[PATCH 5.10 085/104] x86/pci: Create PCI/MSI irqdomain after x86_init.pci.arch_init()

Greg Kroah-Hartman
2021-02-15T15:42:38Z

From: Thomas Gleixner <tglx@linutronix.de>

commit 70245f86c109e0eafb92ea9653184c0e44b4b35c upstream.

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/pci/init.c | 15 +++++++++++----
1 file changed, 11 insertions(+), 4 deletions(-)

--- 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();