Re: [v2 09/12] powerpc/mce: Enable MCE notifiers in external modules

On 7/2/19 11:47 AM, Nicholas Piggin wrote:

Santosh Sivaraj's on July 2, 2019 3:19 pm:

quoted

From: Reza Arbab <redacted>

Signed-off-by: Reza Arbab <redacted>
---
 arch/powerpc/kernel/exceptions-64s.S | 6 ++++++
 arch/powerpc/kernel/mce.c            | 2 ++
 2 files changed, 8 insertions(+)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index c83e38a403fd..311f1392a2ec 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S

@@ -458,6 +458,12 @@ EXC_COMMON_BEGIN(machine_check_handle_early)
 	bl	machine_check_early
 	std	r3,RESULT(r1)	/* Save result */
 
+	/* Notifiers may be in a module, so enable virtual addressing. */
+	mfmsr	r11
+	ori	r11,r11,MSR_IR
+	ori	r11,r11,MSR_DR
+	mtmsr	r11

Can't do this, we could take a machine check somewhere the MMU is
not sane (in fact the guest early mce handling that was added recently
should not be enabling virtual mode either, which needs to be fixed).

Looks like they need this to be able to run notifier chain which may
fail in real mode.

Thanks,
Nick