From: David Hildenbrand <david@redhat.com>
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Joerg Roedel <jroedel@suse.de>, Ard Biesheuvel <ardb@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>,
Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@linux.intel.com>,
David Rientjes <rientjes@google.com>,
Vlastimil Babka <vbabka@suse.cz>,
Tom Lendacky <thomas.lendacky@amd.com>,
Thomas Gleixner <tglx@linutronix.de>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Ingo Molnar <mingo@redhat.com>,
Varad Gautam <varad.gautam@suse.com>,
Dario Faggioli <dfaggioli@suse.com>,
Dave Hansen <dave.hansen@intel.com>,
Brijesh Singh <brijesh.singh@amd.com>,
Mike Rapoport <rppt@kernel.org>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
Mike Rapoport <rppt@linux.ibm.com>
Subject: Re: [PATCHv4 1/8] mm: Add support for unaccepted memory
Date: Fri, 8 Apr 2022 21:04:16 +0200 [thread overview]
Message-ID: <0cbee9cc-f89a-81f2-f24a-784b0fd33bab@redhat.com> (raw)
In-Reply-To: <20220405234343.74045-2-kirill.shutemov@linux.intel.com>
On 06.04.22 01:43, Kirill A. Shutemov wrote:
> UEFI Specification version 2.9 introduces the concept of memory
> acceptance. Some Virtual Machine platforms, such as Intel TDX or AMD
> SEV-SNP, requiring memory to be accepted before it can be used by the
> guest. Accepting happens via a protocol specific for the Virtual Machine
> platform.
>
> Accepting memory is costly and it makes VMM allocate memory for the
> accepted guest physical address range. It's better to postpone memory
> acceptance until memory is needed. It lowers boot time and reduces
> memory overhead.
>
> Support of such memory requires a few changes in core-mm code:
>
> - memblock has to accept memory on allocation;
>
> - page allocator has to accept memory on the first allocation of the
> page;
>
> Memblock change is trivial.
>
> The page allocator is modified to accept pages on the first allocation.
> PageUnaccepted() is used to indicate that the page requires acceptance.
>
> Kernel only needs to accept memory once after boot, so during the boot
> and warm up phase there will be a lot of memory acceptance. After things
> are settled down the only price of the feature if couple of checks for
> PageUnaccepted() in allocate and free paths. The check refers a hot
> variable (that also encodes PageBuddy()), so it is cheap and not visible
> on profiles.
>
> Architecture has to provide two helpers if it wants to support
> unaccepted memory:
>
> - accept_memory() makes a range of physical addresses accepted.
>
> - memory_is_unaccepted() checks anything within the range of physical
> addresses requires acceptance.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> Acked-by: Mike Rapoport <rppt@linux.ibm.com> # memblock
Thanks, I skimmed over most parts and nothing obvious jumped at me. Dave
has some good suggestions; I'll try giving it a thorough in the near future.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2022-04-08 19:04 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-05 23:43 [PATCHv4 0/8] mm, x86/cc: Implement support for unaccepted memory Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 1/8] mm: Add " Kirill A. Shutemov
2022-04-08 18:55 ` Dave Hansen
2022-04-09 15:54 ` Kirill A. Shutemov
2022-04-11 6:38 ` Dave Hansen
2022-04-11 10:07 ` Mike Rapoport
2022-04-13 11:40 ` Kirill A. Shutemov
2022-04-13 14:48 ` Mike Rapoport
2022-04-13 15:15 ` Kirill A. Shutemov
2022-04-13 20:06 ` Mike Rapoport
2022-04-11 8:47 ` David Hildenbrand
2022-04-08 19:04 ` David Hildenbrand [this message]
2022-04-08 19:11 ` Dave Hansen
2022-04-09 17:52 ` Kirill A. Shutemov
2022-04-11 6:41 ` Dave Hansen
2022-04-11 15:55 ` Borislav Petkov
2022-04-11 16:27 ` Dave Hansen
2022-04-11 18:55 ` Tom Lendacky
2022-04-12 8:15 ` David Hildenbrand
2022-04-12 16:08 ` Dave Hansen
2022-04-13 10:36 ` David Hildenbrand
2022-04-13 11:30 ` Kirill A. Shutemov
2022-04-13 11:32 ` David Hildenbrand
2022-04-13 15:36 ` Dave Hansen
2022-04-13 16:07 ` David Hildenbrand
2022-04-13 16:13 ` Dave Hansen
2022-04-13 16:24 ` Kirill A. Shutemov
2022-04-13 14:39 ` Mike Rapoport
2022-04-05 23:43 ` [PATCHv4 2/8] efi/x86: Get full memory map in allocate_e820() Kirill A. Shutemov
[not found] ` <Ylae+bejPzRMPrDw@zn.tnic>
2022-04-13 11:45 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 3/8] efi/x86: Implement support for unaccepted memory Kirill A. Shutemov
2022-04-08 17:26 ` Dave Hansen
2022-04-09 19:41 ` Kirill A. Shutemov
2022-04-14 15:55 ` Borislav Petkov
2022-04-15 22:24 ` Borislav Petkov
2022-04-18 15:55 ` Kirill A. Shutemov
2022-04-18 16:38 ` Borislav Petkov
2022-04-18 20:24 ` Kirill A. Shutemov
2022-04-18 21:01 ` Borislav Petkov
2022-04-18 23:50 ` Kirill A. Shutemov
2022-04-19 7:39 ` Borislav Petkov
2022-04-19 15:30 ` Kirill A. Shutemov
2022-04-19 16:38 ` Dave Hansen
2022-04-19 19:23 ` Borislav Petkov
2022-04-21 12:26 ` Borislav Petkov
2022-04-22 0:21 ` Kirill A. Shutemov
2022-04-22 9:30 ` Borislav Petkov
2022-04-22 13:26 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 4/8] x86/boot/compressed: Handle " Kirill A. Shutemov
2022-04-08 17:57 ` Dave Hansen
2022-04-09 20:20 ` Kirill A. Shutemov
2022-04-11 6:49 ` Dave Hansen
2022-04-05 23:43 ` [PATCHv4 5/8] x86/mm: Reserve unaccepted memory bitmap Kirill A. Shutemov
2022-04-08 18:08 ` Dave Hansen
2022-04-09 20:43 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 6/8] x86/mm: Provide helpers for unaccepted memory Kirill A. Shutemov
2022-04-08 18:15 ` Dave Hansen
2022-04-08 19:21 ` Dave Hansen
2022-04-13 16:08 ` Kirill A. Shutemov
2022-04-05 23:43 ` [PATCHv4 7/8] x86/tdx: Unaccepted memory support Kirill A. Shutemov
2022-04-08 18:28 ` Dave Hansen
2022-04-05 23:43 ` [PATCHv4 8/8] mm/vmstat: Add counter for memory accepting Kirill A. Shutemov
2022-04-12 8:18 ` David Hildenbrand
2022-04-08 17:02 ` [PATCHv4 0/8] mm, x86/cc: Implement support for unaccepted memory Dave Hansen
2022-04-09 23:44 ` Kirill A. Shutemov
2022-04-21 12:29 ` Borislav Petkov
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