Date:   Sat, 11 Mar 2023 19:12:29 +0000
Message-ID: <86r0tvxftu.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Sven Peter <sven@svenpeter.dev>
Cc:     Alyssa Rosenzweig <alyssa@rosenzweig.io>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        Krzysztof =?UTF-8?B?V2lsY3p5xYRza2k=?= <kw@linux.com>,
        Rob Herring <robh@kernel.org>,
        Bjorn Helgaas <bhelgaas@google.com>, linux-pci@vger.kernel.org,
        asahi@lists.linux.dev, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] PCI: apple: Initialize pcie->nvecs before using it
In-Reply-To: <20230311133453.63246-1-sven@svenpeter.dev>
References: <20230311133453.63246-1-sven@svenpeter.dev>
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On Sat, 11 Mar 2023 13:34:53 +0000,
Sven Peter <sven@svenpeter.dev> wrote:
> 
> apple_pcie_setup_port computes ilog2(pcie->nvecs) to setup the number of
> MSIs available for each port. It is however called before apple_msi_init
> which actually initializes pcie->nvecs.
> Luckily, pcie->nvecs is part of kzalloc-ed structure and thus
> initialized as zero. ilog2(0) happens to be 0xffffffff which then just
> configures more MSIs in hardware than we actually have. This doesn't
> break anything because we never hand out those vectors.
> Let's swap the order of the two calls so that we use the correctly
> initialized value.
> 
> Fixes: 476c41ed4597 ("PCI: apple: Implement MSI support")
> Signed-off-by: Sven Peter <sven@svenpeter.dev>

Huh, how embarrassing... :-/

Reviewed-by: Marc Zyngier <maz@kernel.org>

	M.

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