From 1addf57177a5646f86ede4eee385932b0214ab72 Mon Sep 17 00:00:00 2001
From: Ivan Klokov <ivan.klokov@syntacore.com>
Date: Thu, 9 Jan 2025 12:10:43 +0300
Subject: target/riscv: Add RISC-V CSR qtest support

The RISC-V architecture supports the creation of custom
CSR-mapped devices. It would be convenient to test them in the same way
as MMIO-mapped devices. To do this, a new call has been added
to read/write CSR registers.

Signed-off-by: Ivan Klokov <ivan.klokov@syntacore.com>
Acked-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
---
 hw/riscv/riscv_hart.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 55 insertions(+)

(limited to 'hw')

diff --git a/hw/riscv/riscv_hart.c b/hw/riscv/riscv_hart.c
index bc9ffdd..5d64271 100644
--- a/hw/riscv/riscv_hart.c
+++ b/hw/riscv/riscv_hart.c
@@ -22,6 +22,8 @@
 #include "qapi/error.h"
 #include "qemu/module.h"
 #include "system/reset.h"
+#include "system/qtest.h"
+#include "qemu/cutils.h"
 #include "hw/sysbus.h"
 #include "target/riscv/cpu.h"
 #include "hw/qdev-properties.h"
@@ -41,6 +43,55 @@ static void riscv_harts_cpu_reset(void *opaque)
     cpu_reset(CPU(cpu));
 }
 
+#ifndef CONFIG_USER_ONLY
+static void csr_call(char *cmd, uint64_t cpu_num, int csrno, uint64_t *val)
+{
+    RISCVCPU *cpu = RISCV_CPU(cpu_by_arch_id(cpu_num));
+    CPURISCVState *env = &cpu->env;
+
+    int ret = RISCV_EXCP_NONE;
+    if (strcmp(cmd, "get_csr") == 0) {
+        ret = riscv_csrr(env, csrno, (target_ulong *)val);
+    } else if (strcmp(cmd, "set_csr") == 0) {
+        ret = riscv_csrrw(env, csrno, NULL, *(target_ulong *)val,
+                MAKE_64BIT_MASK(0, TARGET_LONG_BITS));
+    }
+
+    g_assert(ret == RISCV_EXCP_NONE);
+}
+
+static bool csr_qtest_callback(CharBackend *chr, gchar **words)
+{
+    if (strcmp(words[0], "csr") == 0) {
+
+        uint64_t cpu;
+        uint64_t val;
+        int rc, csr;
+
+        rc = qemu_strtou64(words[2], NULL, 0, &cpu);
+        g_assert(rc == 0);
+        rc = qemu_strtoi(words[3], NULL, 0, &csr);
+        g_assert(rc == 0);
+        rc = qemu_strtou64(words[4], NULL, 0, &val);
+        g_assert(rc == 0);
+        csr_call(words[1], cpu, csr, &val);
+
+        qtest_send_prefix(chr);
+        qtest_sendf(chr, "OK 0 "TARGET_FMT_lx"\n", (target_ulong)val);
+
+        return true;
+    }
+
+    return false;
+}
+
+static void riscv_cpu_register_csr_qtest_callback(void)
+{
+    static GOnce once;
+    g_once(&once, (GThreadFunc)qtest_set_command_cb, csr_qtest_callback);
+}
+#endif
+
 static bool riscv_hart_realize(RISCVHartArrayState *s, int idx,
                                char *cpu_type, Error **errp)
 {
@@ -58,6 +109,10 @@ static void riscv_harts_realize(DeviceState *dev, Error **errp)
 
     s->harts = g_new0(RISCVCPU, s->num_harts);
 
+#ifndef CONFIG_USER_ONLY
+    riscv_cpu_register_csr_qtest_callback();
+#endif
+
     for (n = 0; n < s->num_harts; n++) {
         if (!riscv_hart_realize(s, n, s->cpu_type, errp)) {
             return;
-- 
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