From: Martin Fernandez <martin.fernandez@eclypsium.com>
To: Borislav Petkov <bp@alien8.de>
Cc: linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
tglx@linutronix.de, mingo@redhat.com,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
ardb@kernel.org, dvhart@infradead.org, andy@infradead.org,
gregkh@linuxfoundation.org, rafael@kernel.org, rppt@kernel.org,
akpm@linux-foundation.org, daniel.gutson@eclypsium.com,
hughsient@gmail.com, alex.bazhaniuk@eclypsium.com,
alison.schofield@intel.com, keescook@chromium.org
Subject: Re: [PATCH v8 0/8] x86: Show in sysfs if a memory node is able to do encryption
Date: Wed, 4 May 2022 14:18:30 -0300 [thread overview]
Message-ID: <CAKgze5YDD02AsrF0yESv2sptZ4qxyTMgCDmnOKcbQWjKQsJRsw@mail.gmail.com> (raw)
In-Reply-To: <YnKr+aMf4PspDpHZ@zn.tnic>
On 5/4/22, Borislav Petkov <bp@alien8.de> wrote:
> On Fri, Apr 29, 2022 at 05:17:09PM -0300, Martin Fernandez wrote:
>> Show for each node if every memory descriptor in that node has the
>> EFI_MEMORY_CPU_CRYPTO attribute.
>>
>> fwupd project plans to use it as part of a check to see if the users
>> have properly configured memory hardware encryption
>> capabilities. fwupd's people have seen cases where it seems like there
>> is memory encryption because all the hardware is capable of doing it,
>> but on a closer look there is not, either because of system firmware
>> or because some component requires updating to enable the feature.
>
> Hm, so in the sysfs patch you have:
>
> + This value is 1 if all system memory in this node is
> + capable of being protected with the CPU's memory
> + cryptographic capabilities.
>
> So this says the node is capable - so what is fwupd going to report -
> that the memory is capable?
>
> From your previous paragraph above it sounds to me like you wanna
> say whether memory encryption is active or not, not that the node is
> capable.
>
> Or what is the use case?
The use case is to know if a user is using hardware encryption or
not. This new sysfs file plus knowing if tme/sev is active you can be
pretty sure about that.
>> It's planned to make it part of a specification that can be passed to
>> people purchasing hardware
>
> So people are supposed to run that fwupd on that new hw to check whether
> they can use memory encryption?
Yes
>> These checks will run at every boot. The specification is called Host
>> Security ID: https://fwupd.github.io/libfwupdplugin/hsi.html.
>>
>> We choosed to do it a per-node basis because although an ABI that
>> shows that the whole system memory is capable of encryption would be
>> useful for the fwupd use case, doing it in a per-node basis gives also
>> the capability to the user to target allocations from applications to
>> NUMA nodes which have encryption capabilities.
>
> That's another hmmm: what systems do not do full system memory
> encryption and do only per-node?
>
> From those I know, you encrypt the whole memory on the whole system and
> that's it. Even if it is a hypervisor which runs a lot of guests, you
> still want the hypervisor itself to run encrypted, i.e., what's called
> SME in AMD's variant.
Dave Hansen pointed those out in a previuos patch serie, here is the
quote:
> CXL devices will have normal RAM on them, be exposed as "System RAM" and
> they won't have encryption capabilities. I think these devices were
> probably the main motivation for EFI_MEMORY_CPU_CRYPTO.
next prev parent reply other threads:[~2022-05-04 18:01 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-29 20:17 [PATCH v8 0/8] x86: Show in sysfs if a memory node is able to do encryption Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 1/8] mm/memblock: Tag memblocks with crypto capabilities Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 2/8] mm/mmzone: Tag pg_data_t " Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 3/8] x86/e820: Add infrastructure to refactor e820__range_{update,remove} Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 4/8] x86/e820: Refactor __e820__range_update Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 5/8] x86/e820: Refactor e820__range_remove Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 6/8] x86/e820: Tag e820_entry with crypto capabilities Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 7/8] x86/efi: Mark e820_entries as crypto capable from EFI memmap Martin Fernandez
2022-04-29 20:17 ` [PATCH v8 8/8] drivers/node: Show in sysfs node's crypto capabilities Martin Fernandez
2022-05-04 16:38 ` [PATCH v8 0/8] x86: Show in sysfs if a memory node is able to do encryption Borislav Petkov
2022-05-04 17:18 ` Martin Fernandez [this message]
2022-05-06 12:44 ` Borislav Petkov
2022-05-06 14:18 ` Limonciello, Mario
2022-05-06 15:32 ` Dave Hansen
2022-05-06 16:00 ` Dan Williams
2022-05-06 17:55 ` Boris Petkov
2022-05-06 18:14 ` Dave Hansen
2022-05-06 18:25 ` Boris Petkov
2022-05-06 18:43 ` Dave Hansen
2022-05-06 19:02 ` Boris Petkov
2022-05-09 18:47 ` Dave Hansen
2022-05-09 22:17 ` Borislav Petkov
2022-05-09 22:56 ` Dave Hansen
2022-05-16 8:39 ` Richard Hughes
2022-05-18 7:52 ` Borislav Petkov
2022-05-18 18:28 ` Dan Williams
2022-05-18 20:23 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAKgze5YDD02AsrF0yESv2sptZ4qxyTMgCDmnOKcbQWjKQsJRsw@mail.gmail.com \
--to=martin.fernandez@eclypsium.com \
--cc=akpm@linux-foundation.org \
--cc=alex.bazhaniuk@eclypsium.com \
--cc=alison.schofield@intel.com \
--cc=andy@infradead.org \
--cc=ardb@kernel.org \
--cc=bp@alien8.de \
--cc=daniel.gutson@eclypsium.com \
--cc=dave.hansen@linux.intel.com \
--cc=dvhart@infradead.org \
--cc=gregkh@linuxfoundation.org \
--cc=hpa@zytor.com \
--cc=hughsient@gmail.com \
--cc=keescook@chromium.org \
--cc=linux-efi@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=platform-driver-x86@vger.kernel.org \
--cc=rafael@kernel.org \
--cc=rppt@kernel.org \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).