> -----Original Message-----
> From: qemu-ppc-bounces+bharat.bhushan=freescale....@nongnu.org
> [mailto:qemu-ppc-
> bounces+bharat.bhushan=freescale....@nongnu.org] On Behalf Of Madhavan
> Srinivasan
> Sent: Sunday, June 15, 2014 2:38 AM
> To: ag...@suse.de; pau...@samba.org
> Cc: Madhavan Srinivasan; qemu-...@nongnu.org; qemu-devel@nongnu.org
> Subject: [Qemu-ppc] [PATCH] qemu/target-ppc: software breakpoint support
>
> This patch adds software breakpoint support for ppc. Patch
> allows to insert and remove sw breakpoints using Qemu
> gdbserver on ppc.
>
> Patch use "abs" instruction as sw breakpoint instruction.
> This instruction with primary opcode 31 and extended opcode 360
> has been dropped from PowerISA (in v2.01) and will generate an
> Emulation assistance interrupt in hypervisor when executed.
> KVM also has to be updated with this to make use of sw breakpoint.
There are already a patch "ppc debug: Add debug stub support" in review which
implements software breakpoint
In addition this patch also implements h/w breakpoints/watchpoints for BOOKE.
But I actually do not know how h/w breakpoints works on BOOK3S and you can help
me figuring out what can be shared between booke and book3s.
>
> Signed-off-by: Madhavan Srinivasan <ma...@linux.vnet.ibm.com>
> ---
> target-ppc/kvm.c | 38 +++++++++++++++++++++++++++++++++++---
> 1 file changed, 35 insertions(+), 3 deletions(-)
>
> diff --git a/target-ppc/kvm.c b/target-ppc/kvm.c
> index 9974b10..fa4b4ec 100644
> --- a/target-ppc/kvm.c
> +++ b/target-ppc/kvm.c
> @@ -1201,6 +1201,17 @@ static int kvmppc_handle_dcr_write(CPUPPCState *env,
> uint32_t dcrn, uint32_t dat
> return 0;
> }
>
> +static int kvmppc_handle_debug(CPUState *cs, struct kvm_debug_exit_arch
> *arch_info)
> +{
> + int ret = -1;
> +
> + if (kvm_find_sw_breakpoint(cs, arch_info->address)) {
> + ret = EXCP_DEBUG;
> + }
> +
> + return ret;
> +}
> +
> int kvm_arch_handle_exit(CPUState *cs, struct kvm_run *run)
> {
> PowerPCCPU *cpu = POWERPC_CPU(cs);
> @@ -1240,7 +1251,10 @@ int kvm_arch_handle_exit(CPUState *cs, struct kvm_run
> *run)
> watchdog_perform_action();
> ret = 0;
> break;
> -
> + case KVM_EXIT_DEBUG:
> + DPRINTF("handle debug exit pc = 0x%lx\n", run->debug.arch.address);
> + ret = kvmppc_handle_debug(cs, &run->debug.arch);
> + break;
> default:
> fprintf(stderr, "KVM: unknown exit reason %d\n", run->exit_reason);
> ret = -1;
> @@ -1901,14 +1915,29 @@ void kvm_arch_init_irq_routing(KVMState *s)
> {
> }
>
> +static const uint8_t dbg_int[] = { 0x7c, 0x00, 0x02, 0xd0};
This should not be hardcoded but we should get this from KVM. Please refer to
patch "ppc debug: Add debug stub support" to know how to get debug instruction.
Thanks
-Bharat
> int kvm_arch_insert_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint
> *bp)
> {
> - return -EINVAL;
> + if( cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn,
> sizeof(dbg_int), 0) ||
> + cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)dbg_int,
> sizeof(dbg_int),
> 1) ){
> + return -EINVAL;
> + }
> + return 0;
> }
>
> int kvm_arch_remove_sw_breakpoint(CPUState *cpu, struct kvm_sw_breakpoint
> *bp)
> {
> - return -EINVAL;
> + uint8_t tmp[4];
> +
> + if (cpu_memory_rw_debug(cpu, bp->pc, tmp, sizeof(dbg_int), 0)) {
> + return -EINVAL;
> + } else if (memcmp(tmp, dbg_int, sizeof(dbg_int))) {
> + return -EINVAL;
> + } else if (cpu_memory_rw_debug(cpu, bp->pc, (uint8_t *)&bp->saved_insn,
> sizeof(dbg_int), 1)) {
> + return -EINVAL;
> + }
> +
> + return 0;
> }
>
> int kvm_arch_insert_hw_breakpoint(target_ulong addr, target_ulong len, int
> type)
> @@ -1927,6 +1956,9 @@ void kvm_arch_remove_all_hw_breakpoints(void)
>
> void kvm_arch_update_guest_debug(CPUState *cpu, struct kvm_guest_debug *dbg)
> {
> + if (kvm_sw_breakpoints_active(cpu)) {
> + dbg->control |= KVM_GUESTDBG_USE_SW_BP;
> + }
> }
>
> struct kvm_get_htab_buf {
> --
> 1.8.3.1
>
