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Commit 11dd6ac0 authored by Laurent Vivier's avatar Laurent Vivier Committed by Paul Mackerras
Browse files

KVM: PPC: Book3S PR: Manage single-step mode 



Until now, when we connect gdb to the QEMU gdb-server, the
single-step mode is not managed.

This patch adds this, only for kvm-pr:

If KVM_GUESTDBG_SINGLESTEP is set, we enable single-step trace bit in the
MSR (MSR_SE) just before the __kvmppc_vcpu_run(), and disable it just after.
In kvmppc_handle_exit_pr, instead of routing the interrupt to
the guest, we return to host, with KVM_EXIT_DEBUG reason.

Signed-off-by: default avatarLaurent Vivier <lvivier@redhat.com>
Reviewed-by: default avatarDavid Gibson <david@gibson.dropbear.id.au>
Reviewed-by: default avatarThomas Huth <thuth@redhat.com>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 05b1159e

arch/powerpc/kvm/book3s_pr.c

+31 −1
Original line number Diff line number Diff line
@@ -882,6 +882,24 @@ void kvmppc_set_fscr(struct kvm_vcpu *vcpu, u64 fscr) 
}

#endif



static void kvmppc_setup_debug(struct kvm_vcpu *vcpu)

{

	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {

		u64 msr = kvmppc_get_msr(vcpu);



		kvmppc_set_msr(vcpu, msr | MSR_SE);

	}

}



static void kvmppc_clear_debug(struct kvm_vcpu *vcpu)

{

	if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {

		u64 msr = kvmppc_get_msr(vcpu);



		kvmppc_set_msr(vcpu, msr & ~MSR_SE);

	}

}



int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu,

			  unsigned int exit_nr)

{
@@ -1207,9 +1225,17 @@ int kvmppc_handle_exit_pr(struct kvm_run *run, struct kvm_vcpu *vcpu, 
		break;

#endif

	case BOOK3S_INTERRUPT_MACHINE_CHECK:

		kvmppc_book3s_queue_irqprio(vcpu, exit_nr);

		r = RESUME_GUEST;

		break;

	case BOOK3S_INTERRUPT_TRACE:

		if (vcpu->guest_debug & KVM_GUESTDBG_SINGLESTEP) {

			run->exit_reason = KVM_EXIT_DEBUG;

			r = RESUME_HOST;

		} else {

			kvmppc_book3s_queue_irqprio(vcpu, exit_nr);

			r = RESUME_GUEST;

		}

		break;

	default:

	{
@@ -1479,6 +1505,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) 
		goto out;

	}



	kvmppc_setup_debug(vcpu);



	/*

	 * Interrupts could be timers for the guest which we have to inject

	 * again, so let's postpone them until we're in the guest and if we
@@ -1501,6 +1529,8 @@ static int kvmppc_vcpu_run_pr(struct kvm_run *kvm_run, struct kvm_vcpu *vcpu) 


	ret = __kvmppc_vcpu_run(kvm_run, vcpu);



	kvmppc_clear_debug(vcpu);



	/* No need for kvm_guest_exit. It's done in handle_exit.

	   We also get here with interrupts enabled. */