From: Andy Lutomirski <luto@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Dave Hansen <dave.hansen@intel.com>,
Marius Hillenbrand <mhillenb@amazon.de>,
kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Kernel Hardening <kernel-hardening@lists.openwall.com>,
Linux-MM <linux-mm@kvack.org>, Alexander Graf <graf@amazon.de>,
David Woodhouse <dwmw@amazon.co.uk>,
"the arch/x86 maintainers" <x86@kernel.org>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC 00/10] Process-local memory allocations for hiding KVM secrets
Date: Sun, 16 Jun 2019 15:18:00 -0700 [thread overview]
Message-ID: <CALCETrWZ4qUW+A+YqE36ZJHqJAzxwDgq77bL99BEKQx-=JYAtA@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.21.1906141618000.1722@nanos.tec.linutronix.de>
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.
next prev parent reply other threads:[~2019-06-16 22:18 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-12 17:08 [RFC 00/10] Process-local memory allocations for hiding KVM secrets Marius Hillenbrand
2019-06-12 17:08 ` [RFC 01/10] x86/mm/kaslr: refactor to use enum indices for regions Marius Hillenbrand
2019-06-12 17:08 ` [RFC 02/10] x86/speculation, mm: add process local virtual memory region Marius Hillenbrand
2019-06-12 17:08 ` [RFC 03/10] x86/mm, mm,kernel: add teardown for process-local memory to mm cleanup Marius Hillenbrand
2019-06-12 17:08 ` [RFC 04/10] mm: allocate virtual space for process-local memory Marius Hillenbrand
2019-06-12 17:08 ` [RFC 05/10] mm: allocate/release physical pages " Marius Hillenbrand
2019-06-12 17:08 ` [RFC 06/10] kvm/x86: add support for storing vCPU state in " Marius Hillenbrand
2019-06-12 17:08 ` [RFC 07/10] kvm, vmx: move CR2 context switch out of assembly path Marius Hillenbrand
2019-06-12 17:08 ` [RFC 08/10] kvm, vmx: move register clearing " Marius Hillenbrand
2019-06-12 17:08 ` [RFC 09/10] kvm, vmx: move gprs to process local memory Marius Hillenbrand
2019-06-12 17:08 ` [RFC 10/10] kvm, x86: move guest FPU state into " Marius Hillenbrand
2019-06-12 18:25 ` [RFC 00/10] Process-local memory allocations for hiding KVM secrets Sean Christopherson
2019-06-13 7:20 ` Alexander Graf
2019-06-13 10:54 ` Liran Alon
2019-06-12 19:55 ` Dave Hansen
2019-06-12 20:27 ` Andy Lutomirski
2019-06-12 20:41 ` Dave Hansen
2019-06-12 20:56 ` Andy Lutomirski
2019-06-13 1:30 ` Andy Lutomirski
2019-06-13 1:50 ` Nadav Amit
2019-06-13 16:16 ` Andy Lutomirski
2019-06-13 7:52 ` Alexander Graf
2019-06-13 16:13 ` Andy Lutomirski
2019-06-13 16:20 ` Dave Hansen
2019-06-13 17:29 ` Nadav Amit
2019-06-13 17:49 ` Dave Hansen
2019-06-13 20:05 ` Sean Christopherson
2019-06-14 14:21 ` Thomas Gleixner
2019-06-16 22:18 ` Andy Lutomirski [this message]
2019-06-16 22:28 ` Thomas Gleixner
2019-06-17 7:38 ` Alexander Graf
2019-06-17 15:50 ` Dave Hansen
2019-06-17 15:54 ` Andy Lutomirski
2019-06-17 16:03 ` Dave Hansen
2019-06-17 16:14 ` Andy Lutomirski
2019-06-17 16:53 ` Nadav Amit
2019-06-17 18:07 ` Dave Hansen
2019-06-17 18:45 ` Konrad Rzeszutek Wilk
2019-06-17 18:49 ` Dave Hansen
2019-06-17 18:53 ` Andy Lutomirski
2019-06-17 18:50 ` Nadav Amit
2019-06-17 18:55 ` Dave Hansen
2019-06-13 7:27 ` Alexander Graf
2019-06-13 14:19 ` Dave Hansen
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