All of lore.kernel.org
 help / color / mirror / Atom feed
From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
	"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH 2/4] x86/P2M: relax guarding of MMIO entries
Date: Tue, 31 Aug 2021 15:16:22 +0200	[thread overview]
Message-ID: <212ac248-1249-3e4c-9800-27c0e8e4c77a@suse.com> (raw)
In-Reply-To: <93ecc397-1293-69b1-e70d-3c5f9317229a@suse.com>

On 30.08.2021 15:02, Jan Beulich wrote:
> One of the changes comprising the fixes for XSA-378 disallows replacing
> MMIO mappings by unintended (for this purpose) code paths. At least in
> the case of PVH Dom0 hitting an RMRR covered by an E820 ACPI region,
> this is too strict. Generally short-circuit requests establishing the
> same kind of mapping that's already in place.
> 
> Further permit "access" to differ in the "executable" attribute. While
> ideally only ROM regions would get mapped with X set, getting there is
> quite a bit of work. Therefore, as a temporary measure, permit X to
> vary. For Dom0 the more permissive of the types will be used, while for
> DomU it'll be the more restrictive one.
> 
> While there, also add a log message to the other domain_crash()
> invocation that did prevent PVH Dom0 from coming up after the XSA-378
> changes.
> 
> Fixes: 753cb68e6530 ("x86/p2m: guard (in particular) identity mapping entries")
> Signed-off-by: Jan Beulich <jbeulich@suse.com>

Btw, I had meant to have this post-commit-message remark here:

TBD: This could be generalized to all of R, W, and X. Dealing with just X
     is merely the minimum I found is immediately necessary.

Jan



  reply	other threads:[~2021-08-31 13:16 UTC|newest]

Thread overview: 40+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-30 13:01 [PATCH 0/4] x86/PVH: Dom0 building adjustments Jan Beulich
2021-08-30 13:02 ` [PATCH 1/4] x86/PVH: de-duplicate mappings for first Mb of Dom0 memory Jan Beulich
2021-08-31 13:02   ` Andrew Cooper
2021-08-31 13:14     ` Jan Beulich
2021-08-31 13:19       ` Jan Beulich
2021-08-31 13:27         ` Andrew Cooper
2021-08-31 13:36           ` Jan Beulich
2021-09-01 11:49             ` Andrew Cooper
2021-09-01  8:41       ` Roger Pau Monné
2021-08-30 13:02 ` [PATCH 2/4] x86/P2M: relax guarding of MMIO entries Jan Beulich
2021-08-31 13:16   ` Jan Beulich [this message]
2021-08-31 13:16   ` Andrew Cooper
2021-08-31 13:26     ` Jan Beulich
2021-08-31 15:25       ` Andrew Cooper
2021-08-31 15:38         ` Jan Beulich
2021-09-01  8:08           ` Jan Beulich
2021-09-01  8:50           ` Roger Pau Monné
2021-09-01  9:53             ` Jan Beulich
2021-09-01 13:48               ` Roger Pau Monné
2021-09-01 14:05                 ` Jan Beulich
2021-09-01 12:47           ` Andrew Cooper
2021-09-01 13:08             ` Jan Beulich
2021-09-06 19:53               ` Andrew Cooper
2021-09-07  6:27                 ` Jan Beulich
2021-08-30 13:03 ` [PATCH 3/4] x86/PVH: improve Dom0 memory size calculation Jan Beulich
2021-08-31 14:07   ` Andrew Cooper
2021-08-31 15:30     ` Jan Beulich
2021-08-30 13:03 ` [PATCH 4/4] x86/PV: properly set shadow allocation for Dom0 Jan Beulich
2021-08-31 13:47   ` Andrew Cooper
2021-08-31 14:25     ` Jan Beulich
2021-08-31 21:08   ` Tim Deegan
2021-08-31  8:53 ` [PATCH 0/4] x86/PVH: Dom0 building adjustments Jan Beulich
2021-09-01 13:56   ` Roger Pau Monné
2021-09-01 14:19     ` Jan Beulich
2021-09-01 14:25       ` Jan Beulich
2021-09-01 16:13       ` Roger Pau Monné
2021-09-02  6:30         ` Jan Beulich
2021-09-01 15:06 ` Jan Beulich
2021-09-01 15:24   ` Juergen Gross
2021-09-01 15:51     ` Jan Beulich

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=212ac248-1249-3e4c-9800-27c0e8e4c77a@suse.com \
    --to=jbeulich@suse.com \
    --cc=andrew.cooper3@citrix.com \
    --cc=roger.pau@citrix.com \
    --cc=wl@xen.org \
    --cc=xen-devel@lists.xenproject.org \
    /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.