[PATCH 6/8] KVM: assigned dev: Preparation for mask support in userspace

[Sheng Yang <sheng@linux.intel.com>]

The feature wouldn't be enabled until later patch set msix_flags_enabled. It
would be enabled along with mask support in kernel.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
 arch/x86/include/asm/kvm_host.h |    2 ++
 include/linux/kvm.h             |    6 +++++-
 include/linux/kvm_host.h        |    1 +
 virt/kvm/assigned-dev.c         |   39 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 47 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index e209078..2bb69ba 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -456,6 +456,8 @@ struct kvm_arch {
 	/* fields used by HYPER-V emulation */
 	u64 hv_guest_os_id;
 	u64 hv_hypercall;
+
+	bool msix_flags_enabled;
 };
 
 struct kvm_vm_stat {
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 919ae53..a699ec9 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -787,11 +787,15 @@ struct kvm_assigned_msix_nr {
 };
 
 #define KVM_MAX_MSIX_PER_DEV		256
+
+#define KVM_MSIX_FLAG_MASK	1
+
 struct kvm_assigned_msix_entry {
 	__u32 assigned_dev_id;
 	__u32 gsi;
 	__u16 entry; /* The index of entry in the MSI-X table */
-	__u16 padding[3];
+	__u16 flags;
+	__u16 padding[2];
 };
 
 #endif /* __LINUX_KVM_H */
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 30f83cd..81a6284 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -438,6 +438,7 @@ struct kvm_irq_ack_notifier {
 };
 
 #define KVM_ASSIGNED_MSIX_PENDING		0x1
+#define KVM_ASSIGNED_MSIX_MASK			0x2
 struct kvm_guest_msix_entry {
 	u32 vector;
 	u16 entry;
diff --git a/virt/kvm/assigned-dev.c b/virt/kvm/assigned-dev.c
index 7c98928..bf96ea7 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -666,11 +666,35 @@ msix_nr_out:
 	return r;
 }
 
+static void update_msix_mask(struct kvm_assigned_dev_kernel *assigned_dev,
+			     int index)
+{
+	int irq;
+	struct irq_desc *desc;
+
+	if (!assigned_dev->dev->msix_enabled ||
+	    !(assigned_dev->irq_requested_type & KVM_DEV_IRQ_HOST_MSIX))
+		return;
+
+	irq = assigned_dev->host_msix_entries[index].vector;
+	BUG_ON(irq == 0);
+	desc = irq_to_desc(irq);
+	BUG_ON(!desc->msi_desc);
+
+	if (assigned_dev->guest_msix_entries[index].flags &
+			KVM_ASSIGNED_MSIX_MASK) {
+		desc->chip->mask(irq);
+		flush_work(&assigned_dev->interrupt_work);
+	} else
+		desc->chip->unmask(irq);
+}
+
 static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
 				       struct kvm_assigned_msix_entry *entry)
 {
 	int r = 0, i;
 	struct kvm_assigned_dev_kernel *adev;
+	bool entry_masked;
 
 	mutex_lock(&kvm->lock);
 
@@ -688,6 +712,21 @@ static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
 			adev->guest_msix_entries[i].entry = entry->entry;
 			adev->guest_msix_entries[i].vector = entry->gsi;
 			adev->host_msix_entries[i].entry = entry->entry;
+			if (!kvm->arch.msix_flags_enabled)
+				break;
+			entry_masked = adev->guest_msix_entries[i].flags &
+				KVM_ASSIGNED_MSIX_MASK;
+			if ((entry->flags & KVM_MSIX_FLAG_MASK) &&
+					!entry_masked) {
+				adev->guest_msix_entries[i].flags |=
+					KVM_ASSIGNED_MSIX_MASK;
+				update_msix_mask(adev, i);
+			} else if (!(entry->flags & KVM_MSIX_FLAG_MASK) &&
+					entry_masked) {
+				adev->guest_msix_entries[i].flags &=
+					~KVM_ASSIGNED_MSIX_MASK;
+				update_msix_mask(adev, i);
+			}
 			break;
 		}
 	if (i == adev->entries_nr) {
-- 
1.7.0.1