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target/riscv/kvm.c: add multi-letter extension KVM properties 

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 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>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Message-Id: <20230706101738.460804-15-dbarboza@ventanamicro.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
This commit is contained in:
Daniel Henrique Barboza 2023-07-06 07:17:32 -03:00 committed by Alistair Francis
parent 7313fffb40
commit f7a69fa6e6
2 changed files with 127 additions and 0 deletions
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8
target/riscv/cpu.c
View File

@ -1860,6 +1860,14 @@ 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);
}

119
target/riscv/kvm.c
View File

@ -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, &reg);
if (ret != 0) {
if (errno == EINVAL) {
/* Silently default to 'false' if KVM does not support it. */
multi_ext_cfg->supported = false;
val = false;
} else {
error_report("Unable to read ISA_EXT KVM register %s, "
"error %d", multi_ext_cfg->name, ret);
kvm_riscv_destroy_scratch_vcpu(kvmcpu);
exit(EXIT_FAILURE);
}
} else {
multi_ext_cfg->supported = true;
}
kvm_cpu_cfg_set(cpu, multi_ext_cfg, val);
}
}
void kvm_riscv_init_user_properties(Object *cpu_obj)
{
RISCVCPU *cpu = RISCV_CPU(cpu_obj);
@ -542,6 +660,7 @@ void kvm_riscv_init_user_properties(Object *cpu_obj)
kvm_riscv_add_cpu_user_properties(cpu_obj);
kvm_riscv_init_machine_ids(cpu, &kvmcpu);
kvm_riscv_init_misa_ext_mask(cpu, &kvmcpu);
kvm_riscv_init_multiext_cfg(cpu, &kvmcpu);
kvm_riscv_destroy_scratch_vcpu(&kvmcpu);
}