Date:	Mon, 10 Nov 2014 14:26:44 +0800
From:	Feng Wu <feng.wu@...el.com>
To:	gleb@...nel.org, pbonzini@...hat.com, dwmw2@...radead.org,
	joro@...tes.org, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org
Cc:	kvm@...r.kernel.org, iommu@...ts.linux-foundation.org,
	linux-kernel@...r.kernel.org, Feng Wu <feng.wu@...el.com>
Subject: [PATCH 05/13] KVM: Update IRTE according to guest interrupt configuration changes

When guest changes its interrupt configuration (such as, vector, etc.)
for direct-assigned devices, we need to update the associated IRTE
with the new guest vector, so external interrupts from the assigned
devices can be injected to guests without VM-Exit.

The current method of handling guest lowest priority interrtups
is to use a counter 'apic_arb_prio' for each VCPU, we choose the
VCPU with smallest 'apic_arb_prio' and then increase it by 1.
However, for VT-d PI, we cannot re-use this, since we no longer
have control to 'apic_arb_prio' with posted interrupt direct
delivery by Hardware.

Here, we introduce a similiar way with 'apic_arb_prio' to handle
guest lowest priority interrtups when VT-d PI is used. Here is the
ideas:
- Each VCPU has a counter 'round_robin_counter'.
- When guests sets an interrupts to lowest priority, we choose
the VCPU with smallest 'round_robin_counter' as the destination,
then increase it.

Signed-off-by: Feng Wu <feng.wu@...el.com>
---
 arch/x86/include/asm/irq_remapping.h |    6 ++
 arch/x86/include/asm/kvm_host.h      |    2 +
 arch/x86/kvm/vmx.c                   |   12 +++
 arch/x86/kvm/x86.c                   |   11 +++
 drivers/iommu/amd_iommu.c            |    6 ++
 drivers/iommu/intel_irq_remapping.c  |   28 +++++++
 drivers/iommu/irq_remapping.c        |    9 ++
 drivers/iommu/irq_remapping.h        |    3 +
 include/linux/dmar.h                 |   26 ++++++
 include/linux/kvm_host.h             |   22 +++++
 include/uapi/linux/kvm.h             |    1 +
 virt/kvm/assigned-dev.c              |  141 ++++++++++++++++++++++++++++++++++
 virt/kvm/irq_comm.c                  |    4 +-
 virt/kvm/irqchip.c                   |   11 ---
 14 files changed, 269 insertions(+), 13 deletions(-)

diff --git a/arch/x86/include/asm/irq_remapping.h b/arch/x86/include/asm/irq_remapping.h
index a3cc437..32d6cc4 100644
--- a/arch/x86/include/asm/irq_remapping.h
+++ b/arch/x86/include/asm/irq_remapping.h
@@ -51,6 +51,7 @@ extern void compose_remapped_msi_msg(struct pci_dev *pdev,
 				     unsigned int irq, unsigned int dest,
 				     struct msi_msg *msg, u8 hpet_id);
 extern int setup_hpet_msi_remapped(unsigned int irq, unsigned int id);
+extern int update_pi_irte(unsigned int irq, u64 pi_desc_addr, u32 vector);
 extern void panic_if_irq_remap(const char *msg);
 extern bool setup_remapped_irq(int irq,
 			       struct irq_cfg *cfg,
@@ -88,6 +89,11 @@ static inline int setup_hpet_msi_remapped(unsigned int irq, unsigned int id)
 	return -ENODEV;
 }
 
+static inline int update_pi_irte(unsigned int irq, u64 pi_desc_addr, u32 vector)
+{
+	return -ENODEV;
+}
+
 static inline void panic_if_irq_remap(const char *msg)
 {
 }
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 6ed0c30..0630161 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -358,6 +358,7 @@ struct kvm_vcpu_arch {
 	struct kvm_lapic *apic;    /* kernel irqchip context */
 	unsigned long apic_attention;
 	int32_t apic_arb_prio;
+	int32_t round_robin_counter;
 	int mp_state;
 	u64 ia32_misc_enable_msr;
 	bool tpr_access_reporting;
@@ -771,6 +772,7 @@ struct kvm_x86_ops {
 	int (*check_nested_events)(struct kvm_vcpu *vcpu, bool external_intr);
 
 	void (*sched_in)(struct kvm_vcpu *kvm, int cpu);
+	u64 (*get_pi_desc_addr)(struct kvm_vcpu *vcpu);
 };
 
 struct kvm_arch_async_pf {
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a4670d3..ae91b72 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -544,6 +544,11 @@ static inline struct vcpu_vmx *to_vmx(struct kvm_vcpu *vcpu)
 	return container_of(vcpu, struct vcpu_vmx, vcpu);
 }
 
