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

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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>
This commit is contained in:
Boris Ostrovsky 2018-09-11 15:55:38 -04:00 committed by Greg Kroah-Hartman
parent d9951521dd
commit 9995545163
1 changed files with 8 additions and 2 deletions
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10
arch/x86/kernel/eisa.c
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;