Commit 6a92b111 authored Sep 11, 2018 by Boris Ostrovsky Committed by Thomas Gleixner Sep 11, 2018

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

parent 07e846ba

arch/x86/kernel/eisa.c

+8 −2

Original line number	Diff line number	Diff line
		@@ -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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