linux-kernel - Re: [PATCH v4 20/28] x86, irq: More strict checking about registering ioapic

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Date:	Mon, 19 Aug 2013 15:47:35 +0800
From:	Lan Tianyu <lantianyu1986@...il.com>
To:	Yinghai Lu <yinghai@...nel.org>
Cc:	Thomas Gleixner <tglx@...utronix.de>, Ingo Molnar <mingo@...e.hu>,
	"H. Peter Anvin" <hpa@...or.com>, Tony Luck <tony.luck@...el.com>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	"Rafael J. Wysocki" <rjw@...k.pl>,
	Linux PCI <linux-pci@...r.kernel.org>,
	"linux-kernel@...r kernel org" <linux-kernel@...r.kernel.org>,
	"linux-acpi@...r.kernel.org" <linux-acpi@...r.kernel.org>,
	Joerg Roedel <joro@...tes.org>,
	Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>,
	Sebastian Andrzej Siewior <sebastian@...akpoint.cc>
Subject: Re: [PATCH v4 20/28] x86, irq: More strict checking about registering ioapic

2013/8/11 Yinghai Lu <yinghai@...nel.org>
>
> 1. check overlaping gsi range
> for hot-add ioapic case, BIOS may have some entries in MADT
> and also have setting in pci root bus with _GSB of DSDT.
>
> 2. check if entries is in right range.
>
> Signed-off-by: Yinghai Lu <yinghai@...nel.org>
> Cc: Joerg Roedel <joro@...tes.org>
> Cc: Konrad Rzeszutek Wilk <konrad.wilk@...cle.com>
> Cc: Sebastian Andrzej Siewior <sebastian@...akpoint.cc>
> ---
>  arch/x86/kernel/apic/io_apic.c | 30 ++++++++++++++++++++++++------
>  1 file changed, 24 insertions(+), 6 deletions(-)
>
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index b026cc7..60c6706 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -3818,12 +3818,9 @@ void __init ioapic_insert_resources(void)
>         }
>  }
>
> -int mp_find_ioapic(u32 gsi)
> +static int __mp_find_ioapic(u32 gsi)
>  {
> -       int i = 0;
> -
> -       if (nr_ioapics == 0)
> -               return -1;
> +       int i;
>
>         /* Find the IOAPIC that manages this GSI. */
>         for_each_ioapic(i) {
> @@ -3833,10 +3830,19 @@ int mp_find_ioapic(u32 gsi)
>                         return i;
>         }
>
> -       printk(KERN_ERR "ERROR: Unable to locate IOAPIC for GSI %d\n", gsi);
>         return -1;
>  }
>
> +int mp_find_ioapic(u32 gsi)
> +{
> +       int ret = __mp_find_ioapic(gsi);
> +
> +       if (ret == -1)
> +               pr_err("ERROR: Unable to locate IOAPIC for GSI %d\n", gsi);
> +
> +       return ret;
> +}
> +
>  int mp_find_ioapic_pin(int ioapic, u32 gsi)
>  {
>         struct mp_ioapic_gsi *gsi_cfg;
> @@ -3888,6 +3894,11 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
>         if (bad_ioapic(address))
>                 return;
>
> +       /* already registered ? */
> +       idx = __mp_find_ioapic(gsi_base);
> +       if (idx >= 0)
> +               return;
> +
>         idx = find_first_zero_bit(ioapics_mask, MAX_IO_APICS);
>         if (idx >= MAX_IO_APICS) {
>                 pr_warn("WARNING: Max # of I/O APICs (%d) exceeded, skipping\n",
> @@ -3914,6 +3925,13 @@ void __init mp_register_ioapic(int id, u32 address, u32 gsi_base)
>          * and to prevent reprogramming of IOAPIC pins (PCI GSIs).
>          */
>         entries = io_apic_get_redir_entries(idx);

 "entries" is possible to be 0?  io_apic_get_redir_entries() returns
"reg_01.bits.entries + 1"
as "entries".

> +
> +       if (!entries || entries > MP_MAX_IOAPIC_PIN) {
> +               clear_fixmap(FIX_IO_APIC_BASE_0 + idx);
> +               memset(&ioapics[idx], 0, sizeof(struct ioapic));
> +               return;
> +       }
> +
>         gsi_cfg = mp_ioapic_gsi_routing(idx);
>         gsi_cfg->gsi_base = gsi_base;
>         gsi_cfg->gsi_end = gsi_base + entries - 1;
> --
> 1.8.1.4
>
> --
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-- 
Best regards
Tianyu Lan
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