target/riscv: Add kvm_riscv_get/put_regs_timer

Add kvm_riscv_get/put_regs_timer to synchronize virtual time context
from KVM.

To set register of RISCV_TIMER_REG(state) will occur a error from KVM
on kvm_timer_state == 0. It's better to adapt in KVM, but it doesn't matter
that adaping in QEMU.

Signed-off-by: Yifei Jiang <jiangyifei@huawei.com>
Signed-off-by: Mingwang Li <limingwang@huawei.com>
Reviewed-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20220112081329.1835-11-jiangyifei@huawei.com
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

target/riscv/cpu.h

@@ -273,6 +273,13 @@ struct CPURISCVState {
 
     hwaddr kernel_addr;
     hwaddr fdt_addr;
+
+    /* kvm timer */
+    bool kvm_timer_dirty;
+    uint64_t kvm_timer_time;
+    uint64_t kvm_timer_compare;
+    uint64_t kvm_timer_state;
+    uint64_t kvm_timer_frequency;
 };
 
 OBJECT_DECLARE_TYPE(RISCVCPU, RISCVCPUClass,

target/riscv/kvm.c

@@ -40,6 +40,7 @@
 #include "kvm_riscv.h"
 #include "sbi_ecall_interface.h"
 #include "chardev/char-fe.h"
+#include "migration/migration.h"
 
 static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
                                  uint64_t idx)
@@ -65,6 +66,9 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
 #define RISCV_CSR_REG(env, name)  kvm_riscv_reg_id(env, KVM_REG_RISCV_CSR, \
                  KVM_REG_RISCV_CSR_REG(name))
 
+#define RISCV_TIMER_REG(env, name)  kvm_riscv_reg_id(env, KVM_REG_RISCV_TIMER, \
+                 KVM_REG_RISCV_TIMER_REG(name))
+
 #define RISCV_FP_F_REG(env, idx)  kvm_riscv_reg_id(env, KVM_REG_RISCV_FP_F, idx)
 
 #define RISCV_FP_D_REG(env, idx)  kvm_riscv_reg_id(env, KVM_REG_RISCV_FP_D, idx)
@@ -85,6 +89,22 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type,
         } \
     } while (0)
 
+#define KVM_RISCV_GET_TIMER(cs, env, name, reg) \
+    do { \
+        int ret = kvm_get_one_reg(cs, RISCV_TIMER_REG(env, name), &reg); \
+        if (ret) { \
+            abort(); \
+        } \
+    } while (0)
+
+#define KVM_RISCV_SET_TIMER(cs, env, name, reg) \
+    do { \
+        int ret = kvm_set_one_reg(cs, RISCV_TIMER_REG(env, time), &reg); \
+        if (ret) { \
+            abort(); \
+        } \
+    } while (0)
+
 static int kvm_riscv_get_regs_core(CPUState *cs)
 {
     int ret = 0;
@@ -236,6 +256,58 @@ static int kvm_riscv_put_regs_fp(CPUState *cs)
     return ret;
 }
 
+static void kvm_riscv_get_regs_timer(CPUState *cs)
+{
+    CPURISCVState *env = &RISCV_CPU(cs)->env;
+
+    if (env->kvm_timer_dirty) {
+        return;
+    }
+
+    KVM_RISCV_GET_TIMER(cs, env, time, env->kvm_timer_time);
+    KVM_RISCV_GET_TIMER(cs, env, compare, env->kvm_timer_compare);
+    KVM_RISCV_GET_TIMER(cs, env, state, env->kvm_timer_state);
+    KVM_RISCV_GET_TIMER(cs, env, frequency, env->kvm_timer_frequency);
+
+    env->kvm_timer_dirty = true;
+}
+
+static void kvm_riscv_put_regs_timer(CPUState *cs)
+{
+    uint64_t reg;
+    CPURISCVState *env = &RISCV_CPU(cs)->env;
+
+    if (!env->kvm_timer_dirty) {
+        return;
+    }
+
+    KVM_RISCV_SET_TIMER(cs, env, time, env->kvm_timer_time);
+    KVM_RISCV_SET_TIMER(cs, env, compare, env->kvm_timer_compare);
+
+    /*
+     * To set register of RISCV_TIMER_REG(state) will occur a error from KVM
+     * on env->kvm_timer_state == 0, It's better to adapt in KVM, but it
+     * doesn't matter that adaping in QEMU now.
+     * TODO If KVM changes, adapt here.
+     */
+    if (env->kvm_timer_state) {
+        KVM_RISCV_SET_TIMER(cs, env, state, env->kvm_timer_state);
+    }
+
+    /*
+     * For now, migration will not work between Hosts with different timer
+     * frequency. Therefore, we should check whether they are the same here
+     * during the migration.
+     */
+    if (migration_is_running(migrate_get_current()->state)) {
+        KVM_RISCV_GET_TIMER(cs, env, frequency, reg);
+        if (reg != env->kvm_timer_frequency) {
+            error_report("Dst Hosts timer frequency != Src Hosts");
+        }
+    }
+
+    env->kvm_timer_dirty = false;
+}
 
 const KVMCapabilityInfo kvm_arch_required_capabilities[] = {
     KVM_CAP_LAST_INFO