From: "Roger Pau Monné" <roger.pau@citrix.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: xen-devel@lists.xenproject.org, julien@xen.org,
pdurrant@amazon.com, dwmw@amazon.com,
"Stefano Stabellini" <sstabellini@kernel.org>,
"Bertrand Marquis" <bertrand.marquis@arm.com>,
"Michal Orzel" <michal.orzel@amd.com>,
"Volodymyr Babchuk" <Volodymyr_Babchuk@epam.com>,
"Andrew Cooper" <andrew.cooper3@citrix.com>,
"George Dunlap" <george.dunlap@citrix.com>,
"Lukasz Hawrylko" <lukasz@hawrylko.pl>,
"Daniel P. Smith" <dpsmith@apertussolutions.com>,
"Mateusz Mówka" <mateusz.mowka@intel.com>,
"Elias El Yandouzi" <eliasely@amazon.com>
Subject: Re: [PATCH V3 (resend) 14/19] Rename mfn_to_virt() calls
Date: Wed, 15 May 2024 11:38:22 +0200 [thread overview]
Message-ID: <ZkSCju4RicXRuAvu@macbook> (raw)
In-Reply-To: <df8cc51d-60ea-452b-809e-c75aab957929@suse.com>
On Tue, May 14, 2024 at 06:22:59PM +0200, Jan Beulich wrote:
> On 14.05.2024 17:45, Roger Pau Monné wrote:
> > On Mon, May 13, 2024 at 01:40:41PM +0000, Elias El Yandouzi wrote:
> >> Until directmap gets completely removed, we'd still need to
> >> keep some calls to mfn_to_virt() for xenheap pages or when the
> >> directmap is enabled.
> >>
> >> Rename the macro to mfn_to_directmap_virt() to flag them and
> >> prevent further use of mfn_to_virt().
> >
> > Both here and in the following patch, I'm afraid I'm unsure of it's
> > usefulness. I'm leaning towards this being code churn for very little
> > benefit.
>
> I expect this patch is a response to an earlier comment of mine. I'm
> rather worried that at the time this series actually goes in, un-audited
> mfn_to_virt() uses remain (perhaps because of introduction between patch
> submission and its committing). Such uses would all very likely end in
> crashes or worse, but they may not be found by testing.
I see, would be good to note the intention on the commit message then.
> > Also, I'm not sure I see how the patch prevents further usage of
> > mfn_to_virt(), as (for Arm) the existing macro is not removed. If
> > anything I would prefer a comment clearly stating that the macro
> > operates on directmap space, and avoid the name change.
>
> But Arm isn't switched to this sparse direct map mode, I think? At which
> point uses in Arm-specific code continue to be okay.
Right, it's just that Arm will have both mfn_to_virt() and
mfn_to_directmap_virt() which seems a bit confusing when they are
actually the same implementation.
Thanks, Roger.
next prev parent reply other threads:[~2024-05-15 9:38 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-13 13:40 [PATCH V3 (resend) 00/19] Remove the directmap Elias El Yandouzi
2024-05-13 13:40 ` [PATCH V3 (resend) 01/19] x86: Create per-domain mapping of guest_root_pt Elias El Yandouzi
2024-05-14 14:51 ` Jan Beulich
2024-05-15 18:25 ` Elias El Yandouzi
2024-05-16 7:17 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 02/19] x86/pv: Domheap pages should be mapped while relocating initrd Elias El Yandouzi
2024-05-13 15:40 ` Roger Pau Monné
2024-05-13 13:40 ` [PATCH V3 (resend) 03/19] x86/pv: Rewrite how building PV dom0 handles domheap mappings Elias El Yandouzi
2024-05-13 16:49 ` Roger Pau Monné
2024-05-14 14:58 ` Jan Beulich
2024-05-14 15:03 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 04/19] x86: Lift mapcache variable to the arch level Elias El Yandouzi
2024-05-14 8:21 ` Roger Pau Monné
2024-05-15 13:11 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 05/19] x86/mapcache: Initialise the mapcache for the idle domain Elias El Yandouzi
2024-05-14 8:42 ` Roger Pau Monné
2024-05-15 13:44 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 06/19] x86: Add a boot option to enable and disable the direct map Elias El Yandouzi
2024-05-14 9:20 ` Roger Pau Monné
2024-05-14 10:20 ` Roger Pau Monné
2024-05-15 13:54 ` Jan Beulich
2024-05-16 9:19 ` Roger Pau Monné
2024-05-16 9:24 ` Jan Beulich
2024-05-15 13:59 ` Jan Beulich
2024-05-15 16:02 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 07/19] xen/x86: Add support for the PMAP Elias El Yandouzi
2024-05-14 9:40 ` Roger Pau Monné
2024-05-14 9:43 ` Jan Beulich
2024-05-14 10:22 ` Roger Pau Monné
2024-05-14 10:26 ` Jan Beulich
2024-05-14 11:51 ` Roger Pau Monné
2024-05-14 12:33 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 08/19] xen/x86: Add build assertion for fixmap entries Elias El Yandouzi
2024-05-14 9:42 ` Roger Pau Monné
2024-05-14 9:45 ` Jan Beulich
2024-05-15 14:03 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 09/19] x86/domain_page: Remove the fast paths when mfn is not in the directmap Elias El Yandouzi
2024-05-14 11:48 ` Roger Pau Monné
2024-05-15 14:21 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 10/19] xen/page_alloc: Add a path for xenheap when there is no direct map Elias El Yandouzi
2024-05-14 13:07 ` Roger Pau Monné
2024-05-15 15:13 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 11/19] x86/setup: Leave early boot slightly earlier Elias El Yandouzi
2024-05-14 14:11 ` Roger Pau Monné
2024-05-15 15:22 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 12/19] x86/setup: vmap heap nodes when they are outside the direct map Elias El Yandouzi
2024-05-14 15:02 ` Roger Pau Monné
2024-05-15 15:28 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 13/19] x86/setup: Do not create valid mappings when directmap=no Elias El Yandouzi
2024-05-14 15:39 ` Roger Pau Monné
2024-05-15 15:50 ` Jan Beulich
2024-05-15 15:59 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 14/19] Rename mfn_to_virt() calls Elias El Yandouzi
2024-05-14 15:45 ` Roger Pau Monné
2024-05-14 16:22 ` Jan Beulich
2024-05-15 9:38 ` Roger Pau Monné [this message]
2024-05-15 9:42 ` Jan Beulich
2024-05-16 8:57 ` Jan Beulich
2024-05-13 13:40 ` [PATCH V3 (resend) 15/19] Rename maddr_to_virt() calls Elias El Yandouzi
2024-05-13 13:40 ` [PATCH V3 (resend) 16/19] xen/arm32: mm: Rename 'first' to 'root' in init_secondary_pagetables() Elias El Yandouzi
2024-05-13 13:40 ` [PATCH V3 (resend) 17/19] xen/arm64: mm: Use per-pCPU page-tables Elias El Yandouzi
2024-05-13 13:40 ` [PATCH V3 (resend) 18/19] xen/arm64: Implement a mapcache for arm64 Elias El Yandouzi
2024-05-13 13:40 ` [PATCH V3 (resend) 19/19] xen/arm64: Allow the admin to enable/disable the directmap Elias El Yandouzi
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