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From: Alex Williamson <alex.williamson@redhat.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Eric Dumazet <eric.dumazet@gmail.com>,
	Konstantin Khlebnikov <khlebnikov@openvz.org>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	linux-kernel@vger.kernel.org, Hugh Dickins <hughd@google.com>,
	Nick Piggin <npiggin@kernel.dk>
Subject: Re: [PATCH v3 10/10] mm: kill vma flag VM_RESERVED and mm->reserved_vm counter
Date: Tue, 09 Oct 2012 22:06:29 -0600	[thread overview]
Message-ID: <1349841989.2759.317.camel@ul30vt.home> (raw)
In-Reply-To: <1349823616.2759.308.camel@ul30vt.home>

On Tue, 2012-10-09 at 17:00 -0600, Alex Williamson wrote:
> On Tue, 2012-10-09 at 08:21 -0600, Alex Williamson wrote:
> > On Tue, 2012-10-09 at 21:12 +0900, Linus Torvalds wrote:
> > > On Tue, Oct 9, 2012 at 7:02 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote:
> > > >
> > > > It seems drivers/vfio/pci/vfio_pci.c uses VM_RESERVED
> > > 
> > > Yeah, I just pushed out what I think is the right (trivial) fix.
> > 
> > Thank you, looks correct to me as well.
> 
> Well, that might still be correct, but it's actually b3b9c293 (mm, x86,
> pat: rework linear pfn-mmap tracking) that breaks vfio.  As soon as I
> add that commit our use of mmap'd device areas stops working, both
> mapping them through the iommu and through kvm.  kvm hits the BUG_ON
> from !kvm_is_mmio_pfn in virt/kvm/kvm_main.c:hva_to_pfn.  Thanks,

It looks like vfio was for some reason relying on the cow special case
in remap_pfn_range() to set vma->vm_pgoff.  Since we're not doing a
is_cow_mapping, vm_pgoff is no longer updated in that function after
b3b9c293.  I'll add a vfio patch to fix this.  Thanks,

Alex

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  reply	other threads:[~2012-10-10  4:06 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-31 10:41 [PATCH RESEND v3 00/10] mm: vma->vm_flags diet Konstantin Khlebnikov
2012-07-31 10:41 ` [PATCH v3 01/10] x86, pat: remove the dependency on 'vm_pgoff' in track/untrack pfn vma routines Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 02/10] x86, pat: separate the pfn attribute tracking for remap_pfn_range and vm_insert_pfn Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 03/10] mm, x86, pat: rework linear pfn-mmap tracking Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 04/10] mm: introduce arch-specific vma flag VM_ARCH_1 Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 05/10] mm: kill vma flag VM_INSERTPAGE Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 06/10] mm: kill vma flag VM_CAN_NONLINEAR Konstantin Khlebnikov
2012-10-09 23:01   ` Sasha Levin
2012-07-31 10:42 ` [PATCH v3 07/10] mm: use mm->exe_file instead of first VM_EXECUTABLE vma->vm_file Konstantin Khlebnikov
2012-08-01  1:34   ` James Morris
2012-07-31 10:42 ` [PATCH v3 08/10] mm: kill vma flag VM_EXECUTABLE and mm->num_exe_file_vmas Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 09/10] mm: prepare VM_DONTDUMP for using in drivers Konstantin Khlebnikov
2012-07-31 10:42 ` [PATCH v3 10/10] mm: kill vma flag VM_RESERVED and mm->reserved_vm counter Konstantin Khlebnikov
2012-10-09 10:02   ` Eric Dumazet
2012-10-09 12:12     ` Linus Torvalds
2012-10-09 14:21       ` Alex Williamson
2012-10-09 23:00         ` Alex Williamson
2012-10-10  4:06           ` Alex Williamson [this message]
2012-07-31 16:31 ` [PATCH RESEND v3 00/10] mm: vma->vm_flags diet Linus Torvalds
  -- strict thread matches above, loose matches on Subject: below --
2012-07-31 10:34 [PATCH " Konstantin Khlebnikov
2012-07-31 10:35 ` [PATCH v3 10/10] mm: kill vma flag VM_RESERVED and mm->reserved_vm counter Konstantin Khlebnikov

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