Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [PATCH v2] x86/ioapic: Don't return 0 from arch_dynirq_lower_bound() | Date | Wed, 12 Apr 2023 17:37:27 +0200 |
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On Tue, Mar 28 2023 at 07:48, Saurabh Singh Sengar wrote: > On Tue, Mar 28, 2023 at 06:59:04AM -0700, H. Peter Anvin wrote: >> >> Is there any reason why this variable can't be initialized to a fixed nonzero number, like 16? > > Yes, initializing gst_top to any non-zero value should fix this issue. > At first I thought to intialize gst_top to 1.
That works only in your case. Some boot time registrations of IO_APICs use gsi_top as the base. So initializing gsi_top to N would move IOAPIC[0] interrupts out to irq N... and make the legacy interrupts fail.
That whole IOAPIC registration could do with some major cleanup, but that's a different story.
Thanks,
tglx
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