From: Avi Kivity <avi@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, Joerg Roedel <joerg.roedel@amd.com>
Subject: Re: [PATCH] KVM: MMU: Don't read pdptrs with mmu spinlock held in mmu_alloc_roots
Date: Mon, 10 May 2010 10:39:01 +0300 [thread overview]
Message-ID: <4BE7B815.2050401@redhat.com> (raw)
In-Reply-To: <20100506191055.GB3432@amt.cnet>
On 05/06/2010 10:10 PM, Marcelo Tosatti wrote:
> On Tue, May 04, 2010 at 01:03:50PM +0300, Avi Kivity wrote:
>
>> On svm, kvm_read_pdptr() may require reading guest memory, which can sleep.
>>
>> Push the spinlock into mmu_alloc_roots(), and only take it after we've read
>> the pdptr.
>>
>> Marcelo, dropping and re-acquiring the lock before mmu_sync_roots(), is fine,
>> yes?
>>
> Yes, but you should call kvm_mmu_free_some_pages after reacquiring the
> spin_lock, to guarantee kvm_mmu_alloc_page won't fail.
>
>
We never fail due to lack of free pages (but I agree it's cleaner).
The patch is already in, I'll send an incremental.
--
error compiling committee.c: too many arguments to function
prev parent reply other threads:[~2010-05-10 7:39 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-04 10:03 [PATCH] KVM: MMU: Don't read pdptrs with mmu spinlock held in mmu_alloc_roots Avi Kivity
2010-05-04 10:59 ` Roedel, Joerg
2010-05-06 19:10 ` Marcelo Tosatti
2010-05-10 7:39 ` Avi Kivity [this message]
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