From: Avi Kivity <avi@redhat.com>
To: Gleb Natapov <gleb@redhat.com>
Cc: kvm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, mingo@elte.hu,
a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com,
riel@redhat.com, cl@linux-foundation.org, mtosatti@redhat.com
Subject: Re: [PATCH v6 03/12] Retry fault before vmentry
Date: Thu, 07 Oct 2010 14:29:07 +0200 [thread overview]
Message-ID: <4CADBD13.4040609@redhat.com> (raw)
In-Reply-To: <1286207794-16120-4-git-send-email-gleb@redhat.com>
On 10/04/2010 05:56 PM, Gleb Natapov wrote:
> When page is swapped in it is mapped into guest memory only after guest
> tries to access it again and generate another fault. To save this fault
> we can map it immediately since we know that guest is going to access
> the page. Do it only when tdp is enabled for now. Shadow paging case is
> more complicated. CR[034] and EFER registers should be switched before
> doing mapping and then switched back.
With non-pv apf, I don't think we can do shadow paging. The guest isn't
aware of the apf, so as far as it is concerned it is allowed to kill the
process and replace it with something else:
guest process x: apf
kvm: timer intr
guest kernel: context switch
very fast guest admin: pkill -9 x
guest kernel: destroy x's cr3
guest kernel: reuse x's cr3 for new process y
kvm: retry fault, instantiating x's page in y's page table
Even with tdp, we have the same case for nnpt (just s/kernel/hypervisor/
and s/process/guest/). What we really need is to only instantiate the
page for direct maps, which are independent of the guest.
Could be done like this:
- at apf time, walk shadow mmu
- if !sp->role.direct, abort
- take reference to sp
- on apf completion, instantiate spte in sp
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
--
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next prev parent reply other threads:[~2010-10-07 12:29 UTC|newest]
Thread overview: 88+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-04 15:56 [PATCH v6 00/12] KVM: Add host swap event notifications for PV guest Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 01/12] Add get_user_pages() variant that fails if major fault is required Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 02/12] Halt vcpu if page it tries to access is swapped out Gleb Natapov
2010-10-05 1:20 ` Rik van Riel
2010-10-05 14:59 ` Marcelo Tosatti
2010-10-06 10:50 ` Avi Kivity
2010-10-06 10:52 ` Gleb Natapov
2010-10-07 9:54 ` Avi Kivity
2010-10-07 17:48 ` Gleb Natapov
2010-10-06 11:15 ` Gleb Natapov
2010-10-07 9:50 ` Avi Kivity
2010-10-07 9:52 ` Avi Kivity
2010-10-07 13:24 ` Rik van Riel
2010-10-07 13:29 ` Avi Kivity
2010-10-07 17:47 ` Gleb Natapov
2010-10-09 18:30 ` Avi Kivity
2010-10-09 18:32 ` Avi Kivity
2010-10-10 7:30 ` Gleb Natapov
2010-10-10 7:29 ` Gleb Natapov
2010-10-10 15:55 ` Avi Kivity
2010-10-10 15:56 ` Avi Kivity
2010-10-10 16:17 ` Gleb Natapov
2010-10-10 16:16 ` Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 03/12] Retry fault before vmentry Gleb Natapov
2010-10-05 15:54 ` Marcelo Tosatti
2010-10-06 11:07 ` Gleb Natapov
2010-10-06 14:20 ` Marcelo Tosatti
2010-10-07 18:44 ` Gleb Natapov
2010-10-08 16:07 ` Marcelo Tosatti
2010-10-07 12:29 ` Avi Kivity [this message]
2010-10-07 17:21 ` Gleb Natapov
2010-10-09 18:42 ` Avi Kivity
2010-10-10 7:35 ` Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 04/12] Add memory slot versioning and use it to provide fast guest write interface Gleb Natapov
2010-10-05 1:29 ` Rik van Riel
2010-10-05 16:57 ` Marcelo Tosatti
2010-10-06 11:14 ` Gleb Natapov
2010-10-06 14:38 ` Marcelo Tosatti
2010-10-06 20:08 ` Gleb Natapov
2010-10-07 10:00 ` Avi Kivity
2010-10-07 15:42 ` Marcelo Tosatti
2010-10-07 16:03 ` Gleb Natapov
2010-10-07 16:20 ` Avi Kivity
2010-10-07 17:23 ` Gleb Natapov
2010-10-10 12:48 ` Avi Kivity
2010-10-07 12:31 ` Avi Kivity
2010-10-04 15:56 ` [PATCH v6 05/12] Move kvm_smp_prepare_boot_cpu() from kvmclock.c to kvm.c Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 06/12] Add PV MSR to enable asynchronous page faults delivery Gleb Natapov
2010-10-07 12:42 ` Avi Kivity
2010-10-07 17:53 ` Gleb Natapov
2010-10-10 12:47 ` Avi Kivity
2010-10-10 13:27 ` Gleb Natapov
2010-10-07 12:58 ` Avi Kivity
2010-10-07 17:59 ` Gleb Natapov
2010-10-09 18:43 ` Avi Kivity
2010-10-04 15:56 ` [PATCH v6 07/12] Add async PF initialization to PV guest Gleb Natapov
2010-10-05 2:34 ` Rik van Riel
2010-10-05 18:25 ` Marcelo Tosatti
2010-10-06 10:55 ` Gleb Natapov
2010-10-06 14:45 ` Marcelo Tosatti
2010-10-06 20:05 ` Gleb Natapov
2010-10-07 12:50 ` Avi Kivity
2010-10-08 7:54 ` Gleb Natapov
2010-10-09 18:44 ` Avi Kivity
2010-10-04 15:56 ` [PATCH v6 08/12] Handle async PF in a guest Gleb Natapov
2010-10-07 13:10 ` Avi Kivity
2010-10-07 17:14 ` Gleb Natapov
2010-10-07 17:18 ` Avi Kivity
2010-10-07 17:48 ` Rik van Riel
2010-10-07 18:03 ` Gleb Natapov
2010-10-09 18:48 ` Avi Kivity
2010-10-10 7:56 ` Gleb Natapov
2010-10-10 12:40 ` Avi Kivity
2010-10-10 12:32 ` Gleb Natapov
2010-10-10 12:38 ` Avi Kivity
2010-10-10 13:22 ` Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 09/12] Inject asynchronous page fault into a PV guest if page is swapped out Gleb Natapov
2010-10-05 2:36 ` Rik van Riel
2010-10-05 19:00 ` Marcelo Tosatti
2010-10-06 10:42 ` Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 10/12] Handle async PF in non preemptable context Gleb Natapov
2010-10-05 19:51 ` Marcelo Tosatti
2010-10-06 10:41 ` Gleb Natapov
2010-10-10 14:25 ` Gleb Natapov
2010-10-04 15:56 ` [PATCH v6 11/12] Let host know whether the guest can handle async PF in non-userspace context Gleb Natapov
2010-10-07 13:36 ` Avi Kivity
2010-10-04 15:56 ` [PATCH v6 12/12] Send async PF when guest is not in userspace too Gleb Natapov
2010-10-05 2:37 ` Rik van Riel
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