x86/ioapic: Correct the PCI/ISA trigger type selection

PCI's default trigger type is level and ISA's is edge. The recent
refactoring made it the other way round, which went unnoticed as it seems
only to cause havoc on some AMD systems.

Make the comment and code do the right thing again.

Fixes: a27dca645d2c ("x86/io_apic: Cleanup trigger/polarity helpers")
Reported-by: Tom Lendacky <thomas.lendacky@amd.com>
Reported-by: Borislav Petkov <bp@alien8.de>
Reported-by: Qian Cai <cai@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Link: https://lore.kernel.org/r/87d00lgu13.fsf@nanos.tec.linutronix.de

diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index 0602c95..089e755 100644 (file)
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -809,9 +809,9 @@ static bool irq_is_level(int idx)
        case MP_IRQTRIG_DEFAULT:
                /*
                 * Conforms to spec, ie. bus-type dependent trigger
-                * mode. PCI defaults to egde, ISA to level.
+                * mode. PCI defaults to level, ISA to edge.
                 */
-               level = test_bit(bus, mp_bus_not_pci);
+               level = !test_bit(bus, mp_bus_not_pci);
                /* Take EISA into account */
                return eisa_irq_is_level(idx, bus, level);
        case MP_IRQTRIG_EDGE: