On 05/06/2012 06:24 PM, Xudong Hao wrote:
> Enable device LTR/OBFF capibility before do device assignment, so that guest can benefit from them.
cc += Alex
> @@ -166,6 +166,10 @@ int kvm_assign_device(struct kvm *kvm,
> if (pdev == NULL)
> return -ENODEV;
>
> + /* Enable some device capibility before do device assignment,
> + * so that guest can benefit from them.
> + */
> + kvm_iommu_enable_dev_caps(pdev);
> r = iommu_attach_device(domain, &pdev->dev);
Suppose we fail here. Do we need to disable_dev_caps()?
> if (r) {
> printk(KERN_ERR "assign device %x:%x:%x.%x failed",
> @@ -228,6 +232,7 @@ int kvm_deassign_device(struct kvm *kvm,
> PCI_SLOT(assigned_dev->host_devfn),
> PCI_FUNC(assigned_dev->host_devfn));
>
> + kvm_iommu_disable_dev_caps(pdev);
> return 0;
> }
>
> @@ -351,3 +356,30 @@ int kvm_iommu_unmap_guest(struct kvm *kvm)
> iommu_domain_free(domain);
> return 0;
> }
> +
> +static void kvm_iommu_enable_dev_caps(struct pci_dev *pdev)
> +{
> + /* set default value */
> + unsigned long type = PCI_EXP_OBFF_SIGNAL_ALWAYS;
> + int snoop_lat_ns = 1024, nosnoop_lat_ns = 1024;
Where does this magic number come from?
> +
> + /* LTR(Latency tolerance reporting) allows devices to send
> + * messages to the root complex indicating their latency
> + * tolerance for snooped & unsnooped memory transactions.
> + */
> + pci_enable_ltr(pdev);
> + pci_set_ltr(pdev, snoop_lat_ns, nosnoop_lat_ns);
> +
> + /* OBFF (optimized buffer flush/fill), where supported,
> + * can help improve energy efficiency by giving devices
> + * information about when interrupts and other activity
> + * will have a reduced power impact.
> + */
> + pci_enable_obff(pdev, type);
> +}
> +
> +static void kvm_iommu_disable_dev_caps(struct pci_dev *pdev)
> +{
> + pci_disble_obff(pdev);
> + pci_disble_ltr(pdev);
> +}
Do we need to communicate something about these capabilities to the guest?
--
error compiling committee.c: too many arguments to function
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