All of lore.kernel.org
 help / color / mirror / Atom feed
From: Paolo Bonzini <pbonzini@redhat.com>
To: speck@linutronix.de
Subject: [MODERATED] Re: [PATCH] SPTE masking
Date: Thu, 9 Aug 2018 11:24:47 +0200	[thread overview]
Message-ID: <f793388f-0cae-4007-f4f7-0a2ce32d4376@redhat.com> (raw)
In-Reply-To: <20180809025756.GD4238@tassilo.jf.intel.com>

[-- Attachment #1: Type: text/plain, Size: 678 bytes --]

On 09/08/2018 04:57, speck for Andi Kleen wrote:
>> [PATCH] kvm: x86: Set highest physical address bit in non-present/reserved SPTEs
>>
>> Always set the upper-most supported physical address bit to 1 for SPTEs
>> that are marked as non-present or reserved, to make them unusable for
>> L1TF attacks from the guest. Currently, this just applies to MMIO SPTEs.
> L1TF only works for cached memory. 
> 
> Are you concerned about cacheable MMIO?

No, he's concerned that KVM stores information in SPTEs that point to
guest MMIO (i.e. emulated devices), and that information is
guest-controlled.  But that would only apply to processors with
MAXPHYADDR=52.

Paolo


  reply	other threads:[~2018-08-09  9:24 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-08 23:21 [MODERATED] [PATCH] SPTE masking Jim Mattson
2018-08-09  2:57 ` [MODERATED] " Andi Kleen
2018-08-09  9:24   ` Paolo Bonzini [this message]
2018-08-09 17:43     ` Andi Kleen
2018-08-10  7:55       ` Paolo Bonzini
2018-08-10 15:59         ` Jim Mattson
2018-08-10 17:23         ` Andi Kleen
2018-08-10 17:32           ` Linus Torvalds
2018-08-10 17:45             ` Andi Kleen
2018-08-10 18:37               ` Paolo Bonzini
2018-08-10 19:17                 ` Andi Kleen
2018-08-12 10:57                   ` Paolo Bonzini
2018-08-09  9:25 ` Paolo Bonzini
2018-08-09  9:33   ` Andrew Cooper
2018-08-09 10:01     ` Paolo Bonzini
2018-08-09 10:47       ` Andrew Cooper
2018-08-09 11:13         ` Paolo Bonzini
2018-08-09 11:46           ` Andrew Cooper
2018-08-09 11:54             ` Paolo Bonzini
2018-08-09 14:01               ` Andrew Cooper
2018-08-09 15:00                 ` Paolo Bonzini
2018-08-09 20:14       ` Jim Mattson

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=f793388f-0cae-4007-f4f7-0a2ce32d4376@redhat.com \
    --to=pbonzini@redhat.com \
    --cc=speck@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.