KVM: PPC: Book3S HV: Native usage of the XIVE interrupt controller

This patch makes KVM capable of using the XIVE interrupt controller
to provide the standard PAPR "XICS" style hypercalls. It is necessary
for proper operations when the host uses XIVE natively.

This has been lightly tested on an actual system, including PCI
pass-through with a TG3 device.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
[mpe: Cleanup pr_xxx(), unsplit pr_xxx() strings, etc., fix build
 failures by adding KVM_XIVE which depends on KVM_XICS and XIVE, and
 adding empty stubs for the kvm_xive_xxx() routines, fixup subject,
 integrate fixes from Paul for building PR=y HV=n]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

arch/powerpc/kvm/book3s_hv.c

@@ -67,6 +67,7 @@
 #include <asm/mmu.h>
 #include <asm/opal.h>
 #include <asm/xics.h>
+#include <asm/xive.h>
 
 #include "book3s.h"
 
@@ -837,6 +838,10 @@ int kvmppc_pseries_do_hcall(struct kvm_vcpu *vcpu)
 	case H_IPOLL:
 	case H_XIRR_X:
 		if (kvmppc_xics_enabled(vcpu)) {
+			if (xive_enabled()) {
+				ret = H_NOT_AVAILABLE;
+				return RESUME_GUEST;
+			}
 			ret = kvmppc_xics_hcall(vcpu, req);
 			break;
 		}
@@ -2947,8 +2952,12 @@ static int kvmppc_vcpu_run_hv(struct kvm_run *run, struct kvm_vcpu *vcpu)
 			r = kvmppc_book3s_hv_page_fault(run, vcpu,
 				vcpu->arch.fault_dar, vcpu->arch.fault_dsisr);
 			srcu_read_unlock(&vcpu->kvm->srcu, srcu_idx);
-		} else if (r == RESUME_PASSTHROUGH)
-			r = kvmppc_xics_rm_complete(vcpu, 0);
+		} else if (r == RESUME_PASSTHROUGH) {
+			if (WARN_ON(xive_enabled()))
+				r = H_SUCCESS;
+			else
+				r = kvmppc_xics_rm_complete(vcpu, 0);
+		}
 	} while (is_kvmppc_resume_guest(r));
 
  out:
@@ -3400,10 +3409,20 @@ static int kvmppc_core_init_vm_hv(struct kvm *kvm)
 	/*
 	 * On POWER9, VPM0 bit is reserved (VPM0=1 behaviour is assumed)
 	 * Set HVICE bit to enable hypervisor virtualization interrupts.
+	 * Set HEIC to prevent OS interrupts to go to hypervisor (should
+	 * be unnecessary but better safe than sorry in case we re-enable
+	 * EE in HV mode with this LPCR still set)
 	 */
 	if (cpu_has_feature(CPU_FTR_ARCH_300)) {
 		lpcr &= ~LPCR_VPM0;
-		lpcr |= LPCR_HVICE;
+		lpcr |= LPCR_HVICE | LPCR_HEIC;
+
+		/*
+		 * If xive is enabled, we route 0x500 interrupts directly
+		 * to the guest.
+		 */
+		if (xive_enabled())
+			lpcr |= LPCR_LPES;
 	}
 
 	/*
@@ -3533,7 +3552,7 @@ static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 	struct kvmppc_irq_map *irq_map;
 	struct kvmppc_passthru_irqmap *pimap;
 	struct irq_chip *chip;
-	int i;
+	int i, rc = 0;
 
 	if (!kvm_irq_bypass)
 		return 1;
@@ -3558,10 +3577,10 @@ static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 	/*
 	 * For now, we only support interrupts for which the EOI operation
 	 * is an OPAL call followed by a write to XIRR, since that's
-	 * what our real-mode EOI code does.
+	 * what our real-mode EOI code does, or a XIVE interrupt
 	 */
 	chip = irq_data_get_irq_chip(&desc->irq_data);
-	if (!chip || !is_pnv_opal_msi(chip)) {
+	if (!chip || !(is_pnv_opal_msi(chip) || is_xive_irq(chip))) {
 		pr_warn("kvmppc_set_passthru_irq_hv: Could not assign IRQ map for (%d,%d)\n",
 			host_irq, guest_gsi);
 		mutex_unlock(&kvm->lock);
@@ -3603,7 +3622,12 @@ static int kvmppc_set_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 	if (i == pimap->n_mapped)
 		pimap->n_mapped++;
 
-	kvmppc_xics_set_mapped(kvm, guest_gsi, desc->irq_data.hwirq);
+	if (xive_enabled())
+		rc = kvmppc_xive_set_mapped(kvm, guest_gsi, desc);
+	else
+		kvmppc_xics_set_mapped(kvm, guest_gsi, desc->irq_data.hwirq);
+	if (rc)
+		irq_map->r_hwirq = 0;
 
 	mutex_unlock(&kvm->lock);
 
@@ -3614,7 +3638,7 @@ static int kvmppc_clr_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 {
 	struct irq_desc *desc;
 	struct kvmppc_passthru_irqmap *pimap;
-	int i;
+	int i, rc = 0;
 
 	if (!kvm_irq_bypass)
 		return 0;
@@ -3641,9 +3665,12 @@ static int kvmppc_clr_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 		return -ENODEV;
 	}
 
-	kvmppc_xics_clr_mapped(kvm, guest_gsi, pimap->mapped[i].r_hwirq);
+	if (xive_enabled())
+		rc = kvmppc_xive_clr_mapped(kvm, guest_gsi, pimap->mapped[i].desc);
+	else
+		kvmppc_xics_clr_mapped(kvm, guest_gsi, pimap->mapped[i].r_hwirq);
 
-	/* invalidate the entry */
+	/* invalidate the entry (what do do on error from the above ?) */
 	pimap->mapped[i].r_hwirq = 0;
 
 	/*
@@ -3652,7 +3679,7 @@ static int kvmppc_clr_passthru_irq(struct kvm *kvm, int host_irq, int guest_gsi)
 	 */
 
 	mutex_unlock(&kvm->lock);
-	return 0;
+	return rc;
 }
 
 static int kvmppc_irq_bypass_add_producer_hv(struct irq_bypass_consumer *cons,
@@ -3930,7 +3957,7 @@ static int kvmppc_book3s_init_hv(void)
 	 * indirectly, via OPAL.
 	 */
 #ifdef CONFIG_SMP
-	if (!get_paca()->kvm_hstate.xics_phys) {
+	if (!xive_enabled() && !get_paca()->kvm_hstate.xics_phys) {
 		struct device_node *np;
 
 		np = of_find_compatible_node(NULL, NULL, "ibm,opal-intc");