From: Marcelo Tosatti <mtosatti@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
Joerg Roedel <joerg.roedel@amd.com>
Subject: Re: [PATCH] Don't map nested_vmcb on INTERCEPT_MSR_PROT
Date: Fri, 4 Sep 2009 21:29:30 -0300 [thread overview]
Message-ID: <20090905002930.GA10975@amt.cnet> (raw)
In-Reply-To: <49C3DCB0-64FB-4B31-8264-41AC9FE217F6@suse.de>
On Sat, Sep 05, 2009 at 12:59:26AM +0200, Alexander Graf wrote:
>
> Am 04.09.2009 um 19:05 schrieb Marcelo Tosatti <mtosatti@redhat.com>:
>
>> On Thu, Sep 03, 2009 at 04:51:52PM +0200, Alexander Graf wrote:
>>> Thanks to Joerg's previous series of cleanups, we now have almost all
>>> information we need to decide what to do on #VMEXIT because we get
>>> the variables from the VMCB on VMRUN.
>>>
>>> Unfortunately there's one piece that slipped through the conversion,
>>> namely the MSR intercept which still tries to map the nested VMCB
>>> to find out if MSRs are intercepted.
>>>
>>> So let's use the cached value, removing the need for two atomic maps
>>> (which breaks anyways) and fix an oops along the way.
>>>
>>> CC: Joerg Roedel <joerg.roedel@amd.com>
>>> Signed-off-by: Alexander Graf <agraf@suse.de>
>>
>> Applied, thanks.
>>
>> BTW, why nested_svm_map takes mmap_sem? Thats looks wrong.
>
> Hm, good question.
>
> As long as it's an atomic section that only touches vcpu local data
> there's no need to lock at all, right?
Yes. gfn_to_page / get_user_pages will grab mmap_sem if required. Can
you please send a patch to drop it from nested_svm_map?
next prev parent reply other threads:[~2009-09-05 0:30 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-09-03 14:51 [PATCH] Don't map nested_vmcb on INTERCEPT_MSR_PROT Alexander Graf
2009-09-03 16:00 ` Joerg Roedel
2009-09-04 17:05 ` Marcelo Tosatti
2009-09-04 22:59 ` Alexander Graf
2009-09-05 0:29 ` Marcelo Tosatti [this message]
-- strict thread matches above, loose matches on Subject: below --
2009-09-03 14:12 Alexander Graf
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