Re: [PATCH v5 2/2] target/arm/hvf: Sync CNTV_CTL_EL0 & CNTV_CVAL_EL0

[Zenghui Yu <zenghui.yu@linux.dev>]

Hi,

On 1/19/26 5:59 AM, Philippe Mathieu-Daudé wrote:
> Keep CNTV_CTL_EL0 and CNTV_CVAL_EL0 synchronized with the
> host hardware accelerator.
> 
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
>  target/arm/hvf/hvf.c | 25 +++++++++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/target/arm/hvf/hvf.c b/target/arm/hvf/hvf.c
> index fcb7fa3b30c..9ce720793d8 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)
> @@ -502,6 +505,7 @@ int hvf_arch_get_registers(CPUState *cpu)
>      uint64_t val;
>      hv_simd_fp_uchar16_t fpval;
>      int i, n;
> +    bool b;
>  
>      for (i = 0; i < ARRAY_SIZE(hvf_reg_match); i++) {
>          ret = hv_vcpu_get_reg(cpu->accel->fd, hvf_reg_match[i].reg, &val);
> @@ -631,6 +635,16 @@ int hvf_arch_get_registers(CPUState *cpu)
>  
>      aarch64_restore_sp(env, arm_current_el(env));
>  
> +    ret = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CVAL_EL0, &val);
> +    assert_hvf_ok(ret);
> +    b = hvf_sysreg_write_cp(cpu, "VTimer", SYSREG_CNTV_CVAL_EL0, val);
> +    assert(b);
> +
> +    ret = hv_vcpu_get_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CTL_EL0, &val);
> +    assert_hvf_ok(ret);
> +    b = hvf_sysreg_write_cp(cpu, "VTimer", SYSREG_CNTV_CTL_EL0, val);
> +    assert(b);
> +
>      return 0;
>  }
>  
> @@ -642,6 +656,7 @@ int hvf_arch_put_registers(CPUState *cpu)
>      uint64_t val;
>      hv_simd_fp_uchar16_t fpval;
>      int i, n;
> +    bool b;
>  
>      for (i = 0; i < ARRAY_SIZE(hvf_reg_match); i++) {
>          val = *(uint64_t *)((void *)env + hvf_reg_match[i].offset);
> @@ -756,6 +771,16 @@ int hvf_arch_put_registers(CPUState *cpu)
>      ret = hv_vcpu_set_vtimer_offset(cpu->accel->fd, hvf_state->vtimer_offset);
>      assert_hvf_ok(ret);
>  
> +    b = hvf_sysreg_read_cp(cpu, "VTimer", SYSREG_CNTV_CVAL_EL0, &val);
> +    assert(b);
> +    ret = hv_vcpu_set_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CVAL_EL0, val);
> +    assert_hvf_ok(ret);
> +
> +    b = hvf_sysreg_read_cp(cpu, "VTimer", SYSREG_CNTV_CTL_EL0, &val);
> +    assert(b);
> +    ret = hv_vcpu_set_sys_reg(cpu->accel->fd, HV_SYS_REG_CNTV_CTL_EL0, val);
> +    assert_hvf_ok(ret);
> +
>      return 0;
>  }

My Linux guest has been unable to start since this patch. I tested it on
M1 (macOS Tahoe 26.2). Not sure if this can be reproduced on your side.

Thanks,
Zenghui