From: Hans de Goede <hdegoede@redhat.com>
To: "Rafael J . Wysocki" <rafael@kernel.org>,
Pavel Machek <pavel@ucw.cz>, Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
Dave Hansen <dave.hansen@linux.intel.com>,
"H . Peter Anvin" <hpa@zytor.com>
Cc: Hans de Goede <hdegoede@redhat.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Dave Hansen <dave.hansen@intel.com>
Subject: [PATCH] x86/cpu: Avoid writing MSR_IA32_TSX_CTRL when writing it is not supported
Date: Tue, 6 Sep 2022 22:17:43 +0200 [thread overview]
Message-ID: <20220906201743.436091-1-hdegoede@redhat.com> (raw)
On an Intel Atom N2600 (and presumable other Cedar Trail models)
MSR_IA32_TSX_CTRL can be read, causing saved_msr.valid to be set for it
by msr_build_context().
This causes restore_processor_state() to try and restore it, but writing
this MSR is not allowed on the Intel Atom N2600 leading to:
[ 99.955141] unchecked MSR access error: WRMSR to 0x122 (tried to write 0x0000000000000002) at rIP: 0xffffffff8b07a574 (native_write_msr+0x4/0x20)
[ 99.955176] Call Trace:
[ 99.955186] <TASK>
[ 99.955195] restore_processor_state+0x275/0x2c0
[ 99.955246] x86_acpi_suspend_lowlevel+0x10e/0x140
[ 99.955273] acpi_suspend_enter+0xd3/0x100
[ 99.955297] suspend_devices_and_enter+0x7e2/0x830
[ 99.955341] pm_suspend.cold+0x2d2/0x35e
[ 99.955368] state_store+0x68/0xd0
[ 99.955402] kernfs_fop_write_iter+0x15e/0x210
[ 99.955442] vfs_write+0x225/0x4b0
[ 99.955523] ksys_write+0x59/0xd0
[ 99.955557] do_syscall_64+0x58/0x80
[ 99.955579] ? do_syscall_64+0x67/0x80
[ 99.955600] ? up_read+0x17/0x20
[ 99.955631] ? lock_is_held_type+0xe3/0x140
[ 99.955670] ? asm_exc_page_fault+0x22/0x30
[ 99.955688] ? lockdep_hardirqs_on+0x7d/0x100
[ 99.955710] entry_SYSCALL_64_after_hwframe+0x63/0xcd
[ 99.955723] RIP: 0033:0x7f7d0fb018f7
[ 99.955741] Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[ 99.955753] RSP: 002b:00007ffd03292ee8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 99.955771] RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 00007f7d0fb018f7
[ 99.955781] RDX: 0000000000000004 RSI: 00007ffd03292fd0 RDI: 0000000000000004
[ 99.955790] RBP: 00007ffd03292fd0 R08: 000000000000c0fe R09: 0000000000000000
[ 99.955799] R10: 00007f7d0fb85fb0 R11: 0000000000000246 R12: 0000000000000004
[ 99.955808] R13: 000055df564173e0 R14: 0000000000000004 R15: 00007f7d0fbf49e0
[ 99.955910] </TASK>
Extend the valid check in msr_build_context() to also do a test write of
the read value to avoid marking MSR-s which may not be written as valid.
Suggested-by: Dave Hansen <dave.hansen@intel.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
arch/x86/power/cpu.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index bb176c72891c..94b41bfd0769 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -433,10 +433,11 @@ static int msr_build_context(const u32 *msr_id, const int num)
}
for (i = saved_msrs->num, j = 0; i < total_num; i++, j++) {
- u64 dummy;
+ u64 value;
msr_array[i].info.msr_no = msr_id[j];
- msr_array[i].valid = !rdmsrl_safe(msr_id[j], &dummy);
+ msr_array[i].valid = !rdmsrl_safe(msr_id[j], &value) &&
+ !wrmsrl_safe(msr_id[j], value);
msr_array[i].info.reg.q = 0;
}
saved_msrs->num = total_num;
--
2.37.2
next reply other threads:[~2022-09-06 20:20 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-06 20:17 Hans de Goede [this message]
2022-09-06 20:43 ` [PATCH] x86/cpu: Avoid writing MSR_IA32_TSX_CTRL when writing it is not supported Peter Zijlstra
2022-09-06 20:56 ` Hans de Goede
2022-09-06 21:00 ` Peter Zijlstra
2022-09-06 23:00 ` Andrew Cooper
2022-09-07 7:32 ` Hans de Goede
2022-09-08 13:34 ` Andrew Cooper
2022-09-08 1:03 ` Pawan Gupta
2022-09-08 13:46 ` Andrew Cooper
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