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From: Christoph Hellwig <hch@infradead.org>
To: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
Cc: "Christoph Hellwig" <hch@infradead.org>,
	dri-devel@lists.freedesktop.org, pv-drivers@vmware.com,
	linux-graphics-maintainer@vmware.com,
	linux-kernel@vger.kernel.org,
	"Thomas Hellstrom" <thellstrom@vmware.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH v2 1/4] x86/mm: Export force_dma_unencrypted
Date: Tue, 3 Sep 2019 09:22:04 -0700	[thread overview]
Message-ID: <20190903162204.GB23281@infradead.org> (raw)
In-Reply-To: <f85e7fa6-54e1-7ac5-ce6c-96349c7af322@shipmail.org>

On Tue, Sep 03, 2019 at 04:32:45PM +0200, Thomas Hellström (VMware) wrote:
> Is this a layer violation concern, that is, would you be ok with a similar
> helper for TTM, or is it that you want to force the graphics drivers into
> adhering strictly to the DMA api, even when it from an engineering
> perspective makes no sense?

From looking at DRM I strongly believe that making DRM use the DMA
mapping properly makes a lot of sense from the engineering perspective,
and this series is a good argument for that positions.  If DRM was using
the DMA properl we would not need this series to start with, all the
SEV handling is hidden behind the DMA API.  While we had occasional
bugs in that support fixing it meant that it covered all drivers
properly using that API.

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>
Cc: "Christoph Hellwig" <hch@infradead.org>,
	dri-devel@lists.freedesktop.org, pv-drivers@vmware.com,
	linux-graphics-maintainer@vmware.com,
	linux-kernel@vger.kernel.org,
	"Thomas Hellstrom" <thellstrom@vmware.com>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Andy Lutomirski" <luto@kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH v2 1/4] x86/mm: Export force_dma_unencrypted
Date: Tue, 3 Sep 2019 09:22:04 -0700	[thread overview]
Message-ID: <20190903162204.GB23281@infradead.org> (raw)
In-Reply-To: <f85e7fa6-54e1-7ac5-ce6c-96349c7af322@shipmail.org>

On Tue, Sep 03, 2019 at 04:32:45PM +0200, Thomas Hellström (VMware) wrote:
> Is this a layer violation concern, that is, would you be ok with a similar
> helper for TTM, or is it that you want to force the graphics drivers into
> adhering strictly to the DMA api, even when it from an engineering
> perspective makes no sense?

>From looking at DRM I strongly believe that making DRM use the DMA
mapping properly makes a lot of sense from the engineering perspective,
and this series is a good argument for that positions.  If DRM was using
the DMA properl we would not need this series to start with, all the
SEV handling is hidden behind the DMA API.  While we had occasional
bugs in that support fixing it meant that it covered all drivers
properly using that API.

  reply	other threads:[~2019-09-03 16:22 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-03 13:15 [PATCH v2 0/4] Have TTM support SEV encryption with coherent memory Thomas Hellström (VMware)
2019-09-03 13:15 ` [PATCH v2 1/4] x86/mm: Export force_dma_unencrypted Thomas Hellström (VMware)
2019-09-03 13:46   ` Christoph Hellwig
2019-09-03 14:32     ` Thomas Hellström (VMware)
2019-09-03 16:22       ` Christoph Hellwig [this message]
2019-09-03 16:22         ` Christoph Hellwig
2019-09-03 20:46         ` Thomas Hellström (VMware)
2019-09-03 20:46           ` Thomas Hellström (VMware)
2019-09-03 21:41           ` Andy Lutomirski
2019-09-04  6:58           ` Christoph Hellwig
2019-09-04  7:32             ` Thomas Hellström (VMware)
2019-09-04 12:22               ` Christoph Hellwig
2019-09-04 17:28                 ` Thomas Hellström (VMware)
2019-09-03 15:14   ` Dave Hansen
2019-09-03 15:14     ` Dave Hansen
2019-09-03 18:50     ` Thomas Hellström (VMware)
2019-09-03 18:50       ` Thomas Hellström (VMware)
2019-09-03 13:15 ` [PATCH v2 2/4] s390/mm: " Thomas Hellström (VMware)
2019-09-03 13:46   ` Christoph Hellwig
2019-09-03 13:15 ` [PATCH v2 3/4] drm/ttm, drm/vmwgfx: Correctly support support AMD memory encryption Thomas Hellström (VMware)
2019-09-03 19:38   ` Dave Hansen
2019-09-03 19:51     ` Daniel Vetter
2019-09-03 19:51       ` Daniel Vetter
2019-09-03 19:55       ` Dave Hansen
2019-09-03 20:36         ` Thomas Hellström (VMware)
2019-09-03 20:51           ` Dave Hansen
2019-09-03 21:05             ` Thomas Hellström (VMware)
2019-09-03 21:46               ` Andy Lutomirski
2019-09-03 22:08                 ` Thomas Hellström (VMware)
2019-09-03 22:15                   ` Thomas Hellström (VMware)
2019-09-03 22:15                     ` Thomas Hellström (VMware)
2019-09-03 23:10                     ` Dave Hansen
2019-09-04  8:34                       ` Thomas Hellström (VMware)
2019-09-03 23:15                     ` Andy Lutomirski
2019-09-04  6:49                       ` Thomas Hellström (VMware)
2019-09-04  7:53                         ` Daniel Vetter
2019-09-04 10:37                           ` Thomas Hellström (VMware)
2019-09-04 10:37                             ` Thomas Hellström (VMware)
2019-09-04 11:43                             ` Daniel Vetter
2019-09-04 18:16                         ` Christoph Hellwig
2019-09-04 18:16                           ` Christoph Hellwig
2019-09-04  7:33               ` Koenig, Christian
2019-09-04  8:19                 ` Thomas Hellström (VMware)
2019-09-04  8:42                   ` Thomas Hellström (VMware)
2019-09-04  8:42                     ` Thomas Hellström (VMware)
2019-09-04 11:10                   ` Koenig, Christian
2019-09-04 11:10                     ` Koenig, Christian
2019-09-04 12:35                     ` Thomas Hellström (VMware)
2019-09-04 12:35                       ` Thomas Hellström (VMware)
2019-09-04 13:05                       ` Thomas Hellström (VMware)
2019-09-03 13:15 ` [PATCH v2 4/4] drm/ttm: Cache dma pool decrypted pages when AMD SEV is active Thomas Hellström (VMware)
2019-09-03 15:18 ` [PATCH v2 0/4] Have TTM support SEV encryption with coherent memory Daniel Vetter
2019-09-05 10:43 ` Thomas Hellström (VMware)

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