From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Dave Hansen <dave.hansen@intel.com>
Cc: Nadav Amit <nadav.amit@gmail.com>,
Andy Lutomirski <luto@kernel.org>,
Alexander Graf <graf@amazon.com>,
Thomas Gleixner <tglx@linutronix.de>,
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>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [RFC 00/10] Process-local memory allocations for hiding KVM secrets
Date: Mon, 17 Jun 2019 14:45:36 -0400 [thread overview]
Message-ID: <20190617184536.GB11017@char.us.oracle.com> (raw)
In-Reply-To: <f6f352ed-750e-d735-a1c9-7ff133ca8aea@intel.com>
On Mon, Jun 17, 2019 at 11:07:45AM -0700, Dave Hansen wrote:
> On 6/17/19 9:53 AM, Nadav Amit wrote:
> >>> For anyone following along at home, I'm going to go off into crazy
> >>> per-cpu-pgds speculation mode now... Feel free to stop reading now. :)
> >>>
> >>> But, I was thinking we could get away with not doing this on _every_
> >>> context switch at least. For instance, couldn't 'struct tlb_context'
> >>> have PGD pointer (or two with PTI) in addition to the TLB info? That
> >>> way we only do the copying when we change the context. Or does that tie
> >>> the implementation up too much with PCIDs?
> >> Hmm, that seems entirely reasonable. I think the nasty bit would be
> >> figuring out all the interactions with PV TLB flushing. PV TLB
> >> flushes already don't play so well with PCID tracking, and this will
> >> make it worse. We probably need to rewrite all that code regardless.
> > How is PCID (as you implemented) related to TLB flushing of kernel (not
> > user) PTEs? These kernel PTEs would be global, so they would be invalidated
> > from all the address-spaces using INVLPG, I presume. No?
>
> 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.
But you would need to invalidate if the process moved to another CPU, correct?
next prev parent reply other threads:[~2019-06-17 18:45 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
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 [this message]
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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