Sheng Yang wrote:
This patch finally enable MSI-X.
What we need for MSI-X:
1. Intercept one page in MMIO region of device. So that we can get guest desired
MSI-X table and set up the real one. Now this have been done by guest, and
transfer to kernel using ioctl KVM_SET_MSIX_NR and KVM_SET_MSIX_ENTRY.
2. Information for incoming interrupt. Now one device can have more than one
interrupt, and they are all handled by one workqueue structure. So we need to
identify them. The previous patch enable gsi_msg_pending_bitmap get this done.
3. Mapping from host IRQ to guest gsi as well as guest gsi to real MSI/MSI-X
message address/data. We used same entry number for the host and guest here, so
that it's easy to find the correlated guest gsi.
What we lack for now:
1. The PCI spec said nothing can existed with MSI-X table in the same page of
MMIO region, except pending bits. The patch ignore pending bits as the first
step (so they are always 0 - no pending).
2. The PCI spec allowed to change MSI-X table dynamically. That means, the OS
can enable MSI-X, then mask one MSI-X entry, modify it, and unmask it. The patch
didn't support this, and Linux also don't work in this way.
3. The patch didn't implement MSI-X mask all and mask single entry. I would
implement the former in driver/pci/msi.c later. And for single entry, userspace
should have reposibility to handle it.
Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
---
include/linux/kvm.h | 8 ++++
virt/kvm/kvm_main.c | 107 ++++++++++++++++++++++++++++++++++++++++++++++++---
2 files changed, 109 insertions(+), 6 deletions(-)
diff --git a/include/linux/kvm.h b/include/linux/kvm.h
index a2dfbe0..78480d0 100644
--- a/include/linux/kvm.h
+++ b/include/linux/kvm.h
@@ -440,6 +440,9 @@ struct kvm_irq_routing {
};
#endif
+#if defined(CONFIG_X86)
+#define KVM_CAP_DEVICE_MSIX 26
+#endif
We switched to a different way of depending on CONFIG_X86, see the other
KVM_CAP defines.
struct kvm_assigned_msix_nr {
__u32 assigned_dev_id;
__u16 entry_nr;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 4010802..d3acb37 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -280,13 +280,33 @@ static void kvm_free_assigned_irq(struct kvm *kvm,
* now, the kvm state is still legal for probably we also have to wait
* interrupt_work done.
*/
- disable_irq_nosync(assigned_dev->host_irq);
- cancel_work_sync(&assigned_dev->interrupt_work);
+ if (assigned_dev->irq_requested_type & KVM_ASSIGNED_DEV_MSIX) {
+ int i;
+ for (i = 0; i < assigned_dev->entries_nr; i++)
+ disable_irq_nosync(assigned_dev->
+ host_msix_entries[i].vector);
+
+ cancel_work_sync(&assigned_dev->interrupt_work);
+
+ for (i = 0; i < assigned_dev->entries_nr; i++)
+ free_irq(assigned_dev->host_msix_entries[i].vector,
+ (void *)assigned_dev);
+
+ assigned_dev->entries_nr = 0;
+ kfree(assigned_dev->host_msix_entries);
+ kfree(assigned_dev->guest_msix_entries);
+ pci_disable_msix(assigned_dev->dev);
+ } else {
+ /* Deal with MSI and INTx */
+ disable_irq_nosync(assigned_dev->host_irq);
+ cancel_work_sync(&assigned_dev->interrupt_work);
How about always have an array? That will also allow us to deal with
INTx where x=B,C,D.
Currently for MSI and INTx the array will hold just one active element.
- free_irq(assigned_dev->host_irq, (void *)assigned_dev);
+ 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);
+ if (assigned_dev->irq_requested_type &
+ KVM_ASSIGNED_DEV_HOST_MSI)
+ pci_disable_msi(assigned_dev->dev);
+ }
All those flags and bits are worrying me. Maybe each entry in the array
can have an ops member, and disabling would work by calling
->ops->disable().
