From: Borislav Petkov <bp@alien8.de>
To: Cathy Zhang <cathy.zhang@intel.com>
Cc: linux-sgx@vger.kernel.org, x86@kernel.org, dave.hansen@intel.com,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH 09/11] x86/microcode: Expose EUPDATESVN procedure via sysfs
Date: Wed, 9 Mar 2022 12:20:16 +0100 [thread overview]
Message-ID: <YiiNPWdsYtWiULZm@zn.tnic> (raw)
In-Reply-To: <20220309104050.18207-10-cathy.zhang@intel.com>
On all your patches for the future: don't forget to Cc LKML.
On Wed, Mar 09, 2022 at 06:40:48PM +0800, Cathy Zhang wrote:
> EUPDATESVN is the SGX instruction which allows enclave attestation
> to include information about updated microcode without a reboot.
>
> Microcode updates which affect SGX require two phases:
>
> 1. Do the main microcode update
> 2. Make the new CPUSVN available for enclave attestation via
> EUPDATESVN.
>
> Before a EUPDATESVN can succeed, all enclave pages (EPC) must be
> marked as unused in the SGX metadata (EPCM). This operation destroys
> all preexisting SGX enclave data and metadata. This is by design and
> mitigates the impact of vulnerabilities that may have compromised
> enclaves or the SGX hardware itself prior to the update.
>
> Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
> ---
> arch/x86/include/asm/microcode.h | 5 ++++
> arch/x86/include/asm/sgx.h | 5 ++++
> arch/x86/kernel/cpu/microcode/core.c | 44 ++++++++++++++++++++++++++++
Why is all this code here at all?
What does that have *actually* to do with microcode loading?
AFAICT, you want to hook into microcode_check() which runs after the
microcode update and do your EUPDATESVN there...
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
next parent reply other threads:[~2022-03-09 11:20 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220309104050.18207-1-cathy.zhang@intel.com>
[not found] ` <20220309104050.18207-10-cathy.zhang@intel.com>
2022-03-09 11:20 ` Borislav Petkov [this message]
2022-03-09 15:42 ` [RFC PATCH 09/11] x86/microcode: Expose EUPDATESVN procedure via sysfs Dave Hansen
2022-03-09 15:48 ` Borislav Petkov
2022-03-10 5:15 ` Zhang, Cathy
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