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From: Dave Hansen <dave.hansen@intel.com>
To: "Thomas Hellström (VMware)" <thomas_os@shipmail.org>,
	"Daniel Vetter" <daniel@ffwll.ch>
Cc: dri-devel <dri-devel@lists.freedesktop.org>,
	pv-drivers@vmware.com,
	"VMware Graphics" <linux-graphics-maintainer@vmware.com>,
	"Linux Kernel Mailing List" <linux-kernel@vger.kernel.org>,
	"Tom Lendacky" <thomas.lendacky@amd.com>,
	"Thomas Hellstrom" <thellstrom@vmware.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Dave Hansen" <dave.hansen@linux.intel.com>,
	"Heiko Carstens" <heiko.carstens@de.ibm.com>,
	"Christian Borntraeger" <borntraeger@de.ibm.com>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>,
	"Andy Lutomirski" <luto@kernel.org>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"Thomas Gleixner" <tglx@linutronix.de>,
	"Christian König" <christian.koenig@amd.com>
Subject: Re: [PATCH v2 3/4] drm/ttm, drm/vmwgfx: Correctly support support AMD memory encryption
Date: Tue, 3 Sep 2019 13:51:28 -0700	[thread overview]
Message-ID: <7fa3b178-b9b4-2df9-1eee-54e24d48342e@intel.com> (raw)
In-Reply-To: <bed2a2d9-17f0-24bd-9f4a-c7ee27f6106e@shipmail.org>

On 9/3/19 1:36 PM, Thomas Hellström (VMware) wrote:
> So the question here should really be, can we determine already at mmap
> time whether backing memory will be unencrypted and adjust the *real*
> vma->vm_page_prot under the mmap_sem?
> 
> Possibly, but that requires populating the buffer with memory at mmap
> time rather than at first fault time.

I'm not connecting the dots.

vma->vm_page_prot is used to create a VMA's PTEs regardless of if they
are created at mmap() or fault time.  If we establish a good
vma->vm_page_prot, can't we just use it forever for demand faults?

Or, are you concerned that if an attempt is made to demand-fault page
that's incompatible with vma->vm_page_prot that we have to SEGV?

> And it still requires knowledge whether the device DMA is always
> unencrypted (or if SEV is active).

I may be getting mixed up on MKTME (the Intel memory encryption) and
SEV.  Is SEV supported on all memory types?  Page cache, hugetlbfs,
anonymous?  Or just anonymous?

  reply	other threads:[~2019-09-03 20:51 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
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 [this message]
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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