From: Andy Lutomirski <luto@kernel.org>
To: Rick Edgecombe <rick.p.edgecombe@intel.com>
Cc: kvm list <kvm@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>, X86 ML <x86@kernel.org>,
Linux-MM <linux-mm@kvack.org>,
Andrew Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Dave Hansen <dave.hansen@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"Christopherson, Sean J" <sean.j.christopherson@intel.com>,
Kees Cook <keescook@chromium.org>,
Kristen Carlson Accardi <kristen@linux.intel.com>,
"Dock, Deneen T" <deneen.t.dock@intel.com>
Subject: Re: [RFC PATCH 00/13] XOM for KVM guest userspace
Date: Fri, 4 Oct 2019 07:56:58 -0700 [thread overview]
Message-ID: <CALCETrW9MEvNt+kB_65cbX9VJiLxktAFagkzSGR0VQfd4VHOiQ@mail.gmail.com> (raw)
In-Reply-To: <20191003212400.31130-1-rick.p.edgecombe@intel.com>
On Thu, Oct 3, 2019 at 2:38 PM Rick Edgecombe
<rick.p.edgecombe@intel.com> wrote:
>
> This patchset enables the ability for KVM guests to create execute-only (XO)
> memory by utilizing EPT based XO permissions. XO memory is currently supported
> on Intel hardware natively for CPU's with PKU, but this enables it on older
> platforms, and can support XO for kernel memory as well.
The patchset seems to sometimes call this feature "XO" and sometimes
call it "NR". To me, XO implies no-read and no-write, whereas NR
implies just no-read. Can you please clarify *exactly* what the new
bit does and be consistent?
I suggest that you make it NR, which allows for PROT_EXEC and
PROT_EXEC|PROT_WRITE and plain PROT_WRITE. WX is of dubious value,
but I can imagine plain W being genuinely useful for logging and for
JITs that could maintain a W and a separate X mapping of some code.
In other words, with an NR bit, all 8 logical access modes are
possible. Also, keeping the paging bits more orthogonal seems nice --
we already have a bit that controls write access.
next prev parent reply other threads:[~2019-10-04 14:57 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-03 21:23 [RFC PATCH 00/13] XOM for KVM guest userspace Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 01/13] kvm: Enable MTRR to work with GFNs with perm bits Rick Edgecombe
2019-10-14 6:47 ` Yu Zhang
2019-10-14 18:44 ` Edgecombe, Rick P
2019-10-03 21:23 ` [RFC PATCH 02/13] kvm: Add support for X86_FEATURE_KVM_XO Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 03/13] kvm: Add XO memslot type Rick Edgecombe
2019-10-04 7:27 ` Paolo Bonzini
2019-10-04 19:06 ` Edgecombe, Rick P
2019-10-06 16:15 ` Paolo Bonzini
2019-10-03 21:23 ` [RFC PATCH 04/13] kvm, vmx: Add support for gva exit qualification Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 05/13] kvm: Add #PF injection for KVM XO Rick Edgecombe
2019-10-04 7:42 ` Paolo Bonzini
2019-10-04 19:11 ` Edgecombe, Rick P
2019-10-03 21:23 ` [RFC PATCH 06/13] kvm: Add KVM_CAP_EXECONLY_MEM Rick Edgecombe
2019-10-04 7:24 ` Paolo Bonzini
2019-10-04 19:11 ` Edgecombe, Rick P
2019-10-03 21:23 ` [RFC PATCH 07/13] kvm: Add docs for KVM_CAP_EXECONLY_MEM Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 08/13] x86/boot: Rename USE_EARLY_PGTABLE_L5 Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 09/13] x86/cpufeature: Add detection of KVM XO Rick Edgecombe
2019-10-29 23:33 ` Kees Cook
2019-10-29 23:52 ` Edgecombe, Rick P
2019-10-30 14:55 ` Sean Christopherson
2019-10-30 21:02 ` Edgecombe, Rick P
2019-10-03 21:23 ` [RFC PATCH 10/13] x86/mm: Add NR page bit for " Rick Edgecombe
2019-10-04 7:33 ` Paolo Bonzini
2019-10-03 21:23 ` [RFC PATCH 11/13] x86, ptdump: Add NR bit to page table dump Rick Edgecombe
2019-10-03 21:23 ` [RFC PATCH 12/13] mmap: Add XO support for KVM XO Rick Edgecombe
2019-10-04 7:34 ` Paolo Bonzini
2019-10-04 19:12 ` Edgecombe, Rick P
2019-10-03 21:24 ` [RFC PATCH 13/13] x86/Kconfig: Add Kconfig for KVM based XO Rick Edgecombe
2019-10-29 23:36 ` Kees Cook
2019-10-30 0:01 ` Edgecombe, Rick P
2019-10-30 18:36 ` Kees Cook
2019-10-04 7:22 ` [RFC PATCH 00/13] XOM for KVM guest userspace Paolo Bonzini
2019-10-04 19:03 ` Edgecombe, Rick P
2019-10-04 14:56 ` Andy Lutomirski [this message]
2019-10-04 20:09 ` Edgecombe, Rick P
2019-10-05 1:33 ` Andy Lutomirski
2019-10-07 18:14 ` Edgecombe, Rick P
2019-10-29 23:40 ` Kees Cook
2019-10-30 0:27 ` Edgecombe, Rick P
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=CALCETrW9MEvNt+kB_65cbX9VJiLxktAFagkzSGR0VQfd4VHOiQ@mail.gmail.com \
--to=luto@kernel.org \
--cc=dave.hansen@intel.com \
--cc=deneen.t.dock@intel.com \
--cc=keescook@chromium.org \
--cc=kristen@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rick.p.edgecombe@intel.com \
--cc=sean.j.christopherson@intel.com \
--cc=x86@kernel.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).