[PATCH v4 1/2] target/riscv: use misa_mxl_max to populate isa string rather than TARGET_LONG_BITS

[Conor Dooley]

From: Conor Dooley <conor.dooley@microchip.com>

A cpu may not have the same xlen as the compile time target, and
misa_mxl_max is the source of truth for what the hart supports.

The conversion from misa_mxl_max to xlen already has one user, so
introduce a helper and use that to populate the isa string.

Link: https://lore.kernel.org/qemu-riscv/20240108-efa3f83dcd3997dc0af458d7@orel/
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
I dropped the tags since I added the helper
---
 target/riscv/cpu.c     | 9 ++++++++-
 target/riscv/cpu.h     | 1 +
 target/riscv/gdbstub.c | 2 +-
 3 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index ad1df2318b..4aa4b2e988 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -307,6 +307,11 @@ void riscv_cpu_set_misa(CPURISCVState *env, RISCVMXL mxl, 
uint32_t ext)
     env->misa_ext_mask = env->misa_ext = ext;
 }
 
+int riscv_cpu_max_xlen(CPURISCVState env)
+{
+    return 16 << env.misa_mxl_max;
+}
+
 #ifndef CONFIG_USER_ONLY
 static uint8_t satp_mode_from_str(const char *satp_mode_str)
 {
@@ -2332,7 +2337,9 @@ char *riscv_isa_string(RISCVCPU *cpu)
     int i;
     const size_t maxlen = sizeof("rv128") + sizeof(riscv_single_letter_exts);
     char *isa_str = g_new(char, maxlen);
-    char *p = isa_str + snprintf(isa_str, maxlen, "rv%d", TARGET_LONG_BITS);
+    int xlen = riscv_cpu_max_xlen(cpu->env);
+    char *p = isa_str + snprintf(isa_str, maxlen, "rv%d", xlen);
+
     for (i = 0; i < sizeof(riscv_single_letter_exts) - 1; i++) {
         if (cpu->env.misa_ext & RV(riscv_single_letter_exts[i])) {
             *p++ = qemu_tolower(riscv_single_letter_exts[i]);
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 05e83c4ac9..aacc031397 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -511,6 +511,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int 
size,
                         MMUAccessType access_type, int mmu_idx,
                         bool probe, uintptr_t retaddr);
 char *riscv_isa_string(RISCVCPU *cpu);
+int riscv_cpu_max_xlen(CPURISCVState env);
 bool riscv_cpu_option_set(const char *optname);
 
 #define cpu_mmu_index riscv_cpu_mmu_index
diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
index 58b3ace0fe..f15980fdcf 100644
--- a/target/riscv/gdbstub.c
+++ b/target/riscv/gdbstub.c
@@ -218,7 +218,7 @@ static int riscv_gen_dynamic_csr_xml(CPUState *cs, int 
base_reg)
     CPURISCVState *env = &cpu->env;
     GString *s = g_string_new(NULL);
     riscv_csr_predicate_fn predicate;
-    int bitsize = 16 << env->misa_mxl_max;
+    int bitsize = riscv_cpu_max_xlen(*env);
     int i;
 
 #if !defined(CONFIG_USER_ONLY)
-- 
2.43.0