KVM: PPC: Book3S HV: Move interrupt delivery on guest entry to C code

This is based on a patch by Suraj Jitindar Singh.

This moves the code in book3s_hv_rmhandlers.S that generates an
external, decrementer or privileged doorbell interrupt just before
entering the guest to C code in book3s_hv_builtin.c.  This is to
make future maintenance and modification easier.  The algorithm
expressed in the C code is almost identical to the previous
algorithm.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 48 insertions, 0 deletions

diff --git a/arch/powerpc/kvm/book3s_hv_builtin.c b/arch/powerpc/kvm/book3s_hv_builtin.c
index fc6bb9630a9c..ccfea5b96d89 100644
--- a/arch/powerpc/kvm/book3s_hv_builtin.c
+++ b/arch/powerpc/kvm/book3s_hv_builtin.c
@@ -729,3 +729,51 @@ void kvmhv_p9_restore_lpcr(struct kvm_split_mode *sip)
 	smp_mb();
 	local_paca->kvm_hstate.kvm_split_mode = NULL;
 }
+
+/*
+ * Is there a PRIV_DOORBELL pending for the guest (on POWER9)?
+ * Can we inject a Decrementer or a External interrupt?
+ */
+void kvmppc_guest_entry_inject_int(struct kvm_vcpu *vcpu)
+{
+	int ext;
+	unsigned long vec = 0;
+	unsigned long lpcr;
+
+	/* Insert EXTERNAL bit into LPCR at the MER bit position */
+	ext = (vcpu->arch.pending_exceptions >> BOOK3S_IRQPRIO_EXTERNAL) & 1;
+	lpcr = mfspr(SPRN_LPCR);
+	lpcr |= ext << LPCR_MER_SH;
+	mtspr(SPRN_LPCR, lpcr);
+	isync();
+
+	if (vcpu->arch.shregs.msr & MSR_EE) {
+		if (ext) {
+			vec = BOOK3S_INTERRUPT_EXTERNAL;
+		} else {
+			long int dec = mfspr(SPRN_DEC);
+			if (!(lpcr & LPCR_LD))
+				dec = (int) dec;
+			if (dec < 0)
+				vec = BOOK3S_INTERRUPT_DECREMENTER;
+		}
+	}
+	if (vec) {
+		unsigned long msr, old_msr = vcpu->arch.shregs.msr;
+
+		kvmppc_set_srr0(vcpu, kvmppc_get_pc(vcpu));
+		kvmppc_set_srr1(vcpu, old_msr);
+		kvmppc_set_pc(vcpu, vec);
+		msr = vcpu->arch.intr_msr;
+		if (MSR_TM_ACTIVE(old_msr))
+			msr |= MSR_TS_S;
+		vcpu->arch.shregs.msr = msr;
+	}
+
+	if (vcpu->arch.doorbell_request) {
+		mtspr(SPRN_DPDES, 1);
+		vcpu->arch.vcore->dpdes = 1;
+		smp_wmb();
+		vcpu->arch.doorbell_request = 0;
+	}
+}