Re: [PATCH] KVM: PowerPC: Disarm old guest debug interface

[Hollis Blanchard <hollisb@us.ibm.com>]

On Wed, 2008-12-24 at 13:48 +0200, Avi Kivity wrote: 
> Jan Kiszka wrote:
> > [Take this as a band-aid, I guess the PowerPC people can do better.]
> >
> > Until PowerPC is updated to the new guest debugging interface, we have
> > to remove the current implementation. This should also unbreak the
> > build.
> >
> >   
> 
> Hollis? Want this or a real fix?

I was trying to come up with a real fix, but unfortunately I don't have
time to reimplement and retest features like this.




kvm: ppc: remove debug support broken by KVM debug rewrite

After the rewrite of KVM's debug support, this code doesn't even build any
more.

Signed-off-by: Hollis Blanchard <hollisb@us.ibm.com>

diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
--- a/arch/powerpc/include/asm/kvm_host.h
+++ b/arch/powerpc/include/asm/kvm_host.h
@@ -118,11 +118,6 @@ struct kvm_arch {
 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];
 	ulong gpr[32];
@@ -200,10 +195,4 @@ struct kvm_vcpu_arch {
 	unsigned long pending_exceptions;
 };
 
-struct kvm_guest_debug {
-	int enabled;
-	unsigned long bp[4];
-	int singlestep;
-};
-
 #endif /* __POWERPC_KVM_HOST_H__ */
diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
--- a/arch/powerpc/include/asm/kvm_ppc.h
+++ b/arch/powerpc/include/asm/kvm_ppc.h
@@ -71,9 +71,6 @@ extern int kvmppc_core_vcpu_translate(st
 extern void kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu);
 extern void kvmppc_core_vcpu_put(struct kvm_vcpu *vcpu);
 
-extern void kvmppc_core_load_guest_debugstate(struct kvm_vcpu *vcpu);
-extern void kvmppc_core_load_host_debugstate(struct kvm_vcpu *vcpu);
-
 extern void kvmppc_core_deliver_interrupts(struct kvm_vcpu *vcpu);
 extern int kvmppc_core_pending_dec(struct kvm_vcpu *vcpu);
 extern void kvmppc_core_queue_program(struct kvm_vcpu *vcpu);
diff --git a/arch/powerpc/kvm/44x.c b/arch/powerpc/kvm/44x.c
--- a/arch/powerpc/kvm/44x.c
+++ b/arch/powerpc/kvm/44x.c
@@ -28,72 +28,6 @@
 
 #include "44x_tlb.h"
 
-/* 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 kvm44x_disable_debug_interrupts(void)
-{
-	mtmsr(mfmsr() & ~MSR_DE);
-}
-
-void kvmppc_core_load_host_debugstate(struct kvm_vcpu *vcpu)
-{
-	kvm44x_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);
-}
-
-void kvmppc_core_load_guest_debugstate(struct kvm_vcpu *vcpu)
-{
-	struct kvm_guest_debug *dbg = &vcpu->guest_debug;
-	u32 dbcr0 = 0;
-
-	vcpu->arch.host_msr = mfmsr();
-	kvm44x_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 kvmppc_core_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
 	kvmppc_44x_tlb_load(vcpu);
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -216,36 +216,18 @@ void kvm_arch_vcpu_uninit(struct kvm_vcp
 
 void kvm_arch_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
 {
-	if (vcpu->guest_debug.enabled)
-		kvmppc_core_load_guest_debugstate(vcpu);
-
 	kvmppc_core_vcpu_load(vcpu, cpu);
 }
 
 void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
 {
-	if (vcpu->guest_debug.enabled)
-		kvmppc_core_load_host_debugstate(vcpu);
-
 	kvmppc_core_vcpu_put(vcpu);
 }
 
 int kvm_arch_vcpu_ioctl_set_guest_debug(struct kvm_vcpu *vcpu,
-					struct kvm_guest_debug *dbg)
+                                        struct kvm_guest_debug *dbg)
 {
-	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;
+	return -EINVAL;
 }
 
 static void kvmppc_complete_dcr_load(struct kvm_vcpu *vcpu,


-- 
Hollis Blanchard
IBM Linux Technology Center