From: Suresh Siddha Date: Fri, 27 Aug 2010 18:09:48 +0000 (-0700) Subject: x86, intr-remap: Set redirection hint in the IRTE X-Git-Tag: firefly_0821_release~9833^2~79^2^2~333 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=bbfc3a3c96fca7386244f1c0ddf88c8a958f044d;p=firefly-linux-kernel-4.4.55.git x86, intr-remap: Set redirection hint in the IRTE 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 LKML-Reference: <20100827181049.013051492@sbsiddha-MOBL3.sc.intel.com> Cc: Weidong Han Signed-off-by: H. Peter Anvin Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c index 5c5b8f3dddb5..ad1515dbc5ef 100644 --- 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 irq, 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_dev *pdev, unsigned int irq, 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)