From: Joerg Roedel <joro@8bytes.org>
To: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Joerg Roedel <jroedel@suse.de>, Andi Kleen <ak@linux.intel.com>,
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>,
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, 26 Jul 2021 21:13:17 +0200 [thread overview]
Message-ID: <YP8JTRvBnSLrJaYb@8bytes.org> (raw)
In-Reply-To: <20210722195130.beazbb5blvj3mruo@box>
Hi Kirill,
On Thu, Jul 22, 2021 at 10:51:30PM +0300, Kirill A. Shutemov wrote:
> Okay, below is my first take on the topic.
Thanks, I havn't looked deeply into the patch yet, but will do so
tomorrow and reply separatly.
> I ended up combing your idea with bitmap with PageOffline(): early boot
> code uses bitmap, but on page allocator init I mark unaccepted pages with
> PageOffline(). This way page allocator need to touch the bitmap only when
> it steps on PageOffline() which shouldn't be often once things settle
> after boot.
I still need to understand the benefit of having this information in the
memmap, but I also don't object to it. For AMD-SNP the bitmap needs to
stay around at least, unless there is another way to implement
kexec/kdump.
> One bit in the bitmap represents 2M region. Any unaligned chunks gets
> accepted when we construct the bitmap. This way one 4K page can represent
> 64 GiB of physical address space.
Yeah, a 2MB chunk size makes sense when it comes to how much we validate
at once. I think it will be good choice for AMD too. On the other side
there is a need for SNP to track shared pages on a 4k granularity. There
are a couple of shared (or at least not valid) pages (GHCB, #HV shared page,
VMSA page) per vCPU which are 4k in size. Oh, and then there is the
.bss_decrypted section, which is also not 2M aligend.
In case of kexec/kdump this information needs to be passed on to the
next kernel.
Regards,
Jörg
next prev parent reply other threads:[~2021-07-26 19:13 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
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 [this message]
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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