[PART2 PATCH v4 11/11] svm: Implements update_pi_irte hook to setup posted interrupt

Suravee Suthikulpanit
2016-07-13T15:59:15Z

This patch implements update_pi_irte function hook to allow SVM
communicate to IOMMU driver regarding how to set up IRTE for handling
posted interrupt.

In case AVIC is enabled, during vcpu_load/unload, SVM needs to update
IOMMU IRTE with appropriate host physical APIC ID. Also, when
vcpu_blocking/unblocking, SVM needs to update the is-running bit in
the IOMMU IRTE. Both are achieved via calling amd_iommu_update_ga().

However, if GA mode is not enabled for the pass-through device,
IOMMU driver will simply just return when calling amd_iommu_update_ga.

Signed-off-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
---
arch/x86/kvm/svm.c | 137 ++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 135 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1d9f2f6..28f4efe 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -43,6 +43,7 @@
#include <asm/desc.h>
#include <asm/debugreg.h>
#include <asm/kvm_para.h>
+#include <asm/irq_remapping.h>

#include <asm/virtext.h>
#include "trace.h"
@@ -1349,6 +1350,13 @@ static void avic_vm_destroy(struct kvm *kvm)
spin_unlock_irqrestore(&svm_vm_data_hash_lock, flags);
}

+static atomic_t avic_vm_id_gen = ATOMIC_INIT(0);
+
+static inline u32 avic_get_next_vm_id(void)
+{
+ return atomic_inc_return(&avic_vm_id_gen);
+}
+
static int avic_vm_init(struct kvm *kvm)
{
unsigned long flags;
@@ -1373,6 +1381,8 @@ static int avic_vm_init(struct kvm *kvm)
if (!l_page)
goto free_avic;

+ vm_data->avic_vm_id = avic_get_next_vm_id();
+
vm_data->avic_logical_id_table_page = l_page;
clear_page(page_address(l_page));

@@ -1387,6 +1397,18 @@ free_avic:
return err;
}

+static inline int
+avic_update_iommu(struct kvm_vcpu *vcpu, int cpu, phys_addr_t pa, bool r)
+{
+ struct kvm_arch *vm_data = &vcpu->kvm->arch;
+
+ if (!kvm_arch_has_assigned_device(vcpu->kvm))
+ return 0;
+
+ return amd_iommu_update_ga(vcpu->vcpu_id, cpu, vm_data->avic_vm_id,
+ (pa & AVIC_HPA_MASK), r);
+}
+
/**
* This function is called during VCPU halt/unhalt.
*/
@@ -1409,9 +1431,16 @@ static void avic_set_running(struct kvm_vcpu *vcpu, bool is_run)
WARN_ON(is_run == !!(entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK));

entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
- if (is_run)
+ if (is_run) {
entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
- WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+ WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+ avic_update_iommu(vcpu, h_physical_id,
+ page_to_phys(svm->avic_backing_page), 1);
+ } else {
+ avic_update_iommu(vcpu, h_physical_id,
+ page_to_phys(svm->avic_backing_page), 0);
+ WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+ }
}

static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
@@ -1438,6 +1467,9 @@ static void avic_vcpu_load(struct kvm_vcpu *vcpu, int cpu)
entry |= AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;

WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
+ avic_update_iommu(vcpu, h_physical_id,
+ page_to_phys(svm->avic_backing_page),
+ svm->avic_is_running);
}

static void avic_vcpu_put(struct kvm_vcpu *vcpu)
@@ -1449,6 +1481,10 @@ static void avic_vcpu_put(struct kvm_vcpu *vcpu)
return;

entry = READ_ONCE(*(svm->avic_physical_id_cache));
+ if (entry & AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK)
+ avic_update_iommu(vcpu, -1,
+ page_to_phys(svm->avic_backing_page), 0);
+
entry &= ~AVIC_PHYSICAL_ID_ENTRY_IS_RUNNING_MASK;
WRITE_ONCE(*(svm->avic_physical_id_cache), entry);
}
@@ -4310,6 +4346,102 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
kvm_vcpu_wake_up(vcpu);
}

+/*
+ * svm_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
+ */
+static int svm_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 = NULL;
+ struct vcpu_data vcpu_info;
+ int idx, ret = -EINVAL;
+ struct vcpu_svm *svm;
+ struct amd_iommu_pi_data pi_data;
+
+ if (!kvm_arch_has_assigned_device(kvm) ||
+ !irq_remapping_cap(IRQ_POSTING_CAP))
+ return 0;
+
+ pr_debug("SVM: %s: host_irq=%#x, guest_irq=%#x, set=%#x\n",
+ __func__, host_irq, guest_irq, set);
+
+ idx = srcu_read_lock(&kvm->irq_srcu);
+ irq_rt = srcu_dereference(kvm->irq_routing, &kvm->irq_srcu);
+ WARN_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;
+
+ /**
+ * Note:
+ * The HW cannot support posting multicast/broadcast
+ * interrupts to a vCPU. So, 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.
+ */
+ kvm_set_msi_irq(e, &irq);
+ if (kvm_intr_is_single_vcpu(kvm, &irq, &vcpu)) {
+ svm = to_svm(vcpu);
+ vcpu_info.pi_desc_addr = page_to_phys(svm->avic_backing_page);
+ vcpu_info.vector = irq.vector;
+
+ trace_kvm_pi_irte_update(vcpu->vcpu_id, host_irq, e->gsi,
+ vcpu_info.vector,
+ vcpu_info.pi_desc_addr, set);
+
+ pi_data.vcpu_id = vcpu->vcpu_id;
+
+ pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
+ irq.vector);
+ } else {
+ set = false;
+
+ pr_debug("SVM: %s: use legacy intr remap mode for irq %u\n",
+ __func__, irq.vector);
+ }
+
+ /**
+ * Note:
+ * When AVIC is disabled, we fall-back to setup
+ * IRTE w/ legacy mode
+ */
+ if (set && kvm_vcpu_apicv_active(&svm->vcpu)) {
+ /* Enable GA mode in IRTE */
+ pi_data.vm_id = kvm->arch.avic_vm_id;
+ pi_data.vcpu_data = &vcpu_info;
+ ret = irq_set_vcpu_affinity(host_irq, &pi_data);
+ } else {
+ /* Use legacy mode in IRTE */
+ pi_data.vcpu_data = NULL;
+ ret = irq_set_vcpu_affinity(host_irq, &pi_data);
+ }
+
+ if (ret < 0) {
+ pr_err("%s: failed to update PI IRTE\n", __func__);
+ goto out;
+ }
+ }
+
+ ret = 0;
+out:
+ srcu_read_unlock(&kvm->irq_srcu, idx);
+ return ret;
+}
+
static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
{
struct vcpu_svm *svm = to_svm(vcpu);
@@ -5136,6 +5268,7 @@ static struct kvm_x86_ops svm_x86_ops = {

.pmu_ops = &amd_pmu_ops,
.deliver_posted_interrupt = svm_deliver_avic_intr,
+ .update_pi_irte = svm_update_pi_irte,
};

static int __init svm_init(void)
--
1.9.1