VT-d: various initialization fixes

Detect invalid/unsupported configurations in iommu_alloc() - offsets
read from hardware must not lead to exceeding a single page (since
only that much gets mapped). This covers the apparently not uncommon
case of the address pointed to by a DMAR reading as all ones (Linux
for example also checks for this).

Further correct error handling of that function: Without storing the
allocated "struct iommu" instance in the drhd, iommu_free() won't do
anything, and hence all successfully set up pieces would be leaked.

Also keep iommu_free() from calling destroy_irq() when no irq was
ever set up.

Additionally, clear_fault_bits() has no need to read the capabilities
field from I/O memory - it's already cached in "struct iommu".

Finally, simplify print_iommu_regs() and its output, and actually use
this function.

Signed-off-by: Jan Beulich <jbeulich@novell.com>

2 files changed, 42 insertions, 52 deletions

diff --git a/xen/drivers/passthrough/vtd/iommu.c b/xen/drivers/passthrough/vtd/iommu.c
index 460e7032cc..6b18216d82 100644
--- a/xen/drivers/passthrough/vtd/iommu.c
+++ b/xen/drivers/passthrough/vtd/iommu.c
@@ -1068,9 +1068,21 @@ static int iommu_alloc(struct acpi_drhd_unit *drhd)
     iommu->cap = dmar_readq(iommu->reg, DMAR_CAP_REG);
     iommu->ecap = dmar_readq(iommu->reg, DMAR_ECAP_REG);
 
-    dprintk(XENLOG_INFO VTDPREFIX,
-             "drhd->address = %"PRIx64"\n", drhd->address);
-    dprintk(XENLOG_INFO VTDPREFIX, "iommu->reg = %p\n", iommu->reg);
+    drhd->iommu = iommu;
+
+    dprintk(XENLOG_DEBUG VTDPREFIX,
+            "drhd->address = %"PRIx64" iommu->reg = %p\n",
+            drhd->address, iommu->reg);
+    dprintk(XENLOG_DEBUG VTDPREFIX,
+            "cap = %"PRIx64" ecap = %"PRIx64"\n", iommu->cap, iommu->ecap);
+    if ( cap_fault_reg_offset(iommu->cap) +
+         cap_num_fault_regs(iommu->cap) * PRIMARY_FAULT_REG_LEN >= PAGE_SIZE ||
+         ecap_iotlb_offset(iommu->ecap) >= PAGE_SIZE )
+    {
+        dprintk(XENLOG_ERR VTDPREFIX, "IOMMU: unsupported\n");
+        print_iommu_regs(drhd);
+        return -ENODEV;
+    }
 
     /* Calculate number of pagetable levels: between 2 and 4. */
     sagaw = cap_sagaw(iommu->cap);
@@ -1081,7 +1093,7 @@ static int iommu_alloc(struct acpi_drhd_unit *drhd)
     {
         dprintk(XENLOG_ERR VTDPREFIX,
                  "IOMMU: unsupported sagaw %lx\n", sagaw);
-        xfree(iommu);
+        print_iommu_regs(drhd);
         return -ENODEV;
     }
     iommu->nr_pt_levels = agaw_to_level(agaw);
@@ -1111,7 +1123,6 @@ static int iommu_alloc(struct acpi_drhd_unit *drhd)
     spin_lock_init(&iommu->lock);
     spin_lock_init(&iommu->register_lock);
 
-    drhd->iommu = iommu;
     return 0;
 }
 
@@ -1122,6 +1133,8 @@ static void iommu_free(struct acpi_drhd_unit *drhd)
     if ( iommu == NULL )
         return;
 
+    drhd->iommu = NULL;
+
     if ( iommu->root_maddr != 0 )
     {
         free_pgtable_maddr(iommu->root_maddr);
@@ -1135,10 +1148,9 @@ static void iommu_free(struct acpi_drhd_unit *drhd)
     xfree(iommu->domid_map);
 
     free_intel_iommu(iommu->intel);
-    destroy_irq(iommu->irq);
+    if ( iommu->irq >= 0 )
+        destroy_irq(iommu->irq);
     xfree(iommu);
-
-    drhd->iommu = NULL;
 }
 
 #define guestwidth_to_adjustwidth(gaw) ({       \
@@ -1765,13 +1777,8 @@ void clear_fault_bits(struct iommu *iommu)
     unsigned long flags;
 
     spin_lock_irqsave(&iommu->register_lock, flags);
-    val = dmar_readq(
-        iommu->reg,
-        cap_fault_reg_offset(dmar_readq(iommu->reg,DMAR_CAP_REG))+0x8);
-    dmar_writeq(
-        iommu->reg,
-        cap_fault_reg_offset(dmar_readq(iommu->reg,DMAR_CAP_REG))+8,
-        val);
+    val = dmar_readq(iommu->reg, cap_fault_reg_offset(iommu->cap) + 8);
+    dmar_writeq(iommu->reg, cap_fault_reg_offset(iommu->cap) + 8, val);
     dmar_writel(iommu->reg, DMAR_FSTS_REG, DMA_FSTS_FAULTS);
     spin_unlock_irqrestore(&iommu->register_lock, flags);
 }
diff --git a/xen/drivers/passthrough/vtd/utils.c b/xen/drivers/passthrough/vtd/utils.c
index 4d5a5430f1..24bb106b39 100644
--- a/xen/drivers/passthrough/vtd/utils.c
+++ b/xen/drivers/passthrough/vtd/utils.c
@@ -59,45 +59,28 @@ void disable_pmr(struct iommu *iommu)
 void print_iommu_regs(struct acpi_drhd_unit *drhd)
 {
     struct iommu *iommu = drhd->iommu;
+    u64 cap;
 
