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Commit 6a0ab738 authored by Hollis Blanchard's avatar Hollis Blanchard Committed by Avi Kivity
Browse files

KVM: ppc: guest breakpoint support 



Allow host userspace to program hardware debug registers to set breakpoints
inside guests.

Signed-off-by: default avatarJerone Young <jyoung5@us.ibm.com>
Signed-off-by: default avatarHollis Blanchard <hollisb@us.ibm.com>
Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent b5e2fec0

arch/powerpc/include/asm/kvm_host.h

+5 −0
Original line number Diff line number Diff line
@@ -86,6 +86,11 @@ struct kvm_vcpu_arch { 


	u32 host_stack;

	u32 host_pid;

	u32 host_dbcr0;

	u32 host_dbcr1;

	u32 host_dbcr2;

	u32 host_iac[4];

	u32 host_msr;



	u64 fpr[32];

	u32 gpr[32];

arch/powerpc/kvm/booke_guest.c

+15 −0
Original line number Diff line number Diff line
@@ -410,6 +410,21 @@ int kvmppc_handle_exit(struct kvm_run *run, struct kvm_vcpu *vcpu, 
		break;

	}



	case BOOKE_INTERRUPT_DEBUG: {

		u32 dbsr;



		vcpu->arch.pc = mfspr(SPRN_CSRR0);



		/* clear IAC events in DBSR register */

		dbsr = mfspr(SPRN_DBSR);

		dbsr &= DBSR_IAC1 | DBSR_IAC2 | DBSR_IAC3 | DBSR_IAC4;

		mtspr(SPRN_DBSR, dbsr);



		run->exit_reason = KVM_EXIT_DEBUG;

		r = RESUME_HOST;

		break;

	}



	default:

		printk(KERN_EMERG "exit_nr %d\n", exit_nr);

		BUG();

arch/powerpc/kvm/booke_interrupts.S

+10 −1
Original line number Diff line number Diff line
@@ -42,7 +42,8 @@ 
#define HOST_STACK_LR   (HOST_STACK_SIZE + 4) /* In caller stack frame. */



#define NEED_INST_MASK ((1<<BOOKE_INTERRUPT_PROGRAM) | \

                        (1<<BOOKE_INTERRUPT_DTLB_MISS))

                        (1<<BOOKE_INTERRUPT_DTLB_MISS) | \

                        (1<<BOOKE_INTERRUPT_DEBUG))



#define NEED_DEAR_MASK ((1<<BOOKE_INTERRUPT_DATA_STORAGE) | \

                        (1<<BOOKE_INTERRUPT_DTLB_MISS))
@@ -431,6 +432,14 @@ lightweight_exit: 
	oris	r3, r3, KVMPPC_MSR_MASK@h

	ori	r3, r3, KVMPPC_MSR_MASK@l

	mtsrr1	r3



	/* Clear any debug events which occurred since we disabled MSR[DE].

	 * XXX This gives us a 3-instruction window in which a breakpoint

	 * intended for guest context could fire in the host instead. */

	lis	r3, 0xffff

	ori	r3, r3, 0xffff

	mtspr	SPRN_DBSR, r3



	lwz	r3, VCPU_GPR(r3)(r4)

	lwz	r4, VCPU_GPR(r4)(r4)

	rfi

arch/powerpc/kvm/powerpc.c

+83 −1
Original line number Diff line number Diff line
@@ -239,18 +239,100 @@ void kvm_arch_vcpu_uninit(struct kvm_vcpu *vcpu) 
{

}



/* Note: clearing MSR[DE] just means that the debug interrupt will not be

 * delivered *immediately*. Instead, it simply sets the appropriate DBSR bits.

 * If those DBSR bits are still set when MSR[DE] is re-enabled, the interrupt

 * will be delivered as an "imprecise debug event" (which is indicated by

 * DBSR[IDE].

 */

static void kvmppc_disable_debug_interrupts(void)

{

	mtmsr(mfmsr() & ~MSR_DE);

}



static void kvmppc_restore_host_debug_state(struct kvm_vcpu *vcpu)

{

	kvmppc_disable_debug_interrupts();



	mtspr(SPRN_IAC1, vcpu->arch.host_iac[0]);

	mtspr(SPRN_IAC2, vcpu->arch.host_iac[1]);

	mtspr(SPRN_IAC3, vcpu->arch.host_iac[2]);

	mtspr(SPRN_IAC4, vcpu->arch.host_iac[3]);

	mtspr(SPRN_DBCR1, vcpu->arch.host_dbcr1);

	mtspr(SPRN_DBCR2, vcpu->arch.host_dbcr2);

	mtspr(SPRN_DBCR0, vcpu->arch.host_dbcr0);

	mtmsr(vcpu->arch.host_msr);

}



static void kvmppc_load_guest_debug_registers(struct kvm_vcpu *vcpu)

{

	struct kvm_guest_debug *dbg = &vcpu->guest_debug;

	u32 dbcr0 = 0;



	vcpu->arch.host_msr = mfmsr();

	kvmppc_disable_debug_interrupts();



	/* Save host debug register state. */

	vcpu->arch.host_iac[0] = mfspr(SPRN_IAC1);

	vcpu->arch.host_iac[1] = mfspr(SPRN_IAC2);

	vcpu->arch.host_iac[2] = mfspr(SPRN_IAC3);

	vcpu->arch.host_iac[3] = mfspr(SPRN_IAC4);

	vcpu->arch.host_dbcr0 = mfspr(SPRN_DBCR0);

	vcpu->arch.host_dbcr1 = mfspr(SPRN_DBCR1);

	vcpu->arch.host_dbcr2 = mfspr(SPRN_DBCR2);



	/* set registers up for guest */



	if (dbg->bp[0]) {

		mtspr(SPRN_IAC1, dbg->bp[0]);

		dbcr0 |= DBCR0_IAC1 | DBCR0_IDM;

	}

	if (dbg->bp[1]) {

		mtspr(SPRN_IAC2, dbg->bp[1]);

		dbcr0 |= DBCR0_IAC2 | DBCR0_IDM;

	}

	if (dbg->bp[2]) {

		mtspr(SPRN_IAC3, dbg->bp[2]);

		dbcr0 |= DBCR0_IAC3 | DBCR0_IDM;

	}

	if (dbg->bp[3]) {

		mtspr(SPRN_IAC4, dbg->bp[3]);

		dbcr0 |= DBCR0_IAC4 | DBCR0_IDM;

	}



	mtspr(SPRN_DBCR0, dbcr0);

	mtspr(SPRN_DBCR1, 0);

	mtspr(SPRN_DBCR2, 0);

}



void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

{

	if (vcpu->guest_debug.enabled)

		kvmppc_load_guest_debug_registers(vcpu);

}



void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)

{

	if (vcpu->guest_debug.enabled)

		kvmppc_restore_host_debug_state(vcpu);

}



int kvm_arch_vcpu_ioctl_debug_guest(struct kvm_vcpu *vcpu,

                                    struct kvm_debug_guest *dbg)

{

	return -ENOTSUPP;

	int i;



	vcpu->guest_debug.enabled = dbg->enabled;

	if (vcpu->guest_debug.enabled) {

		for (i=0; i < ARRAY_SIZE(vcpu->guest_debug.bp); i++) {

			if (dbg->breakpoints[i].enabled)

				vcpu->guest_debug.bp[i] = dbg->breakpoints[i].address;

			else

				vcpu->guest_debug.bp[i] = 0;

		}

	}



	return 0;

}



static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu,