[PATCH 8/9] KVM: Enable MSI for device assignment

Sheng Yang
2008-11-24T06:36:40Z

We enable guest MSI and host MSI support in this patch. The userspace want to
enable MSI should set KVM_DEV_IRQ_ASSIGN_ENABLE_MSI in the assigned_irq's flag.
Function would return -ENOTTY if can't enable MSI, userspace shouldn't set MSI
Enable bit when KVM_ASSIGN_IRQ return -ENOTTY with
KVM_DEV_IRQ_ASSIGN_ENABLE_MSI.

Userspace can tell the support of MSI device from #ifdef KVM_CAP_DEVICE_MSI.

Signed-off-by: Sheng Yang <sheng@linux.intel.com>
---
include/linux/kvm.h | 3 ++
virt/kvm/kvm_main.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++----
2 files changed, 78 insertions(+), 6 deletions(-)

diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index bb283c3..0997e6f 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -392,6 +392,9 @@ struct kvm_trace_rec {
#endif
#define KVM_CAP_IOMMU 18
#define KVM_CAP_NMI 19
+#if defined(CONFIG_X86)
+#define KVM_CAP_DEVICE_MSI 20
+#endif

/*
* ioctls for VM fds
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 228c1d1..bf36ae9 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -159,9 +159,15 @@ static void kvm_assigned_dev_interrupt_work_handler(struct work_struct *work)
* finer-grained lock, update this
*/
mutex_lock(&assigned_dev->kvm->lock);
- kvm_set_irq(assigned_dev->kvm,
- assigned_dev->irq_source_id,
- assigned_dev->guest_irq, 1);
+ if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_GUEST_INTX)
+ kvm_set_irq(assigned_dev->kvm,
+ assigned_dev->irq_source_id,
+ assigned_dev->guest_irq, 1);
+ else if (assigned_dev->irq_requested_type &
+ KVM_ASSIGNED_DEV_GUEST_MSI) {
+ assigned_device_msi_dispatch(assigned_dev);
+ enable_irq(assigned_dev->host_irq);
+ }
mutex_unlock(&assigned_dev->kvm->lock);
kvm_put_kvm(assigned_dev->kvm);
}
@@ -197,6 +203,8 @@ static void kvm_free_assigned_device(struct kvm *kvm,
{
if (irqchip_in_kernel(kvm) && assigned_dev->irq_requested_type)
free_irq(assigned_dev->host_irq, (void *)assigned_dev);
+ if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI)
+ pci_disable_msi(assigned_dev->dev);

kvm_unregister_irq_ack_notifier(&assigned_dev->ack_notifier);
kvm_free_irq_source_id(kvm, assigned_dev->irq_source_id);
@@ -242,6 +250,11 @@ static int assigned_device_update_intx(struct kvm *kvm,
return 0;

if (irqchip_in_kernel(kvm)) {
+ if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI) {
+ free_irq(adev->host_irq, (void *)kvm);
+ pci_disable_msi(adev->dev);
+ }
+
if (!capable(CAP_SYS_RAWIO))
return -EPERM;

@@ -265,6 +278,41 @@ static int assigned_device_update_intx(struct kvm *kvm,
return 0;
}

+#ifdef CONFIG_X86
+static int assigned_device_update_msi(struct kvm *kvm,
+ struct kvm_assigned_dev_kernel *adev,
+ struct kvm_assigned_irq *airq)
+{
+ int r;
+
+ /* x86 don't care upper address of guest msi message addr */
+ adev->guest_msi.address_lo = airq->guest_msi.addr_lo;
+ adev->guest_msi.data = airq->guest_msi.data;
+ adev->ack_notifier.gsi = -1;
+
+ if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI)
+ return 0;
+
+ if (irqchip_in_kernel(kvm)) {
+ if (adev->irq_requested_type & KVM_ASSIGNED_DEV_HOST_INTX)
+ free_irq(adev->host_irq, (void *)adev);
+
+ r = pci_enable_msi(adev->dev);
+ if (r)
+ return r;
+
+ adev->host_irq = adev->dev->irq;
+ if (request_irq(adev->host_irq, kvm_assigned_dev_intr, 0,
+ "kvm_assigned_msi_device", (void *)adev))
+ return -EIO;
+ }
+
+ adev->irq_requested_type = KVM_ASSIGNED_DEV_GUEST_MSI |
+ KVM_ASSIGNED_DEV_HOST_MSI;
+ return 0;
+}
+#endif
+
static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
struct kvm_assigned_irq
*assigned_irq)
@@ -301,9 +349,30 @@ static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
}
}

- r = assigned_device_update_intx(kvm, match, assigned_irq);
- if (r)
- goto out_release;
+ if (assigned_irq->flags & KVM_DEV_IRQ_ASSIGN_ENABLE_MSI) {
+#ifdef CONFIG_X86
+ r = assigned_device_update_msi(kvm, match, assigned_irq);
+ if (r) {
+ printk(KERN_WARNING "kvm: failed to enable "
+ "MSI device!\n");
+ goto out_release;
+ }
+#else
+ r = -ENOTTY;
+#endif
+ } else if (assigned_irq->host_irq == 0 && match->dev->irq == 0) {
+ /* Host device IRQ 0 means don't support INTx */
+ printk(KERN_WARNING "kvm: wait device to enable MSI!\n");
+ r = 0;
+ } else {
+ /* Non-sharing INTx mode */
+ r = assigned_device_update_intx(kvm, match, assigned_irq);
+ if (r) {
+ printk(KERN_WARNING "kvm: failed to enable "
+ "INTx device!\n");
+ goto out_release;
+ }
+ }

mutex_unlock(&kvm->lock);
return r;
--
1.5.4.5