From: David Woodhouse <dwmw2@infradead.org>
To: Patrick Roy <roypat@amazon.co.uk>,
seanjc@google.com, pbonzini@redhat.com,
akpm@linux-foundation.org, rppt@kernel.org, david@redhat.com
Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
willy@infradead.org, graf@amazon.com, derekmn@amazon.com,
kalyazin@amazon.com, kvm@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
dmatlack@google.com, tabba@google.com,
chao.p.peng@linux.intel.com, xmarcalx@amazon.co.uk,
James Gowans <jgowans@amazon.com>
Subject: Re: [RFC PATCH 3/8] kvm: pfncache: enlighten about gmem
Date: Wed, 10 Jul 2024 11:50:04 +0100 [thread overview]
Message-ID: <a232728115a94664c82a27ac78a2ae35bcdd3c37.camel@infradead.org> (raw)
In-Reply-To: <b898824e-23eb-4226-9d55-cb4297b17d5c@amazon.co.uk>
[-- Attachment #1: Type: text/plain, Size: 821 bytes --]
On Wed, 2024-07-10 at 11:46 +0100, Patrick Roy wrote:
> On Wed, 2024-07-10 at 11:20 +0100, David Woodhouse wrote:
> > In that case, wouldn't that mean the explicit checks on gpc->is_private
> > matching kvm_mem_is_private() would be redundant and you can remove
> > them because you can trust that gpc->valid would be cleared?
> >
>
> Right, yes, it would indeed mean that. I'll double-check my assumption
> about the whole invalidation thing and adjust the code for the next
> iteration!
I was going to suggest that you take the check you'd added to
kvm_gpc_check() and move it down below the ->valid check, and turn it
into a BUG_ON() to check that assertion.
You *might* get false positives with that though, if the result of
kvm_mem_is_private() becomes true before the flush actually *happens*?
[-- Attachment #2: smime.p7s --]
[-- Type: application/pkcs7-signature, Size: 5965 bytes --]
next prev parent reply other threads:[~2024-07-10 10:50 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-07-09 13:20 [RFC PATCH 0/8] Unmapping guest_memfd from Direct Map Patrick Roy
2024-07-09 13:20 ` [RFC PATCH 1/8] kvm: Allow reading/writing gmem using kvm_{read,write}_guest Patrick Roy
2024-07-09 13:20 ` [RFC PATCH 2/8] kvm: use slowpath in gfn_to_hva_cache if memory is private Patrick Roy
2024-07-09 13:20 ` [RFC PATCH 3/8] kvm: pfncache: enlighten about gmem Patrick Roy
2024-07-09 14:36 ` David Woodhouse
2024-07-10 9:49 ` Patrick Roy
2024-07-10 10:20 ` David Woodhouse
2024-07-10 10:46 ` Patrick Roy
2024-07-10 10:50 ` David Woodhouse [this message]
2024-07-09 13:20 ` [RFC PATCH 4/8] kvm: x86: support walking guest page tables in gmem Patrick Roy
2024-07-09 13:20 ` [RFC PATCH 5/8] kvm: gmem: add option to remove guest private memory from direct map Patrick Roy
2024-07-10 7:31 ` Mike Rapoport
2024-07-10 9:50 ` Patrick Roy
2024-07-09 13:20 ` [RFC PATCH 6/8] kvm: gmem: Temporarily restore direct map entries when needed Patrick Roy
2024-07-11 6:25 ` Paolo Bonzini
2024-07-09 13:20 ` [RFC PATCH 7/8] mm: secretmem: use AS_INACCESSIBLE to prohibit GUP Patrick Roy
2024-07-09 21:09 ` David Hildenbrand
2024-07-10 7:32 ` Mike Rapoport
2024-07-10 9:50 ` Patrick Roy
2024-07-10 21:14 ` David Hildenbrand
2024-07-09 13:20 ` [RFC PATCH 8/8] kvm: gmem: Allow restricted userspace mappings Patrick Roy
2024-07-09 14:48 ` Fuad Tabba
2024-07-09 21:13 ` David Hildenbrand
2024-07-10 9:51 ` Patrick Roy
2024-07-10 21:12 ` David Hildenbrand
2024-07-10 21:53 ` Sean Christopherson
2024-07-10 21:56 ` David Hildenbrand
2024-07-12 15:59 ` Patrick Roy
2024-07-30 10:15 ` David Hildenbrand
2024-08-01 10:30 ` Patrick Roy
2024-07-22 12:28 ` [RFC PATCH 0/8] Unmapping guest_memfd from Direct Map Vlastimil Babka (SUSE)
2024-07-26 6:55 ` Patrick Roy
2024-07-30 10:17 ` David Hildenbrand
2024-07-26 16:44 ` Yosry Ahmed
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=a232728115a94664c82a27ac78a2ae35bcdd3c37.camel@infradead.org \
--to=dwmw2@infradead.org \
--cc=akpm@linux-foundation.org \
--cc=bp@alien8.de \
--cc=chao.p.peng@linux.intel.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=derekmn@amazon.com \
--cc=dmatlack@google.com \
--cc=graf@amazon.com \
--cc=hpa@zytor.com \
--cc=jgowans@amazon.com \
--cc=kalyazin@amazon.com \
--cc=kvm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mingo@redhat.com \
--cc=pbonzini@redhat.com \
--cc=roypat@amazon.co.uk \
--cc=rppt@kernel.org \
--cc=seanjc@google.com \
--cc=tabba@google.com \
--cc=tglx@linutronix.de \
--cc=willy@infradead.org \
--cc=x86@kernel.org \
--cc=xmarcalx@amazon.co.uk \
/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