From 9995545163fcbf2a8b762c15ce4585ae0924f568 Mon Sep 17 00:00:00 2001 From: Boris Ostrovsky Date: Tue, 11 Sep 2018 15:55:38 -0400 Subject: [PATCH] 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 Signed-off-by: Boris Ostrovsky Signed-off-by: Thomas Gleixner 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 --- arch/x86/kernel/eisa.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/eisa.c b/arch/x86/kernel/eisa.c index f260e45..e8c8c5d 100644 --- a/arch/x86/kernel/eisa.c +++ b/arch/x86/kernel/eisa.c @@ -7,11 +7,17 @@ #include #include +#include + 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; -- 2.7.4