From: Avi Kivity <avi@redhat.com>
To: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>,
LKML <linux-kernel@vger.kernel.org>, KVM <kvm@vger.kernel.org>
Subject: Re: [PATCH 10/11] KVM: MMU: fix detecting misaligned accessed
Date: Wed, 27 Jul 2011 12:15:29 +0300 [thread overview]
Message-ID: <4E2FD731.7010206@redhat.com> (raw)
In-Reply-To: <4E2EA5AA.2010708@cn.fujitsu.com>
On 07/26/2011 02:31 PM, Xiao Guangrong wrote:
> Sometimes, we only modify the last one byte of a pte to update status bit,
> for example, clear_bit is used to clear r/w bit in linux kernel and 'andb'
> instruction is used in this function, in this case, kvm_mmu_pte_write will
> treat it as misaligned access, and the shadow page table is zapped
>
> @@ -3597,6 +3597,14 @@ static bool detect_write_misaligned(struct kvm_mmu_page *sp, gpa_t gpa,
>
> offset = offset_in_page(gpa);
> pte_size = sp->role.cr4_pae ? 8 : 4;
> +
> + /*
> + * Sometimes, the OS only writes the last one bytes to update status
> + * bits, for example, in linux, andb instruction is used in clear_bit().
> + */
> + if (sp->role.level == 1&& !(offset& (pte_size - 1))&& bytes == 1)
> + return false;
> +
Could be true for level > 1, no?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-07-27 9:15 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-26 11:24 [PATCH 0/11] KVM: x86: optimize for guest page written Xiao Guangrong
2011-07-26 11:25 ` [PATCH 01/11] KVM: MMU: avoid pte_list_desc run out in kvm_mmu_pte_write Xiao Guangrong
2011-07-27 9:00 ` Avi Kivity
2011-07-27 9:37 ` Xiao Guangrong
2011-07-26 11:25 ` [PATCH 02/11] KVM: x86: cleanup pio/pout emulated Xiao Guangrong
2011-07-26 11:26 ` [PATCH 03/11] KVM: x86: fast emulate repeat string write instructions Xiao Guangrong
2011-07-26 12:27 ` Gleb Natapov
2011-07-26 13:53 ` Avi Kivity
2011-07-27 1:47 ` Xiao Guangrong
2011-07-27 4:26 ` Gleb Natapov
2011-07-27 6:32 ` Xiao Guangrong
2011-07-27 7:51 ` Gleb Natapov
2011-07-27 9:36 ` Xiao Guangrong
2011-07-27 9:04 ` Avi Kivity
2011-07-27 9:37 ` Xiao Guangrong
2011-07-26 11:28 ` [PATCH 04/11] KVM: MMU: do not mark access bit on pte write path Xiao Guangrong
2011-07-27 9:08 ` Avi Kivity
2011-07-27 10:04 ` Xiao Guangrong
2011-07-26 11:28 ` [PATCH 05/11] KVM: MMU: cleanup FNAME(invlpg) Xiao Guangrong
2011-07-26 11:29 ` [PATCH 06/11] KVM: MMU: fast prefetch spte on invlpg path Xiao Guangrong
2011-07-26 11:29 ` [PATCH 07/11] KVM: MMU: remove unnecessary kvm_mmu_free_some_pages Xiao Guangrong
2011-07-26 11:30 ` [PATCH 08/11] KVM: MMU: split kvm_mmu_pte_write function Xiao Guangrong
2011-07-26 11:31 ` [PATCH 09/11] KVM: MMU: remove the mismatch shadow page Xiao Guangrong
2011-07-27 9:11 ` Avi Kivity
2011-07-27 9:13 ` Avi Kivity
2011-07-27 10:05 ` Xiao Guangrong
2011-07-26 11:31 ` [PATCH 10/11] KVM: MMU: fix detecting misaligned accessed Xiao Guangrong
2011-07-27 9:15 ` Avi Kivity [this message]
2011-07-27 10:10 ` Xiao Guangrong
2011-07-26 11:32 ` [PATCH 11/11] KVM: MMU: improve write flooding detected Xiao Guangrong
2011-07-27 9:23 ` Avi Kivity
2011-07-27 10:20 ` Xiao Guangrong
2011-07-27 11:08 ` Avi Kivity
2011-07-28 2:43 ` Xiao Guangrong
-- strict thread matches above, loose matches on Subject: below --
2011-08-16 6:40 [PATCH 01/11] KVM: MMU: avoid pte_list_desc running out in kvm_mmu_pte_write Xiao Guangrong
2011-08-16 6:46 ` [PATCH 10/11] KVM: MMU: fix detecting misaligned accessed Xiao Guangrong
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