linux-kernel - Re: [PATCH 0/4] mmu_notifier semantic update

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Date:   Tue, 29 Aug 2017 16:15:56 -0400
From:   Jerome Glisse <jglisse@...hat.com>
To:     linux-kernel@...r.kernel.org, linux-mm@...ck.org
Cc:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Bernhard Held <berny156@....de>,
        Adam Borowski <kilobyte@...band.pl>,
        Andrea Arcangeli <aarcange@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>,
        Wanpeng Li <kernellwp@...il.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Takashi Iwai <tiwai@...e.de>,
        Nadav Amit <nadav.amit@...il.com>,
        Mike Galbraith <efault@....de>,
        "Kirill A . Shutemov" <kirill.shutemov@...ux.intel.com>,
        axie <axie@....com>, Andrew Morton <akpm@...ux-foundation.org>,
        Dan Williams <dan.j.williams@...el.com>,
        Ross Zwisler <ross.zwisler@...ux.intel.com>
Subject: Re: [PATCH 0/4] mmu_notifier semantic update

On Tue, Aug 29, 2017 at 04:11:28PM -0400, Jérôme Glisse wrote:
> So we do not want to allow sleep during call to mmu_notifier_invalidate_page()
> but some code do not have surrounding mmu_notifier_invalidate_range_start()/
> mmu_notifier_invalidate_range_end() or mmu_notifier_invalidate_range()
> 
> This patch serie just make sure that there is at least a call (outside spinlock
> section) to mmu_notifier_invalidate_range() after mmu_notifier_invalidate_page()
> 
> This fix issue with AMD IOMMU v2 while avoiding to introduce issue for others
> user of the mmu_notifier API. For releavent threads see:
> 
> https://lkml.kernel.org/r/20170809204333.27485-1-jglisse@redhat.com
> https://lkml.kernel.org/r/20170804134928.l4klfcnqatni7vsc@black.fi.intel.com
> https://marc.info/?l=kvm&m=150327081325160&w=2

Please ignore this. Instead plan is to kill invalidate_page() switch
it to invalidate_range() and make sure there is always range_start/
range_end happening around.

Jérôme