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authorDaniel Henrique Barboza <dbarboza@ventanamicro.com>2023-07-06 07:17:38 -0300
committerAlistair Francis <alistair.francis@wdc.com>2023-07-10 22:29:20 +1000
commitb9f822215ee58b57863bc082c322bb88529bd958 (patch)
tree8c5a4a1cd914da1a8b8b53816b4d4ca9339df401
parenta1be1d9a77a8170822258663e5fb0580f5252536 (diff)
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target/riscv/kvm.c: read/write (cbom|cboz)_blocksize in KVM
If we don't set a proper cbom_blocksize|cboz_blocksize in the FDT the Linux Kernel will fail to detect the availability of the CBOM/CBOZ extensions, regardless of the contents of the 'riscv,isa' DT prop. The FDT is being written using the cpu->cfg.cbom|z_blocksize attributes, so let's expose them as user properties like it is already done with TCG. This will also require us to determine proper blocksize values during init() time since the FDT is already created during realize(). We'll take a ride in kvm_riscv_init_multiext_cfg() to do it. Note that we don't need to fetch both cbom and cboz blocksizes every time: check for their parent extensions (icbom and icboz) and only read the blocksizes if needed. In contrast with cbom|z_blocksize properties from TCG, the user is not able to set any value that is different from the 'host' value when running KVM. KVM can be particularly harsh dealing with it: a ENOTSUPP can be thrown for the mere attempt of executing kvm_set_one_reg() for these 2 regs. Hopefully we don't need to call kvm_set_one_reg() for these regs. We'll check if the user input matches the host value in kvm_cpu_set_cbomz_blksize(), the set() accessor for both blocksize properties. We'll fail fast since it's already known to not be supported. Signed-off-by: Daniel Henrique Barboza <dbarboza@ventanamicro.com> Reviewed-by: Andrew Jones <ajones@ventanamicro.com> Acked-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20230706101738.460804-21-dbarboza@ventanamicro.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com>
-rw-r--r--target/riscv/kvm.c70
1 files changed, 70 insertions, 0 deletions
diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
index fd22ef4..9d8a898 100644
--- a/target/riscv/kvm.c
+++ b/target/riscv/kvm.c
@@ -276,6 +276,42 @@ static void kvm_cpu_set_multi_ext_cfg(Object *obj, Visitor *v,
kvm_cpu_cfg_set(cpu, multi_ext_cfg, value);
}
+static KVMCPUConfig kvm_cbom_blocksize = {
+ .name = "cbom_blocksize",
+ .offset = CPUCFG(cbom_blocksize),
+ .kvm_reg_id = KVM_REG_RISCV_CONFIG_REG(zicbom_block_size)
+};
+
+static KVMCPUConfig kvm_cboz_blocksize = {
+ .name = "cboz_blocksize",
+ .offset = CPUCFG(cboz_blocksize),
+ .kvm_reg_id = KVM_REG_RISCV_CONFIG_REG(zicboz_block_size)
+};
+
+static void kvm_cpu_set_cbomz_blksize(Object *obj, Visitor *v,
+ const char *name,
+ void *opaque, Error **errp)
+{
+ KVMCPUConfig *cbomz_cfg = opaque;
+ RISCVCPU *cpu = RISCV_CPU(obj);
+ uint16_t value, *host_val;
+
+ if (!visit_type_uint16(v, name, &value, errp)) {
+ return;
+ }
+
+ host_val = kvmconfig_get_cfg_addr(cpu, cbomz_cfg);
+
+ if (value != *host_val) {
+ error_report("Unable to set %s to a different value than "
+ "the host (%u)",
+ cbomz_cfg->name, *host_val);
+ exit(EXIT_FAILURE);
+ }
+
+ cbomz_cfg->user_set = true;
+}
+
static void kvm_riscv_update_cpu_cfg_isa_ext(RISCVCPU *cpu, CPUState *cs)
{
CPURISCVState *env = &cpu->env;
@@ -329,6 +365,14 @@ static void kvm_riscv_add_cpu_user_properties(Object *cpu_obj)
kvm_cpu_set_multi_ext_cfg,
NULL, multi_cfg);
}
+
+ object_property_add(cpu_obj, "cbom_blocksize", "uint16",
+ NULL, kvm_cpu_set_cbomz_blksize,
+ NULL, &kvm_cbom_blocksize);
+
+ object_property_add(cpu_obj, "cboz_blocksize", "uint16",
+ NULL, kvm_cpu_set_cbomz_blksize,
+ NULL, &kvm_cboz_blocksize);
}
static int kvm_riscv_get_regs_core(CPUState *cs)
@@ -644,6 +688,24 @@ static void kvm_riscv_init_misa_ext_mask(RISCVCPU *cpu,
env->misa_ext = env->misa_ext_mask;
}
+static void kvm_riscv_read_cbomz_blksize(RISCVCPU *cpu, KVMScratchCPU *kvmcpu,
+ KVMCPUConfig *cbomz_cfg)
+{
+ CPURISCVState *env = &cpu->env;
+ struct kvm_one_reg reg;
+ int ret;
+
+ reg.id = kvm_riscv_reg_id(env, KVM_REG_RISCV_CONFIG,
+ cbomz_cfg->kvm_reg_id);
+ reg.addr = (uint64_t)kvmconfig_get_cfg_addr(cpu, cbomz_cfg);
+ ret = ioctl(kvmcpu->cpufd, KVM_GET_ONE_REG, &reg);
+ if (ret != 0) {
+ error_report("Unable to read KVM reg %s, error %d",
+ cbomz_cfg->name, ret);
+ exit(EXIT_FAILURE);
+ }
+}
+
static void kvm_riscv_init_multiext_cfg(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
{
CPURISCVState *env = &cpu->env;
@@ -675,6 +737,14 @@ static void kvm_riscv_init_multiext_cfg(RISCVCPU *cpu, KVMScratchCPU *kvmcpu)
kvm_cpu_cfg_set(cpu, multi_ext_cfg, val);
}
+
+ if (cpu->cfg.ext_icbom) {
+ kvm_riscv_read_cbomz_blksize(cpu, kvmcpu, &kvm_cbom_blocksize);
+ }
+
+ if (cpu->cfg.ext_icboz) {
+ kvm_riscv_read_cbomz_blksize(cpu, kvmcpu, &kvm_cboz_blocksize);
+ }
}
void kvm_riscv_init_user_properties(Object *cpu_obj)