From: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>
To: "kvm@vger.kernel.org" <kvm@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"keescook@chromium.org" <keescook@chromium.org>,
"Christopherson, Sean J" <sean.j.christopherson@intel.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"x86@kernel.org" <x86@kernel.org>,
"luto@kernel.org" <luto@kernel.org>,
"pbonzini@redhat.com" <pbonzini@redhat.com>,
"Hansen, Dave" <dave.hansen@intel.com>
Cc: "kristen@linux.intel.com" <kristen@linux.intel.com>,
"Dock, Deneen T" <deneen.t.dock@intel.com>,
"yu.c.zhang@linux.intel.com" <yu.c.zhang@linux.intel.com>
Subject: Re: [RFC PATCH 03/13] kvm: Add XO memslot type
Date: Fri, 4 Oct 2019 19:06:49 +0000 [thread overview]
Message-ID: <9b885e65c3ec0ab8b4de0d38f2f20686a7afe0d0.camel@intel.com> (raw)
In-Reply-To: <5201724e-bded-1af1-7f46-0f3e1763c797@redhat.com>
On Fri, 2019-10-04 at 09:27 +0200, Paolo Bonzini wrote:
> On 03/10/19 23:23, Rick Edgecombe wrote:
> > Add XO memslot type to create execute-only guest physical memory based on
> > the RO memslot. Like the RO memslot, disallow changing the memslot type
> > to/from XO.
> >
> > In the EPT case ACC_USER_MASK represents the readable bit, so add the
> > ability for set_spte() to unset this.
> >
> > This is based in part on a patch by Yu Zhang.
> >
> > Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
> > Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
>
> Instead of this, why not check the exit qualification gpa and, if it has
> the XO bit set, mask away both the XO bit and the R bit? It can be done
> unconditionally for all memslots. This should require no change to
> userspace.
>
> Paolo
>
The reasoning was that it seems like KVM leaves it to userspace to control the
physical address space layout since userspace decides the supported physical
address bits and lays out memory in the physical address space. So duplication
with XO memslots was an attempt was to keep the logic around that together.
I'll take another look at doing it this way though. I think userspace may still
need to adjust the MAXPHYADDR and be aware it can't layout memory in the XO
range.
Thanks,
Rick
next prev parent reply other threads:[~2019-10-04 19:06 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 [this message]
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
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
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