From: Avi Kivity <avi@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
joerg.roedel@amd.com
Subject: Re: [PATCH] KVM: MMU: Segregate mmu pages created with different cr4.pge settings
Date: Wed, 07 Jan 2009 12:19:26 +0200 [thread overview]
Message-ID: <496481AE.1060102@redhat.com> (raw)
In-Reply-To: <49645066.4040009@suse.de>
Alexander Graf wrote:
> Using this patch it works. But if I read it correctly, that doesn't
> actually fix anything but only treats NPT/EPT special, which it
> shouldn't, should it?
The patch doesn't fix the bug but is nevertheless correct. cr4.pge only
matters to the mmu if using the shadow mmu; with tdp it only wastes
memory (and exposes the bug which you encountered).
So, wrt to the bug you saw, it's a workaround, but it's also a correct
fix for another bug.
> Maybe this actually even breaks EPT?
>
It shouldn't.
> I remember having seen a lot of CR4 hacks in svm.c when npt is enabled.
> Maybe that is related?
>
No. cr4 controls the guest mmu, but with npt the guest mmu is
completely virtualized, so we need to ignore those bits.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-01-07 10:19 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20081221184146.8E00B250012@cleopatra.tlv.redhat.com>
2009-01-05 14:56 ` [PATCH] KVM: MMU: Segregate mmu pages created with different cr4.pge settings Alexander Graf
2009-01-06 10:41 ` Avi Kivity
2009-01-06 14:11 ` Marcelo Tosatti
2009-01-06 14:29 ` Avi Kivity
2009-01-06 15:06 ` Marcelo Tosatti
2009-01-06 16:43 ` Marcelo Tosatti
2009-01-07 6:49 ` Alexander Graf
2009-01-07 10:19 ` Avi Kivity [this message]
2009-01-07 10:43 ` Marcelo Tosatti
2009-01-07 11:32 ` Avi Kivity
2009-01-07 13:46 ` Marcelo Tosatti
2009-01-08 19:53 ` Alexander Graf
2009-01-09 0:36 ` Marcelo Tosatti
2009-01-09 10:43 ` Alexander Graf
2009-01-11 9:12 Marcelo Tosatti
2009-01-11 9:20 ` Avi Kivity
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