From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Dave Hansen <dave.hansen@intel.com>
Cc: "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>, 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
Subject: Re: [PATCH 2/5] efi/x86: Implement support for unaccepted memory
Date: Fri, 13 Aug 2021 00:17:32 +0300 [thread overview]
Message-ID: <20210812211732.l46uwa5p22s4nsqg@box.shutemov.name> (raw)
In-Reply-To: <ef45d48f-2e7f-850e-f4d0-f518d34c598d@intel.com>
On Tue, Aug 10, 2021 at 12:19:22PM -0700, Dave Hansen wrote:
> On 8/10/21 12:08 PM, Kirill A. Shutemov wrote:
> >>> +config UNACCEPTED_MEMORY
> >>> + bool
> >>> + depends on EFI_STUB
> >>> + help
> >>> + Some Virtual Machine platforms, such as Intel TDX, introduce
> >>> + the concept of memory acceptance, requiring memory to be accepted
> >>> + before it can be used by the guest. This protects against a class of
> >>> + attacks by the virtual machine platform.
> >>> +
> >>> + This option adds support for unaccepted memory and makes such memory
> >>> + usable by kernel.
> >> Do we really need a full-blown user-visible option here? If we, for
> >> instance, just did:
> >>
> >> config UNACCEPTED_MEMORY
> >> bool
> >> depends on EFI_STUB
> >>
> >> it could be 'select'ed from the TDX Kconfig and no users would ever be
> >> bothered with it. Would a user *ever* turn this on if they don't have
> >> TDX (or equivalent)?
> > But it's already not user selectable. Note that there's no prompt next to
> > the "bool". The "help" section is just for documentation. I think it can
> > be useful.
>
> Ahh, gotcha. I misread it. Seems like an odd thing to do, but it's
> also fairly widespread in the tree.
>
> Can you even reach that help text from any of the configuration tools?
> If you're doing an 'oldconfig', you won't get a prompt to do the "?".
> Even in the 'meunconfig' search results, it doesn't display "help" text,
> only the "prompt".
I don't know how get a tool show the text, but my vim sees just fine :P
> BTW, should this text call out that this is for parsing an actual UEFI
> feature along with the spec version? It's not obvious from the text
> that "unaccepted memory" really is a UEFI thing as opposed to being some
> kernel-only concept.
Okay.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-08-12 21:17 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
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 [this message]
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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