kvm tools: Use the new KVM_SIGNAL_MSI ioctl to inject interrupts directly.

We still create GSIs and keep them for two reasons:

 - They're required by virtio-* devices.
 - There's not much overhead since we just create them when starting the
guest, they don't use anything when the guest is running.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/include/kvm/virtio-pci.h b/tools/kvm/include/kvm/virtio-pci.h
index 9e036b24ed9700446835cd36b2a1f3431d8eb1db..44130e0c5c0899010e70356421f1fab28783a50a 100644 (file)
--- a/tools/kvm/include/kvm/virtio-pci.h
+++ b/tools/kvm/include/kvm/virtio-pci.h
@@ -15,6 +15,8 @@ struct virtio_pci_ioevent_param {
        u32                     vq;
 };
 
+#define VIRTIO_PCI_F_SIGNAL_MSI (1 << 0)
+
 struct virtio_pci {
        struct pci_device_header pci_hdr;
        void                    *dev;
@@ -22,6 +24,7 @@ struct virtio_pci {
        u16                     base_addr;
        u8                      status;
        u8                      isr;
+       u32                     features;
 
        /* MSI-X */
        u16                     config_vector;

diff --git a/tools/kvm/virtio/pci.c b/tools/kvm/virtio/pci.c
index f17cd8aff80af13365a335160d594ebc5137c224..4dc79162ad2bf15e2b40120a5ef570bcf05b4764 100644 (file)
--- a/tools/kvm/virtio/pci.c
+++ b/tools/kvm/virtio/pci.c
@@ -7,6 +7,7 @@
 #include "kvm/virtio.h"
 #include "kvm/ioeventfd.h"
 
+#include <sys/ioctl.h>
 #include <linux/virtio_pci.h>
 #include <linux/byteorder.h>
 #include <string.h>
@@ -236,6 +237,17 @@ static void virtio_pci__mmio_callback(u64 addr, u8 *data, u32 len, u8 is_write,
                memcpy(data, table + addr - offset, len);
 }
 
+static void virtio_pci__signal_msi(struct kvm *kvm, struct virtio_pci *vpci, int vec)
+{
+       struct kvm_msi msi = {
+               .address_lo = vpci->msix_table[vec].msg.address_lo,
+               .address_hi = vpci->msix_table[vec].msg.address_hi,
+               .data = vpci->msix_table[vec].msg.data,
+       };
+
+       ioctl(kvm->vm_fd, KVM_SIGNAL_MSI, &msi);
+}
+
 int virtio_pci__signal_vq(struct kvm *kvm, struct virtio_device *vdev, u32 vq)
 {
        struct virtio_pci *vpci = vdev->virtio;
@@ -249,7 +261,10 @@ int virtio_pci__signal_vq(struct kvm *kvm, struct virtio_device *vdev, u32 vq)
                        return 0;
                }
 
-               kvm__irq_trigger(kvm, vpci->gsis[vq]);
+               if (vpci->features & VIRTIO_PCI_F_SIGNAL_MSI)
+                       virtio_pci__signal_msi(kvm, vpci, vpci->vq_vector[vq]);
+               else
+                       kvm__irq_trigger(kvm, vpci->gsis[vq]);
        } else {
                vpci->isr = VIRTIO_IRQ_HIGH;
                kvm__irq_trigger(kvm, vpci->pci_hdr.irq_line);
@@ -270,7 +285,10 @@ int virtio_pci__signal_config(struct kvm *kvm, struct virtio_device *vdev)
                        return 0;
                }
 
-               kvm__irq_trigger(kvm, vpci->config_gsi);
+               if (vpci->features & VIRTIO_PCI_F_SIGNAL_MSI)
+                       virtio_pci__signal_msi(kvm, vpci, vpci->vq_vector[vpci->config_vector]);
+               else
+                       kvm__irq_trigger(kvm, vpci->config_gsi);
        } else {
                vpci->isr = VIRTIO_PCI_ISR_CONFIG;
                kvm__irq_trigger(kvm, vpci->pci_hdr.irq_line);
@@ -347,6 +365,9 @@ int virtio_pci__init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
        if (r < 0)
                goto free_mmio;
 
+       if (kvm__supports_extension(kvm, KVM_CAP_SIGNAL_MSI))
+               vpci->features |= VIRTIO_PCI_F_SIGNAL_MSI;
+
        vpci->pci_hdr.irq_pin   = pin;
        vpci->pci_hdr.irq_line  = line;
        r = pci__register(&vpci->pci_hdr, ndev);