+struct pi_desc *vcpu_to_pi_desc(struct kvm_vcpu *vcpu)
+{
+	return &(to_vmx(vcpu)->pi_desc);
+}
+
 #define VMCS12_OFFSET(x) offsetof(struct vmcs12, x)
 #define FIELD(number, name)	[number] = VMCS12_OFFSET(name)
 #define FIELD64(number, name)	[number] = VMCS12_OFFSET(name), \
@@ -4280,6 +4285,11 @@ static void vmx_sync_pir_to_irr_dummy(struct kvm_vcpu *vcpu)
 	return;
 }
 
+static u64 vmx_get_pi_desc_addr(struct kvm_vcpu *vcpu)
+{
+	return __pa((u64)vcpu_to_pi_desc(vcpu));
+}
+
 /*
  * Set up the vmcs's constant host-state fields, i.e., host-state fields that
  * will not change in the lifetime of the guest.
@@ -9232,6 +9242,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
 	.check_nested_events = vmx_check_nested_events,
 
 	.sched_in = vmx_sched_in,
+
+	.get_pi_desc_addr = vmx_get_pi_desc_addr,
 };
 
 static int __init vmx_init(void)
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b447a98..0c19d15 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7735,6 +7735,17 @@ bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
 }
 EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);
 
+int kvm_update_pi_irte_common(struct kvm *kvm, struct kvm_vcpu *vcpu,
+			u32 guest_vector, int host_irq)
+{
+	u64 pi_desc_addr = kvm_x86_ops->get_pi_desc_addr(vcpu);
+
+	if (update_pi_irte(host_irq, pi_desc_addr, guest_vector))
+		return -1;
+
+	return 0;
+}
+
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
 EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index 505a9ad..a36fdc7 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/drivers/iommu/amd_iommu.c
@@ -4280,6 +4280,11 @@ static int alloc_hpet_msi(unsigned int irq, unsigned int id)
 	return 0;
 }
 
+static int dummy_update_pi_irte(int irq, u64 pi_desc_addr, u32 vector)
+{
+	return -EINVAL;
+}
+
 struct irq_remap_ops amd_iommu_irq_ops = {
 	.supported		= amd_iommu_supported,
 	.prepare		= amd_iommu_prepare,
@@ -4294,5 +4299,6 @@ struct irq_remap_ops amd_iommu_irq_ops = {
 	.msi_alloc_irq		= msi_alloc_irq,
 	.msi_setup_irq		= msi_setup_irq,
 	.alloc_hpet_msi		= alloc_hpet_msi,
+	.update_pi_irte         = dummy_update_pi_irte,
 };
 #endif
diff --git a/drivers/iommu/intel_irq_remapping.c b/drivers/iommu/intel_irq_remapping.c
index 776da10..87c02fe 100644
--- a/drivers/iommu/intel_irq_remapping.c
+++ b/drivers/iommu/intel_irq_remapping.c
@@ -1172,6 +1172,33 @@ static int intel_alloc_hpet_msi(unsigned int irq, unsigned int id)
 	return ret;
 }
 
