From: Tom Lendacky <thomas.lendacky@amd.com>
To: Martin Fernandez <martin.fernandez@eclypsium.com>,
"Limonciello, Mario" <mario.limonciello@amd.com>
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, bp@alien8.de,
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 v6 6/6] drivers/node: Show in sysfs node's crypto capabilities
Date: Fri, 4 Feb 2022 09:59:45 -0600 [thread overview]
Message-ID: <5c5ffe29-d3d3-2955-cf78-ad275110f012@amd.com> (raw)
In-Reply-To: <CAKgze5YM2+BRjj2nvb+_dnuCg5WtWvQ6FQyNYJ1c8G6Orn=aQw@mail.gmail.com>
On 2/4/22 07:21, Martin Fernandez wrote:
> On 2/4/22, Limonciello, Mario <mario.limonciello@amd.com> wrote:
>> On 2/3/2022 10:43, Martin Fernandez wrote:
>>> +static ssize_t crypto_capable_show(struct device *dev,
>>> + struct device_attribute *attr, char *buf)
>>> +{
>>> + struct pglist_data *pgdat = NODE_DATA(dev->id);
>>> +
>>> + return sysfs_emit(buf, "%d\n", pgdat->crypto_capable);
>>
>> As there is interest in seeing these capabilities from userspace, it
>> seems like a logical time to also expose a `crypto_active` attribute.
>
> I planned to do something similar to this, but to show (or actually
> hide if inactive) tme in cpuinfo, just as Borislav Petkov suggested a
> few versions back.
>
> https://lore.kernel.org/linux-efi/YXrnkxgdjWbcPlJA@zn.tnic/
>
>> Then userspace can make a judgement call if the system supports crypto
>> memory (`crypto_capable`) and then also whether or not it's been turned
>> on (`crypto_active`).
>>
>> `crypto_active` could be detected with some existing support in the
>> kernel of `mem_encrypt_active()`. This will then work for a variety of
>> architectures too that offer `mem_encrypt_active()`.
>
> I need a hand with this, I grepped for mem_encrypt_active and nothing
> showed up...
The mem_encrypt_active() function has been replaced by
cc_platform_has(CC_ATTR_MEM_ENCRYPT).
>
>> As it stands today the only reliable way to tell from userspace (at
>> least for AMD's x86 implementation) is by grepping the system log for
>> the line "AMD Memory Encryption Features active".
>
> Isn't enough to grep for sme/sev in cpuinfo?
No, it's not enough. Cpuinfo shows a processors capabilities and not
necessarily whether that capability is being used.
Thanks,
Tom
next prev parent reply other threads:[~2022-02-04 15:59 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-03 16:43 [PATCH v6 0/6] x86: Show in sysfs if a memory node is able to do encryption Martin Fernandez
2022-02-03 16:43 ` [PATCH v6 1/6] mm/memblock: Tag memblocks with crypto capabilities Martin Fernandez
2022-02-03 18:07 ` Mike Rapoport
2022-02-03 18:24 ` Martin Fernandez
2022-02-07 21:18 ` Kees Cook
2022-02-08 14:39 ` Martin Fernandez
2022-02-03 16:43 ` [PATCH v6 2/6] mm/mmzone: Tag pg_data_t " Martin Fernandez
2022-02-07 21:19 ` Kees Cook
2022-02-03 16:43 ` [PATCH v6 3/6] x86/e820: Refactor range_update and range_remove Martin Fernandez
2022-02-07 21:45 ` Kees Cook
2022-02-08 8:40 ` Mike Rapoport
2022-02-08 21:01 ` Martin Fernandez
2022-02-15 7:10 ` Mike Rapoport
2022-02-15 14:14 ` Martin Fernandez
2022-02-08 21:09 ` Martin Fernandez
2022-03-04 20:32 ` Martin Fernandez
2022-02-08 21:04 ` Daniel Gutson
2022-02-03 16:43 ` [PATCH v6 4/6] x86/e820: Tag e820_entry with crypto capabilities Martin Fernandez
2022-02-07 21:56 ` Kees Cook
2022-02-08 14:46 ` Martin Fernandez
2022-02-03 16:43 ` [PATCH v6 5/6] x86/efi: Tag e820_entries as crypto capable from EFI memmap Martin Fernandez
2022-02-03 16:43 ` [PATCH v6 6/6] drivers/node: Show in sysfs node's crypto capabilities Martin Fernandez
2022-02-04 3:47 ` Limonciello, Mario
2022-02-04 13:21 ` Martin Fernandez
2022-02-04 15:59 ` Tom Lendacky [this message]
2022-02-04 16:23 ` Limonciello, Mario
[not found] ` <Yf1UO6jF91o9k4jB@zn.tnic>
2022-02-04 17:12 ` Tom Lendacky
2022-02-04 17:49 ` Limonciello, Mario
[not found] ` <Yf1p0ZjPf9Qaqwtg@zn.tnic>
2022-02-04 18:49 ` Tom Lendacky
2022-02-04 21:49 ` Borislav Petkov
2022-02-07 3:39 ` Kees Cook
2022-02-04 4:56 ` Mike Rapoport
2022-02-04 12:27 ` Martin Fernandez
2022-02-04 13:37 ` Mike Rapoport
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