From: Andrew Jones <drjones@redhat.com>
To: Laszlo Ersek <lersek@redhat.com>
Cc: KVM devel mailing list <kvm@vger.kernel.org>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Marc Zyngier <marc.zyngier@arm.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [RFC/RFT PATCH 0/3] arm64: KVM: work around incoherency with uncached guest mappings
Date: Mon, 2 Mar 2015 18:05:19 +0100 [thread overview]
Message-ID: <20150302170519.GB14186@hawk.usersys.redhat.com> (raw)
In-Reply-To: <54F49610.6090000@redhat.com>
On Mon, Mar 02, 2015 at 05:55:44PM +0100, Laszlo Ersek wrote:
> On 03/02/15 17:47, Paolo Bonzini wrote:
> >
> > Also, we may want to invalidate the cache for dirty pages before
> > returning the dirty bitmap, and probably should do that directly in
> > KVM_GET_DIRTY_LOG.
>
> "I agree."
>
> If KVM_GET_DIRTY_LOG is supposed to be atomic fetch and clear (from
> userspace's aspect), then the cache invalidation should be an atomic
> part of it too (from the same aspect).
>
> (Sorry if I just said something incredibly stupid.)
>
With the path I'm headed down, all cache maintenance operations will
be done before exiting to userspace (and after returning). I was
actually already letting a feature creep into this PoC by setting
KVM_MEM_LOG_DIRTY_PAGES when we see KVM_MEM_INCOHERENT has been set,
and the region isn't readonly. The dirty log would then be used by
KVM internally to know exactly which pages need to be invalidated
before the exit.
drew
next prev parent reply other threads:[~2015-03-02 16:59 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-19 10:54 [RFC/RFT PATCH 0/3] arm64: KVM: work around incoherency with uncached guest mappings Ard Biesheuvel
2015-02-19 10:54 ` [RFC/RFT PATCH 1/3] arm64: KVM: handle some sysreg writes in EL2 Ard Biesheuvel
2015-03-03 17:59 ` Mario Smarduch
2015-02-19 10:54 ` [RFC/RFT PATCH 2/3] arm64: KVM: mangle MAIR register to prevent uncached guest mappings Ard Biesheuvel
2015-02-19 10:54 ` [RFC/RFT PATCH 3/3] arm64: KVM: keep trapping of VM sysreg writes enabled Ard Biesheuvel
2015-02-19 13:40 ` Marc Zyngier
2015-02-19 13:44 ` Ard Biesheuvel
2015-02-19 15:19 ` Marc Zyngier
2015-02-19 15:22 ` Ard Biesheuvel
2015-02-19 14:50 ` [RFC/RFT PATCH 0/3] arm64: KVM: work around incoherency with uncached guest mappings Alexander Graf
2015-02-19 14:56 ` Ard Biesheuvel
2015-02-19 15:27 ` Alexander Graf
2015-02-19 15:31 ` Ard Biesheuvel
2015-02-19 16:57 ` Andrew Jones
2015-02-19 17:19 ` Ard Biesheuvel
2015-02-19 17:55 ` Andrew Jones
2015-02-19 17:57 ` Paolo Bonzini
2015-02-20 14:29 ` Andrew Jones
2015-02-20 14:37 ` Ard Biesheuvel
2015-02-20 15:36 ` Andrew Jones
2015-02-24 14:55 ` Andrew Jones
2015-02-24 17:47 ` Ard Biesheuvel
2015-02-24 19:12 ` Andrew Jones
2015-03-02 16:31 ` Christoffer Dall
2015-03-02 16:47 ` Paolo Bonzini
2015-03-02 16:55 ` Laszlo Ersek
2015-03-02 17:05 ` Andrew Jones [this message]
2015-03-02 16:48 ` Andrew Jones
2015-03-03 2:20 ` Mario Smarduch
2015-03-04 11:35 ` Catalin Marinas
2015-03-04 11:50 ` Ard Biesheuvel
2015-03-04 12:29 ` Catalin Marinas
2015-03-04 12:43 ` Ard Biesheuvel
2015-03-04 14:12 ` Andrew Jones
2015-03-04 14:29 ` Catalin Marinas
2015-03-04 14:34 ` Peter Maydell
2015-03-04 17:03 ` Paolo Bonzini
2015-03-04 17:28 ` Catalin Marinas
2015-03-05 10:12 ` Paolo Bonzini
2015-03-05 11:04 ` Catalin Marinas
2015-03-05 11:52 ` Peter Maydell
2015-03-05 12:03 ` Catalin Marinas
2015-03-05 12:26 ` Paolo Bonzini
2015-03-05 14:58 ` Catalin Marinas
2015-03-05 17:43 ` Paolo Bonzini
2015-03-06 21:08 ` Mario Smarduch
2015-03-09 14:26 ` Andrew Jones
2015-03-09 15:33 ` Mario Smarduch
2015-03-05 19:13 ` Ard Biesheuvel
2015-03-06 20:33 ` Mario Smarduch
2015-02-19 18:44 ` Ard Biesheuvel
2015-03-03 17:34 ` Alexander Graf
2015-03-03 18:13 ` Laszlo Ersek
2015-03-03 20:58 ` Andrew Jones
2015-03-03 18:32 ` Catalin Marinas
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