From: Jan Beulich <jbeulich@suse.com>
To: Rahul Singh <rahul.singh@arm.com>
Cc: bertrand.marquis@arm.com, Paul Durrant <paul@xen.org>,
Andrew Cooper <andrew.cooper3@citrix.com>,
George Dunlap <george.dunlap@citrix.com>,
Ian Jackson <iwj@xenproject.org>, Julien Grall <julien@xen.org>,
Stefano Stabellini <sstabellini@kernel.org>, Wei Liu <wl@xen.org>,
Daniel De Graaf <dgdegra@tycho.nsa.gov>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH v4 3/3] xen/pci: Refactor MSI code that implements MSI functionality within XEN
Date: Mon, 3 May 2021 16:46:36 +0200 [thread overview]
Message-ID: <bbc50008-da47-a5e2-501b-a9c06ce38335@suse.com> (raw)
In-Reply-To: <60b4c33fdcc2f7ad68d383ffae191e22b0b32f1c.1619707144.git.rahul.singh@arm.com>
On 29.04.2021 16:46, Rahul Singh wrote:
> MSI code that implements MSI functionality to support MSI within XEN is
> not usable on ARM. Move the code under CONFIG_HAS_PCI_MSI_INTERCEPT flag
> to gate the code for ARM.
>
> Currently, we have no idea how MSI functionality will be supported for
> other architecture therefore we have decided to move the code under
> CONFIG_PCI_MSI_INTERCEPT. We know this is not the right flag to gate the
> code but to avoid an extra flag we decided to use this.
My objection remains: Actively putting code under the wrong gating
CONFIG_* is imo quite a bit worse than keeping it under a too wide one
(e.g. CONFIG_X86), if introducing a separate CONFIG_HAS_PCI_MSI is
deemed undesirable for whatever reason. Otherwise every abuse of
CONFIG_PCI_MSI_INTERCEPT ought to get a comment to the effect of this
being an abuse, which in particular for code you move into
xen/drivers/passthrough/msi-intercept.c would end up sufficiently odd.
(As a minor extra remark, putting deliberately misplaced code at the
top of a file rather than at its bottom is likely to add to possible
confusion down the road.)
Jan
next prev parent reply other threads:[~2021-05-03 14:46 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-29 14:46 [PATCH v4 0/3] xen/pci: Make PCI passthrough code non-x86 specific Rahul Singh
2021-04-29 14:46 ` [PATCH v4 1/3] xen/iommu: Move iommu_update_ire_from_msi(..) to xen/iommu.h Rahul Singh
2021-04-29 14:46 ` [PATCH v4 2/3] xen/pci: Refactor PCI MSI intercept related code Rahul Singh
2021-05-03 14:38 ` Jan Beulich
2021-05-05 7:51 ` Rahul Singh
2021-04-29 14:46 ` [PATCH v4 3/3] xen/pci: Refactor MSI code that implements MSI functionality within XEN Rahul Singh
2021-05-03 14:46 ` Jan Beulich [this message]
2021-05-05 16:09 ` Rahul Singh
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