[PATCH 4/4] KVM: Device assignemnt with VT-d

Ben-Ami Yassour
2008-07-22T12:15:00Z

From: Kay, Allen M <allen.m.kay@intel.com>

This patch includes the functions to support VT-d for passthrough
devices.

[Ben: fixed memory pinning, cleanup]

Signed-off-by: Kay, Allen M <allen.m.kay@intel.com>
Signed-off-by: Weidong Han <weidong.han@intel.com>
Signed-off-by: Ben-Ami Yassour <benami@il.ibm.com>
---
arch/x86/kvm/Makefile | 2 +-
arch/x86/kvm/vtd.c | 182 ++++++++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.c | 11 +++
include/asm-x86/kvm_host.h | 3 +
include/linux/kvm_host.h | 6 ++
virt/kvm/kvm_main.c | 8 ++-
6 files changed, 210 insertions(+), 2 deletions(-)
create mode 100644 arch/x86/kvm/vtd.c

diff --git a/arch/x86/kvm/Makefile b/arch/x86/kvm/Makefile
index d0e940b..5d9d079 100644
--- a/arch/x86/kvm/Makefile
+++ b/arch/x86/kvm/Makefile
@@ -11,7 +11,7 @@ endif
EXTRA_CFLAGS += -Ivirt/kvm -Iarch/x86/kvm

kvm-objs := $(common-objs) x86.o mmu.o x86_emulate.o i8259.o irq.o lapic.o \
- i8254.o
+ i8254.o vtd.o
obj-$(CONFIG_KVM) += kvm.o
kvm-intel-objs = vmx.o
obj-$(CONFIG_KVM_INTEL) += kvm-intel.o
diff --git a/arch/x86/kvm/vtd.c b/arch/x86/kvm/vtd.c
new file mode 100644
index 0000000..7a3cf4e
--- /dev/null
+++ b/arch/x86/kvm/vtd.c
@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2006, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
+ * Place - Suite 330, Boston, MA 02111-1307 USA.
+ *
+ * Copyright (C) 2006-2008 Intel Corporation
+ * Author: Allen M. Kay <allen.m.kay@intel.com>
+ * Author: Weidong Han <weidong.han@intel.com>
+ */
+
+#include <linux/list.h>
+#include <linux/kvm_host.h>
+#include <linux/pci.h>
+#include <linux/dmar.h>
+#include <linux/intel-iommu.h>
+
+static int kvm_iommu_unmap_memslots(struct kvm *kvm);
+
+int kvm_iommu_map_pages(struct kvm *kvm,
+ gfn_t base_gfn, unsigned long npages)
+{
+ gfn_t gfn = base_gfn;
+ pfn_t pfn;
+ int i, rc;
+ struct dmar_domain *domain = kvm->arch.intel_iommu_domain;
+
+ if (!domain)
+ return -EFAULT;
+
+ for (i = 0; i < npages; i++) {
+ pfn = gfn_to_pfn(kvm, gfn);
+ if (!is_mmio_pfn(pfn)) {
+ rc = intel_iommu_page_mapping(domain,
+ gfn << PAGE_SHIFT,
+ pfn << PAGE_SHIFT,
+ PAGE_SIZE,
+ DMA_PTE_READ |
+ DMA_PTE_WRITE);
+ if (rc)
+ kvm_release_pfn_clean(pfn);
+ } else {
+ printk(KERN_DEBUG "kvm_iommu_map_page:"
+ "invalid pfn=%lx\n", pfn);
+ return 0;
+ }
+
+ gfn++;
+ }
+ return 0;
+}
+
+static int kvm_iommu_map_memslots(struct kvm *kvm)
+{
+ int i, rc;
+ for (i = 0; i < kvm->nmemslots; i++) {
+ rc = kvm_iommu_map_pages(kvm, kvm->memslots[i].base_gfn,
+ kvm->memslots[i].npages);
+ if (rc)
+ return rc;
+ }
+ return 0;
+}
+
+int kvm_iommu_map_guest(struct kvm *kvm,
+ struct kvm_assigned_dev *assigned_dev)
+{
+ struct pci_dev *pdev = NULL;
+
+ 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));
+
+ for_each_pci_dev(pdev) {
+ if ((pdev->bus->number == assigned_dev->host.busnr) &&
+ (pdev->devfn == assigned_dev->host.devfn)) {
+ break;
+ }
+ }
+
+ 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);
+
+ if (kvm_iommu_map_memslots(kvm)) {
+ kvm_iommu_unmap_memslots(kvm);
+ return -EFAULT;
+ }
+
+ intel_iommu_detach_dev(kvm->arch.intel_iommu_domain,
+ pdev->bus->number, pdev->devfn);
+
+ if (intel_iommu_context_mapping(kvm->arch.intel_iommu_domain,
+ pdev)) {
+ printk(KERN_ERR "Domain context map for %s failed",
+ pci_name(pdev));
+ return -EFAULT;
+ }
+ return 0;
+}
+
+static int kvm_iommu_put_pages(struct kvm *kvm,
+ gfn_t base_gfn, unsigned long npages)
+{
+ gfn_t gfn = base_gfn;
+ pfn_t pfn;
+ struct dmar_domain *domain = kvm->arch.intel_iommu_domain;
+ int i;
+
+ if (!domain)
+ return -EFAULT;
+
+ for (i = 0; i < npages; i++) {
+ pfn = (pfn_t)intel_iommu_iova_to_pfn(domain,
+ gfn << PAGE_SHIFT);
+ kvm_release_pfn_clean(pfn);
+ gfn++;
+ }
+ return 0;
+}
+
+static int kvm_iommu_unmap_memslots(struct kvm *kvm)
+{
+ int i, rc;
+ for (i = 0; i < kvm->nmemslots; i++) {
+ rc = kvm_iommu_put_pages(kvm, kvm->memslots[i].base_gfn,
+ kvm->memslots[i].npages);
+ if (rc)
+ return rc;
+ }
+ return 0;
+}
+
+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;
+
+ 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 d9aa931..e57c9e4 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -33,6 +33,7 @@
#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>
@@ -253,9 +254,17 @@ kvm_vm_ioctl_device_assignment(struct kvm *kvm,
}

