[v4 13/16] KVM: x86: kvm-vfio: VT-d posted-interrupts setup

Feng Wu
2015-06-11T11:04:57Z

This patch defines macro __KVM_HAVE_ARCH_KVM_VFIO_POST and
implement kvm_arch_vfio_update_pi_irte for x86 architecture.

Signed-off-by: Feng Wu <feng.wu@intel.com>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/Makefile | 3 +-
arch/x86/kvm/kvm_vfio_x86.c | 85 +++++++++++++++++++++++++++++++++++++++++
3 files changed, 89 insertions(+), 1 deletion(-)
create mode 100644 arch/x86/kvm/kvm_vfio_x86.c

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 31a495f..1605bf8 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -81,6 +81,8 @@ static inline gfn_t gfn_to_index(gfn_t gfn, gfn_t base_gfn, int level)
(base_gfn >> KVM_HPAGE_GFN_SHIFT(level));
}

+#define __KVM_HAVE_ARCH_KVM_VFIO_POST
+
#define KVM_PERMILLE_MMU_PAGES 20
#define KVM_MIN_ALLOC_MMU_PAGES 64
#define KVM_MMU_HASH_SHIFT 10
diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index 16e8f96..6bafc89 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -12,7 +12,8 @@ kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o \
kvm-$(CONFIG_KVM_ASYNC_PF) += $(KVM)/async_pf.o

kvm-y += x86.o mmu.o emulate.o i8259.o irq.o lapic.o \
- i8254.o ioapic.o irq_comm.o cpuid.o pmu.o
+ i8254.o ioapic.o irq_comm.o cpuid.o pmu.o \
+ kvm_vfio_x86.o
kvm-$(CONFIG_KVM_DEVICE_ASSIGNMENT) += assigned-dev.o iommu.o
kvm-intel-y += vmx.o
kvm-amd-y += svm.o
diff --git a/arch/x86/kvm/kvm_vfio_x86.c b/arch/x86/kvm/kvm_vfio_x86.c
new file mode 100644
index 0000000..a2d74f9
--- /dev/null
+++ b/arch/x86/kvm/kvm_vfio_x86.c
@@ -0,0 +1,85 @@
+/*
+ * Copyright (C) 2014 Intel Corporation.
+ * Authors: Feng Wu <feng.wu@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2, as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kvm_host.h>
+#include <asm/irq_remapping.h>
+
+/*
+ * kvm_arch_vfio_update_pi_irte - set IRTE for Posted-Interrupts
+ *
+ * @kvm: kvm
+ * @host_irq: host irq of the interrupt
+ * @guest_irq: gsi of the interrupt
+ * @set: set or unset PI
+ * returns 0 on success, < 0 on failure
+ */
+int kvm_arch_vfio_update_pi_irte(struct kvm *kvm, unsigned int host_irq,
+ uint32_t guest_irq, bool set)
+{
+ struct kvm_kernel_irq_routing_entry *e;
+ struct kvm_irq_routing_table *irq_rt;
+ struct kvm_lapic_irq irq;
+ struct kvm_vcpu *vcpu;
+ struct vcpu_data vcpu_info;
+ int idx, ret = -EINVAL;
+
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
+ BUG_ON(guest_irq >= irq_rt->nr_rt_entries);
+
+ hlist_for_each_entry(e, &irq_rt->map[guest_irq], link) {
+ if (e->type != KVM_IRQ_ROUTING_MSI)
+ continue;
+ /*
+ * VT-d PI cannot support posting multicast/broadcast
+ * interrupts to a VCPU, we still use interrupt remapping
+ * for these kind of interrupts.
+ *
+ * For lowest-priority interrupts, we only support
+ * those with single CPU as the destination, e.g. user
+ * configures the interrupts via /proc/irq or uses
+ * irqbalance to make the interrupts single-CPU.
+ *
+ * We will support full lowest-priority interrupt later.
+ *
+ */
+
+ kvm_set_msi_irq(e, &irq);
+ if (!kvm_intr_is_single_vcpu(kvm, &irq, &vcpu))
+ continue;
+
+ vcpu_info.pi_desc_addr = kvm_x86_ops->get_pi_desc_addr(vcpu);
+ vcpu_info.vector = irq.vector;
+
+ if (set)
+ ret = irq_set_vcpu_affinity(host_irq, &vcpu_info);
+ else {
+ /* suppress notification event before unposting */
+ kvm_x86_ops->pi_set_sn(vcpu);
+ ret = irq_set_vcpu_affinity(host_irq, NULL);
+ kvm_x86_ops->pi_clear_sn(vcpu);
+ }
+
+ if (ret < 0) {
+ printk(KERN_INFO "%s: failed to update PI IRTE\n",
+ __func__);
+ goto out;
+ }
+ }
+
+ ret = 0;
+out:
+ srcu_read_unlock(&kvm->irq_srcu, idx);
+ return ret;
+}
--
2.1.0