[PATCH v6 10/16] KVM: x86: Update IRTE for posted-interrupts

From: Feng Wu
Date: Tue Aug 11 2015 - 02:26:08 EST


This patch adds the routine to update IRTE for posted-interrupts
when guest changes the interrupt configuration.

Signed-off-by: Feng Wu <feng.wu@xxxxxxxxx>
---
arch/x86/kvm/x86.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 73 insertions(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 5ef2560..8f09a76 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -63,6 +63,7 @@
#include <asm/fpu/internal.h> /* Ugh! */
#include <asm/pvclock.h>
#include <asm/div64.h>
+#include <asm/irq_remapping.h>

#define MAX_IO_MSRS 256
#define KVM_MAX_MCE_BANKS 32
@@ -8248,6 +8249,78 @@ bool kvm_arch_has_noncoherent_dma(struct kvm *kvm)
}
EXPORT_SYMBOL_GPL(kvm_arch_has_noncoherent_dma);

+/*
+ * kvm_arch_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_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;
+
+ if (!irq_remapping_cap(IRQ_POSTING_CAP))
+ return 0;
+
+ 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;
+}
+
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_exit);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_inj_virq);
EXPORT_TRACEPOINT_SYMBOL_GPL(kvm_page_fault);
--
2.1.0

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