device MMIO Qian Cai
2020-05-22 22:25   ` Alex Williamson

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