From: Christoph Hellwig <hch@lst.de>
To: "Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
"Maciej W. Rozycki" <macro@linux-mips.org>,
Eric Biggers <ebiggers@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Imre Deak <imre.deak@intel.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Benjamin Gaignard <benjamin.gaignard@linaro.org>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
Emil Velikov <emil.velikov@collabora.com>,
Rob Clark <robdclark@chromium.org>,
Paul Burton <paul.burton@mips.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
<linux-arm-kernel@lists.infradead.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
"open list:MIPS" <linux-mips@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Robin Murphy <robin.murphy@arm.com>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<linux-arm-msm@vger.kernel.org>,
"Sharma, Deepak" <Deepak.Sharma@amd.com>,
Joerg Roedel <jroedel@suse.de>, Arnd Bergmann <arnd@arndb.de>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Hauke Mehrtens <hauke@hauke-m.de>,
Jesper Dangaard Brouer <brouer@redhat.com>,
"Wolfram Sang \(Renesas\)" <wsa+renesas@sang-engineering.com>,
"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
<linuxppc-dev@lists.ozlabs.org>,
Alexios Zavras <alexios.zavras@intel.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Doug Anderson <armlinux@m.disordat.com>,
Thomas Gleixner <tglx@linutronix.de>, Sean Paul <sean@poorly.run>,
Allison Randal <allison@lohutok.net>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Enrico Weigelt <info@metux.net>,
open list <linux-kernel@vger.kernel.org>,
Rob Clark <robdclark@gmail.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<freedreno@lists.freedesktop.org>
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:27:42 +0200 [thread overview]
Message-ID: <20190815182742.GA20859@lst.de> (raw)
In-Reply-To: <e3f73b3c-49d5-3c19-dfff-0a24b4617e50@amd.com>
On Thu, Aug 15, 2019 at 06:21:00PM +0000, Koenig, Christian wrote:
> > (2) Add support for DMA_ATTR_NO_KERNEL_MAPPING to this new API instead
> > of dma_alloc_attrs. The initial difference with that flag is just
> > that we allow highmem, but in the future we could also unmap this
> > memory from the kernel linear mapping entirely on architectures
> > where we can easily do that.
>
> Mhm, why would we want to do this?
To avoid the CPU misspeculating into this memory. For example NVMe SSDs
have a feature called host memory buffer that is a lot like your stolen
main ram for the GPU case. We currently hand the SSD a
DMA_ATTR_NO_KERNEL_MAPPING allocation if it requests such a buffer. If
possible we'd really like to make sure no speculative execution bug
(or intentional attacker with a kernel exploit for that matter) can easily
access that memory.
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@lst.de>
To: "Koenig, Christian" <Christian.Koenig@amd.com>
Cc: Kate Stewart <kstewart@linuxfoundation.org>,
Masayoshi Mizuma <m.mizuma@jp.fujitsu.com>,
"Maciej W. Rozycki" <macro@linux-mips.org>,
Eric Biggers <ebiggers@google.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Imre Deak <imre.deak@intel.com>,
dri-devel <dri-devel@lists.freedesktop.org>,
Chris Wilson <chris@chris-wilson.co.uk>,
Masahiro Yamada <yamada.masahiro@socionext.com>,
Benjamin Gaignard <benjamin.gaignard@linaro.org>,
Mauro Carvalho Chehab <mchehab+samsung@kernel.org>,
Will Deacon <will@kernel.org>, Christoph Hellwig <hch@lst.de>,
Emil Velikov <emil.velikov@collabora.com>,
Rob Clark <robdclark@chromium.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Paul Burton <paul.burton@mips.com>,
Mike Rapoport <rppt@linux.ibm.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
"moderated list:ARM64 PORT \(AARCH64 ARCHITECTURE\)"
<linux-arm-kernel@lists.infradead.org>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
"open list:MIPS" <linux-mips@vger.kernel.org>,
Linus Walleij <linus.walleij@linaro.org>,
Robin Murphy <robin.murphy@arm.com>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<linux-arm-msm@vger.kernel.org>,
"Sharma, Deepak" <Deepak.Sharma@amd.com>,
Joerg Roedel <jroedel@suse.de>, Arnd Bergmann <arnd@arndb.de>,
