Patch "x86/EISA: Don't probe EISA bus for Xen PV guests" has been added to the 4.18-stable tree

Patch "x86/EISA: Don't probe EISA bus for Xen PV guests" has been added to the 4.18-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

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

to the 4.18-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-eisa-don-t-probe-eisa-bus-for-xen-pv-guests.patch
and it can be found in the queue-4.18 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


From 6a92b11169a65b3f8cc512c75a252cbd0d096ba0 Mon Sep 17 00:00:00 2001
From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Date: Tue, 11 Sep 2018 15:55:38 -0400
Subject: x86/EISA: Don't probe EISA bus for Xen PV guests

From: Boris Ostrovsky <boris.ostrovsky@oracle.com>

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>

---
 arch/x86/kernel/eisa.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

--- a/arch/x86/kernel/eisa.c
+++ b/arch/x86/kernel/eisa.c
@@ -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;


Patches currently in stable-queue which might be from boris.ostrovsky@oracle.com are

queue-4.18/xen-netfront-fix-waiting-for-xenbus-state-change.patch
queue-4.18/x86-eisa-don-t-probe-eisa-bus-for-xen-pv-guests.patch
queue-4.18/x86-mm-pti-add-an-overflow-check-to-pti_clone_pmds.patch

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