KVM: Switch assigned device IRQ forwarding to threaded handler

This improves the IRQ forwarding for assigned devices: By using the
kernel's threaded IRQ scheme, we can get rid of the latency-prone work
queue and simplify the code in the same run.

Moreover, we no longer have to hold assigned_dev_lock while raising the
guest IRQ, which can be a lenghty operation as we may have to iterate
over all VCPUs. The lock is now only used for synchronizing masking vs.
unmasking of INTx-type IRQs, thus is renames to intx_lock.

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2d63f2c0137c..9fe7fefe76b1 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -470,16 +470,8 @@ struct kvm_irq_ack_notifier {
         void (*irq_acked)(struct kvm_irq_ack_notifier *kian);
 };
 
-#define KVM_ASSIGNED_MSIX_PENDING               0x1
-struct kvm_guest_msix_entry {
-        u32 vector;
-        u16 entry;
-        u16 flags;
-};
-
 struct kvm_assigned_dev_kernel {
         struct kvm_irq_ack_notifier ack_notifier;
-        struct work_struct interrupt_work;
         struct list_head list;
         int assigned_dev_id;
         int host_segnr;
@@ -490,13 +482,13 @@ struct kvm_assigned_dev_kernel {
         bool host_irq_disabled;
         struct msix_entry *host_msix_entries;
         int guest_irq;
-        struct kvm_guest_msix_entry *guest_msix_entries;
+        struct msix_entry *guest_msix_entries;
         unsigned long irq_requested_type;
         int irq_source_id;
         int flags;
         struct pci_dev *dev;
         struct kvm *kvm;
-        spinlock_t assigned_dev_lock;
+        spinlock_t intx_lock;
 };
 
 struct kvm_irq_mask_notifier {