Re: [PATCH v4 23/23] accel/hvf: Sync CNTV_CTL_EL0 & CNTV_CVAL_EL0

[Akihiko Odaki]

On 2025/11/03 19:10, Philippe Mathieu-Daudé wrote:
Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  target/arm/hvf/hvf.c | 39 +++++++++++++++++++++++++++++++++++++++
  1 file changed, 39 insertions(+)
diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
index 268a0bcd8ea..60378075882 100644
--- a/target/arm/hvf/hvf.c
+++ b/target/arm/hvf/hvf.c
@@ -200,6 +200,9 @@ void hvf_arm_init_debug(void)
  #define SYSREG_PMCEID0_EL0    SYSREG(3, 3, 9, 12, 6)
  #define SYSREG_PMCEID1_EL0    SYSREG(3, 3, 9, 12, 7)
  #define SYSREG_PMCCNTR_EL0    SYSREG(3, 3, 9, 13, 0)
+
+#define SYSREG_CNTV_CTL_EL0   SYSREG(3, 3, 14, 3, 1)
+#define SYSREG_CNTV_CVAL_EL0  SYSREG(3, 3, 14, 3, 2)
  #define SYSREG_PMCCFILTR_EL0  SYSREG(3, 3, 14, 15, 7)
  
  #define SYSREG_ICC_AP0R0_EL1     SYSREG(3, 0, 12, 8, 4)
@@ -2017,13 +2020,49 @@ static int hvf_handle_vmexit(CPUState *cpu, 
hv_vcpu_exit_t *exit)
      return ret;
  }
  
+static void hvf_sync_vtimer_pre_exec(CPUState *cpu)
+{
+    hv_return_t r;
+    uint64_t val;
+    bool b;
+
+    b = hvf_sysreg_read_cp(cpu, "VTimer", SYSREG_CNTV_CVAL_EL0, &val);
+    assert(b);
+    r = hv_vcpu_set_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CVAL_EL0, val);
+    assert_hvf_ok(r);
+
+    b = hvf_sysreg_read_cp(cpu, "VTimer", SYSREG_CNTV_CTL_EL0, &val);
+    assert(b);
+    r = hv_vcpu_set_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CTL_EL0, val);
+    assert_hvf_ok(r);
+}
+
+static void hvf_sync_vtimer_post_exec(CPUState *cpu)
+{
+    hv_return_t r;
+    uint64_t val;
+    bool b;
+
+    r = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CVAL_EL0, &val);
+    assert_hvf_ok(r);
+    b = hvf_sysreg_write_cp(cpu, "VTimer", SYSREG_CNTV_CVAL_EL0, val);
+    assert(b);
+
+    r = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CTL_EL0, &val);
+    assert_hvf_ok(r);
+    b = hvf_sysreg_write_cp(cpu, "VTimer", SYSREG_CNTV_CTL_EL0, val);
+    assert(b);
+}
+
  void hvf_arch_cpu_synchronize_pre_exec(CPUState *cpu)
  {
+    hvf_sync_vtimer_pre_exec(cpu);

Perhaps this should be called from hvf_put_registers(). It will gate the 
logic behind the vcpu_dirty flag, and, after all, hvf_put_registers() is 
a function for setting registers like what hvf_sync_vtimer_pre_exec() sets.

      flush_cpu_state(cpu);
  }
  
  void hvf_arch_cpu_synchronize_post_exec(CPUState *cpu)
  {
+    hvf_sync_vtimer_post_exec(cpu);
  }
  
  int hvf_arch_vcpu_exec(CPUState *cpu)