From bf4159da4751ab8eea43ca6e7c49193dbce8398c Mon Sep 17 00:00:00 2001 From: Benjamin Herrenschmidt Date: Fri, 12 Jan 2018 13:37:12 +1100 Subject: KVM: PPC: Book3S HV: Enable use of the new XIVE "single escalation" feature That feature, provided by Power9 DD2.0 and later, when supported by newer OPAL versions, allows us to sacrifice a queue (priority 7) in favor of merging all the escalation interrupts of the queues of a single VP into a single interrupt. This reduces the number of host interrupts used up by KVM guests especially when those guests use multiple priorities. It will also enable a future change to control the masking of the escalation interrupts more precisely to avoid spurious ones. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Paul Mackerras --- arch/powerpc/kvm/book3s_xive.c | 48 ++++++++++++++++++++++++++++-------------- 1 file changed, 32 insertions(+), 16 deletions(-) (limited to 'arch/powerpc/kvm/book3s_xive.c') diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c index 6cff5bd..a102efe 100644 --- a/arch/powerpc/kvm/book3s_xive.c +++ b/arch/powerpc/kvm/book3s_xive.c @@ -112,19 +112,21 @@ static int xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio) return -EIO; } - /* - * Future improvement: start with them disabled - * and handle DD2 and later scheme of merged escalation - * interrupts - */ - name = kasprintf(GFP_KERNEL, "kvm-%d-%d-%d", - vcpu->kvm->arch.lpid, xc->server_num, prio); + if (xc->xive->single_escalation) + name = kasprintf(GFP_KERNEL, "kvm-%d-%d", + vcpu->kvm->arch.lpid, xc->server_num); + else + name = kasprintf(GFP_KERNEL, "kvm-%d-%d-%d", + vcpu->kvm->arch.lpid, xc->server_num, prio); if (!name) { pr_err("Failed to allocate escalation irq name for queue %d of VCPU %d\n", prio, xc->server_num); rc = -ENOMEM; goto error; } + + pr_devel("Escalation %s irq %d (prio %d)\n", name, xc->esc_virq[prio], prio); + rc = request_irq(xc->esc_virq[prio], xive_esc_irq, IRQF_NO_THREAD, name, vcpu); if (rc) { @@ -191,12 +193,12 @@ static int xive_check_provisioning(struct kvm *kvm, u8 prio) pr_devel("Provisioning prio... %d\n", prio); - /* Provision each VCPU and enable escalations */ + /* Provision each VCPU and enable escalations if needed */ kvm_for_each_vcpu(i, vcpu, kvm) { if (!vcpu->arch.xive_vcpu) continue; rc = xive_provision_queue(vcpu, prio); - if (rc == 0) + if (rc == 0 && !xive->single_escalation) xive_attach_escalation(vcpu, prio); if (rc) return rc; @@ -1081,6 +1083,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, /* Allocate IPI */ xc->vp_ipi = xive_native_alloc_irq(); if (!xc->vp_ipi) { + pr_err("Failed to allocate xive irq for VCPU IPI\n"); r = -EIO; goto bail; } @@ -1091,18 +1094,33 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, goto bail; /* + * Enable the VP first as the single escalation mode will + * affect escalation interrupts numbering + */ + r = xive_native_enable_vp(xc->vp_id, xive->single_escalation); + if (r) { + pr_err("Failed to enable VP in OPAL, err %d\n", r); + goto bail; + } + + /* * Initialize queues. Initially we set them all for no queueing * and we enable escalation for queue 0 only which we'll use for * our mfrr change notifications. If the VCPU is hot-plugged, we - * do handle provisioning however. + * do handle provisioning however based on the existing "map" + * of enabled queues. */ for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) { struct xive_q *q = &xc->queues[i]; + /* Single escalation, no queue 7 */ + if (i == 7 && xive->single_escalation) + break; + /* Is queue already enabled ? Provision it */ if (xive->qmap & (1 << i)) { r = xive_provision_queue(vcpu, i); - if (r == 0) + if (r == 0 && !xive->single_escalation) xive_attach_escalation(vcpu, i); if (r) goto bail; @@ -1122,11 +1140,6 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev, if (r) goto bail; - /* Enable the VP */ - r = xive_native_enable_vp(xc->vp_id); - if (r) - goto bail; - /* Route the IPI */ r = xive_native_configure_irq(xc->vp_ipi, xc->vp_id, 0, XICS_IPI); if (!r) @@ -1473,6 +1486,7 @@ static int xive_set_source(struct kvmppc_xive *xive, long irq, u64 addr) pr_devel(" val=0x016%llx (server=0x%x, guest_prio=%d)\n", val, server, guest_prio); + /* * If the source doesn't already have an IPI, allocate * one and get the corresponding data @@ -1761,6 +1775,8 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type) if (xive->vp_base == XIVE_INVALID_VP) ret = -ENOMEM; + xive->single_escalation = xive_native_has_single_escalation(); + if (ret) { kfree(xive); return ret; -- cgit v1.1