Patch-mainline: v5.11
Git-commit: 70245f86c109e0eafb92ea9653184c0e44b4b35c
References: bsc#1181572
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 10 Feb 2021 16:27:41 +0100
Subject: [PATCH] x86/pci: Create PCI/MSI irqdomain after
 x86_init.pci.arch_init()

Invoking x86_init.irqs.create_pci_msi_domain() before
x86_init.pci.arch_init() breaks XEN PV.

The XEN_PV specific pci.arch_init() function overrides the default
create_pci_msi_domain() which is obviously too late.

As a consequence the XEN PV PCI/MSI allocation goes through the native
path which runs out of vectors and causes malfunction.

Invoke it after x86_init.pci.arch_init().

Fixes: 6b15ffa07dc3 ("x86/irq: Initialize PCI/MSI domain at PCI init time")
Reported-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/87pn18djte.fsf@nanos.tec.linutronix.de
Signed-off-by: Juergen Gross <jgross@suse.com>
---
 arch/x86/pci/init.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

diff --git a/arch/x86/pci/init.c b/arch/x86/pci/init.c
index 00bfa1ebad6c..0bb3b8b44e4e 100644
--- a/arch/x86/pci/init.c
+++ b/arch/x86/pci/init.c
@@ -9,16 +9,23 @@
    in the right sequence from here. */
 static __init int pci_arch_init(void)
 {
-	int type;
-
-	x86_create_pci_msi_domain();
+	int type, pcbios = 1;
 
 	type = pci_direct_probe();
 
 	if (!(pci_probe & PCI_PROBE_NOEARLY))
 		pci_mmcfg_early_init();
 
-	if (x86_init.pci.arch_init && !x86_init.pci.arch_init())
+	if (x86_init.pci.arch_init)
+		pcbios = x86_init.pci.arch_init();
+
+	/*
+	 * Must happen after x86_init.pci.arch_init(). Xen sets up the
+	 * x86_init.irqs.create_pci_msi_domain there.
+	 */
+	x86_create_pci_msi_domain();
+
+	if (!pcbios)
 		return 0;
 
 	pci_pcbios_init();
-- 
2.26.2