x86/amd-iommu: Add passthrough mode initialization functions
When iommu=pt is passed on kernel command line the devices
should run untranslated. This requires the allocation of a
special domain for that purpose. This patch implements the
allocation and initialization path for iommu=pt.
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
diff --git a/arch/x86/kernel/amd_iommu.c b/arch/x86/kernel/amd_iommu.c
index 0934348..7987f20 100644
--- a/arch/x86/kernel/amd_iommu.c
+++ b/arch/x86/kernel/amd_iommu.c
@@ -41,6 +41,12 @@
static LIST_HEAD(iommu_pd_list);
static DEFINE_SPINLOCK(iommu_pd_list_lock);
+/*
+ * Domain for untranslated devices - only allocated
+ * if iommu=pt passed on kernel cmd line.
+ */
+static struct protection_domain *pt_domain;
+
#ifdef CONFIG_IOMMU_API
static struct iommu_ops amd_iommu_ops;
#endif
@@ -1067,9 +1073,9 @@
* If a device is not yet associated with a domain, this function does
* assigns it visible for the hardware
*/
-static void attach_device(struct amd_iommu *iommu,
- struct protection_domain *domain,
- u16 devid)
+static void __attach_device(struct amd_iommu *iommu,
+ struct protection_domain *domain,
+ u16 devid)
{
unsigned long flags;
u64 pte_root = virt_to_phys(domain->pt_root);
@@ -1087,12 +1093,19 @@
amd_iommu_pd_table[devid] = domain;
write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+}
- /*
- * We might boot into a crash-kernel here. The crashed kernel
- * left the caches in the IOMMU dirty. So we have to flush
- * here to evict all dirty stuff.
- */
+static void attach_device(struct amd_iommu *iommu,
+ struct protection_domain *domain,
+ u16 devid)
+{
+ __attach_device(iommu, domain, devid);
+
+ /*
+ * We might boot into a crash-kernel here. The crashed kernel
+ * left the caches in the IOMMU dirty. So we have to flush
+ * here to evict all dirty stuff.
+ */
iommu_queue_inv_dev_entry(iommu, devid);
iommu_flush_tlb_pde(iommu, domain->id);
}
@@ -2219,3 +2232,46 @@
.domain_has_cap = amd_iommu_domain_has_cap,
};
+/*****************************************************************************
+ *
+ * The next functions do a basic initialization of IOMMU for pass through
+ * mode
+ *
+ * In passthrough mode the IOMMU is initialized and enabled but not used for
+ * DMA-API translation.
+ *
+ *****************************************************************************/
+
+int __init amd_iommu_init_passthrough(void)
+{
+ struct pci_dev *dev = NULL;
+ u16 devid, devid2;
+
+ /* allocate passthroug domain */
+ pt_domain = protection_domain_alloc();
+ if (!pt_domain)
+ return -ENOMEM;
+
+ pt_domain->mode |= PAGE_MODE_NONE;
+
+ while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+ struct amd_iommu *iommu;
+
+ devid = calc_devid(dev->bus->number, dev->devfn);
+ if (devid > amd_iommu_last_bdf)
+ continue;
+
+ devid2 = amd_iommu_alias_table[devid];
+
+ iommu = amd_iommu_rlookup_table[devid2];
+ if (!iommu)
+ continue;
+
+ __attach_device(iommu, pt_domain, devid);
+ __attach_device(iommu, pt_domain, devid2);
+ }
+
+ pr_info("AMD-Vi: Initialized for Passthrough Mode\n");
+
+ return 0;
+}