From: "kirill.shutemov@linux.intel.com" <kirill.shutemov@linux.intel.com>
To: Michael Kelley <mhklinux@outlook.com>
Cc: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>,
"linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
"ardb@kernel.org" <ardb@kernel.org>,
"Lutomirski, Andy" <luto@kernel.org>,
"hch@infradead.org" <hch@infradead.org>,
"dave.hansen@linux.intel.com" <dave.hansen@linux.intel.com>,
"thomas.lendacky@amd.com" <thomas.lendacky@amd.com>,
"haiyangz@microsoft.com" <haiyangz@microsoft.com>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"seanjc@google.com" <seanjc@google.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"Cui, Dexuan" <decui@microsoft.com>,
"urezki@gmail.com" <urezki@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"hpa@zytor.com" <hpa@zytor.com>, "bp@alien8.de" <bp@alien8.de>,
"wei.liu@kernel.org" <wei.liu@kernel.org>,
"Rodel, Jorg" <jroedel@suse.de>,
"sathyanarayanan.kuppuswamy@linux.intel.com"
<sathyanarayanan.kuppuswamy@linux.intel.com>,
"lstoakes@gmail.com" <lstoakes@gmail.com>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [PATCH v3 1/3] x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback
Date: Mon, 15 Jan 2024 13:00:11 +0300 [thread overview]
Message-ID: <20240115100011.yvecjjezrkcptnle@box.shutemov.name> (raw)
In-Reply-To: <SN6PR02MB415720444A3D848D444BB58AD46F2@SN6PR02MB4157.namprd02.prod.outlook.com>
On Fri, Jan 12, 2024 at 07:24:35PM +0000, Michael Kelley wrote:
> From: Edgecombe, Rick P <rick.p.edgecombe@intel.com> Sent: Friday, January 12, 2024 9:17 AM
> >
> > On Fri, 2024-01-12 at 15:07 +0000, Michael Kelley wrote:
> > > The comment is Kirill Shutemov's suggestion based on comments in
> > > an earlier version of the patch series. See [1]. The intent is to
> > > prevent
> > > some later revision to slow_virt_to_phys() from adding a check for
> > > the
> > > present bit and breaking the CoCo VM hypervisor callback. Yes, the
> > > comment could get stale, but I'm not sure how else to call out the
> > > implicit dependency. The idea of creating a private version of
> > > slow_virt_to_phys() for use only in the CoCo VM hypervisor callback
> > > is also discussed in the thread, but that seems worse overall.
> >
> > Well, it's not a huge deal, but I would have just put a comment at the
> > caller like:
> >
> > /*
> > * Use slow_virt_to_phys() instead of vmalloc_to_page(), because it
> > * returns the PFN even for NP PTEs.
> > */
>
> Yes, that comment is added in this patch.
>
> >
> > If someone is changing slow_virt_to_phys() they should check the
> > callers to make sure they won't break anything. They can see the
> > comment then and have an easy time.
> >
> > An optional comment at slow_virt_to_phys() could explain how the
> > function works in regards to the present bit, but not include details
> > about CoCoO VM page transition's usage of the present bit. The proposed
> > comment text looks like something more appropriate for a commit log.
>
> Kirill -- you originally asked for a comment in slow_virt_to_phys(). [1]
> Are you OK with Rick's proposal?
Yes, sounds sensible.
--
Kiryl Shutsemau / Kirill A. Shutemov
next prev parent reply other threads:[~2024-01-15 10:00 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-05 18:30 [PATCH v3 0/3] x86/hyperv: Mark CoCo VM pages not present when changing encrypted state mhkelley58
2024-01-05 18:30 ` [PATCH v3 1/3] x86/hyperv: Use slow_virt_to_phys() in page transition hypervisor callback mhkelley58
2024-01-08 13:07 ` kirill.shutemov
2024-01-08 16:00 ` Michael Kelley
2024-01-12 1:20 ` Edgecombe, Rick P
2024-01-12 15:07 ` Michael Kelley
2024-01-12 17:17 ` Edgecombe, Rick P
2024-01-12 19:24 ` Michael Kelley
2024-01-15 10:00 ` kirill.shutemov [this message]
2024-01-05 18:30 ` [PATCH v3 2/3] x86/mm: Regularize set_memory_p() parameters and make non-static mhkelley58
2024-01-08 13:10 ` kirill.shutemov
2024-01-12 0:56 ` Edgecombe, Rick P
2024-01-05 18:30 ` [PATCH v3 3/3] x86/hyperv: Make encrypted/decrypted changes safe for load_unaligned_zeropad() mhkelley58
2024-01-08 18:37 ` Kuppuswamy Sathyanarayanan
2024-01-08 19:13 ` Michael Kelley
2024-01-08 19:24 ` Kuppuswamy Sathyanarayanan
2024-01-12 0:26 ` Edgecombe, Rick P
2024-01-12 3:19 ` Michael Kelley
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=20240115100011.yvecjjezrkcptnle@box.shutemov.name \
--to=kirill.shutemov@linux.intel.com \
--cc=akpm@linux-foundation.org \
--cc=ardb@kernel.org \
--cc=bp@alien8.de \
--cc=dave.hansen@linux.intel.com \
--cc=decui@microsoft.com \
--cc=haiyangz@microsoft.com \
--cc=hch@infradead.org \
--cc=hpa@zytor.com \
--cc=jroedel@suse.de \
--cc=linux-coco@lists.linux.dev \
--cc=linux-hyperv@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=lstoakes@gmail.com \
--cc=luto@kernel.org \
--cc=mhklinux@outlook.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rick.p.edgecombe@intel.com \
--cc=sathyanarayanan.kuppuswamy@linux.intel.com \
--cc=seanjc@google.com \
--cc=tglx@linutronix.de \
--cc=thomas.lendacky@amd.com \
--cc=urezki@gmail.com \
--cc=wei.liu@kernel.org \
--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 read-only IMAP folder(s) and NNTP newsgroup(s).