Re: [Patch V4 01/42] x86, irq: update high address field when updating affinity for MSI IRQ

Yinghai Lu
2014-06-09T23:46:11Z

On Mon, Jun 9, 2014 at 1:19 AM, Jiang Liu <jiang.liu@linux.intel.com> wrote:
> If x2apic is enabled, the MSI high address field should also be aslo
> updated when setting affinity for MSI IRQ, otherwise the MSI IRQ may
> target wrong APIC IDs.

Do you have any test case to reveal the problem?

>
> Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
> Cc: stable@vger.kernel.org
> ---
> arch/x86/kernel/apic/io_apic.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
> index 9d0a9795a0f8..2de992501a1b 100644
> --- a/arch/x86/kernel/apic/io_apic.c
> +++ b/arch/x86/kernel/apic/io_apic.c
> @@ -3007,6 +3007,10 @@ msi_set_affinity(struct irq_data *data, const struct cpumask *mask, bool force)
>
> __get_cached_msi_msg(data->msi_desc, &msg);
>
> + msg.address_hi = MSI_ADDR_BASE_HI;
> + if (x2apic_enabled())
> + msg.address_hi |= MSI_ADDR_EXT_DEST_ID(dest);
> +
> msg.data &= ~MSI_DATA_VECTOR_MASK;
> msg.data |= MSI_DATA_VECTOR(cfg->vector);
> msg.address_lo &= ~MSI_ADDR_DEST_ID_MASK;

No. This change is not needed.

When x2apic is used, and apicid > 255, irq remapping is used.

msi_chip.irq_set_affinity will be changed from msi_set_affinity to
x86_io_apic_ops.set_affinity (aka intel_setup_ioapic_entry), via
irq_remap_modify_chip_defaults().

Thanks

Yinghai