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From: Dave Hansen <dave.hansen@intel.com>
To: "Kirill A. Shutemov" <kirill@shutemov.name>,
	Tom Lendacky <thomas.lendacky@amd.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	Michael Roth <michael.roth@amd.com>,
	Joerg Roedel <jroedel@suse.de>,
	Dionna Glaze <dionnaglaze@google.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ard Biescheuvel <ardb@kernel.org>,
	"Min M. Xu" <min.m.xu@intel.com>,
	Gerd Hoffmann <kraxel@redhat.com>,
	James Bottomley <jejb@linux.ibm.com>,
	Jiewen Yao <jiewen.yao@intel.com>,
	Erdem Aktas <erdemaktas@google.com>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH v7 6/6] x86/efi: Safely enable unaccepted memory in UEFI
Date: Tue, 4 Apr 2023 10:57:52 -0700	[thread overview]
Message-ID: <bc9e6d82-c7c1-47dc-e91f-57d9b4e2bb0a@intel.com> (raw)
In-Reply-To: <20230404174506.pjdikxvk2fsyy4au@box.shutemov.name>

On 4/4/23 10:45, Kirill A. Shutemov wrote:
> I still think it is a bad idea.
> 
> As I asked before, please include my
> 
> Nacked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> 
> into the patch.

I was pretty opposed to this when I first saw it too.  But, Tom and
company have worn down my opposition a bit.

The fact is that we have upstream kernels out there with SEV-SNP support
that don't know anything about unaccepted memory.  They're either
relegated to using the pre-accepted memory (4GB??) or _some_ entity
needs to accept the memory.  That entity obviously can't be the kernel
unless we backport unaccepted memory support.

This both lets the BIOS be the page-accepting entity _and_ allows the
entity to delegate that to the kernel when it needs to.

As much as I want to nak this and pretend that that those existing
kernel's don't exist, my powers of self-delusion do have their limits.

If our AMD friends don't do this, what is their alternative?

  reply	other threads:[~2023-04-04 17:57 UTC|newest]

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-03-30 11:49 [PATCHv9 00/14] mm, x86/cc: Implement support for unaccepted memory Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 01/14] x86/boot: Centralize __pa()/__va() definitions Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 02/14] mm: Add support for unaccepted memory Kirill A. Shutemov
2023-04-03  9:26   ` Vlastimil Babka
2023-04-03 10:02     ` Kirill A. Shutemov
2023-04-03 13:07       ` Vlastimil Babka
2023-03-30 11:49 ` [PATCHv9 03/14] mm/page_alloc: Fake " Kirill A. Shutemov
2023-04-03 13:39   ` Vlastimil Babka
2023-04-03 14:39     ` Kirill A. Shutemov
2023-04-03 15:50       ` Kirill A. Shutemov
2023-04-14 10:19         ` Kirill A. Shutemov
2023-04-03 14:43   ` David Hildenbrand
2023-04-03 14:47     ` Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 04/14] mm/page_alloc: Add sysfs handle to accept accept_memory Kirill A. Shutemov
2023-04-03 13:43   ` Vlastimil Babka
2023-04-03 14:41     ` Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 05/14] efi/x86: Get full memory map in allocate_e820() Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 06/14] x86/boot: Add infrastructure required for unaccepted memory support Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 07/14] efi/x86: Implement support for unaccepted memory Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 08/14] x86/boot/compressed: Handle " Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 09/14] x86/mm: Reserve unaccepted memory bitmap Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 10/14] x86/mm: Provide helpers for unaccepted memory Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 11/14] x86/mm: Avoid load_unaligned_zeropad() stepping into " Kirill A. Shutemov
2023-04-03 13:28   ` Vlastimil Babka
2023-04-03 14:42     ` Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 12/14] x86/tdx: Make _tdx_hypercall() and __tdx_module_call() available in boot stub Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 13/14] x86/tdx: Refactor try_accept_one() Kirill A. Shutemov
2023-03-30 11:49 ` [PATCHv9 14/14] x86/tdx: Add unaccepted memory support Kirill A. Shutemov
2023-04-03 14:42 ` [PATCHv9 00/14] mm, x86/cc: Implement support for unaccepted memory Vlastimil Babka
2023-04-16 19:19   ` Kirill A. Shutemov
2023-04-17  7:37     ` Vlastimil Babka
2023-04-04 17:23 ` [PATCH v7 0/6] Provide SEV-SNP " Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 1/6] x86/sev: Fix calculation of end address based on number of pages Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 2/6] x86/sev: Put PSC struct on the stack in prep for unaccepted memory support Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 3/6] x86/sev: Allow for use of the early boot GHCB for PSC requests Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 4/6] x86/sev: Use large PSC requests if applicable Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 5/6] x86/sev: Add SNP-specific unaccepted memory support Tom Lendacky
2023-04-04 17:23   ` [PATCH v7 6/6] x86/efi: Safely enable unaccepted memory in UEFI Tom Lendacky
2023-04-04 17:45     ` Kirill A. Shutemov
2023-04-04 17:57       ` Dave Hansen [this message]
2023-04-04 18:09         ` Kirill A. Shutemov
2023-04-04 19:27           ` Dave Hansen
2023-04-04 19:49           ` Ard Biesheuvel
2023-04-04 20:24             ` Kirill A. Shutemov
2023-04-04 20:41               ` Ard Biesheuvel
2023-04-04 21:01                 ` Kirill A. Shutemov
2023-04-05  7:46                   ` Ard Biesheuvel
2023-04-05 13:00                     ` Dave Hansen
2023-04-05 13:44                       ` Ard Biesheuvel
2023-04-05 16:15                         ` Dave Hansen
2023-04-05 19:06                           ` Kirill A. Shutemov
2023-04-05 20:11                             ` Tom Lendacky
2023-04-05 21:22                               ` Dave Hansen
2023-04-05 21:34                                 ` Ard Biesheuvel
2023-04-05 13:42                     ` Kirill A. Shutemov
2023-04-05 13:51                       ` Ard Biesheuvel
2023-04-05 10:06                   ` Gerd Hoffmann

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