[RFC PATCH v6 0/2] Support RISC-V CSR read/write in Qtest environment

[RFC PATCH v6 0/2] Support RISC-V CSR read/write in Qtest environment

[Ivan Klokov]

These patches add functionality for unit testing RISC-V-specific registers.
The first patch adds a Qtest backend, and the second implements a simple test.

---
v6:
   - Refactor code and fix checkpatch errors.
---

Ivan Klokov (2):
  target/riscv: Add RISC-V CSR qtest support
  tests/qtest: QTest example for RISC-V CSR register

 hw/riscv/riscv_hart.c        | 55 +++++++++++++++++++++++++++++++++++
 tests/qtest/libqtest.c       | 27 +++++++++++++++++
 tests/qtest/libqtest.h       | 14 +++++++++
 tests/qtest/meson.build      |  2 +-
 tests/qtest/riscv-csr-test.c | 56 ++++++++++++++++++++++++++++++++++++
 5 files changed, 153 insertions(+), 1 deletion(-)
 create mode 100644 tests/qtest/riscv-csr-test.c

-- 
2.34.1

[RFC PATCH v6 1/2] target/riscv: Add RISC-V CSR qtest support

[Ivan Klokov]

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>
---
 hw/riscv/riscv_hart.c  | 55 ++++++++++++++++++++++++++++++++++++++++++
 tests/qtest/libqtest.c | 27 +++++++++++++++++++++
 tests/qtest/libqtest.h | 14 +++++++++++
 3 files changed, 96 insertions(+)

diff --git a/hw/riscv/riscv_hart.c b/hw/riscv/riscv_hart.c
index 613ea2aaa0..0b725ff9ce 100644
--- a/hw/riscv/riscv_hart.c
+++ b/hw/riscv/riscv_hart.c
@@ -21,6 +21,8 @@
 #include "qemu/osdep.h"
 #include "qapi/error.h"
 #include "qemu/module.h"
+#include "qemu/cutils.h"
+#include "sysemu/qtest.h"
 #include "sysemu/reset.h"
 #include "hw/sysbus.h"
 #include "target/riscv/cpu.h"
@@ -42,6 +44,55 @@ 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 %"PRIx64" "TARGET_FMT_lx"\n", res, (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)
 {
@@ -59,6 +110,10 @@ 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;
diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 817fd7aac5..43bfa496e9 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -1202,6 +1202,33 @@ uint64_t qtest_rtas_call(QTestState *s, const char *name,
     return 0;
 }
 
+static void qtest_rsp_csr(QTestState *s, uint64_t *val)
+{
+    gchar **args;
+    uint64_t ret;
+    int rc;
+
+    args = qtest_rsp_args(s, 3);
+
+    rc = qemu_strtou64(args[1], NULL, 16, &ret);
+    g_assert(rc == 0);
+    rc = qemu_strtou64(args[2], NULL, 16, val);
+    g_assert(rc == 0);
+
+    g_strfreev(args);
+}
+
+uint64_t qtest_csr_call(QTestState *s, const char *name,
+                         uint64_t cpu, int csr,
+                         uint64_t *val)
+{
+    qtest_sendf(s, "csr %s 0x%"PRIx64" %d 0x%"PRIx64"\n",
+                    name, cpu, csr, *val);
+
+    qtest_rsp_csr(s, val);
+    return 0;
+}
+
 void qtest_add_func(const char *str, void (*fn)(void))
 {
     gchar *path = g_strdup_printf("/%s/%s", qtest_get_arch(), str);
diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
index beb96b18eb..b516a16bd4 100644
--- a/tests/qtest/libqtest.h
+++ b/tests/qtest/libqtest.h
@@ -575,6 +575,20 @@ uint64_t qtest_rtas_call(QTestState *s, const char *name,
                          uint32_t nargs, uint64_t args,
                          uint32_t nret, uint64_t ret);
 
