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    SubjectRe: [RFC 00/10] Process-local memory allocations for hiding KVM secrets
    On Fri, Jun 14, 2019 at 7:21 AM Thomas Gleixner <tglx@linutronix.de> wrote:
    >
    > On Wed, 12 Jun 2019, Andy Lutomirski wrote:
    > > > On Jun 12, 2019, at 12:55 PM, Dave Hansen <dave.hansen@intel.com> wrote:
    > > >
    > > >> On 6/12/19 10:08 AM, Marius Hillenbrand wrote:
    > > >> This patch series proposes to introduce a region for what we call
    > > >> process-local memory into the kernel's virtual address space.
    > > >
    > > > It might be fun to cc some x86 folks on this series. They might have
    > > > some relevant opinions. ;)
    > > >
    > > > A few high-level questions:
    > > >
    > > > Why go to all this trouble to hide guest state like registers if all the
    > > > guest data itself is still mapped?
    > > >
    > > > Where's the context-switching code? Did I just miss it?
    > > >
    > > > We've discussed having per-cpu page tables where a given PGD is only in
    > > > use from one CPU at a time. I *think* this scheme still works in such a
    > > > case, it just adds one more PGD entry that would have to context-switched.
    > >
    > > Fair warning: Linus is on record as absolutely hating this idea. He might
    > > change his mind, but it’s an uphill battle.
    >
    > Yes I know, but as a benefit we could get rid of all the GSBASE horrors in
    > the entry code as we could just put the percpu space into the local PGD.
    >

    I have personally suggested this to Linus on a couple of occasions,
    and he seemed quite skeptical.

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