linux-kernel - [PATCH 3.16.y-ckt 098/185] MIPS: Fix KVM guest fixmap address

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Message-Id: <1436951580-15977-99-git-send-email-luis.henriques@canonical.com>
Date:	Wed, 15 Jul 2015 10:11:33 +0100
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	James Hogan <james.hogan@...tec.com>, linux-mips@...ux-mips.org,
	Ralf Baechle <ralf@...ux-mips.org>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 098/185] MIPS: Fix KVM guest fixmap address

3.16.7-ckt15 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Hogan <james.hogan@...tec.com>

commit 8e748c8d09a9314eedb5c6367d9acfaacddcdc88 upstream.

KVM guest kernels for trap & emulate run in user mode, with a modified
set of kernel memory segments. However the fixmap address is still in
the normal KSeg3 region at 0xfffe0000 regardless, causing problems when
cache alias handling makes use of them when handling copy on write.

Therefore define FIXADDR_TOP as 0x7ffe0000 in the guest kernel mapped
region when CONFIG_KVM_GUEST is defined.

Signed-off-by: James Hogan <james.hogan@...tec.com>
Cc: linux-mips@...ux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/9887/
Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 arch/mips/include/asm/mach-generic/spaces.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/mips/include/asm/mach-generic/spaces.h b/arch/mips/include/asm/mach-generic/spaces.h
index 9488fa5f8866..afc96ecb9004 100644
--- a/arch/mips/include/asm/mach-generic/spaces.h
+++ b/arch/mips/include/asm/mach-generic/spaces.h
@@ -94,7 +94,11 @@
 #endif
 
 #ifndef FIXADDR_TOP
+#ifdef CONFIG_KVM_GUEST
+#define FIXADDR_TOP		((unsigned long)(long)(int)0x7ffe0000)
+#else
 #define FIXADDR_TOP		((unsigned long)(long)(int)0xfffe0000)
 #endif
+#endif
 
 #endif /* __ASM_MACH_GENERIC_SPACES_H */
--
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