target/arm: Implement FEAT_LVA

This feature is relatively small, as it applies only to
64k pages and thus requires no additional changes to the
table descriptor walking algorithm, only a change to the
minimum TSZ (which is the inverse of the maximum virtual
address space size).

Note that this feature widens VBAR_ELx, but we already
treat the register as being 64 bits wide.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220301215958.157011-10-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index 144dc491d95b2a2ece6ea663d06b90c88afe0f95..f3eabddfb5af4d73cb8d8e213d43f35e54f333d8 100644 (file)
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -27,6 +27,7 @@ the following architecture extensions:
 - FEAT_LRCPC (Load-acquire RCpc instructions)
 - FEAT_LRCPC2 (Load-acquire RCpc instructions v2)
 - FEAT_LSE (Large System Extensions)
+- FEAT_LVA (Large Virtual Address space)
 - FEAT_MTE (Memory Tagging Extension)
 - FEAT_MTE2 (Memory Tagging Extension)
 - FEAT_MTE3 (MTE Asymmetric Fault Handling)

diff --git a/target/arm/cpu-param.h b/target/arm/cpu-param.h
index 7f38d33b8eabc7ebf8ea31f0aa4fd5e41552a8c1..5f9c288b1a6b8cdd0c953e8a62f28ef2ca48e231 100644 (file)
--- a/target/arm/cpu-param.h
+++ b/target/arm/cpu-param.h
@@ -11,7 +11,7 @@
 #ifdef TARGET_AARCH64
 # define TARGET_LONG_BITS             64
 # define TARGET_PHYS_ADDR_SPACE_BITS  48
-# define TARGET_VIRT_ADDR_SPACE_BITS  48
+# define TARGET_VIRT_ADDR_SPACE_BITS  52
 #else
 # define TARGET_LONG_BITS             32
 # define TARGET_PHYS_ADDR_SPACE_BITS  40

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index c6a4d50e8219b6c0d09b1e5358bb40ea6d6c3c58..c52d56f66998e5ce32b33d3f21f61428b12d7036 100644 (file)
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -4289,6 +4289,11 @@ static inline bool isar_feature_aa64_ccidx(const ARMISARegisters *id)
     return FIELD_EX64(id->id_aa64mmfr2, ID_AA64MMFR2, CCIDX) != 0;
 }
 
+static inline bool isar_feature_aa64_lva(const ARMISARegisters *id)
+{
+    return FIELD_EX64(id->id_aa64mmfr2, ID_AA64MMFR2, VARANGE) != 0;
+}
+
 static inline bool isar_feature_aa64_tts2uxn(const ARMISARegisters *id)
 {
     return FIELD_EX64(id->id_aa64mmfr1, ID_AA64MMFR1, XNX) != 0;

diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 1171ab16b94ccd64626c1a7b2c21d0fffd36e01e..1de31ffb406dbc98da795e3e33da259baa920ad3 100644 (file)
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -811,6 +811,7 @@ static void aarch64_max_initfn(Object *obj)
     t = FIELD_DP64(t, ID_AA64MMFR2, UAO, 1);
     t = FIELD_DP64(t, ID_AA64MMFR2, CNP, 1); /* TTCNP */
     t = FIELD_DP64(t, ID_AA64MMFR2, ST, 1); /* TTST */
+    t = FIELD_DP64(t, ID_AA64MMFR2, VARANGE, 1); /* FEAT_LVA */
     cpu->isar.id_aa64mmfr2 = t;
 
     t = cpu->isar.id_aa64zfr0;

diff --git a/target/arm/helper.c b/target/arm/helper.c
index 2eff30d18c662dc3d24523e7a4933ef34dcdc2c1..28b43472131fdada940f32a790766c3a76e68426 100644 (file)
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11271,7 +11271,14 @@ ARMVAParameters aa64_va_parameters(CPUARMState *env, uint64_t va,
     } else {
         max_tsz = 39;
     }
-    min_tsz = 16;  /* TODO: ARMv8.2-LVA  */
+
+    min_tsz = 16;
+    if (using64k) {
+        if (cpu_isar_feature(aa64_lva, env_archcpu(env))) {
+            min_tsz = 12;
+        }
+    }
+    /* TODO: FEAT_LPA2 */
 
     if (tsz > max_tsz) {
         tsz = max_tsz;