Let's add KVM user properties for the multi-letter extensions that KVM
currently supports: zicbom, zicboz, zihintpause, zbb, ssaia, sstc,
svinval and svpbmt.
As with MISA extensions, we're using the KVMCPUConfig type to hold
information about the state of each extension. However, multi-letter
extensions have more cases to cover than MISA extensions, so we're
adding an extra 'supported' flag as well. This flag will reflect if a
given extension is supported by KVM, i.e. KVM knows how to handle it.
This is determined during KVM extension discovery in
kvm_riscv_init_multiext_cfg(), where we test for EINVAL errors. Any
other error different from EINVAL will cause an abort.
The use of the 'user_set' is similar to what we already do with MISA
extensions: the flag set only if the user is changing the extension
state.
The 'supported' flag will be used later on to make an exception for
users that are disabling multi-letter extensions that are unknown to
KVM.
Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
---
target/riscv/cpu.c | 8 +++
target/riscv/kvm.c | 119 +++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 127 insertions(+)
diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index a9df61c9b4..f348424170 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -1778,6 +1778,14 @@ static void riscv_cpu_add_user_properties(Object *obj)
riscv_cpu_add_misa_properties(obj);
for (prop = riscv_cpu_extensions; prop && prop->name; prop++) {
+#ifndef CONFIG_USER_ONLY
+ if (kvm_enabled()) {
+ /* Check if KVM created the property already */
+ if (object_property_find(obj, prop->name)) {
+ continue;
+ }
+ }
+#endif
qdev_property_add_static(dev, prop);
}
diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
index 7afd6024e6..6ef81a6825 100644
--- a/target/riscv/kvm.c
+++ b/target/riscv/kvm.c
@@ -113,6 +113,7 @@ typedef struct KVMCPUConfig {
target_ulong offset;
int kvm_reg_id;
bool user_set;
+ bool supported;
} KVMCPUConfig;
#define KVM_MISA_CFG(_bit, _reg_id) \
@@ -197,6 +198,81 @@ static void kvm_riscv_update_cpu_misa_ext(RISCVCPU *cpu,
CPUState *cs)
}
}
+#define CPUCFG(_prop) offsetof(struct RISCVCPUConfig, _prop)
+
+#define KVM_EXT_CFG(_name, _prop, _reg_id) \
+ {.name = _name, .offset = CPUCFG(_prop), \
+ .kvm_reg_id = _reg_id}
+
+static KVMCPUConfig kvm_multi_ext_cfgs[] = {
+ KVM_EXT_CFG("zicbom", ext_icbom, KVM_RISCV_ISA_EXT_ZICBOM),
+ KVM_EXT_CFG("zicboz", ext_icboz, KVM_RISCV_ISA_EXT_ZICBOZ),
+ KVM_EXT_CFG("zihintpause", ext_zihintpause, KVM_RISCV_ISA_EXT_ZIHINTPAUSE),
+ KVM_EXT_CFG("zbb", ext_zbb, KVM_RISCV_ISA_EXT_ZBB),
+ KVM_EXT_CFG("ssaia", ext_ssaia, KVM_RISCV_ISA_EXT_SSAIA),
+ KVM_EXT_CFG("sstc", ext_sstc, KVM_RISCV_ISA_EXT_SSTC),
+ KVM_EXT_CFG("svinval", ext_svinval, KVM_RISCV_ISA_EXT_SVINVAL),
+ KVM_EXT_CFG("svpbmt", ext_svpbmt, KVM_RISCV_ISA_EXT_SVPBMT),
+};
+
+static void kvm_cpu_cfg_set(RISCVCPU *cpu, KVMCPUConfig *multi_ext,
+ uint32_t val)
+{
+ int cpu_cfg_offset = multi_ext->offset;
+ bool *ext_enabled = (void *)&cpu->cfg + cpu_cfg_offset;
+
+ *ext_enabled = val;
+}
+
+static uint32_t kvm_cpu_cfg_get(RISCVCPU *cpu,
+ KVMCPUConfig *multi_ext)
+{
+ int cpu_cfg_offset = multi_ext->offset;
+ bool *ext_enabled = (void *)&cpu->cfg + cpu_cfg_offset;
+
+ return *ext_enabled;
+}
+
+static void kvm_cpu_set_multi_ext_cfg(Object *obj, Visitor *v,
+ const char *name,
+ void *opaque, Error **errp)
+{
+ KVMCPUConfig *multi_ext_cfg = opaque;
+ RISCVCPU *cpu = RISCV_CPU(obj);
+ bool value, host_val;
+
+ if (!visit_type_bool(v, name, &value, errp)) {
+ return;
+ }
+
+ host_val = kvm_cpu_cfg_get(cpu, multi_ext_cfg);
+
+ /*
+ * Ignore if the user is setting the same value
+ * as the host.
+ */
+ if (value == host_val) {
+ return;
+ }
+
+ if (!multi_ext_cfg->supported) {
+ /*
+ * Error out if the user is trying to enable an
+ * extension that KVM doesn't support. Ignore
+ * option otherwise.
+ */
+ if (value) {
+ error_setg(errp, "KVM does not support disabling extension %s",
+ multi_ext_cfg->name);
+ }
+
+ return;
+ }
+
+ multi_ext_cfg->user_set = true;
+ kvm_cpu_cfg_set(cpu, multi_ext_cfg, value);
+}
+
static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
{
int i;
@@ -215,6 +291,15 @@ static void kvm_riscv_add_cpu_user_properties(Object
*cpu_obj)
object_property_set_description(cpu_obj, misa_cfg->name,
misa_cfg->description);
}
+
+ for (i = 0; i < ARRAY_SIZE(kvm_multi_ext_cfgs); i++) {
+ KVMCPUConfig *multi_cfg = &kvm_multi_ext_cfgs[i];
+
+ object_property_add(cpu_obj, multi_cfg->name, "bool",
+ NULL,
+ kvm_cpu_set_multi_ext_cfg,
+ NULL, multi_cfg);
+ }
}
static int kvm_riscv_get_regs_core(CPUState *cs)
@@ -530,6 +615,39 @@ static void kvm_riscv_init_misa_ext_mask(RISCVCPU *cpu,
env->misa_ext = env->misa_ext_mask;
}
+static void kvm_riscv_init_multiext_cfg(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
+{
+ CPURISCVState *env = &cpu->env;
+ uint64_t val;
+ int i, ret;
+
+ for (i = 0; i < ARRAY_SIZE(kvm_multi_ext_cfgs); i++) {
+ KVMCPUConfig *multi_ext_cfg = &kvm_multi_ext_cfgs[i];
+ struct kvm_one_reg reg;
+
+ reg.id = kvm_riscv_reg_id(env, KVM_REG_RISCV_ISA_EXT,
+ multi_ext_cfg->kvm_reg_id);
+ reg.addr = (uint64_t)&val;
+ ret = ioctl(kvmcpu->cpufd, KVM_GET_ONE_REG, ®);
+ if (ret != 0) {