From: Avi Kivity <avi@qumranet.com>
To: Joerg Rodel <joerg.roedel@amd.com>
Cc: Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, stable@kernel.org,
Alexander Graf <agraf@suse.de>
Subject: Re: [PATCH] KVM: SVM: fix random segfaults with NPT enabled
Date: Thu, 28 Aug 2008 18:15:57 +0300 [thread overview]
Message-ID: <48B6C12D.1020501@qumranet.com> (raw)
In-Reply-To: <20080828145838.GA4971@amd.com>
Joerg Rodel wrote:
> I did a bit meditation about the softmmu code today. In the path of the
> NPT fault the function kvm_mmu_free_some_pages() is called which itself
> calls kvm_mmu_zap_page(). There the two functions
> kvm_mmu_page_unlink_children() and kvm_mmu_unlink_parents() are called.
> They both call mmu_page_remove_parent_pte() which modifies ptes. But
> only the first function, kvm_mmu_page_unlink_children(), flushes remote
> TLBs. The function kvm_mmu_unlink_parents() does not. Is this correct?
>
>
It isn't correct. I'll move the flush below. Good catch.
However, I can't believe this is responsible. There is very little page
zapping going on with npt.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2008-08-28 15:15 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-27 12:18 [PATCH] KVM: SVM: fix random segfaults with NPT enabled Joerg Rodel
2008-08-27 13:11 ` Avi Kivity
2008-08-27 13:53 ` Joerg Rodel
2008-08-27 15:21 ` Avi Kivity
2008-08-27 15:32 ` Joerg Roedel
2008-08-27 13:53 ` Avi Kivity
2008-08-27 13:57 ` Joerg Rodel
2008-08-27 15:22 ` Avi Kivity
2008-08-27 15:35 ` Joerg Roedel
2008-08-27 15:50 ` Avi Kivity
2008-08-27 16:27 ` Joerg Rodel
2008-08-27 16:49 ` Avi Kivity
2008-08-27 16:59 ` Avi Kivity
2008-08-28 14:58 ` Joerg Rodel
2008-08-28 15:15 ` Avi Kivity [this message]
2008-08-28 15:19 ` Joerg Roedel
2008-08-28 15:47 ` Avi Kivity
2008-08-28 15:29 ` Avi Kivity
2008-08-28 15:58 ` Joerg Roedel
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