+static int intel_update_pi_irte(int irq, u64 pi_desc_addr, u32 vector)
+{
+	struct irte irte;
+
+	if (get_irte(irq, &irte))
+		return -1;
+
+	irte.irq_post_low.urg = 0;
+	irte.irq_post_low.vector = vector;
+	irte.irq_post_low.pda_l = (pi_desc_addr >> (32 - PDA_LOW_BIT)) &
+			~(-1UL << PDA_LOW_BIT);
+	irte.irq_post_high.pda_h = (pi_desc_addr >> 32) &
+			~(-1UL << PDA_HIGH_BIT);
+
+	irte.irq_post_low.__reserved_1 = 0;
+	irte.irq_post_low.__reserved_2 = 0;
+	irte.irq_post_low.__reserved_3 = 0;
+	irte.irq_post_high.__reserved_4 = 0;
+
+	irte.irq_post_low.pst = 1;
+
+	if (modify_irte(irq, &irte))
+		return -1;
+
+	return 0;
+}
+
 struct irq_remap_ops intel_irq_remap_ops = {
 	.supported		= intel_irq_remapping_supported,
 	.prepare		= dmar_table_init,
@@ -1186,4 +1213,5 @@ struct irq_remap_ops intel_irq_remap_ops = {
 	.msi_alloc_irq		= intel_msi_alloc_irq,
 	.msi_setup_irq		= intel_msi_setup_irq,
 	.alloc_hpet_msi		= intel_alloc_hpet_msi,
+	.update_pi_irte         = intel_update_pi_irte,
 };
diff --git a/drivers/iommu/irq_remapping.c b/drivers/iommu/irq_remapping.c
index 2f8ee00..0e36860 100644
--- a/drivers/iommu/irq_remapping.c
+++ b/drivers/iommu/irq_remapping.c
@@ -362,6 +362,15 @@ int setup_hpet_msi_remapped(unsigned int irq, unsigned int id)
 	return default_setup_hpet_msi(irq, id);
 }
 
+int update_pi_irte(unsigned int irq, u64 pi_desc_addr, u32 vector)
+{
+	if (!remap_ops || !remap_ops->update_pi_irte)
+		return -ENODEV;
+
+	return remap_ops->update_pi_irte(irq, pi_desc_addr, vector);
+}
+EXPORT_SYMBOL_GPL(update_pi_irte);
+
 void panic_if_irq_remap(const char *msg)
 {
 	if (irq_remapping_enabled)
diff --git a/drivers/iommu/irq_remapping.h b/drivers/iommu/irq_remapping.h
index 7bb5913..2d8f740 100644
--- a/drivers/iommu/irq_remapping.h
+++ b/drivers/iommu/irq_remapping.h
@@ -84,6 +84,9 @@ struct irq_remap_ops {
 
 	/* Setup interrupt remapping for an HPET MSI */
 	int (*alloc_hpet_msi)(unsigned int, unsigned int);
+
+	/* Update IRTE for posted-interrupt */
+	int (*update_pi_irte)(int irq, u64 pi_desc_addr, u32 vector);
 };
 
 extern struct irq_remap_ops intel_irq_remap_ops;
diff --git a/include/linux/dmar.h b/include/linux/dmar.h
index 8be5d42..e1ff4f7 100644
--- a/include/linux/dmar.h
+++ b/include/linux/dmar.h
@@ -160,6 +160,20 @@ struct irte {
 				__reserved_2	: 8,
 				dest_id		: 32;
 		} irq_remap_low;
+
+		struct {
+			__u64   present		: 1,
+				fpd		: 1,
+				__reserved_1	: 6,
+				avail	: 4,
+				__reserved_2	: 2,
+				urg		: 1,
+				pst		: 1,
+				vector	: 8,
+				__reserved_3	: 14,
+				pda_l	: 26;
+		} irq_post_low;
+
 		__u64 low;
 	};
 
@@ -170,10 +184,22 @@ struct irte {
 				svt		: 2,
 				__reserved_3	: 44;
 		} irq_remap_high;
+
+		struct {
+			__u64	sid:	16,
+				sq:		2,
+				svt:	2,
+				__reserved_4:	12,
+				pda_h:	32;
+		} irq_post_high;
+
 		__u64 high;
 	};
 };
 
+#define PDA_LOW_BIT    26
+#define PDA_HIGH_BIT   32
+
 enum {
 	IRQ_REMAP_XAPIC_MODE,
 	IRQ_REMAP_X2APIC_MODE,
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index ea53b04..6bb8287 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -335,6 +335,25 @@ struct kvm_kernel_irq_routing_entry {
 	struct hlist_node link;
 };
 
