[PATCH v4 09/17] arm/cpu: accessors for writable id registers

[Eric Auger <eric.auger@redhat.com>]

From: Cornelia Huck <cohuck@redhat.com>

Introduce ARM_FEATURE_ID_RANGE_IDX macro that converts opcodes
into the index used to access the 3 * 8 * 8 feature id array.

KVM_ARM_GET_REG_WRITABLE_MASKS populates writable masks with
that indexing.

Signed-off-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Eric Auger <eric.auger@redhat.com>
---
 target/arm/cpu.h | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index 2aa22360d2..0ac0fd13cf 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -886,6 +886,13 @@ typedef struct IdRegMap {
     uint64_t regs[NR_ID_REG_MASKS]; /* writable masks for registers */
 } IdRegMap;
 
+#define ARM_FEATURE_ID_RANGE_IDX(op0, op1, crn, crm, op2)               \
+        ({                                                              \
+                __u64 __op1 = (op1) & 3;                                \
+                __op1 -= (__op1 == 3);                                  \
+                (__op1 << 6 | ((crm) & 7) << 3 | (op2));                \
+        })
+
 /* REG is ID_XXX */
 #define FIELD_DP64_IDREG(ISAR, REG, FIELD, VALUE)                       \
     ({                                                                  \
-- 
2.53.0