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

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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: Laurent Vivier <lvivier@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
This commit is contained in:
Laurent Vivier 2016-04-08 18:05:00 +02:00 committed by Paul Mackerras
parent 05b1159e64
commit 11dd6ac025
1 changed files with 31 additions and 1 deletions
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32
arch/powerpc/kvm/book3s_pr.c
View File

@ -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)
{
@ -1207,10 +1225,18 @@ program_interrupt:
break;
#endif
case BOOK3S_INTERRUPT_MACHINE_CHECK:
case BOOK3S_INTERRUPT_TRACE:
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:
{
ulong shadow_srr1 = vcpu->arch.shadow_srr1;
@ -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. */