target/riscv: move 'pmu-mask' and 'pmu-num' to riscv_cpu_properties[]

Every property in riscv_cpu_options[] will be migrated to
riscv_cpu_properties[]. This will make their default values init
earlier, allowing cpu_init() functions to overwrite them. We'll also
implement common getters and setters that both accelerators will use,
allowing them to share validations that TCG is doing.

At the same time, some options (namely 'vlen', 'elen' and the cache
blocksizes) need a way of tracking if the user set a value for them.
This is benign for TCG since the cost of always validating these values
are small, but for KVM we need syscalls to read the host values to make
the validations, thus knowing whether the user didn't touch the values
makes a difference.

We'll track user setting for these properties using a hash, like we do
in the TCG driver. All riscv cpu options will update this hash in case
the user sets it. The KVM driver will use this hash to minimize the
amount of syscalls done.

For now, both 'pmu-mask' and 'pmu-num' shouldn't be changed for vendor
CPUs. The existing setter for 'pmu-num' is changed to add this
restriction. New getters and setters are required for 'pmu-mask'

While we're at it, add a 'static' modifier to 'prop_pmu_num' since we're
not exporting it.

Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Tested-by: Vladimir Isaev <vladimir.isaev@syntacore.com>
Message-ID: <20240105230546.265053-4-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 84 insertions, 7 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 1718a21..1b11e90 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -58,6 +58,15 @@ bool riscv_cpu_is_32bit(RISCVCPU *cpu)
     return riscv_cpu_mxl(&cpu->env) == MXL_RV32;
 }
 
+/* Hash that stores general user set numeric options */
+static GHashTable *general_user_opts;
+
+static void cpu_option_add_user_setting(const char *optname, uint32_t value)
+{
+    g_hash_table_insert(general_user_opts, (gpointer)optname,
+                        GUINT_TO_POINTER(value));
+}
+
 #define ISA_EXT_DATA_ENTRY(_name, _min_ver, _prop) \
     {#_name, _min_ver, CPU_CFG_OFFSET(_prop)}
 
@@ -1268,11 +1277,15 @@ static void riscv_cpu_post_init(Object *obj)
 
 static void riscv_cpu_init(Object *obj)
 {
+    RISCVCPU *cpu = RISCV_CPU(obj);
+
 #ifndef CONFIG_USER_ONLY
     qdev_init_gpio_in(DEVICE(obj), riscv_cpu_set_irq,
                       IRQ_LOCAL_MAX + IRQ_LOCAL_GUEST_MAX);
 #endif /* CONFIG_USER_ONLY */
 
+    general_user_opts = g_hash_table_new(g_str_hash, g_str_equal);
+
     /*
      * The timer and performance counters extensions were supported
      * in QEMU before they were added as discrete extensions in the
@@ -1282,6 +1295,9 @@ static void riscv_cpu_init(Object *obj)
      */
     RISCV_CPU(obj)->cfg.ext_zicntr = true;
     RISCV_CPU(obj)->cfg.ext_zihpm = true;
+
+    /* Default values for non-bool cpu properties */
+    cpu->cfg.pmu_mask = MAKE_64BIT_MASK(3, 16);
 }
 
 typedef struct misa_ext_info {
@@ -1491,26 +1507,46 @@ const RISCVCPUMultiExtConfig riscv_cpu_deprecated_exts[] = {
     DEFINE_PROP_END_OF_LIST(),
 };
 
+static void cpu_set_prop_err(RISCVCPU *cpu, const char *propname,
+                             Error **errp)
+{
+    g_autofree char *cpuname = riscv_cpu_get_name(cpu);
+    error_setg(errp, "CPU '%s' does not allow changing the value of '%s'",
+               cpuname, propname);
+}
+
 static void prop_pmu_num_set(Object *obj, Visitor *v, const char *name,
                              void *opaque, Error **errp)
 {
     RISCVCPU *cpu = RISCV_CPU(obj);
-    uint8_t pmu_num;
+    uint8_t pmu_num, curr_pmu_num;
+    uint32_t pmu_mask;
 
     visit_type_uint8(v, name, &pmu_num, errp);
 