+ if (intel_iommu_found()) {
+ r = kvm_iommu_map_guest(kvm, assigned_dev);
+ if (r)
+ goto out_intr;
+ }
+
out:
mutex_unlock(&kvm->lock);
return r;
+out_intr:
+ free_irq(dev->irq, match);
out_list_del:
list_del(&match->list);
pci_release_regions(dev);
@@ -4171,6 +4180,8 @@ static void kvm_free_vcpus(struct kvm *kvm)

void kvm_arch_destroy_vm(struct kvm *kvm)
{
+ if (intel_iommu_found())
+ kvm_iommu_unmap_guest(kvm);
kvm_free_assigned_devices(kvm);
kvm_free_pit(kvm);
kfree(kvm->arch.vpic);
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index 34eb3e7..75b088b 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -357,6 +357,7 @@ struct kvm_arch{
*/
struct list_head active_mmu_pages;
struct list_head assigned_dev_head;
+ struct dmar_domain *intel_iommu_domain;
struct kvm_pic *vpic;
struct kvm_ioapic *vioapic;
struct kvm_pit *vpit;
@@ -506,6 +507,8 @@ int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
int kvm_pv_mmu_op(struct kvm_vcpu *vcpu, unsigned long bytes,
gpa_t addr, unsigned long *ret);

+int is_mmio_pfn(pfn_t pfn);
+
extern bool tdp_enabled;

enum emulation_result {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 3798097..506b595 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -279,6 +279,12 @@ 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);

+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 *assigned_dev);
+int kvm_iommu_unmap_guest(struct kvm *kvm);
+
static inline void kvm_guest_enter(void)
{
account_system_vtime(current);
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 5b470a1..49c4ed3 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -41,6 +41,7 @@
#include <linux/pagemap.h>
#include <linux/mman.h>
#include <linux/swap.h>
+#include <linux/intel-iommu.h>

#include <asm/processor.h>
#include <asm/io.h>
@@ -76,7 +77,7 @@ static inline int valid_vcpu(int n)
return likely(n >= 0 && n < KVM_MAX_VCPUS);
}

-static inline int is_mmio_pfn(pfn_t pfn)
+inline int is_mmio_pfn(pfn_t pfn)
{
if (pfn_valid(pfn))
return PageReserved(pfn_to_page(pfn));
@@ -431,6 +432,11 @@ int __kvm_set_memory_region(struct kvm *kvm,
}

kvm_free_physmem_slot(&old, &new);
+
+ /* map the pages in iommu page table */
+ if (intel_iommu_found())
+ kvm_iommu_map_pages(kvm, base_gfn, npages);
+
return 0;

out_free:
--
1.5.6