linux-kernel - Re: [PATCH] x86: fix: make PCI ECS for AMD CPUs hotplug capable

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Date:	Fri, 22 Aug 2008 11:56:08 -0700
From:	"Yinghai Lu" <yhlu.kernel@...il.com>
To:	"Robert Richter" <robert.richter@....com>
Cc:	"Ingo Molnar" <mingo@...e.hu>,
	"Thomas Gleixner" <tglx@...utronix.de>,
	LKML <linux-kernel@...r.kernel.org>,
	"Jan Beulich" <jbeulich@...ell.com>
Subject: Re: [PATCH] x86: fix: make PCI ECS for AMD CPUs hotplug capable

On Fri, Aug 22, 2008 at 11:23 AM, Robert Richter <robert.richter@....com> wrote:
> Until now, PCI ECS setup was performed at boot time only and for cpus
> that are enabled then. This patch fixes this and adds cpu hotplug.
>
> Tests sequence (check if ECS bit is set when bringing cpu online again):
>
>  # ( perl -e 'sysseek(STDIN, 0xC001001F, 0)'; hexdump -n 8 -e '2/4 "%08x " "\n"' )   < /dev/cpu/1/msr
>  00000008 00404010
>  # ( perl -e 'sysseek(STDOUT, 0xC001001F, 0); print pack "l*", 8, 0x00400010' ) > /dev/cpu/1/msr
>  # ( perl -e 'sysseek(STDIN, 0xC001001F, 0)'; hexdump -n 8 -e '2/4 "%08x " "\n"' )   < /dev/cpu/1/msr
>  00000008 00400010
>  # echo 0 > /sys/devices/system/cpu/cpu1/online
>  # echo 1 > /sys/devices/system/cpu/cpu1/online
>  # ( perl -e 'sysseek(STDIN, 0xC001001F, 0)'; hexdump -n 8 -e '2/4 "%08x " "\n"' )   < /dev/cpu/1/msr
>  00000008 00404010
>
> Cc: Jan Beulich <jbeulich@...ell.com>
> Cc: Yinghai Lu <yhlu.kernel@...il.com>
> Signed-off-by: Robert Richter <robert.richter@....com>
> ---
>  arch/x86/pci/amd_bus.c |   35 +++++++++++++++++++++++++++++++----
>  1 files changed, 31 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/pci/amd_bus.c b/arch/x86/pci/amd_bus.c
> index 4a6f1a6..6a0fca7 100644
> --- a/arch/x86/pci/amd_bus.c
> +++ b/arch/x86/pci/amd_bus.c
> @@ -1,6 +1,7 @@
>  #include <linux/init.h>
>  #include <linux/pci.h>
>  #include <linux/topology.h>
> +#include <linux/cpu.h>
>  #include "pci.h"
>
>  #ifdef CONFIG_X86_64
> @@ -565,7 +566,7 @@ static int __init early_fill_mp_bus_info(void) { return 0; }
>
>  #define ENABLE_CF8_EXT_CFG      (1ULL << 46)
>
> -static void enable_pci_io_ecs_per_cpu(void *unused)
> +static void enable_pci_io_ecs(void *unused)
>  {
>        u64 reg;
>        rdmsrl(MSR_AMD64_NB_CFG, reg);
> @@ -575,13 +576,39 @@ static void enable_pci_io_ecs_per_cpu(void *unused)
>        }
>  }
>
> -static int __init enable_pci_io_ecs(void)
> +static int __cpuinit amd_cpu_notify(struct notifier_block *self,
> +                                   unsigned long action, void *hcpu)
>  {
> +       int cpu = (long)hcpu;
> +       switch(action) {
> +       case CPU_ONLINE:
> +       case CPU_ONLINE_FROZEN:
> +               smp_call_function_single(cpu, enable_pci_io_ecs, NULL, 0);
> +               break;
> +       default:
> +               break;
> +       }
> +       return NOTIFY_OK;
> +}
> +
> +static struct notifier_block __cpuinitdata amd_cpu_notifier = {
> +       .notifier_call  = amd_cpu_notify,
> +};
> +
> +static int __init pci_io_ecs_init(void)
> +{
> +       int cpu;
> +
>        /* assume all cpus from fam10h have IO ECS */
>         if (boot_cpu_data.x86 < 0x10)
>                return 0;
> -       on_each_cpu(enable_pci_io_ecs_per_cpu, NULL, 1);
> +
> +       register_cpu_notifier(&amd_cpu_notifier);
> +       for_each_online_cpu(cpu)
> +               amd_cpu_notify(&amd_cpu_notifier, (unsigned long)CPU_ONLINE,
> +                              (void *)(long)cpu);

wonder if those two lines should be reversed.

>        pci_probe |= PCI_HAS_IO_ECS;
> +
>        return 0;
>  }
>
> @@ -591,7 +618,7 @@ static int __init amd_postcore_init(void)
>                return 0;
>
>        early_fill_mp_bus_info();
> -       enable_pci_io_ecs();
> +       pci_io_ecs_init();
>
>        return 0;
>  }
> --
> 1.5.6.4
>
>
>
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