[PATCH v2 1/1] target/riscv/kvm: fix timebase-frequency when using KVM acceleration

[Yong-Xuan Wang]

The timebase-frequency of guest OS should be the same with host
machine. The timebase-frequency value in DTS should be got from
hypervisor when using KVM acceleration.

Reviewed-by: Andrew Jones <ajo...@ventanamicro.com>
Signed-off-by: Yong-Xuan Wang <yongxuan.w...@sifive.com>

---
Changelog
v2:
- update the function definition
- restructure if-else statement
---
 hw/riscv/virt.c              | 2 ++
 target/riscv/kvm/kvm-cpu.c   | 9 +++++++++
 target/riscv/kvm/kvm_riscv.h | 1 +
 3 files changed, 12 insertions(+)

diff --git a/hw/riscv/virt.c b/hw/riscv/virt.c
index a094af97c32a..533b17799581 100644
--- a/hw/riscv/virt.c
+++ b/hw/riscv/virt.c
@@ -711,6 +711,8 @@ static void create_fdt_sockets(RISCVVirtState *s, const 
MemMapEntry *memmap,
 
     qemu_fdt_add_subnode(ms->fdt, "/cpus");
     qemu_fdt_setprop_cell(ms->fdt, "/cpus", "timebase-frequency",
+                          kvm_enabled() ?
+                          kvm_riscv_get_timebase_frequency(first_cpu) :
                           RISCV_ACLINT_DEFAULT_TIMEBASE_FREQ);
     qemu_fdt_setprop_cell(ms->fdt, "/cpus", "#size-cells", 0x0);
     qemu_fdt_setprop_cell(ms->fdt, "/cpus", "#address-cells", 0x1);
diff --git a/target/riscv/kvm/kvm-cpu.c b/target/riscv/kvm/kvm-cpu.c
index c7afdb1e81b7..bbb115eaa867 100644
--- a/target/riscv/kvm/kvm-cpu.c
+++ b/target/riscv/kvm/kvm-cpu.c
@@ -739,6 +739,15 @@ static void kvm_riscv_put_regs_timer(CPUState *cs)
     env->kvm_timer_dirty = false;
 }
 
+uint64_t kvm_riscv_get_timebase_frequency(CPUState *cs)
+{
+    uint64_t reg;
+
+    KVM_RISCV_GET_TIMER(cs, frequency, reg);
+
+    return reg;
+}
+
 static int kvm_riscv_get_regs_vector(CPUState *cs)
 {
     RISCVCPU *cpu = RISCV_CPU(cs);
diff --git a/target/riscv/kvm/kvm_riscv.h b/target/riscv/kvm/kvm_riscv.h
index 4bd98fddc776..58518988681d 100644
--- a/target/riscv/kvm/kvm_riscv.h
+++ b/target/riscv/kvm/kvm_riscv.h
@@ -28,5 +28,6 @@ void kvm_riscv_aia_create(MachineState *machine, uint64_t 
group_shift,
 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);
+uint64_t kvm_riscv_get_timebase_frequency(CPUState *cs);
 
 #endif
-- 
2.17.1