intel-iommu: Unify hardware and software passthrough support
This makes the hardware passthrough mode work a lot more like the
software version, so that the behaviour of a kernel with 'iommu=pt'
is the same whether the hardware supports passthrough or not.
In particular:
- We use a single si_domain for the pass-through devices.
- 32-bit devices can be taken out of the pass-through domain so that
they don't have to use swiotlb.
- Devices will work again after being removed from a KVM guest.
- A potential oops on OOM (in init_context_pass_through()) is fixed.
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
diff --git a/drivers/pci/intel-iommu.c b/drivers/pci/intel-iommu.c
index 097d5da..147b3b9 100644
--- a/drivers/pci/intel-iommu.c
+++ b/drivers/pci/intel-iommu.c
@@ -251,7 +251,8 @@
* 2. It maps to each iommu if successful.
* 3. Each iommu mapps to this domain if successful.
*/
-struct dmar_domain *si_domain;
+static struct dmar_domain *si_domain;
+static int hw_pass_through = 1;
/* devices under the same p2p bridge are owned in one domain */
#define DOMAIN_FLAG_P2P_MULTIPLE_DEVICES (1 << 0)
@@ -1948,14 +1949,24 @@
struct dmar_domain *domain;
int ret;
- printk(KERN_INFO
- "IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
- pci_name(pdev), start, end);
-
domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
if (!domain)
return -ENOMEM;
+ /* For _hardware_ passthrough, don't bother. But for software
+ passthrough, we do it anyway -- it may indicate a memory
+ range which is reserved in E820, so which didn't get set
+ up to start with in si_domain */
+ if (domain == si_domain && hw_pass_through) {
+ printk("Ignoring identity map for HW passthrough device %s [0x%Lx - 0x%Lx]\n",
+ pci_name(pdev), start, end);
+ return 0;
+ }
+
+ printk(KERN_INFO
+ "IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
+ pci_name(pdev), start, end);
+
ret = iommu_domain_identity_map(domain, start, end);
if (ret)
goto error;
@@ -2006,23 +2017,6 @@
}
#endif /* !CONFIG_DMAR_FLPY_WA */
-/* Initialize each context entry as pass through.*/
-static int __init init_context_pass_through(void)
-{
- struct pci_dev *pdev = NULL;
- struct dmar_domain *domain;
- int ret;
-
- for_each_pci_dev(pdev) {
- domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
- ret = domain_context_mapping(domain, pdev,
- CONTEXT_TT_PASS_THROUGH);
- if (ret)
- return ret;
- }
- return 0;
-}
-
static int md_domain_init(struct dmar_domain *domain, int guest_width);
static int __init si_domain_work_fn(unsigned long start_pfn,
@@ -2037,7 +2031,7 @@
}
-static int si_domain_init(void)
+static int si_domain_init(int hw)
{
struct dmar_drhd_unit *drhd;
struct intel_iommu *iommu;
@@ -2064,6 +2058,9 @@
si_domain->flags = DOMAIN_FLAG_STATIC_IDENTITY;
+ if (hw)
+ return 0;
+
for_each_online_node(nid) {
work_with_active_regions(nid, si_domain_work_fn, &ret);
if (ret)
@@ -2155,24 +2152,26 @@
return 1;
}
-static int iommu_prepare_static_identity_mapping(void)
+static int iommu_prepare_static_identity_mapping(int hw)
{
struct pci_dev *pdev = NULL;
int ret;
- ret = si_domain_init();
+ ret = si_domain_init(hw);
if (ret)
return -EFAULT;
for_each_pci_dev(pdev) {
if (iommu_should_identity_map(pdev, 1)) {
- printk(KERN_INFO "IOMMU: identity mapping for device %s\n",
- pci_name(pdev));
+ printk(KERN_INFO "IOMMU: %s identity mapping for device %s\n",
+ hw ? "hardware" : "software", pci_name(pdev));
ret = domain_context_mapping(si_domain, pdev,
+ hw ? CONTEXT_TT_PASS_THROUGH :
CONTEXT_TT_MULTI_LEVEL);
if (ret)
return ret;
+
ret = domain_add_dev_info(si_domain, pdev);
if (ret)
return ret;
@@ -2189,14 +2188,6 @@
struct pci_dev *pdev;
struct intel_iommu *iommu;
int i, ret;
- int pass_through = 1;
-
- /*
- * In case pass through can not be enabled, iommu tries to use identity
- * mapping.
- */
- if (iommu_pass_through)
- iommu_identity_mapping = 1;
/*
* for each drhd
@@ -2250,14 +2241,8 @@
goto error;
}
if (!ecap_pass_through(iommu->ecap))
- pass_through = 0;
+ hw_pass_through = 0;
}
- if (iommu_pass_through)
- if (!pass_through) {
- printk(KERN_INFO
- "Pass Through is not supported by hardware.\n");
- iommu_pass_through = 0;
- }
/*
* Start from the sane iommu hardware state.
