Re: [PATCH] target/arm: kvm64: remove a redundant KVM_CAP_SET_GUEST_DEBUG probe

["Chao Du" <duchao@eswincomputing.com>]

Hi,

Kindly ping. :)

Thanks,
Chao


> -----Original Messages-----From:"Chao Du" <duchao@eswincomputing.com>Sent Time:2023-10-25 15:07:26 (Wednesday)To:qemu-devel@nongnu.org, qemu-arm@nongnu.orgCc:Subject:[PATCH] target/arm: kvm64: remove a redundant KVM_CAP_SET_GUEST_DEBUG probe
> 
> The KVM_CAP_SET_GUEST_DEBUG is probed during kvm_init().
> gdbserver will fail to start if the CAP is not supported.
> So no need to make another probe here, like other targets.
> 
> Signed-off-by: Chao Du <duchao@eswincomputing.com>
> ---
>  target/arm/kvm64.c | 28 +++++++---------------------
>  1 file changed, 7 insertions(+), 21 deletions(-)
> 
> diff --git a/target/arm/kvm64.c b/target/arm/kvm64.c
> index 4bb68646e4..b0bf59b5a1 100644
> --- a/target/arm/kvm64.c
> +++ b/target/arm/kvm64.c
> @@ -31,13 +31,9 @@
>  #include "hw/acpi/acpi.h"
>  #include "hw/acpi/ghes.h"
>  
> -static bool have_guest_debug;
>  
>  void kvm_arm_init_debug(KVMState *s)
>  {
> -    have_guest_debug = kvm_check_extension(s,
> -                                           KVM_CAP_SET_GUEST_DEBUG);
> -
>      max_hw_wps = kvm_check_extension(s, KVM_CAP_GUEST_DEBUG_HW_WPS);
>      hw_watchpoints = g_array_sized_new(true, true,
>                                         sizeof(HWWatchpoint), max_hw_wps);
> @@ -1140,33 +1136,23 @@ static const uint32_t brk_insn = 0xd4200000;
>  
>  int kvm_arch_insert_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
>  {
> -    if (have_guest_debug) {
> -        if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 0) ||
> -            cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk_insn, 4, 1)) {
> -            return -EINVAL;
> -        }
> -        return 0;
> -    } else {
> -        error_report("guest debug not supported on this kernel");
> +    if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 0) ||
> +        cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk_insn, 4, 1)) {
>          return -EINVAL;
>      }
> +    return 0;
>  }
>  
>  int kvm_arch_remove_sw_breakpoint(CPUState *cs, struct kvm_sw_breakpoint *bp)
>  {
>      static uint32_t brk;
>  
> -    if (have_guest_debug) {
> -        if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk, 4, 0) ||
> -            brk != brk_insn ||
> -            cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 1)) {
> -            return -EINVAL;
> -        }
> -        return 0;
> -    } else {
> -        error_report("guest debug not supported on this kernel");
> +    if (cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&brk, 4, 0) ||
> +        brk != brk_insn ||
> +        cpu_memory_rw_debug(cs, bp->pc, (uint8_t *)&bp->saved_insn, 4, 1)) {
>          return -EINVAL;
>      }
> +    return 0;
>  }
>  
>  /* See v8 ARM ARM D7.2.27 ESR_ELx, Exception Syndrome Register
> -- 
> 2.17.1