target/arm: Implement FEAT_LPA

This feature widens physical addresses (and intermediate physical
addresses for 2-stage translation) from 48 to 52 bits, when using
64k pages.  The only thing left at this point is to handle the
extra bits in the TTBR and in the table descriptors.

Note that PAR_EL1 and HPFAR_EL2 are nominally extended, but we don't
mask out the high bits when writing to those registers, so no changes
are required there.

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20220301215958.157011-11-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 19 insertions, 5 deletions

diff --git a/docs/system/arm/emulation.rst b/docs/system/arm/emulation.rst
index f3eabdd..0053ddc 100644
--- a/docs/system/arm/emulation.rst
+++ b/docs/system/arm/emulation.rst
@@ -24,6 +24,7 @@ the following architecture extensions:
 - FEAT_I8MM (AArch64 Int8 matrix multiplication instructions)
 - FEAT_JSCVT (JavaScript conversion instructions)
 - FEAT_LOR (Limited ordering regions)
+- FEAT_LPA (Large Physical Address space)
 - FEAT_LRCPC (Load-acquire RCpc instructions)
 - FEAT_LRCPC2 (Load-acquire RCpc instructions v2)
 - FEAT_LSE (Large System Extensions)
diff --git a/target/arm/cpu-param.h b/target/arm/cpu-param.h
index 5f9c288..b59d505 100644
--- a/target/arm/cpu-param.h
+++ b/target/arm/cpu-param.h
@@ -10,7 +10,7 @@
 
 #ifdef TARGET_AARCH64
 # define TARGET_LONG_BITS             64
-# define TARGET_PHYS_ADDR_SPACE_BITS  48
+# define TARGET_PHYS_ADDR_SPACE_BITS  52
 # define TARGET_VIRT_ADDR_SPACE_BITS  52
 #else
 # define TARGET_LONG_BITS             32
diff --git a/target/arm/cpu64.c b/target/arm/cpu64.c
index 1de31ff..d88662c 100644
--- a/target/arm/cpu64.c
+++ b/target/arm/cpu64.c
@@ -795,7 +795,7 @@ static void aarch64_max_initfn(Object *obj)
     cpu->isar.id_aa64pfr1 = t;
 
     t = cpu->isar.id_aa64mmfr0;
-    t = FIELD_DP64(t, ID_AA64MMFR0, PARANGE, 5); /* PARange: 48 bits */
+    t = FIELD_DP64(t, ID_AA64MMFR0, PARANGE, 6); /* FEAT_LPA: 52 bits */
     cpu->isar.id_aa64mmfr0 = t;
 
     t = cpu->isar.id_aa64mmfr1;
diff --git a/target/arm/helper.c b/target/arm/helper.c
index 28b4347..950f565 100644
--- a/target/arm/helper.c
+++ b/target/arm/helper.c
@@ -11173,6 +11173,7 @@ static const uint8_t pamax_map[] = {
     [3] = 42,
     [4] = 44,
     [5] = 48,
+    [6] = 52,
 };
 
 /* The cpu-specific constant value of PAMax; also used by hw/arm/virt. */
@@ -11564,11 +11565,15 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
     descaddr = extract64(ttbr, 0, 48);
 
     /*
-     * If the base address is out of range, raise AddressSizeFault.
+     * For FEAT_LPA and PS=6, bits [51:48] of descaddr are in [5:2] of TTBR.
+     *
+     * Otherwise, if the base address is out of range, raise AddressSizeFault.
      * In the pseudocode, this is !IsZero(baseregister<47:outputsize>),
      * but we've just cleared the bits above 47, so simplify the test.
      */
-    if (descaddr >> outputsize) {
+    if (outputsize > 48) {
+        descaddr |= extract64(ttbr, 2, 4) << 48;
+    } else if (descaddr >> outputsize) {
         level = 0;
         fault_type = ARMFault_AddressSize;
         goto do_fault;
@@ -11620,7 +11625,15 @@ static bool get_phys_addr_lpae(CPUARMState *env, uint64_t address,
         }
 
         descaddr = descriptor & descaddrmask;
-        if (descaddr >> outputsize) {
+
+        /*
+         * For FEAT_LPA and PS=6, bits [51:48] of descaddr are in [15:12]
+         * of descriptor.  Otherwise, if descaddr is out of range, raise
+         * AddressSizeFault.
+         */
+        if (outputsize > 48) {
+            descaddr |= extract64(descriptor, 12, 4) << 48;
+        } else if (descaddr >> outputsize) {
             fault_type = ARMFault_AddressSize;
             goto do_fault;
         }