@@ -2312,63 +2297,56 @@
}
}
- /*
- * If pass through is set and enabled, context entries of all pci
- * devices are intialized by pass through translation type.
- */
- if (iommu_pass_through) {
- ret = init_context_pass_through();
- if (ret) {
- printk(KERN_ERR "IOMMU: Pass through init failed.\n");
- iommu_pass_through = 0;
- }
- }
-
+ if (iommu_pass_through)
+ iommu_identity_mapping = 1;
+#ifdef CONFIG_DMAR_BROKEN_GFX_WA
+ else
+ iommu_identity_mapping = 2;
+#endif
/*
* If pass through is not set or not enabled, setup context entries for
* identity mappings for rmrr, gfx, and isa and may fall back to static
* identity mapping if iommu_identity_mapping is set.
*/
- if (!iommu_pass_through) {
-#ifdef CONFIG_DMAR_BROKEN_GFX_WA
- if (!iommu_identity_mapping)
- iommu_identity_mapping = 2;
-#endif
- if (iommu_identity_mapping)
- iommu_prepare_static_identity_mapping();
- /*
- * For each rmrr
- * for each dev attached to rmrr
- * do
- * locate drhd for dev, alloc domain for dev
- * allocate free domain
- * allocate page table entries for rmrr
- * if context not allocated for bus
- * allocate and init context
- * set present in root table for this bus
- * init context with domain, translation etc
- * endfor
- * endfor
- */
- printk(KERN_INFO "IOMMU: Setting RMRR:\n");
- for_each_rmrr_units(rmrr) {
- for (i = 0; i < rmrr->devices_cnt; i++) {
- pdev = rmrr->devices[i];
- /*
- * some BIOS lists non-exist devices in DMAR
- * table.
- */
- if (!pdev)
- continue;
- ret = iommu_prepare_rmrr_dev(rmrr, pdev);
- if (ret)
- printk(KERN_ERR
- "IOMMU: mapping reserved region failed\n");
- }
+ if (iommu_identity_mapping) {
+ ret = iommu_prepare_static_identity_mapping(hw_pass_through);
+ if (ret) {
+ printk(KERN_CRIT "Failed to setup IOMMU pass-through\n");
+ goto error;
}
-
- iommu_prepare_isa();
}
+ /*
+ * For each rmrr
+ * for each dev attached to rmrr
+ * do
+ * locate drhd for dev, alloc domain for dev
+ * allocate free domain
+ * allocate page table entries for rmrr
+ * if context not allocated for bus
+ * allocate and init context
+ * set present in root table for this bus
+ * init context with domain, translation etc
+ * endfor
+ * endfor
+ */
+ printk(KERN_INFO "IOMMU: Setting RMRR:\n");
+ for_each_rmrr_units(rmrr) {
+ for (i = 0; i < rmrr->devices_cnt; i++) {
+ pdev = rmrr->devices[i];
+ /*
+ * some BIOS lists non-exist devices in DMAR
+ * table.
+ */
+ if (!pdev)
+ continue;
+ ret = iommu_prepare_rmrr_dev(rmrr, pdev);
+ if (ret)
+ printk(KERN_ERR
+ "IOMMU: mapping reserved region failed\n");
+ }
+ }
+
+ iommu_prepare_isa();
/*
* for each drhd
@@ -2536,7 +2514,10 @@
ret = domain_add_dev_info(si_domain, pdev);
if (ret)
return 0;
- ret = domain_context_mapping(si_domain, pdev, CONTEXT_TT_MULTI_LEVEL);
+ ret = domain_context_mapping(si_domain, pdev,
+ hw_pass_through ?
+ CONTEXT_TT_PASS_THROUGH :
+ CONTEXT_TT_MULTI_LEVEL);
if (!ret) {
printk(KERN_INFO "64bit %s uses identity mapping\n",
pci_name(pdev));
@@ -3202,7 +3183,7 @@
* Check the need for DMA-remapping initialization now.
* Above initialization will also be used by Interrupt-remapping.
*/
- if (no_iommu || (swiotlb && !iommu_pass_through) || dmar_disabled)
+ if (no_iommu || swiotlb || dmar_disabled)
return -ENODEV;
iommu_init_mempool();
@@ -3222,14 +3203,7 @@
init_timer(&unmap_timer);
force_iommu = 1;
-
- if (!iommu_pass_through) {
- printk(KERN_INFO
- "Multi-level page-table translation for DMAR.\n");
- dma_ops = &intel_dma_ops;
- } else
- printk(KERN_INFO
- "DMAR: Pass through translation for DMAR.\n");
+ dma_ops = &intel_dma_ops;
init_iommu_sysfs();