From 13001cb1ede15656310e32715b92e16d78d3bdf5 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 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 --- 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 f260e452e4f87..e8c8c5d78dbdd 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; -- 2.39.5