iommu: populate functions for setup/teardown of page tables
* setup_page_tables(): add pci_device to a proc's addr space
* teardown_page_tables(): remove pci_device from the proc's addr space
Signed-off-by: Aditya Basu <mitthu@google.com>
Signed-off-by: Barret Rhoden <brho@cs.berkeley.edu>
diff --git a/kern/drivers/dev/iommu.c b/kern/drivers/dev/iommu.c
index 9ae50fb..6fcb5a4 100644
--- a/kern/drivers/dev/iommu.c
+++ b/kern/drivers/dev/iommu.c
@@ -154,14 +154,72 @@
return rt;
}
-static void setup_page_tables(struct proc *p, struct pci_device *d)
+static struct context_entry *get_ctx_for(int bus, int dev, int func,
+ physaddr_t roottable)
{
- // setup the pte; use the pip as did
+ struct root_entry *rte;
+ physaddr_t cte_phy;
+ struct context_entry *cte;
+ uint32_t offset = 0;
+
+ rte = get_root_entry(roottable) + bus;
+
+ cte_phy = rte->lo & 0xFFFFFFFFFFFFF000;
+ cte = get_context_entry(cte_phy);
+
+ offset = (dev * 8) + func;
+ cte += offset;
+
+ return cte;
}
+/* The process pid is used as the Domain ID (DID) */
+static void setup_page_tables(struct proc *p, struct pci_device *d)
+{
+ uint32_t cmd, status;
+ uint16_t did = p->pid; /* casts down to 16-bit */
+ struct iommu *iommu = d->iommu;
+ struct context_entry *cte =
+ get_ctx_for(d->bus, d->dev, d->func, iommu->roottable);
+
+ /* Mark the entry as not present */
+ cte->lo &= ~0x1;
+ write_buffer_flush(iommu);
+ iotlb_flush(iommu, IOMMU_DID_DEFAULT);
+
+ cte->hi = 0
+ | (did << CTX_HI_DID_SHIFT) // DID bit: 72 to 87
+ | (CTX_AW_L4 << CTX_HI_AW_SHIFT); // AW
+
+ cte->lo = PTE_ADDR(p->env_pgdir.eptp)
+ | (0x0 << CTX_LO_TRANS_SHIFT)
+ | (0x1 << CTX_LO_FPD_SHIFT) // disable faults
+ | (0x1 << CTX_LO_PRESENT_SHIFT); /* mark present */
+}
+
+/* TODO: We should mark the entry as not present to block any stray DMAs from
+ * reaching the kernel. To force a re-attach the device to the kernel, we can
+ * use pid 0. */
static void teardown_page_tables(struct proc *p, struct pci_device *d)
{
- // revert to default did
+ uint16_t did = IOMMU_DID_DEFAULT;
+ struct iommu *iommu = d->iommu;
+ struct context_entry *cte =
+ get_ctx_for(d->bus, d->dev, d->func, iommu->roottable);
+
+ /* Mark the entry as not present */
+ cte->lo &= ~0x1;
+ write_buffer_flush(iommu);
+ iotlb_flush(iommu, p->pid);
+
+ cte->hi = 0
+ | (did << CTX_HI_DID_SHIFT) // DID bit: 72 to 87
+ | (CTX_AW_L4 << CTX_HI_AW_SHIFT); // AW
+
+ cte->lo = 0 /* assumes page alignment */
+ | (0x2 << CTX_LO_TRANS_SHIFT)
+ | (0x1 << CTX_LO_FPD_SHIFT) // disable faults
+ | (0x1 << CTX_LO_PRESENT_SHIFT); /* mark present */
}
static bool _iommu_enable(struct iommu *iommu)
