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authorSheng Yang <sheng@linux.intel.com>2009-04-27 20:35:43 +0800
committerAvi Kivity <avi@redhat.com>2009-06-10 11:48:50 +0300
commit522c68c4416de3cd3e11a9ff10d58e776a69ae1e (patch)
tree62940e35988f5e2a52df10276882ec64518ee369 /virt
parent4b12f0de33a64dfc624b2480f55b674f7fa23ef2 (diff)
downloadlinux-linaro-stable-522c68c4416de3cd3e11a9ff10d58e776a69ae1e.tar.gz
KVM: Enable snooping control for supported hardware
Memory aliases with different memory type is a problem for guest. For the guest without assigned device, the memory type of guest memory would always been the same as host(WB); but for the assigned device, some part of memory may be used as DMA and then set to uncacheable memory type(UC/WC), which would be a conflict of host memory type then be a potential issue. Snooping control can guarantee the cache correctness of memory go through the DMA engine of VT-d. [avi: fix build on ia64] Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt')
-rw-r--r--virt/kvm/iommu.c27
1 files changed, 24 insertions, 3 deletions
diff --git a/virt/kvm/iommu.c b/virt/kvm/iommu.c
index 4c4037503600..15147583abd1 100644
--- a/virt/kvm/iommu.c
+++ b/virt/kvm/iommu.c
@@ -39,11 +39,16 @@ int kvm_iommu_map_pages(struct kvm *kvm,
pfn_t pfn;
int i, r = 0;
struct iommu_domain *domain = kvm->arch.iommu_domain;
+ int flags;
/* check if iommu exists and in use */
if (!domain)
return 0;
+ flags = IOMMU_READ | IOMMU_WRITE;
+ if (kvm->arch.iommu_flags & KVM_IOMMU_CACHE_COHERENCY)
+ flags |= IOMMU_CACHE;
+
for (i = 0; i < npages; i++) {
/* check if already mapped */
if (iommu_iova_to_phys(domain, gfn_to_gpa(gfn)))
@@ -53,8 +58,7 @@ int kvm_iommu_map_pages(struct kvm *kvm,
r = iommu_map_range(domain,
gfn_to_gpa(gfn),
pfn_to_hpa(pfn),
- PAGE_SIZE,
- IOMMU_READ | IOMMU_WRITE);
+ PAGE_SIZE, flags);
if (r) {
printk(KERN_ERR "kvm_iommu_map_address:"
"iommu failed to map pfn=%lx\n", pfn);
@@ -88,7 +92,7 @@ int kvm_assign_device(struct kvm *kvm,
{
struct pci_dev *pdev = NULL;
struct iommu_domain *domain = kvm->arch.iommu_domain;
- int r;
+ int r, last_flags;
/* check if iommu exists and in use */
if (!domain)
@@ -107,12 +111,29 @@ int kvm_assign_device(struct kvm *kvm,
return r;
}
+ last_flags = kvm->arch.iommu_flags;
+ if (iommu_domain_has_cap(kvm->arch.iommu_domain,
+ IOMMU_CAP_CACHE_COHERENCY))
+ kvm->arch.iommu_flags |= KVM_IOMMU_CACHE_COHERENCY;
+
+ /* Check if need to update IOMMU page table for guest memory */
+ if ((last_flags ^ kvm->arch.iommu_flags) ==
+ KVM_IOMMU_CACHE_COHERENCY) {
+ kvm_iommu_unmap_memslots(kvm);
+ r = kvm_iommu_map_memslots(kvm);
+ if (r)
+ goto out_unmap;
+ }
+
printk(KERN_DEBUG "assign device: host bdf = %x:%x:%x\n",
assigned_dev->host_busnr,
PCI_SLOT(assigned_dev->host_devfn),
PCI_FUNC(assigned_dev->host_devfn));
return 0;
+out_unmap:
+ kvm_iommu_unmap_memslots(kvm);
+ return r;
}
int kvm_deassign_device(struct kvm *kvm,