From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: David Hildenbrand <david@redhat.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Sean Christopherson <seanjc@google.com>,
Jim Mattson <jmattson@google.com>,
David Rientjes <rientjes@google.com>,
"Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"Kleen, Andi" <andi.kleen@intel.com>,
"Yamahata, Isaku" <isaku.yamahata@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>,
Oscar Salvador <osalvador@suse.de>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: [RFCv1 7/7] KVM: unmap guest memory using poisoned pages
Date: Fri, 9 Apr 2021 17:12:11 +0300 [thread overview]
Message-ID: <20210409141211.wfbyzflj7ygtx7ex@box.shutemov.name> (raw)
In-Reply-To: <5ef83789-ffa5-debd-9ea2-50d831262237@redhat.com>
On Fri, Apr 09, 2021 at 03:50:42PM +0200, David Hildenbrand wrote:
> > > 3. Allow selected users to still grab the pages (esp. KVM to fault them into
> > > the page tables).
> >
> > As long as fault leads to non-present PTEs we are fine. Usespace still may
> > want to mlock() some of guest memory. There's no reason to prevent this.
>
> I'm curious, even get_user_pages() will lead to a present PTE as is, no? So
> that will need modifications I assume. (although I think it fundamentally
> differs to the way get_user_pages() works - trigger a fault first, then
> lookup the PTE in the page tables).
For now, the patch has two step poisoning: first fault in, on the add to
shadow PTE -- poison. By the time VM has chance to use the page it's
poisoned and unmapped from the host userspace.
--
Kirill A. Shutemov
next prev parent reply other threads:[~2021-04-09 14:12 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-02 15:26 [RFCv1 0/7] TDX and guest memory unmapping Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 1/7] x86/mm: Move force_dma_unencrypted() to common code Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 2/7] x86/kvm: Introduce KVM memory protection feature Kirill A. Shutemov
2021-04-08 9:52 ` Borislav Petkov
2021-04-09 13:36 ` Kirill A. Shutemov
2021-04-09 14:37 ` Borislav Petkov
2021-04-02 15:26 ` [RFCv1 3/7] x86/kvm: Make DMA pages shared Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 4/7] x86/kvm: Use bounce buffers for KVM memory protection Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 5/7] x86/kvmclock: Share hvclock memory with the host Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 6/7] x86/realmode: Share trampoline area if KVM memory protection enabled Kirill A. Shutemov
2021-04-02 15:26 ` [RFCv1 7/7] KVM: unmap guest memory using poisoned pages Kirill A. Shutemov
2021-04-06 7:44 ` David Hildenbrand
2021-04-06 10:50 ` Kirill A. Shutemov
2021-04-06 14:33 ` Dave Hansen
2021-04-06 14:57 ` David Hildenbrand
2021-04-07 13:16 ` Kirill A. Shutemov
2021-04-07 13:31 ` Christophe de Dinechin
2021-04-07 14:09 ` Andi Kleen
2021-04-07 14:09 ` Andi Kleen
2021-04-07 14:09 ` David Hildenbrand
2021-04-07 14:36 ` Kirill A. Shutemov
2021-04-06 17:52 ` Tom Lendacky
2021-04-07 14:55 ` David Hildenbrand
2021-04-07 15:10 ` Andi Kleen
2021-04-07 15:10 ` Andi Kleen
2021-04-09 13:33 ` Kirill A. Shutemov
2021-04-09 13:50 ` David Hildenbrand
2021-04-09 14:12 ` Kirill A. Shutemov [this message]
2021-04-09 14:18 ` David Hildenbrand
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=20210409141211.wfbyzflj7ygtx7ex@box.shutemov.name \
--to=kirill@shutemov.name \
--cc=andi.kleen@intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=isaku.yamahata@intel.com \
--cc=jmattson@google.com \
--cc=kirill.shutemov@linux.intel.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=n-horiguchi@ah.jp.nec.com \
--cc=osalvador@suse.de \
--cc=peterz@infradead.org \
--cc=rick.p.edgecombe@intel.com \
--cc=rientjes@google.com \
--cc=seanjc@google.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 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.