[PATCH v4 10/12] target/riscv: Add kvm_riscv_get/put_regs_timer

[Yifei Jiang <jiangyifei@xxxxxxxxxx>]

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@xxxxxxxxxx>
Signed-off-by: Mingwang Li <limingwang@xxxxxxxxxx>
Reviewed-by: Anup Patel <anup.patel@xxxxxxx>
---
 target/riscv/cpu.h |  7 +++++
 target/riscv/kvm.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+)

diff --git a/target/riscv/cpu.h b/target/riscv/cpu.h
index 5f54fae7cc..9eceded96c 100644
--- a/target/riscv/cpu.h
+++ b/target/riscv/cpu.h
@@ -261,6 +261,13 @@ 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,
diff --git a/target/riscv/kvm.c b/target/riscv/kvm.c
index ded2a8c29d..b1f1d55f29 100644
--- a/target/riscv/kvm.c
+++ b/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)
 {
@@ -64,6 +65,9 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type, uint64_t idx
 #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)
@@ -84,6 +88,22 @@ static uint64_t kvm_riscv_reg_id(CPURISCVState *env, uint64_t type, uint64_t idx
         } \
     } 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;
@@ -235,6 +255,58 @@ 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
-- 
2.19.1