* Re: [PATCH] PCI: apple: Initialize pcie->nvecs before using it
2023-03-11 13:34 [PATCH] PCI: apple: Initialize pcie->nvecs before using it Sven Peter
@ 2023-03-11 14:10 ` Eric Curtin
2023-03-11 14:34 ` alyssa
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Eric Curtin @ 2023-03-11 14:10 UTC (permalink / raw)
To: Sven Peter
Cc: Alyssa Rosenzweig, Marc Zyngier, Lorenzo Pieralisi,
Krzysztof Wilczyński, Rob Herring, Bjorn Helgaas, linux-pci,
asahi, linux-kernel
On Sat, 11 Mar 2023 at 13:41, 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>
Reviewed-by: Eric Curtin <ecurtin@redhat.com>
Is mise le meas/Regards,
Eric Curtin
> ---
> drivers/pci/controller/pcie-apple.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index 66f37e403a09..8b7b084cf287 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -783,6 +783,10 @@ static int apple_pcie_init(struct pci_config_window *cfg)
> cfg->priv = pcie;
> INIT_LIST_HEAD(&pcie->ports);
>
> + ret = apple_msi_init(pcie);
> + if (ret)
> + return ret;
> +
> for_each_child_of_node(dev->of_node, of_port) {
> ret = apple_pcie_setup_port(pcie, of_port);
> if (ret) {
> @@ -792,7 +796,7 @@ static int apple_pcie_init(struct pci_config_window *cfg)
> }
> }
>
> - return apple_msi_init(pcie);
> + return 0;
> }
>
> static int apple_pcie_probe(struct platform_device *pdev)
> --
> 2.25.1
>
>
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PCI: apple: Initialize pcie->nvecs before using it
2023-03-11 13:34 [PATCH] PCI: apple: Initialize pcie->nvecs before using it Sven Peter
2023-03-11 14:10 ` Eric Curtin
@ 2023-03-11 14:34 ` alyssa
2023-03-11 19:12 ` Marc Zyngier
2023-06-24 17:04 ` Krzysztof Wilczyński
3 siblings, 0 replies; 5+ messages in thread
From: alyssa @ 2023-03-11 14:34 UTC (permalink / raw)
To: Sven Peter, Marc Zyngier
Cc: Lorenzo Pieralisi, Krzysztof Wilczyński, Rob Herring,
Bjorn Helgaas, linux-pci, asahi, linux-kernel
Whoops!
Reviewed-by: Alyssa Rosenzweig <alyssa@rosenzweig.io>
March 11, 2023 8:34 AM, "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>
> ---
> drivers/pci/controller/pcie-apple.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/pcie-apple.c b/drivers/pci/controller/pcie-apple.c
> index 66f37e403a09..8b7b084cf287 100644
> --- a/drivers/pci/controller/pcie-apple.c
> +++ b/drivers/pci/controller/pcie-apple.c
> @@ -783,6 +783,10 @@ static int apple_pcie_init(struct pci_config_window *cfg)
> cfg->priv = pcie;
> INIT_LIST_HEAD(&pcie->ports);
>
> + ret = apple_msi_init(pcie);
> + if (ret)
> + return ret;
> +
> for_each_child_of_node(dev->of_node, of_port) {
> ret = apple_pcie_setup_port(pcie, of_port);
> if (ret) {
> @@ -792,7 +796,7 @@ static int apple_pcie_init(struct pci_config_window *cfg)
> }
> }
>
> - return apple_msi_init(pcie);
> + return 0;
> }
>
> static int apple_pcie_probe(struct platform_device *pdev)
> --
> 2.25.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PCI: apple: Initialize pcie->nvecs before using it
2023-03-11 13:34 [PATCH] PCI: apple: Initialize pcie->nvecs before using it Sven Peter
2023-03-11 14:10 ` Eric Curtin
2023-03-11 14:34 ` alyssa
@ 2023-03-11 19:12 ` Marc Zyngier
2023-06-24 17:04 ` Krzysztof Wilczyński
3 siblings, 0 replies; 5+ messages in thread
From: Marc Zyngier @ 2023-03-11 19:12 UTC (permalink / raw)
To: Sven Peter
Cc: Alyssa Rosenzweig, Lorenzo Pieralisi, Krzysztof Wilczyński,
Rob Herring, Bjorn Helgaas, linux-pci, asahi, linux-kernel
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.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] PCI: apple: Initialize pcie->nvecs before using it
2023-03-11 13:34 [PATCH] PCI: apple: Initialize pcie->nvecs before using it Sven Peter
` (2 preceding siblings ...)
2023-03-11 19:12 ` Marc Zyngier
@ 2023-06-24 17:04 ` Krzysztof Wilczyński
3 siblings, 0 replies; 5+ messages in thread
From: Krzysztof Wilczyński @ 2023-06-24 17:04 UTC (permalink / raw)
To: Sven Peter
Cc: Alyssa Rosenzweig, Marc Zyngier, Lorenzo Pieralisi, Rob Herring,
Bjorn Helgaas, linux-pci, asahi, linux-kernel
Hello,
> 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.
Applied to controller/apple, thank you!
[1/1] PCI: apple: Initialize pcie->nvecs before use
https://git.kernel.org/pci/pci/c/328a16477027
Krzysztof
^ permalink raw reply [flat|nested] 5+ messages in thread