linux-kernel - [patch 29/58] x86/ioapic/32: Decrapify phys_id_present

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Message-ID: <20230717223224.801556578@linutronix.de>
Date:   Tue, 18 Jul 2023 01:15:19 +0200 (CEST)
From:   Thomas Gleixner <tglx@...utronix.de>
To:     LKML <linux-kernel@...r.kernel.org>
Cc:     x86@...nel.org, Linus Torvalds <torvalds@...ux-foundation.org>,
        Andrew Cooper <andrew.cooper3@...rix.com>,
        Tom Lendacky <thomas.lendacky@....com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Wei Liu <wei.liu@...nel.org>,
        Arjan van de Ven <arjan@...ux.intel.com>,
        Juergen Gross <jgross@...e.com>
Subject: [patch 29/58] x86/ioapic/32: Decrapify phys_id_present_map operation

The operation to set the IOAPIC ID in phys_id_present_map is as convoluted
as it can be.

  1) Allocate a bitmap of 32byte size on the stack
  2) Zero the bitmap and set the IOAPIC ID bit
  3) Or the temporary bitmap over phys_id_present_map

The same functionality can be achieved by setting the IOAPIC ID bit
directly in the phys_id_present_map.

Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
---
 arch/x86/kernel/apic/io_apic.c |    5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -1511,12 +1511,9 @@ void __init setup_ioapic_ids_from_mpc_no
 			physid_set(i, phys_id_present_map);
 			ioapics[ioapic_idx].mp_config.apicid = i;
 		} else {
-			physid_mask_t tmp;
-
-			physid_set_mask_of_physid(mpc_ioapic_id(ioapic_idx), &tmp);
 			apic_printk(APIC_VERBOSE, "Setting %d in the phys_id_present_map\n",
 				    mpc_ioapic_id(ioapic_idx));
-			physids_or(phys_id_present_map, phys_id_present_map, tmp);
+			physid_set(mpc_ioapic_id(ioapic_idx), phys_id_present_map);
 		}
 
 		/*