+#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
+
+struct kvm_irq_routing_table {
+	int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
+	struct kvm_kernel_irq_routing_entry *rt_entries;
+	u32 nr_rt_entries;
+	/*
+	 * Array indexed by gsi. Each entry contains list of irq chips
+	 * the gsi is connected to.
+	 */
+	struct hlist_head map[0];
+};
+
+#else
+
+struct kvm_irq_routing_table {};
+
+#endif
+
 #ifndef KVM_PRIVATE_MEM_SLOTS
 #define KVM_PRIVATE_MEM_SLOTS 0
 #endif
@@ -766,6 +785,9 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 				   struct kvm_irq_ack_notifier *kian);
 int kvm_request_irq_source_id(struct kvm *kvm);
 void kvm_free_irq_source_id(struct kvm *kvm, int irq_source_id);
+void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
+				   struct kvm_lapic_irq *irq);
+bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq);
 
 #ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
 int kvm_iommu_map_pages(struct kvm *kvm, struct kvm_memory_slot *slot);
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7593c52..509223a 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1027,6 +1027,7 @@ struct kvm_s390_ucas_mapping {
 #define KVM_XEN_HVM_CONFIG        _IOW(KVMIO,  0x7a, struct kvm_xen_hvm_config)
 #define KVM_SET_CLOCK             _IOW(KVMIO,  0x7b, struct kvm_clock_data)
 #define KVM_GET_CLOCK             _IOR(KVMIO,  0x7c, struct kvm_clock_data)
+#define KVM_ASSIGN_DEV_PI_UPDATE  _IOR(KVMIO,  0x7d, __u32)
 /* Available with KVM_CAP_PIT_STATE2 */
 #define KVM_GET_PIT2              _IOR(KVMIO,  0x9f, struct kvm_pit_state2)
 #define KVM_SET_PIT2              _IOW(KVMIO,  0xa0, struct kvm_pit_state2)
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index e05000e..e154009 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -326,6 +326,135 @@ void kvm_free_all_assigned_devices(struct kvm *kvm)
 	}
 }
 
