[Qemu-devel] [PATCH] target-ppc: disable unsupported modes for SPR_CTRL/SPR_UCTRL

[Alexey Kardashevskiy]

The Figure 17 "SPR encodings" of the PowerISA 2.07 describes CTRL SPR as:

                       priviledged
#   spr5-9 spr0-4 name mtspr mfspr len cat
136 00100  01000  CTRL   -    no    32  S
152 00100  11000  CTRL  yes    -    32  S

According to this chart, the hypervisor's CTRL (#152) does not support
reading, the user-space's CTRL (UCTRL, #136) does not support writing.

This replaces unsupported operations with the default SPR_NOACCESS hook.

Signed-off-by: Alexey Kardashevskiy <address@hidden>
---

While we are on this topic, I thought it makes sense to fix this too.
This does not seem to affect anything in the current QEMU but it is more
correct/clean.


---
 target-ppc/translate_init.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/target-ppc/translate_init.c b/target-ppc/translate_init.c
index 93ad762..860e241 100644
--- a/target-ppc/translate_init.c
+++ b/target-ppc/translate_init.c
@@ -6737,11 +6737,11 @@ static void init_proc_970FX (CPUPPCState *env)
                  0x00000000);
     spr_register(env, SPR_CTRL, "SPR_CTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x00000000);
     spr_register(env, SPR_UCTRL, "SPR_UCTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x00000000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,
@@ -6902,11 +6902,11 @@ static void init_proc_power5plus(CPUPPCState *env)
                  0x00000000);
     spr_register(env, SPR_CTRL, "SPR_CTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x00000000);
     spr_register(env, SPR_UCTRL, "SPR_UCTRL",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x00000000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,
@@ -7002,11 +7002,11 @@ static void init_proc_POWER7 (CPUPPCState *env)
     /* XXX : not implemented */
     spr_register(env, SPR_CTRL, "SPR_CTRLT",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 SPR_NOACCESS, &spr_write_generic,
                  0x80800000);
     spr_register(env, SPR_UCTRL, "SPR_CTRLF",
                  SPR_NOACCESS, SPR_NOACCESS,
-                 &spr_read_generic, &spr_write_generic,
+                 &spr_read_generic, SPR_NOACCESS,
                  0x80800000);
     spr_register(env, SPR_VRSAVE, "SPR_VRSAVE",
                  &spr_read_generic, &spr_write_generic,
-- 
1.8.4.rc4