From: Marcelo Tosatti <marcelo@kvack.org>
To: Izik Eidus <izike@qumranet.com>
Cc: kvm-devel <kvm-devel@lists.sourceforge.net>,
Avi Kivity <avi@qumranet.com>
Subject: Re: [PATCH] replace the slots lock from the mmap_sem to private kvm lock
Date: Mon, 11 Feb 2008 15:08:12 -0200 [thread overview]
Message-ID: <20080211170812.GA13173@dmt> (raw)
In-Reply-To: <47B065EA.7010805@qumranet.com>
On Mon, Feb 11, 2008 at 05:12:42PM +0200, Izik Eidus wrote:
> right now kvm take the down_read(mmap_sem) lock to make sure that no
> slots will be
> removed while trying to get them / make the dirty log safe,
> but in some cases when the down_read(mmap_sem) is called and after that
> kvm_read_guest() is called
> copy_from_user can result in a page fault that will lead to recursivly
> taking the mmap_sem,
>
> this patch remove the mmap_sem, with new kvm private lock.
Hi Izik,
do_mmap/do_munmap requires the mmap_sem in write-mode.
I couldnt find any sequence which grabs mmap_sem and then slots_lock,
but it would be nice to verify again that can't happen.
Other than that looks good.
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next prev parent reply other threads:[~2008-02-11 17:08 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-02-11 15:12 [PATCH] replace the slots lock from the mmap_sem to private kvm lock Izik Eidus
2008-02-11 17:08 ` Marcelo Tosatti [this message]
2008-02-11 17:26 ` Izik Eidus
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