From: Andrew Jones <drjones@redhat.com>
To: Peter Maydell <peter.maydell@linaro.org>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
"Marc Zyngier" <marc.zyngier@arm.com>,
"Catalin Marinas" <catalin.marinas@arm.com>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"QEMU Developers" <qemu-devel@nongnu.org>,
"Alexander Graf" <agraf@suse.de>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Jérémy Fanguède" <j.fanguede@virtualopensystems.com>,
"Laszlo Ersek" <lersek@redhat.com>,
"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>,
"Christoffer Dall" <christoffer.dall@linaro.org>,
"Mario Smarduch" <m.smarduch@samsung.com>
Subject: Re: [Qemu-devel] [RFC/RFT PATCH v2 0/3] KVM: Introduce KVM_MEM_UNCACHED
Date: Thu, 14 May 2015 15:00:37 +0200 [thread overview]
Message-ID: <20150514130037.GB12812@localhost.localdomain> (raw)
In-Reply-To: <CAFEAcA_OXHH2NmU6c=KB+DgRQS=+YYX4es+otjE_k0qzn+6+0Q@mail.gmail.com>
On Thu, May 14, 2015 at 01:38:11PM +0100, Peter Maydell wrote:
> On 14 May 2015 at 13:28, Paolo Bonzini <pbonzini@redhat.com> wrote:
> > Well, PCI BARs are generally MMIO resources, and hence should not be cached.
> >
> > As an optimization, OS drivers can mark them as cacheable or
> > write-combining or something like that, but in general it's a safe
> > default to leave them uncached---one would think.
>
> Isn't this handled by the OS mapping them in the 'prefetchable'
> MMIO window rather than the 'non-prefetchable' one? (QEMU's
> generic-PCIe device doesn't yet support the prefetchable window.)
I was thinking (with my limited PCI knowledge) the same thing, and
was planning on experimenting with that.
drew
next prev parent reply other threads:[~2015-05-14 13:40 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 [this message]
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
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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