Anshuman Khandual <anshuman.khandual@arm.com>,
Hauke Mehrtens <hauke@hauke-m.de>,
Jesper Dangaard Brouer <brouer@redhat.com>,
"Wolfram Sang \(Renesas\)" <wsa+renesas@sang-engineering.com>,
"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
<linuxppc-dev@lists.ozlabs.org>,
Alexios Zavras <alexios.zavras@intel.com>,
Russell King <rmk+kernel@armlinux.org.uk>,
Doug Anderson <armlinux@m.disordat.com>,
Thomas Gleixner <tglx@linutronix.de>, Sean Paul <sean@poorly.run>,
Allison Randal <allison@lohutok.net>,
Christophe Leroy <christophe.leroy@c-s.fr>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Enrico Weigelt <info@metux.net>,
open list <linux-kernel@vger.kernel.org>,
Rob Clark <robdclark@gmail.com>,
Souptick Joarder <jrdr.linux@gmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
"open list:DRM DRIVER FOR MSM ADRENO GPU"
<freedreno@lists.freedesktop.org>
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:27:42 +0200 [thread overview]
Message-ID: <20190815182742.GA20859@lst.de> (raw)
In-Reply-To: <e3f73b3c-49d5-3c19-dfff-0a24b4617e50@amd.com>
On Thu, Aug 15, 2019 at 06:21:00PM +0000, Koenig, Christian wrote:
> > (2) Add support for DMA_ATTR_NO_KERNEL_MAPPING to this new API instead
> > of dma_alloc_attrs. The initial difference with that flag is just
> > that we allow highmem, but in the future we could also unmap this
> > memory from the kernel linear mapping entirely on architectures
> > where we can easily do that.
>
> Mhm, why would we want to do this?
To avoid the CPU misspeculating into this memory. For example NVMe SSDs
have a feature called host memory buffer that is a lot like your stolen
main ram for the GPU case. We currently hand the SSD a
DMA_ATTR_NO_KERNEL_MAPPING allocation if it requests such a buffer. If
possible we'd really like to make sure no speculative execution bug
(or intentional attacker with a kernel exploit for that matter) can easily
access that memory.
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>
To: "Koenig, Christian" <Christian.Koenig-5C7GfCeVMHo@public.gmane.org>
Cc: Kate Stewart
<kstewart-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
Masayoshi Mizuma
<m.mizuma-+CUm20s59erQFUHtdCDX3A@public.gmane.org>,
"Maciej W. Rozycki"
<macro-6z/3iImG2C8G8FEW9MqTrA@public.gmane.org>,
Eric Biggers <ebiggers-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
Catalin Marinas <catalin.marinas-5wv7dgnIgG8@public.gmane.org>,
Imre Deak <imre.deak-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
dri-devel
<dri-devel-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org>,
Chris Wilson
<chris-Y6uKTt2uX1cEflXRtASbqLVCufUGDwFn@public.gmane.org>,
Masahiro Yamada
<yamada.masahiro-uWyLwvC0a2jby3iVrkZq2A@public.gmane.org>,
Benjamin Gaignard
<benjamin.gaignard-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>,
Mauro Carvalho Chehab
<mchehab+samsung-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Will Deacon <will-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Christoph Hellwig <hch-jcswGhMUV9g@public.gmane.org>,
Emil Velikov
<emil.velikov-ZGY8ohtN/8qB+jHODAdFcQ@public.gmane.org>,
Rob Clark <robdclark-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
Paul Burton <paul.burton-8NJIiSa5LzA@public.gmane.org>,
Mike Rapoport <rppt-tEXmvtCZX7AybS5Ee8rs3A@public.gmane.org>,
Geert Uytterhoeven
<geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org>,
"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)"
<linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org>,
Daniel
Subject: Re: [PATCH 0/6] drm+dma: cache support for arm, etc
Date: Thu, 15 Aug 2019 20:27:42 +0200 [thread overview]
Message-ID: <20190815182742.GA20859@lst.de> (raw)
In-Reply-To: <e3f73b3c-49d5-3c19-dfff-0a24b4617e50-5C7GfCeVMHo@public.gmane.org>
On Thu, Aug 15, 2019 at 06:21:00PM +0000, Koenig, Christian wrote:
> > (2) Add support for DMA_ATTR_NO_KERNEL_MAPPING to this new API instead
> > of dma_alloc_attrs. The initial difference with that flag is just
> > that we allow highmem, but in the future we could also unmap this
> > memory from the kernel linear mapping entirely on architectures
> > where we can easily do that.
