[PATCH v5 4/6] target-arm: kvm - support for single step
Peter Maydell
peter.maydell at linaro.org
Thu Jun 4 03:59:17 PDT 2015
On 29 May 2015 at 16:19, Alex Bennée <alex.bennee at linaro.org> wrote:
> This adds support for single-step. There isn't much to do on the QEMU
> side as after we set-up the request for single step via the debug ioctl
> it is all handled within the kernel.
>
> Signed-off-by: Alex Bennée <alex.bennee at linaro.org>
>
> ---
> v2
> - convert to using HSR_EC
> v3
> - use internals.h definitions
> ---
> target-arm/kvm.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/target-arm/kvm.c b/target-arm/kvm.c
> index c3bad6f..de2865a 100644
> --- a/target-arm/kvm.c
> +++ b/target-arm/kvm.c
> @@ -528,6 +528,13 @@ static int kvm_handle_debug(CPUState *cs, struct kvm_run *run)
> kvm_cpu_synchronize_state(cs);
>
> switch (hsr_ec) {
> + case EC_SOFTWARESTEP:
> + if (cs->singlestep_enabled) {
> + return true;
> + } else {
> + error_report("Came out of SINGLE STEP when not enabled");
All-caps there is a bit odd.
> + }
> + break;
> case EC_AA64_BKPT:
> if (kvm_find_sw_breakpoint(cs, env->pc)) {
> return true;
> @@ -588,6 +595,9 @@ int kvm_arch_on_sigbus(int code, void *addr)
>
> void kvm_arch_update_guest_debug(CPUState *cs, struct kvm_guest_debug *dbg)
> {
> + if (cs->singlestep_enabled) {
> + dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_SINGLESTEP;
> + }
> if (kvm_sw_breakpoints_active(cs)) {
> dbg->control |= KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_USE_SW_BP;
> }
Again, is there a guard somewhere to prevent us trying to enable
singlestep if the kernel doesn't support it?
-- PMM
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