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From: Andrew Jones <drjones@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	QEMU Developers <qemu-devel@nongnu.org>,
	Alexander Graf <agraf@suse.de>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Laszlo Ersek <lersek@redhat.com>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
	Christoffer Dall <christoffer.dall@linaro.org>
Subject: Re: [Qemu-devel] [RFC/RFT PATCH v2 0/3] KVM: Introduce KVM_MEM_UNCACHED
Date: Thu, 14 May 2015 15:03:18 +0200	[thread overview]
Message-ID: <20150514130318.GC12812@localhost.localdomain> (raw)
In-Reply-To: <CAFEAcA_EEA=TZ1jxL_rptAx5_sGa8NLMffePAw3eb-3pBgdg5w@mail.gmail.com>

On Thu, May 14, 2015 at 11:37:46AM +0100, Peter Maydell wrote:
> On 14 May 2015 at 11:31, Andrew Jones <drjones@redhat.com> wrote:
> > Forgot to (4): switch from setting userspace's mapping to
> > device memory to normal, non-cacheable. Using device memory
> > caused a problem that Alex Graf found, and Peter Maydell suggested
> > using normal, non-cacheable instead.
> 
> Did you check that non-cacheable is definitely the correct
> kind of Normal memory attribute we want? (ie not write-through).

I was concerned that write-through wouldn't be sufficient. If the
guest writes to its non-cached memory, and QEMU needs to see what
it wrote, then won't write-through fail to work? Unless we some
how invalidate the cache first?

drew

  reply	other threads:[~2015-05-14 13:03 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-13 11:31 [Qemu-devel] [RFC/RFT PATCH v2 0/3] KVM: Introduce KVM_MEM_UNCACHED Andrew Jones
2015-05-13 11:31 ` [Qemu-devel] [RFC/RFT PATCH v2 1/3] arm/arm64: pageattr: add set_memory_nc Andrew Jones
2015-05-14 11:05   ` Christoffer Dall
2015-05-14 13:46     ` Andrew Jones
2015-05-15 14:51       ` Christoffer Dall
2015-05-18 15:53       ` Catalin Marinas
2015-05-19 10:03         ` Andrew Jones
2015-05-19 11:18           ` Catalin Marinas
2015-05-19 11:38             ` Andrew Jones
2015-05-20 10:01             ` Christoffer Dall
2015-05-20 11:24               ` Catalin Marinas
2015-05-23  1:08         ` Mario Smarduch
2015-05-25 17:11           ` Andrew Jones
2015-05-27  1:08             ` Mario Smarduch
2015-05-13 11:31 ` [Qemu-devel] [RFC/RFT PATCH v2 2/3] KVM: promote KVM_MEMSLOT_INCOHERENT to uapi Andrew Jones
2015-05-14 10:12   ` Paolo Bonzini
2015-05-14 10:34   ` Christoffer Dall
2015-05-13 11:31 ` [Qemu-devel] [RFC/RFT PATCH v2 3/3] arm/arm64: KVM: implement 'uncached' mem coherency Andrew Jones
2015-05-14 10:55   ` Christoffer Dall
2015-05-14 13:32     ` Andrew Jones
2015-05-15 15:02       ` Christoffer Dall
2015-05-15 17:04         ` Andrew Jones
2015-05-15 20:16           ` Jérémy Fanguède
2015-05-21  2:29           ` Mario Smarduch
2015-05-21 16:50             ` Andrew Jones
2015-05-14 10:30 ` [Qemu-devel] [RFC/RFT PATCH v2 0/3] KVM: Introduce KVM_MEM_UNCACHED Christoffer Dall
2015-05-14 11:09   ` Laszlo Ersek
2015-05-14 11:29     ` Christoffer Dall
2015-05-14 11:31       ` Paolo Bonzini
2015-05-14 11:36         ` Christoffer Dall
2015-05-14 11:38           ` Paolo Bonzini
2015-05-14 12:00             ` Christoffer Dall
2015-05-14 12:08               ` Paolo Bonzini
2015-05-14 12:24                 ` Christoffer Dall
2015-05-14 12:28                   ` Paolo Bonzini
2015-05-14 12:34                     ` Christoffer Dall
2015-05-14 13:01                       ` Laszlo Ersek
2015-05-14 12:38                     ` Peter Maydell
2015-05-14 13:00                       ` Andrew Jones
2015-05-14 13:32                         ` Laszlo Ersek
2015-05-14 13:48                           ` Michael S. Tsirkin
2015-05-14 14:19                             ` Laszlo Ersek
2015-05-14 14:41                               ` Michael S. Tsirkin
2015-05-15  9:00                                 ` Ard Biesheuvel
2015-05-14 10:31 ` Andrew Jones
2015-05-14 10:37   ` Peter Maydell
2015-05-14 13:03     ` Andrew Jones [this message]
2015-05-14 13:11       ` Peter Maydell
2015-05-14 13:33         ` Laszlo Ersek
2015-05-14 13:36         ` Andrew Jones
2015-05-15 15:09           ` Christoffer Dall

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