Messages in this thread Patch in this message | | | Date | Fri, 19 Nov 2010 13:55:41 -0800 | From | Greg KH <> | Subject | [20/82] x86, intr-remap: Set redirection hint in the IRTE |
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2.6.35-stable review patch. If anyone has any objections, please let us know.
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From: Suresh Siddha <suresh.b.siddha@intel.com>
commit 75e3cfbed6f71a8f151dc6e413b6ce3c390030cb upstream.
Currently the redirection hint in the interrupt-remapping table entry is set to 0, which means the remapped interrupt is directed to the processors listed in the destination. So in logical flat mode in the presence of intr-remapping, this results in a single interrupt multi-casted to multiple cpu's as specified by the destination bit mask. But what we really want is to send that interrupt to one of the cpus based on the lowest priority delivery mode.
Set the redirection hint in the IRTE to '1' to indicate that we want the remapped interrupt to be directed to only one of the processors listed in the destination.
This fixes the issue of same interrupt getting delivered to multiple cpu's in the logical flat mode in the presence of interrupt-remapping. While there is no functional issue observed with this behavior, this will impact performance of such configurations (<=8 cpu's using logical flat mode in the presence of interrupt-remapping)
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com> LKML-Reference: <20100827181049.013051492@sbsiddha-MOBL3.sc.intel.com> Cc: Weidong Han <weidong.han@intel.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/kernel/apic/io_apic.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/arch/x86/kernel/apic/io_apic.c +++ b/arch/x86/kernel/apic/io_apic.c @@ -1397,6 +1397,7 @@ int setup_ioapic_entry(int apic_id, int irte.dlvry_mode = apic->irq_delivery_mode; irte.vector = vector; irte.dest_id = IRTE_DEST(destination); + irte.redir_hint = 1; /* Set source-id of interrupt request */ set_ioapic_sid(&irte, apic_id); @@ -3348,6 +3349,7 @@ static int msi_compose_msg(struct pci_de irte.dlvry_mode = apic->irq_delivery_mode; irte.vector = cfg->vector; irte.dest_id = IRTE_DEST(dest); + irte.redir_hint = 1; /* Set source-id of interrupt request */ if (pdev)
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