target/ppc: Eliminate htab_base and htab_mask variables

CPUPPCState includes fields htab_base and htab_mask which store the base
address (GPA) and size (as a mask) of the guest's hashed page table (HPT).
These are set when the SDR1 register is updated.

Keeping these in sync with the SDR1 is actually a little bit fiddly, and
probably not useful for performance, since keeping them expands the size of
CPUPPCState.  It also makes some upcoming changes harder to implement.

This patch removes these fields, in favour of calculating them directly
from the SDR1 contents when necessary.

This does make a change to the behaviour of attempting to write a bad value
(invalid HPT size) to the SDR1 with an mtspr instruction.  Previously, the
bad value would be stored in SDR1 and could be retrieved with a later
mfspr, but the HPT size as used by the softmmu would be, clamped to the
allowed values.  Now, writing a bad value is treated as a no-op.  An error
message is printed in both new and old versions.

I'm not sure which behaviour, if either, matches real hardware.  I don't
think it matters that much, since it's pretty clear that if an OS writes
a bad value to SDR1, it's not going to boot.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru>

1 files changed, 0 insertions, 11 deletions

diff --git a/target/ppc/cpu.h b/target/ppc/cpu.h
index 051298b40f..aaf79f52b9 100644
--- a/target/ppc/cpu.h
+++ b/target/ppc/cpu.h
@@ -306,14 +306,6 @@ union ppc_tlb_t {
 #define TLB_MAS                3
 #endif
 
-#define SDR_32_HTABORG         0xFFFF0000UL
-#define SDR_32_HTABMASK        0x000001FFUL
-
-#if defined(TARGET_PPC64)
-#define SDR_64_HTABORG         0xFFFFFFFFFFFC0000ULL
-#define SDR_64_HTABSIZE        0x000000000000001FULL
-#endif /* defined(TARGET_PPC64 */
-
 typedef struct ppc_slb_t ppc_slb_t;
 struct ppc_slb_t {
     uint64_t esid;
@@ -1006,9 +998,6 @@ struct CPUPPCState {
     /* tcg TLB needs flush (deferred slb inval instruction typically) */
 #endif
     /* segment registers */
-    hwaddr htab_base;
-    /* mask used to normalize hash value to PTEG index */
-    hwaddr htab_mask;
     target_ulong sr[32];
     /* externally stored hash table */
     uint8_t *external_htab;