From: David Hildenbrand <david@redhat.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>,
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>
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>,
x86@kernel.org, linux-mm@kvack.org, linux-coco@lists.linux.dev,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH 1/5] mm: Add support for unaccepted memory
Date: Tue, 10 Aug 2021 09:48:04 +0200 [thread overview]
Message-ID: <dd4b7aff-ccf3-24f6-3f6e-14c4b6aa8b64@redhat.com> (raw)
In-Reply-To: <20210810062626.1012-2-kirill.shutemov@linux.intel.com>
On 10.08.21 08:26, Kirill A. Shutemov wrote:
> UEFI Specification version 2.9 introduces 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 Virtrual 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
> acceptation until memory is needed. It lowers boot time and reduces
> memory overhead.
>
> Support of such memory requires 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.
>
> Page allocator is modified to accept pages on the first allocation.
> PageOffline() is used to indicate that the page requires acceptance.
> The flag currently used by hotplug and balloon. Such pages are not
> available to page allocator.
>
> An architecture has to provide three helpers if it wants to support
> unaccepted memory:
>
> - accept_memory() makes a range of physical addresses accepted.
>
> - maybe_set_page_offline() marks a page PageOffline() if it requires
> acceptance. Used during boot to put pages on free lists.
>
> - clear_page_offline() clears makes a page accepted and clears
> PageOffline().
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
> mm/internal.h | 14 ++++++++++++++
> mm/memblock.c | 1 +
> mm/page_alloc.c | 13 ++++++++++++-
> 3 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/mm/internal.h b/mm/internal.h
> index 31ff935b2547..d2fc8a17fbe0 100644
> --- a/mm/internal.h
> +++ b/mm/internal.h
> @@ -662,4 +662,18 @@ void vunmap_range_noflush(unsigned long start, unsigned long end);
> int numa_migrate_prep(struct page *page, struct vm_area_struct *vma,
> unsigned long addr, int page_nid, int *flags);
>
> +#ifndef CONFIG_UNACCEPTED_MEMORY
> +static inline void maybe_set_page_offline(struct page *page, unsigned int order)
> +{
> +}
> +
> +static inline void clear_page_offline(struct page *page, unsigned int order)
> +{
> +}
> +
> +static inline void accept_memory(phys_addr_t start, phys_addr_t end)
> +{
> +}
Can we find better fitting names for the first two? The function names
are way too generic. For example:
accept_or_set_page_offline()
accept_and_clear_page_offline()
I thought for a second if
PAGE_TYPE_OPS(Unaccepted, offline)
makes sense as well, not sure.
Also, please update the description of PageOffline in page-flags.h to
include the additional usage with PageBuddy set at the same time.
I assume you don't have to worry about page_offline_freeze/thaw ... as
we only set PageOffline initially, but not later at runtime when other
subsystems (/proc/kcore) might stumble over it.
--
Thanks,
David / dhildenb
next prev parent reply other threads:[~2021-08-10 7:48 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-10 6:26 [PATCH 0/5] x86: Impplement support for unaccepted memory Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 1/5] mm: Add " Kirill A. Shutemov
2021-08-10 7:48 ` David Hildenbrand [this message]
2021-08-10 15:02 ` Kirill A. Shutemov
2021-08-10 15:21 ` David Hildenbrand
2021-08-12 20:34 ` Kirill A. Shutemov
2021-08-10 18:13 ` Dave Hansen
2021-08-10 18:30 ` Andi Kleen
2021-08-10 18:56 ` Dave Hansen
2021-08-10 19:23 ` Andi Kleen
2021-08-10 19:46 ` Dave Hansen
2021-08-10 21:20 ` Andi Kleen
2021-08-12 8:19 ` Joerg Roedel
2021-08-12 14:14 ` Dave Hansen
2021-08-12 20:49 ` Kirill A. Shutemov
2021-08-12 20:59 ` Dave Hansen
2021-08-12 21:23 ` Kirill A. Shutemov
2021-08-13 14:49 ` Joerg Roedel
2021-08-17 15:00 ` David Hildenbrand
2021-08-19 9:55 ` Joerg Roedel
2021-08-19 10:06 ` David Hildenbrand
2021-08-10 20:50 ` Dave Hansen
2021-08-12 21:08 ` Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 2/5] efi/x86: Implement " Kirill A. Shutemov
2021-08-10 17:50 ` Dave Hansen
2021-08-12 21:14 ` Kirill A. Shutemov
2021-08-12 21:43 ` Dave Hansen
2021-08-10 18:30 ` Dave Hansen
2021-08-10 19:08 ` Kirill A. Shutemov
2021-08-10 19:19 ` Dave Hansen
2021-08-12 21:17 ` Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 3/5] x86/boot/compressed: Handle " Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 4/5] x86/mm: Provide helpers for " Kirill A. Shutemov
2021-08-10 18:16 ` Dave Hansen
2021-08-12 20:31 ` Kirill A. Shutemov
2021-08-10 6:26 ` [PATCH 5/5] x86/tdx: Unaccepted memory support Kirill A. Shutemov
2021-08-10 14:08 ` [PATCH 0/5] x86: Impplement support for unaccepted memory Dave Hansen
2021-08-10 15:15 ` Kirill A. Shutemov
2021-08-10 15:51 ` Dave Hansen
2021-08-10 17:31 ` Kirill A. Shutemov
2021-08-10 17:36 ` Dave Hansen
2021-08-10 17:51 ` Kirill A. Shutemov
2021-08-10 18:19 ` Dave Hansen
2021-08-10 18:39 ` Kirill A. Shutemov
2021-08-12 8:23 ` Joerg Roedel
2021-08-12 10:10 ` Kirill A. Shutemov
2021-08-12 19:33 ` Andi Kleen
2021-08-12 20:22 ` Kirill A. Shutemov
2021-08-13 14:56 ` Joerg Roedel
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