From: Sukadev Bhattiprolu <redacted>

The ultravisor processor mode is introduced in POWER platforms that
supports the Protected Execution Facility (PEF). Ultravisor is higher
privileged than hypervisor mode.

In PEF enabled platforms, the MSR_S bit is used to indicate if the
thread is in secure state. With the MSR_S bit, the privilege state of
the thread is now determined by MSR_S, MSR_HV and MSR_PR, as follows:

S   HV  PR
-----------------------
0   x   1   problem
1   0   1   problem
x   x   0   privileged
x   1   0   hypervisor
1   1   0   ultravisor
1   1   1   reserved

The hypervisor doesn't (and can't) run with the MSR_S bit set, but a
secure guest and the ultravisor firmware do.

Signed-off-by: Sukadev Bhattiprolu <redacted>
Signed-off-by: Ram Pai <redacted>
[ Update the commit message ]
Signed-off-by: Claudio Carvalho <redacted>
---
 arch/powerpc/include/asm/reg.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/include/asm/reg.h b/arch/powerpc/include/asm/reg.h
index 10caa145f98b..39b4c0a519f5 100644
--- a/arch/powerpc/include/asm/reg.h
+++ b/arch/powerpc/include/asm/reg.h

@@ -38,6 +38,7 @@
 #define MSR_TM_LG	32		/* Trans Mem Available */
 #define MSR_VEC_LG	25	        /* Enable AltiVec */
 #define MSR_VSX_LG	23		/* Enable VSX */
+#define MSR_S_LG	22		/* Secure VM bit */
 #define MSR_POW_LG	18		/* Enable Power Management */
 #define MSR_WE_LG	18		/* Wait State Enable */
 #define MSR_TGPR_LG	17		/* TLB Update registers in use */

@@ -71,11 +72,13 @@
 #define MSR_SF		__MASK(MSR_SF_LG)	/* Enable 64 bit mode */
 #define MSR_ISF		__MASK(MSR_ISF_LG)	/* Interrupt 64b mode valid on 630 */
 #define MSR_HV 		__MASK(MSR_HV_LG)	/* Hypervisor state */
+#define MSR_S		__MASK(MSR_S_LG)	/* Secure state */
 #else
 /* so tests for these bits fail on 32-bit */
 #define MSR_SF		0
 #define MSR_ISF		0
 #define MSR_HV		0
+#define MSR_S		0
 #endif
 
 /*

-- 
2.20.1