linux-kernel - Re: [RFC 00/10] Process-local memory allocations for hiding KVM secrets

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Date:   Mon, 17 Jun 2019 11:55:58 -0700
From:   Dave Hansen <dave.hansen@...el.com>
To:     Nadav Amit <nadav.amit@...il.com>
Cc:     Andy Lutomirski <luto@...nel.org>,
        Alexander Graf <graf@...zon.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Marius Hillenbrand <mhillenb@...zon.de>,
        kvm list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Kernel Hardening <kernel-hardening@...ts.openwall.com>,
        Linux-MM <linux-mm@...ck.org>, Alexander Graf <graf@...zon.de>,
        David Woodhouse <dwmw@...zon.co.uk>,
        the arch/x86 maintainers <x86@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Subject: Re: [RFC 00/10] Process-local memory allocations for hiding KVM
 secrets

On 6/17/19 11:50 AM, Nadav Amit wrote:
>> The idea is that you have a per-cpu address space.  Certain kernel
>> virtual addresses would map to different physical address based on where
>> you are running.  Each of the physical addresses would be "owned" by a
>> single CPU and would, by convention, never use a PGD that mapped an
>> address unless that CPU that "owned" it.
>>
>> In that case, you never really invalidate those addresses.
> I understand, but as I see it, this is not related directly to PCIDs.

Yeah, the only link I was thinking of is that we can manage per-CPU PGDs
in the same way that we manage PCIDs.  Basically we can reuse a chunk of
the software concept.