+/**
+ * qtest_csr_call:
+ * @s: #QTestState instance to operate on.
+ * @name: name of the command to call.
+ * @cpu: hart number.
+ * @csr: CSR number.
+ * @val: Value for reading/writing.
+ *
+ * Call an RISC-V CSR read/write function
+ */
+uint64_t qtest_csr_call(QTestState *s, const char *name,
+                         uint64_t cpu, int csr,
+                         unsigned long *val);
+
 /**
  * qtest_bufread:
  * @s: #QTestState instance to operate on.
-- 
2.34.1

[RFC PATCH v6 2/2] tests/qtest: QTest example for RISC-V CSR register

[Ivan Klokov]

Added demo for reading CSR register from qtest environment.

Signed-off-by: Ivan Klokov <ivan.klokov@syntacore.com>
---
 tests/qtest/meson.build      |  2 +-
 tests/qtest/riscv-csr-test.c | 56 ++++++++++++++++++++++++++++++++++++
 2 files changed, 57 insertions(+), 1 deletion(-)
 create mode 100644 tests/qtest/riscv-csr-test.c

diff --git a/tests/qtest/meson.build b/tests/qtest/meson.build
index aa93e98418..4ec5b0afbb 100644
--- a/tests/qtest/meson.build
+++ b/tests/qtest/meson.build
@@ -271,7 +271,7 @@ qtests_s390x = \
 qtests_riscv32 = \
   (config_all_devices.has_key('CONFIG_SIFIVE_E_AON') ? ['sifive-e-aon-watchdog-test'] : [])
 
-qtests_riscv64 = \
+qtests_riscv64 = ['riscv-csr-test'] + \
   (unpack_edk2_blobs ? ['bios-tables-test'] : [])
 
 qos_test_ss = ss.source_set()
diff --git a/tests/qtest/riscv-csr-test.c b/tests/qtest/riscv-csr-test.c
new file mode 100644
index 0000000000..ff5c29e6c6
--- /dev/null
+++ b/tests/qtest/riscv-csr-test.c
@@ -0,0 +1,56 @@
+/*
+ * QTest testcase for RISC-V CSRs
+ *
+ * Copyright (c) 2024 Syntacore.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest.h"
+
+#define CSR_MVENDORID       0xf11
+#define CSR_MISELECT        0x350
+
+static void run_test_csr(void)
+{
+    uint64_t res;
+    uint64_t val = 0;
+
+    QTestState *qts = qtest_init("-machine virt -cpu veyron-v1");
+
+    res = qtest_csr_call(qts, "get_csr", 0, CSR_MVENDORID, &val);
+
+    g_assert_cmpint(res, ==, 0);
+    g_assert_cmpint(val, ==, 0x61f);
+
+    val = 0xff;
+    res = qtest_csr_call(qts, "set_csr", 0, CSR_MISELECT, &val);
+
+    g_assert_cmpint(res, ==, 0);
+
+    val = 0;
+    res = qtest_csr_call(qts, "get_csr", 0, CSR_MISELECT, &val);
+
+    g_assert_cmpint(res, ==, 0);
+    g_assert_cmpint(val, ==, 0xff);
+
+    qtest_quit(qts);
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    qtest_add_func("/cpu/csr", run_test_csr);
+
+    return g_test_run();
+}
-- 
2.34.1

Re: [RFC PATCH v6 1/2] target/riscv: Add RISC-V CSR qtest support

[Fabiano Rosas]

Ivan Klokov <ivan.klokov@syntacore.com> writes:

> 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>
> ---
>  hw/riscv/riscv_hart.c  | 55 ++++++++++++++++++++++++++++++++++++++++++
>  tests/qtest/libqtest.c | 27 +++++++++++++++++++++
>  tests/qtest/libqtest.h | 14 +++++++++++
>  3 files changed, 96 insertions(+)
>
> diff --git a/hw/riscv/riscv_hart.c b/hw/riscv/riscv_hart.c
> index 613ea2aaa0..0b725ff9ce 100644
> --- a/hw/riscv/riscv_hart.c
> +++ b/hw/riscv/riscv_hart.c
> @@ -21,6 +21,8 @@
>  #include "qemu/osdep.h"
>  #include "qapi/error.h"
>  #include "qemu/module.h"
> +#include "qemu/cutils.h"
> +#include "sysemu/qtest.h"
>  #include "sysemu/reset.h"
>  #include "hw/sysbus.h"
>  #include "target/riscv/cpu.h"
> @@ -42,6 +44,55 @@ 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 %"PRIx64" "TARGET_FMT_lx"\n", res, (target_ulong)val);

