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Date:   Fri, 29 Jul 2022 14:22:18 -0500
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Subject: Re: [PATCH v1 1/2] x86/sev: Use per-CPU PSC structure in prep for
 unaccepted memory support
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To:     Dave Hansen <dave.hansen@intel.com>, linux-kernel@vger.kernel.org,
        x86@kernel.org
Cc:     Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Michael Roth <michael.roth@amd.com>,
        Joerg Roedel <jroedel@suse.de>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>
References: <20220614120231.48165-1-kirill.shutemov@linux.intel.com>
 <cover.1659103274.git.thomas.lendacky@amd.com>
 <658c455c40e8950cb046dd885dd19dc1c52d060a.1659103274.git.thomas.lendacky@amd.com>
 <d27e42a8-b2af-f922-4cea-b1ddaa2a0af0@intel.com>
 <9da5204f-5c8f-b47b-bcc6-d68ca63db08d@amd.com>
 <377f6c30-bdfc-55a4-bda7-f29c60c53300@intel.com>
From:   Tom Lendacky <thomas.lendacky@amd.com>
In-Reply-To: <377f6c30-bdfc-55a4-bda7-f29c60c53300@intel.com>
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On 7/29/22 14:08, Dave Hansen wrote:
> On 7/29/22 07:25, Tom Lendacky wrote:
>>> Considering that runtime acceptance is already single-threaded[1] *and*
>>> there's a fallback method, why not just have a single copy of this
>>> guarded by a single lock?
>>
>> This function is called for more than just memory acceptance. It's also
>> called for any changes from or to private or shared, which isn't
>> single-threaded.
> 
> I think this tidbit from the changelog threw me off:
> 
>> Protect the use of the per-CPU structure by disabling interrupts during
>> memory acceptance.
> 
> Could you please revise that to accurately capture the impact of this
> change?

Is s/memory acceptance/page state changes/ enough of what you are looking 
for or something more?

Thanks,
Tom