We can do that later.
assigned_dev->irq_requested_type = 0;
}
@@ -415,6 +435,69 @@ static int assigned_device_update_msi(struct kvm *kvm,
adev->irq_requested_type |= KVM_ASSIGNED_DEV_HOST_MSI;
return 0;
}
+
+static int assigned_device_update_msix(struct kvm *kvm,
+ struct kvm_assigned_dev_kernel *adev,
+ struct kvm_assigned_irq *airq)
+{
+ /* TODO Deal with KVM_DEV_IRQ_ASSIGNED_MASK_MSIX */
+ int i, r;
+
+ adev->ack_notifier.gsi = -1;
+
+ if (irqchip_in_kernel(kvm)) {
+ if (airq->flags & KVM_DEV_IRQ_ASSIGN_MASK_MSIX) {
+ printk(KERN_WARNING
+ "kvm: unsupported mask MSI-X, flags 0x%x!\n",
+ airq->flags);
error, not printk
+ return 0;
+ }
+
+ if (!(airq->flags & KVM_DEV_IRQ_ASSIGN_ENABLE_MSIX)) {
+ /* Guest disable MSI-X */
+ kvm_free_assigned_irq(kvm, adev);
+ if (msi2intx) {
+ pci_enable_msi(adev->dev);
+ if (adev->dev->msi_enabled)
+ return assigned_device_update_msi(kvm,
+ adev, airq);
+ }
+ return assigned_device_update_intx(kvm, adev, airq);
+ }
+
+ /* host_msix_entries and guest_msix_entries should have been
+ * initialized */
+
+ if (adev->entries_nr == 0) {
+ printk(KERN_ERR
+ "kvm: MSI-X entry not initialized!\n");
+ return -EFAULT;
-EFAULT is for accesses to unmapped user memory; drop the printk.
+ }
+
+ kvm_free_assigned_irq(kvm, adev);
+
+ r = pci_enable_msix(adev->dev, adev->host_msix_entries,
+ adev->entries_nr);
+ if (r) {
+ printk(KERN_ERR "Fail to enable MSI-X feature!\n");
Drop the printk.
+ return r;
+ }
+
+ for (i = 0; i < adev->entries_nr; i++) {
+ r = request_irq((adev->host_msix_entries + i)->vector,
+ kvm_assigned_dev_intr, 0,
+ "kvm_assigned_msix_device",
+ (void *)adev);
+ if (r)
+ return r;
+ }
+ }
+
+ adev->irq_requested_type |= KVM_ASSIGNED_DEV_MSIX;
+
+ return 0;
+}
+
#endif
static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
@@ -461,12 +544,24 @@ static int kvm_vm_ioctl_assign_irq(struct kvm *kvm,
}
}
- if ((match->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI) &&
+ if (match->irq_requested_type & KVM_ASSIGNED_DEV_MSIX)
+ current_flags |= KVM_DEV_IRQ_ASSIGN_ENABLE_MSIX;
+ else if ((match->irq_requested_type & KVM_ASSIGNED_DEV_HOST_MSI) &&
(match->irq_requested_type & KVM_ASSIGNED_DEV_GUEST_MSI))
current_flags |= KVM_DEV_IRQ_ASSIGN_ENABLE_MSI;
changed_flags = assigned_irq->flags ^ current_flags;
+#ifdef CONFIG_X86
+ if (changed_flags & KVM_DEV_IRQ_ASSIGN_MSIX_ACTION) {
+ r = assigned_device_update_msix(kvm, match, assigned_irq);
+ if (r) {
+ printk(KERN_WARNING "kvm: failed to execute "
+ "MSI-X action!\n");
+ goto out_release;
+ }
+ } else
+#endif
if ((changed_flags & KVM_DEV_IRQ_ASSIGN_MSI_ACTION) ||
(msi2intx && match->dev->msi_enabled)) {
#ifdef CONFIG_X86
--
I have a truly marvellous patch that fixes the bug which this
signature is too narrow to contain.
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