[kvm-unit-tests PATCH v9 07/12] s390x: define function to wait for interrupt

[Pierre Morel <pmorel@linux.ibm.com>]

Allow the program to wait for an interrupt.

The interrupt handler is in charge to remove the WAIT bit
when it finished handling the interrupt.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
---
 lib/s390x/asm/arch_def.h | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index fa71653..ff2ee20 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -10,9 +10,11 @@
 #ifndef _ASM_S390X_ARCH_DEF_H_
 #define _ASM_S390X_ARCH_DEF_H_
 
+#define PSW_MASK_IO			0x0200000000000000UL
 #define PSW_MASK_EXT			0x0100000000000000UL
 #define PSW_MASK_DAT			0x0400000000000000UL
 #define PSW_MASK_SHORT_PSW		0x0008000000000000UL
+#define PSW_MASK_WAIT			0x0002000000000000UL
 #define PSW_MASK_PSTATE			0x0001000000000000UL
 #define PSW_MASK_BA			0x0000000080000000UL
 #define PSW_MASK_EA			0x0000000100000000UL
@@ -253,6 +255,18 @@ static inline void load_psw_mask(uint64_t mask)
 		: "+r" (tmp) :  "a" (&psw) : "memory", "cc" );
 }
 
+static inline void wait_for_interrupt(uint64_t irq_mask)
+{
+	uint64_t psw_mask = extract_psw_mask();
+
+	load_psw_mask(psw_mask | irq_mask | PSW_MASK_WAIT);
+	/*
+	 * After being woken and having processed the interrupt, let's restore
+	 * the PSW mask.
+	 */
+	load_psw_mask(psw_mask);
+}
+
 static inline void enter_pstate(void)
 {
 	uint64_t mask;
-- 
2.25.1