* On Thursday 07 Aug 2008 19:44:47 Ben-Ami Yassour wrote:
> Based on a patch by: Kay, Allen M <[EMAIL PROTECTED]>
>
> This patch enables pci device assignment based on VT-d support.
> When a device is assigned to the guest, the guest memory is pinned and
> the mapping is updated in the VT-d IOMMU.
>
> Signed-off-by: Kay, Allen M <[EMAIL PROTECTED]>
> Signed-off-by: Weidong Han <[EMAIL PROTECTED]>
> Signed-off-by: Ben-Ami Yassour <[EMAIL PROTECTED]>
> ---
> arch/x86/kvm/Makefile | 3 +
> arch/x86/kvm/vtd.c | 203
> ++++++++++++++++++++++++++++++++++++++++++++ arch/x86/kvm/x86.c |
> 10 ++
> include/asm-x86/kvm_host.h | 3 +
> include/linux/kvm_host.h | 32 +++++++
> virt/kvm/kvm_main.c | 9 ++-
> 6 files changed, 259 insertions(+), 1 deletions(-)
> create mode 100644 arch/x86/kvm/vtd.c
> +int kvm_iommu_map_guest(struct kvm *kvm,
> + struct kvm_assigned_dev_kernel *assigned_dev)
> +{
> + struct pci_dev *pdev = NULL;
> + int rc;
> +
> + if (!intel_iommu_found()) {
> + printk(KERN_ERR "intel iommu not found\n");
> + return -ENODEV;
> + }
> +
> + printk(KERN_DEBUG "VT-d direct map: host bdf = %x:%x:%x\n",
> + assigned_dev->host_busnr,
> + PCI_SLOT(assigned_dev->host_devfn),
> + PCI_FUNC(assigned_dev->host_devfn));
> +
> + pdev = assigned_dev->dev;
> +
> + if (pdev == NULL) {
> + if (kvm->arch.intel_iommu_domain) {
> + intel_iommu_domain_exit(kvm->arch.intel_iommu_domain);
> + kvm->arch.intel_iommu_domain = NULL;
> + }
> + return -ENODEV;
> + }
> +
> + kvm->arch.intel_iommu_domain = intel_iommu_domain_alloc(pdev);
> +int kvm_iommu_unmap_guest(struct kvm *kvm)
> +{
> + struct kvm_assigned_dev_kernel *entry;
> + struct pci_dev *pdev = NULL;
> + struct dmar_domain *domain = kvm->arch.intel_iommu_domain;
> +
> + /* check if iommu exists and in use */
> + if (!domain)
> + return 0;
> +
> + list_for_each_entry(entry, &kvm->arch.assigned_dev_head, list) {
> + printk(KERN_DEBUG "VT-d unmap: host bdf = %x:%x:%x\n",
> + entry->host_busnr,
> + PCI_SLOT(entry->host_devfn),
> + PCI_FUNC(entry->host_devfn));
> +
> + for_each_pci_dev(pdev) {
> + if ((pdev->bus->number == entry->host_busnr) &&
> + (pdev->devfn == entry->host_devfn))
> + break;
> + }
> +
> + if (pdev == NULL)
> + return -ENODEV;
> +
> + /* detach kvm dmar domain */
> + intel_iommu_detach_dev(domain,
> + pdev->bus->number, pdev->devfn);
> + }
> + kvm_iommu_unmap_memslots(kvm);
> + intel_iommu_domain_exit(domain);
> + return 0;
> +}
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index a97157c..5cfc21a 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -35,6 +35,7 @@
> #include <linux/module.h>
> #include <linux/mman.h>
> #include <linux/highmem.h>
> +#include <linux/intel-iommu.h>
>
> #include <asm/uaccess.h>
> #include <asm/msr.h>
> @@ -271,9 +272,17 @@ static int kvm_vm_ioctl_assign_device(struct kvm *kvm,
>
> list_add(&match->list, &kvm->arch.assigned_dev_head);
>
> + /* currenlty iommu is required for handling dma */
> + r = kvm_iommu_map_guest(kvm, match);
> + if (r)
> + goto out_list_del;
> +
This will break pvdma support. Please check if intel-iommu is found and only
then bail out of here.
Even though pvdma is out-of-tree, it doesn't make sense to restrict our usage
here. AMD IOMMU support will need this to be handled in the right way as
well.
> out:
> mutex_unlock(&kvm->lock);
> return r;
> +out_list_del:
> + list_del(&match->list);
> + pci_release_regions(dev);
> out_disable:
> pci_disable_device(dev);
> out_put:
> @@ -4219,6 +4228,7 @@ static void kvm_free_vcpus(struct kvm *kvm)
>
> void kvm_arch_destroy_vm(struct kvm *kvm)
> {
> + kvm_iommu_unmap_guest(kvm);
Likewise, check if intel-iommu is found as a first step in this function.
As part of getting AMD-iommu and pvdma support in, we should have generic
function names, but that can be done later.
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index a18aaad..b703890 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -285,6 +285,33 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v);
> int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu);
> void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
>
> +#ifdef CONFIG_DMAR
> +int kvm_iommu_map_pages(struct kvm *kvm, gfn_t base_gfn,
> + unsigned long npages);
> +int kvm_iommu_map_guest(struct kvm *kvm,
> + struct kvm_assigned_dev_kernel *assigned_dev);
> +int kvm_iommu_unmap_guest(struct kvm *kvm);
> +#else /* CONFIG_DMAR */
> +static inline int kvm_iommu_map_pages(struct kvm *kvm,
> + gfn_t base_gfn,
> + unsigned long npages)
> +{
> + return 0;
> +}
> +
> +static inline int kvm_iommu_map_guest(struct kvm *kvm,
> + struct kvm_assigned_dev_kernel
> + *assigned_dev)
> +{
> + return -ENODEV;
> +}
> +
> +static inline int kvm_iommu_unmap_guest(struct kvm *kvm)
> +{
> + return 0;
> +}
> +#endif /* CONFIG_DMAR */
This means you can't use pvdma with iommu. Make these functions that check if
iommu support for device assignment is enabled. A command-line parameter to
qemu stating you want to enable vt-d for device assignment would be
appropriate.
For example, we could have the device assignment parameter changed to look
like this:
-pcidevice dev=00:13.0,dma=vtd,dma=pvdma
which will mean we should use vtd in conjunction with pvdma for this assigned
device.
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