target/arm: Define and use new regime_tcr_value() function

The regime_tcr() function returns a pointer to a struct TCR
corresponding to the TCR controlling a translation regime.  The
struct TCR has the raw value of the register, plus two fields mask
and base_mask which are used as a small optimization in the case of
32-bit short-descriptor lookups.  Almost all callers of regime_tcr()
only want the raw register value.  Define and use a new
regime_tcr_value() function which returns only the raw 64-bit
register value.

This is a preliminary to removing the 32-bit short descriptor
optimization -- it only saves a handful of bit operations, which is
tiny compared to the overhead of doing a page table walk at all, and
the TCR struct is awkward and makes fixing
https://gitlab.com/qemu-project/qemu/-/issues/1103 unnecessarily
difficult.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220714132303.1287193-2-peter.maydell@linaro.org

4 files changed, 14 insertions, 8 deletions

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 24c45a9..c245922 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -4216,7 +4216,7 @@ static int vae1_tlbmask(CPUARMState *env)
 static int tlbbits_for_regime(CPUARMState *env, ARMMMUIdx mmu_idx,
                               uint64_t addr)
 {
-    uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
+    uint64_t tcr = regime_tcr_value(env, mmu_idx);
     int tbi = aa64_va_parameter_tbi(tcr, mmu_idx);
     int select = extract64(addr, 55, 1);
 
@@ -10158,7 +10158,7 @@ static int aa64_va_parameter_tcma(uint64_t tcr, ARMMMUIdx mmu_idx)
 ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
                                    ARMMMUIdx mmu_idx, bool data)
 {
-    uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
+    uint64_t tcr = regime_tcr_value(env, mmu_idx);
     bool epd, hpd, using16k, using64k, tsz_oob, ds;
     int select, tsz, tbi, max_tsz, min_tsz, ps, sh;
     ARMCPU *cpu = env_archcpu(env);
@@ -10849,7 +10849,7 @@ static CPUARMTBFlags rebuild_hflags_a64(CPUARMState *env, int el, int fp_el,
 {
     CPUARMTBFlags flags = {};
     ARMMMUIdx stage1 = stage_1_mmu_idx(mmu_idx);
-    uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
+    uint64_t tcr = regime_tcr_value(env, mmu_idx);
     uint64_t sctlr;
     int tbii, tbid;
 
diff --git a/target/arm/internals.h b/target/arm/internals.h
index 00e2e71..fa04612 100644
--- a/target/arm/internals.h
+++ b/target/arm/internals.h
@@ -793,6 +793,12 @@ static inline TCR *regime_tcr(CPUARMState *env, ARMMMUIdx mmu_idx)
     return &env->cp15.tcr_el[regime_el(env, mmu_idx)];
 }
 
+/* Return the raw value of the TCR controlling this translation regime */
+static inline uint64_t regime_tcr_value(CPUARMState *env, ARMMMUIdx mmu_idx)
+{
+    return regime_tcr(env, mmu_idx)->raw_tcr;
+}
+
 /**
  * arm_num_brps: Return number of implemented breakpoints.
  * Note that the ID register BRPS field is "number of bps - 1",
diff --git a/target/arm/ptw.c b/target/arm/ptw.c
index e71fc1f..0d7e8ff 100644
--- a/target/arm/ptw.c
+++ b/target/arm/ptw.c
@@ -820,7 +820,7 @@ static int get_S1prot(CPUARMState *env, ARMMMUIdx mmu_idx, bool is_aa64,
 static ARMVAParameters aa32_va_parameters(CPUARMState *env, uint32_t va,
                                           ARMMMUIdx mmu_idx)
 {
-    uint64_t tcr = regime_tcr(env, mmu_idx)->raw_tcr;
+    uint64_t tcr = regime_tcr_value(env, mmu_idx);
     uint32_t el = regime_el(env, mmu_idx);
     int select, tsz;
     bool epd, hpd;
@@ -994,7 +994,7 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
     uint32_t attrs;
     int32_t stride;
     int addrsize, inputsize, outputsize;
-    TCR *tcr = regime_tcr(env, mmu_idx);
+    uint64_t tcr = regime_tcr_value(env, mmu_idx);
     int ap, ns, xn, pxn;
     uint32_t el = regime_el(env, mmu_idx);
     uint64_t descaddrmask;
@@ -1112,8 +1112,8 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
          * For stage 2 translations the starting level is specified by the
          * VTCR_EL2.SL0 field (whose interpretation depends on the page size)
          */
-        uint32_t sl0 = extract32(tcr->raw_tcr, 6, 2);
-        uint32_t sl2 = extract64(tcr->raw_tcr, 33, 1);
+        uint32_t sl0 = extract32(tcr, 6, 2);
+        uint32_t sl2 = extract64(tcr, 33, 1);
         uint32_t startlevel;
         bool ok;
 
diff --git a/target/arm/tlb_helper.c b/target/arm/tlb_helper.c
index 7d8a86b..a2f87a5 100644
--- a/target/arm/tlb_helper.c
+++ b/target/arm/tlb_helper.c
@@ -20,7 +20,7 @@ bool regime_using_lpae_format(CPUARMState *env, ARMMMUIdx mmu_idx)
         return true;
     }
     if (arm_feature(env, ARM_FEATURE_LPAE)
-        && (regime_tcr(env, mmu_idx)->raw_tcr & TTBCR_EAE)) {
+        && (regime_tcr_value(env, mmu_idx) & TTBCR_EAE)) {
         return true;
     }
     return false;