From: Alexey Dobriyan <adobriyan@gmail.com>
Date: Fri, 2 Aug 2024 15:42:51 +0000 (+0300)
Subject: xen, pvh: fix unbootable VMs (PVH + KASAN - AMD_MEM_ENCRYPT)
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=661362e3dcab464d6b6976c019fd5b5433bda85f;p=users%2Fdwmw2%2Flinux.git

xen, pvh: fix unbootable VMs (PVH + KASAN - AMD_MEM_ENCRYPT)

Uninstrument arch/x86/platform/pvh/enlighten.c: KASAN has not been setup
_this_ early in the boot process.

Steps to reproduce:

	make allnoconfig
	make sure CONFIG_AMD_MEM_ENCRYPT is disabled
		AMD_MEM_ENCRYPT independently uninstruments lib/string.o
		so PVH boot code calls into uninstrumented memset() and
		memcmp() which can make the bug disappear depending on
		the compiler.
	enable CONFIG_PVH
	enable CONFIG_KASAN
	enable serial console
		this is fun exercise if you never done it from nothing :^)

	make

	qemu-system-x86_64	\
		-enable-kvm	\
		-cpu host	\
		-smp cpus=1	\
		-m 4096		\
		-serial stdio	\
		-kernel vmlinux \
		-append 'console=ttyS0 ignore_loglevel'

Messages on serial console will easily tell OK kernel from unbootable
kernel. In bad case qemu hangs in an infinite loop stroboscoping
"SeaBIOS" message.

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Acked-by: Juergen Gross <jgross@suse.com>
Message-ID: <20240802154253.482658-1-adobriyan@gmail.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
---

diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile
index 5dec5067c9fb7..c43fb7964dc4d 100644
--- a/arch/x86/platform/pvh/Makefile
+++ b/arch/x86/platform/pvh/Makefile
@@ -1,5 +1,6 @@
 # SPDX-License-Identifier: GPL-2.0
 OBJECT_FILES_NON_STANDARD_head.o := y
+KASAN_SANITIZE := n
 
 obj-$(CONFIG_PVH) += enlighten.o
 obj-$(CONFIG_PVH) += head.o