From: Joerg Roedel <jroedel@suse.de>
To: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Vlastimil Babka <vbabka@suse.cz>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Andi Kleen <ak@linux.intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Tom Lendacky <thomas.lendacky@amd.com>,
Jon Grimm <jon.grimm@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
"Kaplan, David" <David.Kaplan@amd.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev
Subject: Re: Runtime Memory Validation in Intel-TDX and AMD-SNP
Date: Mon, 19 Jul 2021 17:02:24 +0200 [thread overview]
Message-ID: <YPWUAInpncx+LPo6@suse.de> (raw)
In-Reply-To: <YPV5H0A+HB/t6y+z@casper.infradead.org>
On Mon, Jul 19, 2021 at 02:07:43PM +0100, Matthew Wilcox wrote:
> I think this proposal skips (intentionally?) something that s390 already
> implemented: the secure guest deliberately allowing the hypervisor to
> access certain pages for a period and then re-validating them. I hope x86
> can use the same interface as s390 for this, or if not, the interface can
> be modified to be usable by all architectures. See commit f28d43636d6f
> ("mm/gup/writeback: add callbacks for inaccessible pages").
Yeah, sharing memory with the Hypervisor is not the main scope of the
proposal. The requirement I put in step 8. about returning only
validated memory (which means it is not shared with the HV anymore) to
the memory allocator slightly touches this.
In general, on x86 the hypervisor can only write to eplicitly shared and
unencrypted regions of guest memory. The guest decides where those are
and is responsible for setting these areas up.
For x86 this happens mainly in the DMA-API backend and to some degree in
other code which sets up non-DMA shared data structures with the host
(like the code setting up the GHCBs for SEV-ES).
That said, I don't see an immediate use of the API introduced in the
patch above for x86.
Regards,
Joerg
next prev parent reply other threads:[~2021-07-19 15:02 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-19 12:58 Runtime Memory Validation in Intel-TDX and AMD-SNP Joerg Roedel
2021-07-19 13:07 ` Matthew Wilcox
2021-07-19 15:02 ` Joerg Roedel [this message]
2021-07-19 20:39 ` Andi Kleen
2021-07-20 8:55 ` Joerg Roedel
2021-07-20 9:34 ` Dr. David Alan Gilbert
2021-07-20 11:50 ` Joerg Roedel
2021-07-20 0:26 ` Andy Lutomirski
[not found] ` <CAAYXXYwFzrf8uY-PFkMRSG28+HztfGdJft8kB3Y3keWCx9K8TQ@mail.gmail.com>
2021-07-20 2:00 ` Erdem Aktas
2021-07-20 5:17 ` Andi Kleen
2021-07-20 9:11 ` Joerg Roedel
2021-07-20 17:32 ` Andi Kleen
2021-07-20 23:09 ` Erdem Aktas
2021-07-21 0:38 ` Andi Kleen
2021-07-22 17:31 ` Marc Orr
2021-07-26 18:55 ` Joerg Roedel
[not found] ` <eacb9c1f-2c61-4a7f-b5a3-7bf579e6cbf6@www.fastmail.com>
2021-07-20 19:54 ` Erdem Aktas
2021-07-20 22:01 ` Andi Kleen
2021-07-20 23:55 ` Erdem Aktas
2021-07-21 0:35 ` Andi Kleen
2021-07-21 8:51 ` Joerg Roedel
2021-07-20 8:44 ` Joerg Roedel
2021-07-20 14:14 ` Dave Hansen
2021-07-20 17:30 ` Kirill A. Shutemov
2021-07-21 9:20 ` Mike Rapoport
2021-07-21 10:02 ` Kirill A. Shutemov
2021-07-21 10:22 ` Mike Rapoport
2021-07-21 10:53 ` Joerg Roedel
2021-07-21 9:25 ` Joerg Roedel
2021-07-21 10:25 ` Kirill A. Shutemov
2021-07-21 10:48 ` Joerg Roedel
2021-07-22 15:46 ` David Hildenbrand
2021-07-26 19:02 ` Joerg Roedel
2021-07-27 9:34 ` David Hildenbrand
2021-08-02 10:19 ` Joerg Roedel
2021-08-02 18:47 ` David Hildenbrand
2021-07-22 15:57 ` David Hildenbrand
2021-07-22 19:51 ` Kirill A. Shutemov
2021-07-23 15:23 ` Mike Rapoport
2021-07-23 16:29 ` Kirill A. Shutemov
2021-07-25 9:16 ` Mike Rapoport
2021-07-25 18:28 ` Kirill A. Shutemov
2021-07-26 10:00 ` Mike Rapoport
2021-07-26 11:53 ` Kirill A. Shutemov
2021-07-26 19:13 ` Joerg Roedel
2021-07-26 23:02 ` Erdem Aktas
2021-07-26 23:54 ` Kirill A. Shutemov
2021-07-27 1:35 ` Erdem Aktas
2021-07-23 11:04 ` Varad Gautam
2021-07-23 14:34 ` Kaplan, David
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