../hw/riscv/riscv_hart.c: In function ‘csr_qtest_callback’:
../hw/riscv/riscv_hart.c:81:60: error: ‘res’ undeclared (first use in this function)
         qtest_sendf(chr, "OK %"PRIx64" "TARGET_FMT_lx"\n", res, (target_ulong)val);
                                                            ^~~
compilation terminated due to -Wfatal-errors.

I'll leave the rest of the review to the riscv people. Please when you
resend add a:

Acked-by: Fabiano Rosas <farosas@suse.de>

> +
> +        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)
>  {
> @@ -59,6 +110,10 @@ 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;
> diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
> index 817fd7aac5..43bfa496e9 100644
> --- a/tests/qtest/libqtest.c
> +++ b/tests/qtest/libqtest.c
> @@ -1202,6 +1202,33 @@ uint64_t qtest_rtas_call(QTestState *s, const char *name,
>      return 0;
>  }
>  
> +static void qtest_rsp_csr(QTestState *s, uint64_t *val)
> +{
> +    gchar **args;
> +    uint64_t ret;
> +    int rc;
> +
> +    args = qtest_rsp_args(s, 3);
> +
> +    rc = qemu_strtou64(args[1], NULL, 16, &ret);
> +    g_assert(rc == 0);
> +    rc = qemu_strtou64(args[2], NULL, 16, val);
> +    g_assert(rc == 0);
> +
> +    g_strfreev(args);
> +}
> +
> +uint64_t qtest_csr_call(QTestState *s, const char *name,
> +                         uint64_t cpu, int csr,
> +                         uint64_t *val)
> +{
> +    qtest_sendf(s, "csr %s 0x%"PRIx64" %d 0x%"PRIx64"\n",
> +                    name, cpu, csr, *val);
> +
> +    qtest_rsp_csr(s, val);
> +    return 0;
> +}
> +
>  void qtest_add_func(const char *str, void (*fn)(void))
>  {
>      gchar *path = g_strdup_printf("/%s/%s", qtest_get_arch(), str);
> diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
> index beb96b18eb..b516a16bd4 100644
> --- a/tests/qtest/libqtest.h
> +++ b/tests/qtest/libqtest.h
> @@ -575,6 +575,20 @@ uint64_t qtest_rtas_call(QTestState *s, const char *name,
>                           uint32_t nargs, uint64_t args,
>                           uint32_t nret, uint64_t ret);
>  
> +/**
> + * qtest_csr_call:
> + * @s: #QTestState instance to operate on.
> + * @name: name of the command to call.
> + * @cpu: hart number.
> + * @csr: CSR number.
> + * @val: Value for reading/writing.
> + *
> + * Call an RISC-V CSR read/write function
> + */
> +uint64_t qtest_csr_call(QTestState *s, const char *name,
> +                         uint64_t cpu, int csr,
> +                         unsigned long *val);
> +
>  /**
>   * qtest_bufread:
>   * @s: #QTestState instance to operate on.

Re: [RFC PATCH v6 2/2] tests/qtest: QTest example for RISC-V CSR register

[Fabiano Rosas]

Ivan Klokov <ivan.klokov@syntacore.com> writes:

> Added demo for reading CSR register from qtest environment.
>
> Signed-off-by: Ivan Klokov <ivan.klokov@syntacore.com>

You forgot to carry my reviewed-by. Please include it when you resend:

Reviewed-by: Fabiano Rosas <farosas@suse.de>