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

[Richard Henderson]

On 11/22/23 02:15, Chao Du wrote:

Hi,

Kindly ping. :)

Thanks,
Chao

-----Original Messages-----From:"Chao Du" <duc...@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 <duc...@eswincomputing.com>

Correct: all handled by kvm_supports_guest_debug.

Reviewed-by: Richard Henderson <richard.hender...@linaro.org>


r~

---
  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