Commit 99955451 authored Sep 11, 2018 by Boris Ostrovsky Committed by Greg Kroah-Hartman Sep 26, 2018

x86/EISA: Don't probe EISA bus for Xen PV guests



commit 6a92b11169a65b3f8cc512c75a252cbd0d096ba0 upstream.

For unprivileged Xen PV guests this is normal memory and ioremap will
not be able to properly map it.

While at it, since ioremap may return NULL, add a test for pointer's
validity.

Reported-by: Andy Smith <andy@strugglers.net>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: hpa@zytor.com
Cc: xen-devel@lists.xenproject.org
Cc: jgross@suse.com
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20180911195538.23289-1-boris.ostrovsky@oracle.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

parent d9951521

arch/x86/kernel/eisa.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -7,11 +7,17 @@
		#include <linux/eisa.h>
		#include <linux/io.h>

		#include <xen/xen.h>

		static __init int eisa_bus_probe(void)
		{
		void __iomem *p = ioremap(0x0FFFD9, 4);
		void __iomem *p;

		if (xen_pv_domain() && !xen_initial_domain())
		return 0;

		if (readl(p) == 'E' + ('I'<<8) + ('S'<<16) + ('A'<<24))
		p = ioremap(0x0FFFD9, 4);
		if (p && readl(p) == 'E' + ('I' << 8) + ('S' << 16) + ('A' << 24))
		EISA_bus = 1;
		iounmap(p);
		return 0;