Re: [patch 0/8] PCI/MSI, x86: Cure a couple of inconsistencies

From: Marc Zyngier
Date: Thu Jul 22 2021 - 11:21:39 EST


On Wed, 21 Jul 2021 20:11:26 +0100,
Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:
>
> A recent discussion about the PCI/MSI management for virtio unearthed a
> violation of the MSI-X specification vs. writing the MSI-X message: under
> certain circumstances the entry is written without being masked.
>
> While looking at that and the related violation of the x86 non-remapped
> interrupt affinity mechanism a few other issues were discovered by
> inspection.
>
> The following series addresses these.
>
> Note this does not fix the virtio issue, but while staring at the above
> problems I came up with a plan to address this. I'm still trying to
> convince myself that I can get away without sprinkling locking all over the
> place, so don't hold your breath that this will materialize tomorrow.
>
> The series is also available from git:
>
> git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git irq/msi
>
> Thanks,
>
> tglx
> ---
> arch/x86/kernel/apic/io_apic.c | 6 +-
> arch/x86/kernel/apic/msi.c | 11 +++-
> arch/x86/kernel/hpet.c | 2
> drivers/pci/msi.c | 98 +++++++++++++++++++++++++++--------------
> include/linux/irq.h | 2
> kernel/irq/chip.c | 5 +-
> 6 files changed, 85 insertions(+), 39 deletions(-)

The couple of nits I mentioned notwithstanding, this looks good to me.
I've taken it for a short ride on an arm64 box (both bare metal and
guests), and nothing exploded. Must be good!

Reviewed-by: Marc Zyngier <maz@xxxxxxxxxx>

M.

--
Without deviation from the norm, progress is not possible.