4 files changed, 72 insertions, 5 deletions

diff --git a/target/riscv/cpu.c b/target/riscv/cpu.c
index 1d4b2b1544..3703efe702 100644
--- a/target/riscv/cpu.c
+++ b/target/riscv/cpu.c
@@ -68,6 +68,11 @@ static void cpu_option_add_user_setting(const char *optname, uint32_t value)
                         GUINT_TO_POINTER(value));
 }
 
+bool riscv_cpu_option_set(const char *optname)
+{
+    return g_hash_table_contains(general_user_opts, optname);
+}
+
 #define ISA_EXT_DATA_ENTRY(_name, _min_ver, _prop) \
     {#_name, _min_ver, CPU_CFG_OFFSET(_prop)}
 
@@ -1114,17 +1119,18 @@ void riscv_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
     }
 #endif
 
-    /*
-     * KVM accel does not have a specialized finalize()
-     * callback because its extensions are validated
-     * in the get()/set() callbacks of each property.
-     */
     if (tcg_enabled()) {
         riscv_tcg_cpu_finalize_features(cpu, &local_err);
         if (local_err != NULL) {
             error_propagate(errp, local_err);
             return;
         }
+    } else if (kvm_enabled()) {
+        riscv_kvm_cpu_finalize_features(cpu, &local_err);
+        if (local_err != NULL) {
+            error_propagate(errp, local_err);
+            return;
+        }
     }
 }
 
diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 2a5e67c141..3e342a5ae5 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -510,6 +510,7 @@ bool riscv_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
                         MMUAccessType access_type, int mmu_idx,
                         bool probe, uintptr_t retaddr);
 char *riscv_isa_string(RISCVCPU *cpu);
+bool riscv_cpu_option_set(const char *optname);
 
 #ifndef CONFIG_USER_ONLY
 void riscv_cpu_do_transaction_failed(CPUState *cs, hwaddr physaddr,
diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index 680a729cd8..dc0466df69 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -1598,6 +1598,65 @@ static bool kvm_cpu_realize(CPUState *cs, Error **errp)
    return true;
 }
 
+void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp)
+{
+    CPURISCVState *env = &cpu->env;
+    KVMScratchCPU kvmcpu;
+    struct kvm_one_reg reg;
+    uint64_t val;
+    int ret;
+
+    /* short-circuit without spinning the scratch CPU */
+    if (!cpu->cfg.ext_zicbom && !cpu->cfg.ext_zicboz) {
+        return;
+    }
+
+    if (!kvm_riscv_create_scratch_vcpu(&kvmcpu)) {
+        error_setg(errp, "Unable to create scratch KVM cpu");
+        return;
+    }
+
+    if (cpu->cfg.ext_zicbom &&
+        riscv_cpu_option_set(kvm_cbom_blocksize.name)) {
+
+        reg.id = kvm_riscv_reg_id_ulong(env, KVM_REG_RISCV_CONFIG,
+                                        kvm_cbom_blocksize.kvm_reg_id);
+        reg.addr = (uint64_t)&val;
+        ret = ioctl(kvmcpu.cpufd, KVM_GET_ONE_REG, &reg);
+        if (ret != 0) {
+            error_setg(errp, "Unable to read cbom_blocksize, error %d", errno);
+            return;
+        }
+
+        if (cpu->cfg.cbom_blocksize != val) {
+            error_setg(errp, "Unable to set cbom_blocksize to a different "
+                       "value than the host (%lu)", val);
+            return;
+        }
+    }
+
+    if (cpu->cfg.ext_zicboz &&
+        riscv_cpu_option_set(kvm_cboz_blocksize.name)) {
+
+        reg.id = kvm_riscv_reg_id_ulong(env, KVM_REG_RISCV_CONFIG,
+                                        kvm_cboz_blocksize.kvm_reg_id);
+        reg.addr = (uint64_t)&val;
+        ret = ioctl(kvmcpu.cpufd, KVM_GET_ONE_REG, &reg);
+        if (ret != 0) {
+            error_setg(errp, "Unable to read cboz_blocksize, error %d", errno);
+            return;
+        }
+
+        if (cpu->cfg.cboz_blocksize != val) {
+            error_setg(errp, "Unable to set cboz_blocksize to a different "
+                       "value than the host (%lu)", val);
+            return;
+        }
+    }
+
+    kvm_riscv_destroy_scratch_vcpu(&kvmcpu);
+}
+
 static void kvm_cpu_accel_class_init(ObjectClass *oc, void *data)
 {
     AccelCPUClass *acc = ACCEL_CPU_CLASS(oc);
diff --git a/target/riscv/kvm/kvm_riscv.h b/target/riscv/kvm/kvm_riscv.h
index 8329cfab82..4bd98fddc7 100644
--- a/target/riscv/kvm/kvm_riscv.h
+++ b/target/riscv/kvm/kvm_riscv.h
@@ -27,5 +27,6 @@ void kvm_riscv_aia_create(MachineState *machine, uint64_t group_shift,
                           uint64_t guest_num);
 void riscv_kvm_aplic_request(void *opaque, int irq, int level);
 int kvm_riscv_sync_mpstate_to_kvm(RISCVCPU *cpu, int state);
+void riscv_kvm_cpu_finalize_features(RISCVCPU *cpu, Error **errp);
 
 #endif