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

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
This commit is contained in:
Boris Ostrovsky 2018-09-11 15:55:38 -04:00 committed by Thomas Gleixner
parent 07e846bace
commit 6a92b11169
1 changed files with 8 additions and 2 deletions

View File

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