[PATCH 1/3] KVM: Emulation MSI-X mask bits for assigned devices

[Sheng Yang <sheng@xxxxxxxxxxxxxxx>]

This patch enable per-vector mask for assigned devices using MSI-X.

Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
---
 arch/x86/kvm/x86.c       |    1 +
 include/linux/kvm.h      |    9 ++++++++-
 include/linux/kvm_host.h |    1 +
 virt/kvm/assigned-dev.c  |   39 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 49 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8412c91..e6933e6 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1927,6 +1927,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 	case KVM_CAP_DEBUGREGS:
 	case KVM_CAP_X86_ROBUST_SINGLESTEP:
 	case KVM_CAP_XSAVE:
+	case KVM_CAP_DEVICE_MSIX_MASK:
 		r = 1;
 		break;
 	case KVM_CAP_COALESCED_MMIO:
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index 919ae53..f2b7cdc 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -540,6 +540,9 @@ struct kvm_ppc_pvinfo {
 #endif
 #define KVM_CAP_PPC_GET_PVINFO 57
 #define KVM_CAP_PPC_IRQ_LEVEL 58
+#ifdef __KVM_HAVE_MSIX
+#define KVM_CAP_DEVICE_MSIX_MASK 59
+#endif
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -787,11 +790,15 @@ 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 0b89d00..a43405c 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -415,6 +415,7 @@ 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..15b8c32 100644
--- a/virt/kvm/assigned-dev.c
+++ b/virt/kvm/assigned-dev.c
@@ -17,6 +17,8 @@
 #include <linux/pci.h>
 #include <linux/interrupt.h>
 #include <linux/slab.h>
+#include <linux/irqnr.h>
+
 #include "irq.h"
 
 static struct kvm_assigned_dev_kernel *kvm_find_assigned_dev(struct list_head *head,
@@ -666,6 +668,30 @@ msix_nr_out:
 	return r;
 }
 
+static void update_msix_mask(struct kvm_assigned_dev_kernel *assigned_dev,
+			     int index)
+{
+	int irq;
+
+	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;
+
+	ASSERT(irq != 0);
+
+	if (assigned_dev->guest_msix_entries[index].flags &
+			KVM_ASSIGNED_MSIX_MASK)
+		disable_irq(irq);
+	else {
+		enable_irq(irq);
+		if (assigned_dev->guest_msix_entries[index].flags &
+				KVM_ASSIGNED_MSIX_PENDING)
+			schedule_work(&assigned_dev->interrupt_work);
+	}
+}
+
 static int kvm_vm_ioctl_set_msix_entry(struct kvm *kvm,
 				       struct kvm_assigned_msix_entry *entry)
 {
@@ -688,6 +714,19 @@ 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 ((entry->flags & KVM_MSIX_FLAG_MASK) &&
+					!(adev->guest_msix_entries[i].flags &
+					KVM_ASSIGNED_MSIX_MASK)) {
+				adev->guest_msix_entries[i].flags |=
+					KVM_ASSIGNED_MSIX_MASK;
+				update_msix_mask(adev, i);
+			} else if (!(entry->flags & KVM_MSIX_FLAG_MASK) &&
+					(adev->guest_msix_entries[i].flags &
+					KVM_ASSIGNED_MSIX_MASK)) {
+				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

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