>
> Mhm, why would we want to do this?
To avoid the CPU misspeculating into this memory. For example NVMe SSDs
have a feature called host memory buffer that is a lot like your stolen
main ram for the GPU case. We currently hand the SSD a
DMA_ATTR_NO_KERNEL_MAPPING allocation if it requests such a buffer. If
possible we'd really like to make sure no speculative execution bug
(or intentional attacker with a kernel exploit for that matter) can easily
access that memory.
_______________________________________________
Freedreno mailing list
Freedreno@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/freedreno
next prev parent reply other threads:[~2019-08-15 18:29 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-14 21:59 [PATCH 0/6] drm+dma: cache support for arm, etc Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` [PATCH 1/6] arm64: export arch_sync_dma_for_*() Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` [PATCH 2/6] mips: " Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` [PATCH 3/6] powerpc: " Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` [PATCH 4/6] arm: add arch_sync_dma_for_*() Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 21:59 ` Rob Clark
2019-08-14 22:00 ` [PATCH 5/6] drm/msm: stop abusing DMA API Rob Clark
2019-08-14 22:00 ` [PATCH 6/6] drm/vgem: fix cache synchronization on arm/arm64 (take two) Rob Clark
2019-08-15 6:51 ` [PATCH 0/6] drm+dma: cache support for arm, etc Christoph Hellwig
2019-08-15 6:51 ` Christoph Hellwig
2019-08-15 6:51 ` Christoph Hellwig
2019-08-15 13:54 ` Rob Clark
2019-08-15 13:54 ` Rob Clark
2019-08-15 13:54 ` Rob Clark
2019-08-15 17:53 ` Christoph Hellwig
2019-08-15 17:53 ` Christoph Hellwig
2019-08-15 17:53 ` Christoph Hellwig
2019-08-15 18:21 ` Koenig, Christian
2019-08-15 18:21 ` Koenig, Christian
2019-08-15 18:21 ` Koenig, Christian
2019-08-15 18:27 ` Christoph Hellwig [this message]
2019-08-15 18:27 ` Christoph Hellwig
2019-08-15 18:27 ` Christoph Hellwig
2019-08-16 21:04 ` Rob Clark
2019-08-16 21:04 ` Rob Clark
2019-08-16 21:04 ` Rob Clark
2019-08-19 5:23 ` Christoph Hellwig
2019-08-19 5:23 ` Christoph Hellwig
2019-08-19 5:23 ` Christoph Hellwig
2019-08-19 14:39 ` Rob Clark
2019-08-19 14:39 ` Rob Clark
2019-08-19 14:39 ` Rob Clark
-- strict thread matches above, loose matches on Subject: below --
2019-08-15 18:48 Koenig, Christian
2019-08-15 18:48 ` Koenig, Christian
2019-08-15 18:52 ` Christoph Hellwig
2019-08-15 18:52 ` Christoph Hellwig
2019-08-15 18:52 ` Christoph Hellwig
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