[kvm-unit-tests PATCH v11 5/9] 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 | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/lib/s390x/asm/arch_def.h b/lib/s390x/asm/arch_def.h
index 1b3bb0c..022a564 100644
--- a/lib/s390x/asm/arch_def.h
+++ b/lib/s390x/asm/arch_def.h
@@ -17,6 +17,7 @@ struct psw {
 
 #define PSW_MASK_EXT			0x0100000000000000UL
 #define PSW_MASK_DAT			0x0400000000000000UL
+#define PSW_MASK_WAIT			0x0002000000000000UL
 #define PSW_MASK_PSTATE			0x0001000000000000UL
 
 #define CR0_EXTM_SCLP			0x0000000000000200UL
@@ -246,6 +247,18 @@ 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