target/arm: Make stage_2_format for cache attributes optional

The v8R PMSAv8 has a two-stage MPU translation process, but, unlike
VMSAv8, the stage 2 attributes are in the same format as the stage 1
attributes (8-bit MAIR format). Rather than converting the MAIR
format to the format used for VMSA stage 2 (bits [5:2] of a VMSA
stage 2 descriptor) and then converting back to do the attribute
combination, allow combined_attrs_nofwb() to accept s2 attributes
that are already in the MAIR format.

We move the assert() to combined_attrs_fwb(), because that function
really does require a VMSA stage 2 attribute format. (We will never
get there for v8R, because PMSAv8 does not implement FEAT_S2FWB.)

Signed-off-by: Tobias Röhmel <tobias.roehmel@rwth-aachen.de>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20221206102504.165775-4-tobias.roehmel@rwth-aachen.de
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index 2e7826d..1c7c9cb 100644 (file)
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -2361,7 +2361,11 @@ static uint8_t combined_attrs_nofwb(uint64_t hcr,
 {
     uint8_t s1lo, s2lo, s1hi, s2hi, s2_mair_attrs, ret_attrs;
 
-    s2_mair_attrs = convert_stage2_attrs(hcr, s2.attrs);
+    if (s2.is_s2_format) {
+        s2_mair_attrs = convert_stage2_attrs(hcr, s2.attrs);
+    } else {
+        s2_mair_attrs = s2.attrs;
+    }
 
     s1lo = extract32(s1.attrs, 0, 4);
     s2lo = extract32(s2_mair_attrs, 0, 4);
@@ -2418,6 +2422,8 @@ static uint8_t force_cacheattr_nibble_wb(uint8_t attr)
  */
 static uint8_t combined_attrs_fwb(ARMCacheAttrs s1, ARMCacheAttrs s2)
 {
+    assert(s2.is_s2_format && !s1.is_s2_format);
+
     switch (s2.attrs) {
     case 7:
         /* Use stage 1 attributes */
@@ -2467,7 +2473,7 @@ static ARMCacheAttrs combine_cacheattrs(uint64_t hcr,
     ARMCacheAttrs ret;
     bool tagged = false;
 
-    assert(s2.is_s2_format && !s1.is_s2_format);
+    assert(!s1.is_s2_format);
     ret.is_s2_format = false;
 
     if (s1.attrs == 0xf0) {