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authorAlex Bennée <alex.bennee@linaro.org>2015-12-17 13:37:15 +0000
committerPeter Maydell <peter.maydell@linaro.org>2015-12-17 13:37:15 +0000
commit34c45d53026d9c135415d034a8bc30c1a30acf1c (patch)
treea95e4d71c40efbe9be47465130fe61cb54b7c0b2 /target-arm
parente4482ab7e3849fb5e01ccacfc13f424cc6acb8d5 (diff)
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target-arm: kvm - re-inject guest debug exceptions
If we can't find details for the debug exception in our debug state then we can assume the exception is due to debugging inside the guest. To inject the exception into the guest state we re-use the TCG exception code (do_interrupt). However while guest debugging is in effect we currently can't handle the guest using single step as we will keep trapping to back to userspace. GDB makes heavy use of single-step behind the scenes which effectively means the guest's ability to debug itself is disabled while it is being debugged. Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 1449599553-24713-6-git-send-email-alex.bennee@linaro.org [PMM: Fixed a few typos in comments and commit message] Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'target-arm')
-rw-r--r--target-arm/helper-a64.c12
-rw-r--r--target-arm/kvm64.c24
2 files changed, 27 insertions, 9 deletions
diff --git a/target-arm/helper-a64.c b/target-arm/helper-a64.c
index deb8dbe..fc3ccdf 100644
--- a/target-arm/helper-a64.c
+++ b/target-arm/helper-a64.c
@@ -25,6 +25,7 @@
#include "qemu/bitops.h"
#include "internals.h"
#include "qemu/crc32c.h"
+#include "sysemu/kvm.h"
#include <zlib.h> /* For crc32 */
/* C2.4.7 Multiply and divide */
@@ -469,7 +470,8 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
new_el);
if (qemu_loglevel_mask(CPU_LOG_INT)
&& !excp_is_internal(cs->exception_index)) {
- qemu_log_mask(CPU_LOG_INT, "...with ESR 0x%" PRIx32 "\n",
+ qemu_log_mask(CPU_LOG_INT, "...with ESR %x/0x%" PRIx32 "\n",
+ env->exception.syndrome >> ARM_EL_EC_SHIFT,
env->exception.syndrome);
}
@@ -535,6 +537,12 @@ void aarch64_cpu_do_interrupt(CPUState *cs)
aarch64_restore_sp(env, new_el);
env->pc = addr;
- cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
+
+ qemu_log_mask(CPU_LOG_INT, "...to EL%d PC 0x%" PRIx64 " PSTATE 0x%x\n",
+ new_el, env->pc, pstate_read(env));
+
+ if (!kvm_enabled()) {
+ cs->interrupt_request |= CPU_INTERRUPT_EXITTB;
+ }
}
#endif
diff --git a/target-arm/kvm64.c b/target-arm/kvm64.c
index 771ecdb..bb9531f 100644
--- a/target-arm/kvm64.c
+++ b/target-arm/kvm64.c
@@ -871,6 +871,7 @@ bool kvm_arm_handle_debug(CPUState *cs, struct kvm_debug_exit_arch *debug_exit)
{
int hsr_ec = debug_exit->hsr >> ARM_EL_EC_SHIFT;
ARMCPU *cpu = ARM_CPU(cs);
+ CPUClass *cc = CPU_GET_CLASS(cs);
CPUARMState *env = &cpu->env;
/* Ensure PC is synchronised */
@@ -881,7 +882,14 @@ bool kvm_arm_handle_debug(CPUState *cs, struct kvm_debug_exit_arch *debug_exit)
if (cs->singlestep_enabled) {
return true;
} else {
- error_report("Came out of SINGLE STEP when not enabled");
+ /*
+ * The kernel should have suppressed the guest's ability to
+ * single step at this point so something has gone wrong.
+ */
+ error_report("%s: guest single-step while debugging unsupported"
+ " (%"PRIx64", %"PRIx32")\n",
+ __func__, env->pc, debug_exit->hsr);
+ return false;
}
break;
case EC_AA64_BKPT:
@@ -908,12 +916,14 @@ bool kvm_arm_handle_debug(CPUState *cs, struct kvm_debug_exit_arch *debug_exit)
__func__, debug_exit->hsr, env->pc);
}
- /* If we don't handle this it could be it really is for the
- guest to handle */
- qemu_log_mask(LOG_UNIMP,
- "%s: re-injecting exception not yet implemented"
- " (0x%"PRIx32", %"PRIx64")\n",
- __func__, hsr_ec, env->pc);
+ /* If we are not handling the debug exception it must belong to
+ * the guest. Let's re-use the existing TCG interrupt code to set
+ * everything up properly.
+ */
+ cs->exception_index = EXCP_BKPT;
+ env->exception.syndrome = debug_exit->hsr;
+ env->exception.vaddress = debug_exit->far;
+ cc->do_interrupt(cs);
return false;
}