public inbox for linux-kernel@vger.kernel.org
 help / color / mirror / Atom feed
From: Alexey Dobriyan <adobriyan@gmail.com>
To: jgross@suse.com, boris.ostrovsky@oracle.com, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com
Cc: adobriyan@gmail.com, linux-kernel@vger.kernel.org,
	x86@kernel.org, hpa@zytor.com
Subject: [PATCH 1/3] xen, pvh: fix unbootable VMs (PVH + KASAN - AMD_MEM_ENCRYPT)
Date: Fri,  2 Aug 2024 18:42:51 +0300	[thread overview]
Message-ID: <20240802154253.482658-1-adobriyan@gmail.com> (raw)

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>
---
 arch/x86/platform/pvh/Makefile | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/platform/pvh/Makefile b/arch/x86/platform/pvh/Makefile
index 5dec5067c9fb..c43fb7964dc4 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
-- 
2.45.0


             reply	other threads:[~2024-08-02 15:43 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-08-02 15:42 Alexey Dobriyan [this message]
2024-08-02 15:42 ` [PATCH 2/3] x86/cpu: fix unbootable VMs by inlining memcmp() in hypervisor_cpuid_base() Alexey Dobriyan
2024-08-15 13:32   ` Jürgen Groß
2024-08-02 15:42 ` [PATCH 3/3] xen, pvh: fix unbootable VMs by inlining memset() in xen_prepare_pvh() Alexey Dobriyan
2024-08-15 13:33   ` Jürgen Groß

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20240802154253.482658-1-adobriyan@gmail.com \
    --to=adobriyan@gmail.com \
    --cc=boris.ostrovsky@oracle.com \
    --cc=bp@alien8.de \
    --cc=dave.hansen@linux.intel.com \
    --cc=hpa@zytor.com \
    --cc=jgross@suse.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=tglx@linutronix.de \
    --cc=x86@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox