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Date:   Fri, 12 Jun 2020 11:12:11 +0200
From:   Joerg Roedel <joro@8bytes.org>
To:     x86@kernel.org
Cc:     hpa@zytor.com, Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Hellstrom <thellstrom@vmware.com>,
        Jiri Slaby <jslaby@suse.cz>,
        Dan Williams <dan.j.williams@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        Juergen Gross <jgross@suse.com>,
        Kees Cook <keescook@chromium.org>,
        David Rientjes <rientjes@google.com>,
        Cfir Cohen <cfir@google.com>,
        Erdem Aktas <erdemaktas@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Mike Stunes <mstunes@vmware.com>,
        Joerg Roedel <jroedel@suse.de>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org, virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v3 64/75] x86/sev-es: Cache CPUID results for improved
 performance
Message-ID: <20200612091210.GA3701@8bytes.org>
References: <20200428151725.31091-1-joro@8bytes.org>
 <20200428151725.31091-65-joro@8bytes.org>
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On Tue, Apr 28, 2020 at 05:17:14PM +0200, Joerg Roedel wrote:
> From: Mike Stunes <mstunes@vmware.com>
> 
> To avoid a future VMEXIT for a subsequent CPUID function, cache the
> results returned by CPUID into an xarray.
> 
>  [tl: coding standard changes, register zero extension]
> 
> Signed-off-by: Mike Stunes <mstunes@vmware.com>
> Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
> [ jroedel@suse.de: - Wrapped cache handling into vc_handle_cpuid_cached()
>                    - Used lower_32_bits() where applicable
> 		   - Moved cache_index out of struct es_em_ctxt ]
> Co-developed-by: Joerg Roedel <jroedel@suse.de>
> Signed-off-by: Joerg Roedel <jroedel@suse.de>
> ---
>  arch/x86/kernel/sev-es-shared.c |  12 ++--
>  arch/x86/kernel/sev-es.c        | 119 +++++++++++++++++++++++++++++++-
>  2 files changed, 124 insertions(+), 7 deletions(-)

Okay, following the discussion, I am dropping this patch for now. We can
revisit CPUID caching later when we have a better justification.

Regards,

	Joerg