+    curr_pmu_num = ctpop32(cpu->cfg.pmu_mask);
+
+    if (pmu_num != curr_pmu_num && riscv_cpu_is_vendor(obj)) {
+        cpu_set_prop_err(cpu, name, errp);
+        error_append_hint(errp, "Current '%s' val: %u\n",
+                          name, curr_pmu_num);
+        return;
+    }
+
     if (pmu_num > (RV_MAX_MHPMCOUNTERS - 3)) {
         error_setg(errp, "Number of counters exceeds maximum available");
         return;
     }
 
     if (pmu_num == 0) {
-        cpu->cfg.pmu_mask = 0;
+        pmu_mask = 0;
     } else {
-        cpu->cfg.pmu_mask = MAKE_64BIT_MASK(3, pmu_num);
+        pmu_mask = MAKE_64BIT_MASK(3, pmu_num);
     }
 
     warn_report("\"pmu-num\" property is deprecated; use \"pmu-mask\"");
+    cpu->cfg.pmu_mask = pmu_mask;
+    cpu_option_add_user_setting("pmu-mask", pmu_mask);
 }
 
 static void prop_pmu_num_get(Object *obj, Visitor *v, const char *name,
@@ -1522,16 +1558,54 @@ static void prop_pmu_num_get(Object *obj, Visitor *v, const char *name,
     visit_type_uint8(v, name, &pmu_num, errp);
 }
 
-const PropertyInfo prop_pmu_num = {
+static const PropertyInfo prop_pmu_num = {
     .name = "pmu-num",
     .get = prop_pmu_num_get,
     .set = prop_pmu_num_set,
 };
 
-Property riscv_cpu_options[] = {
-    DEFINE_PROP_UINT32("pmu-mask", RISCVCPU, cfg.pmu_mask, MAKE_64BIT_MASK(3, 16)),
-    {.name = "pmu-num", .info = &prop_pmu_num}, /* Deprecated */
+static void prop_pmu_mask_set(Object *obj, Visitor *v, const char *name,
+                             void *opaque, Error **errp)
+{
+    RISCVCPU *cpu = RISCV_CPU(obj);
+    uint32_t value;
+    uint8_t pmu_num;
 
+    visit_type_uint32(v, name, &value, errp);
+
+    if (value != cpu->cfg.pmu_mask && riscv_cpu_is_vendor(obj)) {
+        cpu_set_prop_err(cpu, name, errp);
+        error_append_hint(errp, "Current '%s' val: %x\n",
+                          name, cpu->cfg.pmu_mask);
+        return;
+    }
+
+    pmu_num = ctpop32(value);
+
+    if (pmu_num > (RV_MAX_MHPMCOUNTERS - 3)) {
+        error_setg(errp, "Number of counters exceeds maximum available");
+        return;
+    }
+
+    cpu_option_add_user_setting(name, value);
+    cpu->cfg.pmu_mask = value;
+}
+
+static void prop_pmu_mask_get(Object *obj, Visitor *v, const char *name,
+                             void *opaque, Error **errp)
+{
+    uint8_t pmu_mask = RISCV_CPU(obj)->cfg.pmu_mask;
+
+    visit_type_uint8(v, name, &pmu_mask, errp);
+}
+
+static const PropertyInfo prop_pmu_mask = {
+    .name = "pmu-mask",
+    .get = prop_pmu_mask_get,
+    .set = prop_pmu_mask_set,
+};
+
+Property riscv_cpu_options[] = {
     DEFINE_PROP_BOOL("mmu", RISCVCPU, cfg.mmu, true),
     DEFINE_PROP_BOOL("pmp", RISCVCPU, cfg.pmp, true),
 
@@ -1618,6 +1692,9 @@ RISCVCPUProfile *riscv_profiles[] = {
 static Property riscv_cpu_properties[] = {
     DEFINE_PROP_BOOL("debug", RISCVCPU, cfg.debug, true),
 
+    {.name = "pmu-mask", .info = &prop_pmu_mask},
+    {.name = "pmu-num", .info = &prop_pmu_num}, /* Deprecated */
+
 #ifndef CONFIG_USER_ONLY
     DEFINE_PROP_UINT64("resetvec", RISCVCPU, env.resetvec, DEFAULT_RSTVEC),
 #endif