[PATCH] x86/apic: Update virtual irq base for DT/OF based system as well

[Rahul Tanwar]

'ioapic_dynirq_base' contains the virtual IRQ base number. Presently, it is
updated to the end of hardware IRQ numbers but this is done only when IOAPIC
configuration type is IOAPIC_DOMAIN_LEGACY or IOAPIC_DOMAIN_STRICT. There is
a third type IOAPIC_DOMAIN_DYNAMIC which applies when IOAPIC configuration
comes from devicetree.
Please see dtb_add_ioapic() in arch/x86/kernel/devicetree.c

In case of IOAPIC_DOMAIN_DYNAMIC (DT/OF based system), 'ioapic_dynirq_base'
remains to zero initialized value. This means that for OF based systems,
virtual IRQ base will get set to zero. Zero value for a virtual IRQ is a
invalid value.
Please see https://yarchive.net/comp/linux/zero.html for more details.

Update 'ioapic_dynirq_base' for IOAPIC_DOMAIN_DYNAMIC case as well just like
it is presently updated for IOAPIC_DOMAIN_LEGACY & IOAPIC_DOMAIN_STRICT i.e.
set the virtual IRQ base to the end of hardware IRQ numbers when IOAPIC
configuration comes from devicetree.

Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
---
 arch/x86/kernel/apic/io_apic.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index c7bb6c69f21c..fe50cd91122b 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -2336,7 +2336,8 @@ static int mp_irqdomain_create(int ioapic)
 	ip->irqdomain->parent = parent;
 
 	if (cfg->type == IOAPIC_DOMAIN_LEGACY ||
-	    cfg->type == IOAPIC_DOMAIN_STRICT)
+	    cfg->type == IOAPIC_DOMAIN_STRICT ||
+	    cfg->type == IOAPIC_DOMAIN_DYNAMIC)
 		ioapic_dynirq_base = max(ioapic_dynirq_base,
 					 gsi_cfg->gsi_end + 1);
 
-- 
2.11.0