From: Liran Alon <liran.alon@oracle.com>
To: Mike Rapoport <rppt@kernel.org>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
David Rientjes <rientjes@google.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Kees Cook <keescook@chromium.org>, Will Drewry <wad@chromium.org>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"Kleen, Andi" <andi.kleen@intel.com>,
x86@kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [RFC 00/16] KVM protected memory extension
Date: Tue, 26 May 2020 13:16:14 +0300 [thread overview]
Message-ID: <8866ff79-e8fd-685d-9a1d-72acff5bf6bb@oracle.com> (raw)
In-Reply-To: <20200526061721.GB48741@kernel.org>
On 26/05/2020 9:17, Mike Rapoport wrote:
> On Mon, May 25, 2020 at 04:47:18PM +0300, Liran Alon wrote:
>> On 22/05/2020 15:51, Kirill A. Shutemov wrote:
>>
>> Furthermore, I would like to point out that just unmapping guest data from
>> kernel direct-map is not sufficient to prevent all
>> guest-to-guest info-leaks via a kernel memory info-leak vulnerability. This
>> is because host kernel VA space have other regions
>> which contains guest sensitive data. For example, KVM per-vCPU struct (which
>> holds vCPU state) is allocated on slab and therefore
>> still leakable.
> Objects allocated from slab use the direct map, vmalloc() is another story.
It doesn't matter. This patch series, like XPFO, only removes guest
memory pages from direct-map.
Not things such as KVM per-vCPU structs. That's why Julian & Marius
(AWS), created the "Process local kernel VA region" patch-series
that declare a single PGD entry, which maps a kernelspace region, to
have different PFN between different tasks.
For more information, see my KVM Forum talk slides I gave in previous
reply and related AWS patch-series:
https://patchwork.kernel.org/cover/10990403/
>
>>> - Touching direct mapping leads to fragmentation. We need to be able to
>>> recover from it. I have a buggy patch that aims at recovering 2M/1G page.
>>> It has to be fixed and tested properly
>> As I've mentioned above, not mapping all guest memory from 1GB hugetlbfs
>> will lead to holes in kernel direct-map which force it to not be mapped
>> anymore as a series of 1GB huge-pages.
>> This have non-trivial performance cost. Thus, I am not sure addressing this
>> use-case is valuable.
> Out of curiosity, do we actually have some numbers for the "non-trivial
> performance cost"? For instance for KVM usecase?
>
Dig into XPFO mailing-list discussions to find out...
I just remember that this was one of the main concerns regarding XPFO.
-Liran
next prev parent reply other threads:[~2020-05-26 10:17 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-22 12:51 [RFC 00/16] KVM protected memory extension Kirill A. Shutemov
2020-05-22 12:51 ` [RFC 01/16] x86/mm: Move force_dma_unencrypted() to common code Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 02/16] x86/kvm: Introduce KVM memory protection feature Kirill A. Shutemov
2020-05-25 14:58 ` Vitaly Kuznetsov
2020-05-25 15:15 ` Kirill A. Shutemov
2020-05-27 5:03 ` Sean Christopherson
2020-05-27 8:39 ` Vitaly Kuznetsov
2020-05-27 8:52 ` Sean Christopherson
2020-06-03 2:09 ` Huang, Kai
2020-06-03 11:14 ` Vitaly Kuznetsov
2020-05-22 12:52 ` [RFC 03/16] x86/kvm: Make DMA pages shared Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 04/16] x86/kvm: Use bounce buffers for KVM memory protection Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 05/16] x86/kvm: Make VirtIO use DMA API in KVM guest Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 06/16] KVM: Use GUP instead of copy_from/to_user() to access guest memory Kirill A. Shutemov
2020-05-25 15:08 ` Vitaly Kuznetsov
2020-05-25 15:17 ` Kirill A. Shutemov
2020-06-01 16:35 ` Paolo Bonzini
2020-06-02 13:33 ` Kirill A. Shutemov
2020-05-26 6:14 ` Mike Rapoport
2020-05-26 21:56 ` Kirill A. Shutemov
2020-05-29 15:24 ` Kees Cook
2020-05-22 12:52 ` [RFC 07/16] KVM: mm: Introduce VM_KVM_PROTECTED Kirill A. Shutemov
2020-05-26 6:15 ` Mike Rapoport
2020-05-26 22:01 ` Kirill A. Shutemov
2020-05-26 6:40 ` John Hubbard
2020-05-26 22:04 ` Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 08/16] KVM: x86: Use GUP for page walk instead of __get_user() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 09/16] KVM: Protected memory extension Kirill A. Shutemov
2020-05-25 15:26 ` Vitaly Kuznetsov
2020-05-25 15:34 ` Kirill A. Shutemov
2020-06-03 1:34 ` Huang, Kai
2020-05-22 12:52 ` [RFC 10/16] KVM: x86: Enabled protected " Kirill A. Shutemov
2020-05-25 15:26 ` Vitaly Kuznetsov
2020-05-26 6:16 ` Mike Rapoport
2020-05-26 21:58 ` Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 11/16] KVM: Rework copy_to/from_guest() to avoid direct mapping Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 12/16] x86/kvm: Share steal time page with host Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 13/16] x86/kvmclock: Share hvclock memory with the host Kirill A. Shutemov
2020-05-25 15:22 ` Vitaly Kuznetsov
2020-05-25 15:25 ` Kirill A. Shutemov
2020-05-25 15:42 ` Vitaly Kuznetsov
2020-05-22 12:52 ` [RFC 14/16] KVM: Introduce gfn_to_pfn_memslot_protected() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 15/16] KVM: Handle protected memory in __kvm_map_gfn()/__kvm_unmap_gfn() Kirill A. Shutemov
2020-05-22 12:52 ` [RFC 16/16] KVM: Unmap protected pages from direct mapping Kirill A. Shutemov
2020-05-26 6:16 ` Mike Rapoport
2020-05-26 22:10 ` Kirill A. Shutemov
2020-05-25 5:27 ` [RFC 00/16] KVM protected memory extension Kirill A. Shutemov
2020-05-25 13:47 ` Liran Alon
2020-05-25 14:46 ` Kirill A. Shutemov
2020-05-25 15:56 ` Liran Alon
2020-05-26 6:17 ` Mike Rapoport
2020-05-26 10:16 ` Liran Alon [this message]
2020-05-26 11:38 ` Mike Rapoport
2020-05-27 15:45 ` Dave Hansen
2020-05-27 21:22 ` Mike Rapoport
2020-06-04 15:15 ` Marc Zyngier
2020-06-04 15:48 ` Sean Christopherson
2020-06-04 16:27 ` Marc Zyngier
2020-06-04 16:35 ` Will Deacon
2020-06-04 19:09 ` Nakajima, Jun
2020-06-04 21:03 ` Jim Mattson
2020-06-04 23:29 ` Nakajima, Jun
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=8866ff79-e8fd-685d-9a1d-72acff5bf6bb@oracle.com \
--to=liran.alon@oracle.com \
--cc=aarcange@redhat.com \
--cc=andi.kleen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=jmattson@google.com \
--cc=joro@8bytes.org \
--cc=keescook@chromium.org \
--cc=kirill.shutemov@linux.intel.com \
--cc=kirill@shutemov.name \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=pbonzini@redhat.com \
--cc=peterz@infradead.org \
--cc=rick.p.edgecombe@intel.com \
--cc=rientjes@google.com \
--cc=rppt@kernel.org \
--cc=sean.j.christopherson@intel.com \
--cc=vkuznets@redhat.com \
--cc=wad@chromium.org \
--cc=wanpengli@tencent.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).