From: Dave Hansen <dave.hansen@intel.com>
To: Andy Lutomirski <luto@kernel.org>,
Alexander Graf <graf@amazon.com>, Nadav Amit <namit@vmware.com>
Cc: 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: Thu, 13 Jun 2019 09:20:53 -0700 [thread overview]
Message-ID: <f1dfbfb4-d2d5-bf30-600f-9e756a352860@intel.com> (raw)
In-Reply-To: <CALCETrVRuQb-P7auHCgxzs5L=qA2_qHzVGTtRMAqoMAut0ETFw@mail.gmail.com>
On 6/13/19 9:13 AM, Andy Lutomirski wrote:
>> It might make sense to use it for kmap_atomic() for debug purposes, as
>> it ensures that other users can no longer access the same mapping
>> through the linear map. However, it does come at quite a big cost, as we
>> need to shoot down the TLB of all other threads in the system. So I'm
>> not sure it's of general value?
> What I meant was that kmap_atomic() could use mm-local memory so that
> it doesn't need to do a global shootdown. But I guess it's not
> actually used for real on 64-bit, so this is mostly moot. Are you
> planning to support mm-local on 32-bit?
Do we *do* global shootdowns on kmap_atomic()s on 32-bit? I thought we
used entirely per-cpu addresses, so a stale entry from another CPU can
get loaded in the TLB speculatively but it won't ever actually get used.
I think it goes:
kunmap_atomic() ->
__kunmap_atomic() ->
kpte_clear_flush() ->
__flush_tlb_one_kernel() ->
__flush_tlb_one_user() ->
__native_flush_tlb_one_user() ->
invlpg
The per-cpu address calculation is visible in kmap_atomic_prot():
idx = type + KM_TYPE_NR*smp_processor_id();
next prev parent reply other threads:[~2019-06-13 16:21 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 [this message]
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
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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