+int __weak kvm_update_pi_irte_common(struct kvm *kvm, struct kvm_vcpu *vcpu,
+					u32 guest_vector, int host_irq)
+{
+	return 0;
+}
+
+int kvm_compare_rr_counter(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2)
+{
+	return vcpu1->arch.round_robin_counter -
+			vcpu2->arch.round_robin_counter;
+}
+
+bool kvm_pi_find_dest_vcpu(struct kvm *kvm, struct kvm_lapic_irq *irq,
+				struct kvm_vcpu **dest_vcpu)
+{
+	int i, r = 0;
+	struct kvm_vcpu *vcpu, *dest = NULL;
+
+	kvm_for_each_vcpu(i, vcpu, kvm) {
+		if (!kvm_apic_present(vcpu))
+			continue;
+
+		if (!kvm_apic_match_dest(vcpu, NULL, irq->shorthand,
+					irq->dest_id, irq->dest_mode))
+			continue;
+
+		if (!kvm_is_dm_lowest_prio(irq)) {
+			r++;
+			*dest_vcpu = vcpu;
+		} else if (kvm_lapic_enabled(vcpu)) {
+			if (!dest)
+				dest = vcpu;
+			else if (kvm_compare_rr_counter(vcpu, dest) < 0)
+				dest = vcpu;
+		}
+	}
+
+	if (dest) {
+		dest->arch.round_robin_counter++;
+		*dest_vcpu = dest;
+		return true;
+	} else if (r == 1)
+		return true;
+
+	return false;
+}
+
+static int __kvm_update_pi_irte(struct kvm *kvm, int host_irq, int guest_irq)
+{
+	struct kvm_kernel_irq_routing_entry *e;
+	struct kvm_irq_routing_table *irq_rt;
+	struct kvm_lapic_irq irq;
+	struct kvm_vcpu *vcpu;
+	int idx, ret = -EINVAL;
+
+	idx = srcu_read_lock(&kvm->irq_srcu);
+	irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
+	ASSERT(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 posted-interrupt has the following
+		 * limitations:
+		 *  - No support for posting multicast/broadcast
+		 *    interrupts to a VCPU
+		 * Still use interrupt remapping for these
+		 * kind of interrupts
+		 */
+
+		kvm_set_msi_irq(e, &irq);
+		if (!kvm_pi_find_dest_vcpu(kvm, &irq, &vcpu)) {
+			printk(KERN_INFO "%s: can not find the target VCPU\n",
+					__func__);
+			ret = -EINVAL;
+			goto out;
+		}
+
+		if (kvm_update_pi_irte_common(kvm, vcpu, irq.vector,
+				host_irq)) {
+			printk(KERN_INFO "%s: failed to update PI IRTE\n",
+					__func__);
+			ret = -EINVAL;
+			goto out;
+		}
+	}
+
+	ret = 0;
+out:
+	srcu_read_unlock(&kvm->irq_srcu, idx);
+	return ret;
+}
+
+int kvm_update_pi_irte(struct kvm *kvm, u32 dev_id)
+{
+	int i, rc = -1;
+	struct kvm_assigned_dev_kernel *dev;
+
+	mutex_lock(&kvm->lock);
+	dev = kvm_find_assigned_dev(&kvm->arch.assigned_dev_head, dev_id);
+	if (!dev) {
+		printk(KERN_INFO "%s: cannot find the assigned dev.\n",
+				__func__);
+		rc = -1;
+		goto out;
+	}
+
+	BUG_ON(dev->irq_requested_type == 0);
+
+	if ((dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSI) &&
+		(dev->dev->msi_enabled == 1)) {
+			__kvm_update_pi_irte(kvm,
+					dev->host_irq, dev->guest_irq);
+	} else if ((dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX) &&
+		(dev->dev->msix_enabled == 1)) {
+		for (i = 0; i < dev->entries_nr; i++) {
+			__kvm_update_pi_irte(kvm,
+					dev->host_msix_entries[i].vector,
+					dev->guest_msix_entries[i].vector);
+		}
+	}
+
+out:
+	rc = 0;
+	mutex_unlock(&kvm->lock);
+	return rc;
+}
+
 static int assigned_device_enable_host_intx(struct kvm *kvm,
 					    struct kvm_assigned_dev_kernel *dev)
 {
@@ -1017,6 +1146,18 @@ long kvm_vm_ioctl_assigned_device(struct kvm *kvm, unsigned ioctl,
 		r = kvm_vm_ioctl_set_pci_irq_mask(kvm, &assigned_dev);
 		break;
 	}
+	case KVM_ASSIGN_DEV_PI_UPDATE: {
+		u32 dev_id;
+
+		r = -EFAULT;
+		if (copy_from_user(&dev_id, argp, sizeof(dev_id)))
+			goto out;
+		r = kvm_update_pi_irte(kvm, dev_id);
+		if (r)
+			goto out;
+		break;
+
+	}
 	default:
 		r = -ENOTTY;
 		break;
diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 963b899..f51aed3 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -55,7 +55,7 @@ static int kvm_set_ioapic_irq(struct kvm_kernel_irq_routing_entry *e,
 				line_status);
 }
 
-inline static bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
+bool kvm_is_dm_lowest_prio(struct kvm_lapic_irq *irq)
 {
 #ifdef CONFIG_IA64
 	return irq->delivery_mode ==
@@ -106,7 +106,7 @@ int kvm_irq_delivery_to_apic(struct kvm *kvm, struct kvm_lapic *src,
 	return r;
 }
 
-static inline void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
+void kvm_set_msi_irq(struct kvm_kernel_irq_routing_entry *e,
 				   struct kvm_lapic_irq *irq)
 {
 	trace_kvm_msi_set_irq(e->msi.address_lo, e->msi.data);
diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
index 7f256f3..cdf29a6 100644
--- a/virt/kvm/irqchip.c
+++ b/virt/kvm/irqchip.c
@@ -31,17 +31,6 @@
 #include <trace/events/kvm.h>
 #include "irq.h"
 
-struct kvm_irq_routing_table {
-	int chip[KVM_NR_IRQCHIPS][KVM_IRQCHIP_NUM_PINS];
-	struct kvm_kernel_irq_routing_entry *rt_entries;
-	u32 nr_rt_entries;
-	/*
-	 * Array indexed by gsi. Each entry contains list of irq chips
-	 * the gsi is connected to.
-	 */
-	struct hlist_head map[0];
-};
-
 int kvm_irq_map_gsi(struct kvm *kvm,
 		    struct kvm_kernel_irq_routing_entry *entries, int gsi)
 {
-- 
1.7.1

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