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From: Alexander Graf <agraf@suse.de>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Avi Kivity <avi@redhat.com>,
	"kvm@vger.kernel.org" <kvm@vger.kernel.org>,
	"joerg.roedel@amd.com" <joerg.roedel@amd.com>
Subject: Re: [PATCH] KVM: MMU: Segregate mmu pages created with different cr4.pge settings
Date: Thu, 8 Jan 2009 20:53:21 +0100	[thread overview]
Message-ID: <585C48B8-973C-4792-9122-F0ED36C05754@suse.de> (raw)
In-Reply-To: <20090107134606.GA4977@amt.cnet>

Sorry for the late reply - I wanted to know who kvm hangs in the host  
kernel context :)

On 07.01.2009, at 14:46, Marcelo Tosatti <mtosatti@redhat.com> wrote:

> On Wed, Jan 07, 2009 at 01:32:41PM +0200, Avi Kivity wrote:
>> Marcelo Tosatti wrote:
>>> Let me shoot at one direction: a shadow page with PGE bit in either
>>> state is created. Later that shadow page is nuked (via mmu  
>>> notifiers,
>>> for example).
>>
>> I doubt that mmu notifiers were invoked in this case (the bug would  
>> be
>> very rare); in any case we flush the tlb.
>
> This comment is worrying
>
>        /*
>         * FIXME: Tis shouldn't be necessary here, but there is a flush
>         * missing in the MMU code. Until we find this bug, flush the
>         * complete TLB here on an NPF
>         */
>        if (npt_enabled)
>                svm_flush_tlb(&svm->vcpu);
>

This is in, because netbench in an npt-guest failed after a few  
minutes (see Alex W's bug report) and this appeard to fix it.


> Alexander, you might want to try this patch, -ENONPT here (and  
> revert the previous
> one).

Eh, what?

> I have no clue, what else could be causing this?
>
> diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
> index 10bdb2a..bf68e5b 100644
> --- a/arch/x86/kvm/mmu.c
> +++ b/arch/x86/kvm/mmu.c
> @@ -33,6 +33,7 @@
> #include <asm/cmpxchg.h>
> #include <asm/io.h>
> #include <asm/vmx.h>
> +#include <asm/tlbflush.h>
>
> /*
>  * When setting this variable to true it enables Two-Dimensional- 
> Paging
> @@ -1850,6 +1851,11 @@ static int __direct_map(struct kvm_vcpu  
> *vcpu, gpa_t v, int write,
>
>        if (*iterator.sptep == shadow_trap_nonpresent_pte) {
>            pseudo_gfn = (iterator.addr & PT64_DIR_BASE_ADDR_MASK) >>  
> PAGE_SHIFT;
> +
> +                        kvm_flush_remote_tlbs(vcpu->kvm);
> +                        kvm_mmu_flush_tlb(vcpu);
> +                        __flush_tlb();
> +
>            sp = kvm_mmu_get_page(vcpu, pseudo_gfn, iterator.addr,
>                          iterator.level - 1,
>                          1, ACC_ALL, iterator.sptep);
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

  reply	other threads:[~2009-01-08 19:53 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
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 [this message]
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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