     printk("---- print_iommu_regs ----\n");
-    printk("print_iommu_regs: drhd->address = %"PRIx64"\n", drhd->address);
-    printk("print_iommu_regs: DMAR_VER_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_VER_REG));
-    printk("print_iommu_regs: DMAR_CAP_REG = %"PRIx64"\n",
-           dmar_readq(iommu->reg,DMAR_CAP_REG));
-    printk("print_iommu_regs: n_fault_reg = %"PRIx64"\n",
-           cap_num_fault_regs(dmar_readq(iommu->reg, DMAR_CAP_REG)));
-    printk("print_iommu_regs: fault_recording_offset_l = %"PRIx64"\n",
-           cap_fault_reg_offset(dmar_readq(iommu->reg, DMAR_CAP_REG)));
-    printk("print_iommu_regs: fault_recording_offset_h = %"PRIx64"\n",
-           cap_fault_reg_offset(dmar_readq(iommu->reg, DMAR_CAP_REG)) + 8);
-    printk("print_iommu_regs: fault_recording_reg_l = %"PRIx64"\n",
-           dmar_readq(iommu->reg,
-               cap_fault_reg_offset(dmar_readq(iommu->reg, DMAR_CAP_REG))));
-    printk("print_iommu_regs: fault_recording_reg_h = %"PRIx64"\n",
-           dmar_readq(iommu->reg,
-               cap_fault_reg_offset(dmar_readq(iommu->reg, DMAR_CAP_REG)) + 8));
-    printk("print_iommu_regs: DMAR_ECAP_REG = %"PRIx64"\n",
-           dmar_readq(iommu->reg,DMAR_ECAP_REG));
-    printk("print_iommu_regs: DMAR_GCMD_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_GCMD_REG));
-    printk("print_iommu_regs: DMAR_GSTS_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_GSTS_REG));
-    printk("print_iommu_regs: DMAR_RTADDR_REG = %"PRIx64"\n",
-           dmar_readq(iommu->reg,DMAR_RTADDR_REG));
-    printk("print_iommu_regs: DMAR_CCMD_REG = %"PRIx64"\n",
-           dmar_readq(iommu->reg,DMAR_CCMD_REG));
-    printk("print_iommu_regs: DMAR_FSTS_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_FSTS_REG));
-    printk("print_iommu_regs: DMAR_FECTL_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_FECTL_REG));
-    printk("print_iommu_regs: DMAR_FEDATA_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_FEDATA_REG));
-    printk("print_iommu_regs: DMAR_FEADDR_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_FEADDR_REG));
-    printk("print_iommu_regs: DMAR_FEUADDR_REG = %x\n",
-           dmar_readl(iommu->reg,DMAR_FEUADDR_REG));
+    printk(" drhd->address = %"PRIx64"\n", drhd->address);
+    printk(" VER = %x\n", dmar_readl(iommu->reg, DMAR_VER_REG));
+    printk(" CAP = %"PRIx64"\n", cap = dmar_readq(iommu->reg, DMAR_CAP_REG));
+    printk(" n_fault_reg = %"PRIx64"\n", cap_num_fault_regs(cap));
+    printk(" fault_recording_offset = %"PRIx64"\n", cap_fault_reg_offset(cap));
+    printk(" fault_recording_reg_l = %"PRIx64"\n",
+           dmar_readq(iommu->reg, cap_fault_reg_offset(cap)));
+    printk(" fault_recording_reg_h = %"PRIx64"\n",
+           dmar_readq(iommu->reg, cap_fault_reg_offset(cap) + 8));
+    printk(" ECAP = %"PRIx64"\n", dmar_readq(iommu->reg, DMAR_ECAP_REG));
+    printk(" GCMD = %x\n", dmar_readl(iommu->reg, DMAR_GCMD_REG));
+    printk(" GSTS = %x\n", dmar_readl(iommu->reg, DMAR_GSTS_REG));
+    printk(" RTADDR = %"PRIx64"\n", dmar_readq(iommu->reg,DMAR_RTADDR_REG));
+    printk(" CCMD = %"PRIx64"\n", dmar_readq(iommu->reg, DMAR_CCMD_REG));
+    printk(" FSTS = %x\n", dmar_readl(iommu->reg, DMAR_FSTS_REG));
+    printk(" FECTL = %x\n", dmar_readl(iommu->reg, DMAR_FECTL_REG));
+    printk(" FEDATA = %x\n", dmar_readl(iommu->reg, DMAR_FEDATA_REG));
+    printk(" FEADDR = %x\n", dmar_readl(iommu->reg, DMAR_FEADDR_REG));
+    printk(" FEUADDR = %x\n", dmar_readl(iommu->reg, DMAR_FEUADDR_REG));
 }
 
 static u32 get_level_index(unsigned long gmfn, int level)