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Message-ID: <87sfysczw9.wl-maz@kernel.org>
Date: Sun, 29 Aug 2021 11:24:06 +0100
From: Marc Zyngier <maz@...nel.org>
To: Huacai Chen <chenhuacai@...ngson.cn>
Cc: Thomas Gleixner <tglx@...utronix.de>, linux-kernel@...r.kernel.org,
Xuefeng Li <lixuefeng@...ngson.cn>,
Huacai Chen <chenhuacai@...il.com>,
Jiaxun Yang <jiaxun.yang@...goat.com>, stable@...r.kernel.org
Subject: Re: [PATCH] irqchip/loongson-pch-msi: Fix hwirq setting problem
On Sun, 29 Aug 2021 10:29:33 +0100,
Huacai Chen <chenhuacai@...ngson.cn> wrote:
>
> The default msi_domain_ops_init() doesn't set hwirq for irq_data,
> which causes the hwirq displayed in /proc/interrupts very strange.
> We fix this by providing a custom msi_domain_ops_init().
I suggest you start by reading pci_msi_domain_set_desc(). Can you
demonstrate that this function isn't called and that the numbers
displayed in /proc/interrupts are just random crap pulled out of thin
air?
>
> Before this patch:
>
> root@...ngson-pc:~# cat /proc/interrupts
> CPU0 CPU1
> 30: 0 0 PCH PIC 47 acpi
> 42: 80020 0 LIOINTC 10 ttyS0
> 44: 1 0 PCH PIC 49 ohci_hcd:usb3
> 45: 0 0 PCH PIC 48 ehci_hcd:usb1
> 46: 1 0 PCH PIC 51 ohci_hcd:usb4
> 47: 0 0 PCH PIC 50 ehci_hcd:usb2
> 54: 0 0 PCH PIC 16 ahci[0000:00:08.0]
> 55: 4364 0 PCH PIC 17 ahci[0000:00:08.1]
> 56: 103 0 PCH PIC 18 ahci[0000:00:08.2]
> 57: 0 0 PCH PCI MSI 1048576 ahci[0000:02:00.0]
> 58: 0 0 PCH PCI MSI 524288 xhci_hcd
> 59: 0 0 PCH PCI MSI 524289 xhci_hcd
> 60: 0 0 PCH PCI MSI 524290 xhci_hcd
> 61: 0 0 PCH PCI MSI 524291 xhci_hcd
> 62: 1 0 PCH PCI MSI 1572864 enp3s0f0
> 63: 6 173 PCH PCI MSI 1572865 enp3s0f0-rx-0
> 64: 6 151 PCH PCI MSI 1572866 enp3s0f0-rx-1
> 65: 6 151 PCH PCI MSI 1572867 enp3s0f0-rx-2
> 66: 20 0 PCH PCI MSI 1572868 enp3s0f0-tx-0
> 67: 20 0 PCH PCI MSI 1572869 enp3s0f0-tx-1
> 68: 170 0 PCH PCI MSI 1572870 enp3s0f0-tx-2
>
> After this patch:
>
> root@...ngson-pc:~# cat /proc/interrupts
> CPU0 CPU1
> 30: 0 0 PCH PIC 47 acpi
> 42: 83960 0 LIOINTC 10 ttyS0
> 44: 1 0 PCH PIC 49 ohci_hcd:usb3
> 45: 0 0 PCH PIC 48 ehci_hcd:usb1
> 46: 1 0 PCH PIC 51 ohci_hcd:usb4
> 47: 0 0 PCH PIC 50 ehci_hcd:usb2
> 54: 0 0 PCH PIC 16 ahci[0000:00:08.0]
> 55: 6688 13 PCH PIC 17 ahci[0000:00:08.1]
> 56: 113 2 PCH PIC 18 ahci[0000:00:08.2]
> 57: 0 0 PCH PCI MSI 67 ahci[0000:02:00.0]
> 58: 0 0 PCH PCI MSI 68 xhci_hcd
> 59: 0 0 PCH PCI MSI 69 xhci_hcd
> 60: 0 0 PCH PCI MSI 70 xhci_hcd
> 61: 0 0 PCH PCI MSI 71 xhci_hcd
> 62: 1 0 PCH PCI MSI 72 enp3s0f0
> 63: 12 4 PCH PCI MSI 73 enp3s0f0-rx-0
> 64: 12 4 PCH PCI MSI 74 enp3s0f0-rx-1
> 65: 12 0 PCH PCI MSI 75 enp3s0f0-rx-2
> 66: 16 0 PCH PCI MSI 76 enp3s0f0-tx-0
> 67: 22 0 PCH PCI MSI 77 enp3s0f0-tx-1
> 68: 12 0 PCH PCI MSI 78 enp3s0f0-tx-2
>
> Fixes: 632dcc2c75ef6de327 ("irqchip: Add Loongson PCH MSI controller")
> Cc: stable@...r.kernel.org
> Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
> ---
> drivers/irqchip/irq-loongson-pch-msi.c | 19 ++++++++++++++++++-
> 1 file changed, 18 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-loongson-pch-msi.c b/drivers/irqchip/irq-loongson-pch-msi.c
> index 32562b7e681b..c91a731abd99 100644
> --- a/drivers/irqchip/irq-loongson-pch-msi.c
> +++ b/drivers/irqchip/irq-loongson-pch-msi.c
> @@ -81,10 +81,25 @@ static void pch_msi_compose_msi_msg(struct irq_data *data,
> msg->data = data->hwirq;
> }
>
> +static int msi_domain_ops_init(struct irq_domain *domain,
> + struct msi_domain_info *info,
> + unsigned int virq, irq_hw_number_t hwirq,
> + msi_alloc_info_t *arg)
> +{
> + irq_domain_set_hwirq_and_chip(domain, virq, arg->hwirq, info->chip,
> + info->chip_data);
> + return 0;
> +}
> +
> +static struct msi_domain_ops pch_msi_domain_ops = {
> + .msi_init = msi_domain_ops_init,
> +};
> +
> static struct msi_domain_info pch_msi_domain_info = {
> .flags = MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS |
> MSI_FLAG_MULTI_PCI_MSI | MSI_FLAG_PCI_MSIX,
> .chip = &pch_msi_irq_chip,
> + .ops = &pch_msi_domain_ops,
> };
>
> static struct irq_chip middle_irq_chip = {
> @@ -112,8 +127,9 @@ static int pch_msi_middle_domain_alloc(struct irq_domain *domain,
> unsigned int virq,
> unsigned int nr_irqs, void *args)
> {
> - struct pch_msi_data *priv = domain->host_data;
> int hwirq, err, i;
> + struct pch_msi_data *priv = domain->host_data;
> + msi_alloc_info_t *info = (msi_alloc_info_t *)args;
>
> hwirq = pch_msi_allocate_hwirq(priv, nr_irqs);
> if (hwirq < 0)
> @@ -127,6 +143,7 @@ static int pch_msi_middle_domain_alloc(struct irq_domain *domain,
> irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> &middle_irq_chip, priv);
> }
> + info->hwirq = hwirq;
>
> return 0;
>
There is nothing to fix here. The hwirq numbers in /proc/interrupts
are the way they are for a good reason, and there is no need to make
them look "better".
M.
--
Without deviation from the norm, progress is not possible.
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