Commit 99955451 authored by Boris Ostrovsky's avatar Boris Ostrovsky Committed by Greg Kroah-Hartman

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

commit 6a92b111 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: default avatarAndy Smith <andy@strugglers.net>
Signed-off-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarThomas 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.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent d9951521
......@@ -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;
......
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