[PATCH 11/17] AMD/IOMMU: walk trees upon page fault

[Jan Beulich <jbeulich@xxxxxxxx>]

This is to aid diagnosing issues and largely matches VT-d's behavior.
Since I'm adding permissions output here as well, take the opportunity
and also add their displaying to amd_dump_page_table_level().

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/xen/drivers/passthrough/amd/iommu.h
+++ b/xen/drivers/passthrough/amd/iommu.h
@@ -235,6 +235,8 @@ int __must_check amd_iommu_flush_iotlb_p
                                              unsigned long page_count,
                                              unsigned int flush_flags);
 int __must_check amd_iommu_flush_iotlb_all(struct domain *d);
+void amd_iommu_print_entries(const struct amd_iommu *iommu, unsigned int 
dev_id,
+                             dfn_t dfn);
 
 /* device table functions */
 int get_dma_requestor_id(uint16_t seg, uint16_t bdf);
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -573,6 +573,9 @@ static void parse_event_log_entry(struct
                (flags & 0x002) ? " NX" : "",
                (flags & 0x001) ? " GN" : "");
 
+        if ( iommu_verbose )
+            amd_iommu_print_entries(iommu, device_id, daddr_to_dfn(addr));
+
         for ( bdf = 0; bdf < ivrs_bdf_entries; bdf++ )
             if ( get_dma_requestor_id(iommu->seg, bdf) == device_id )
                 pci_check_disable_device(iommu->seg, PCI_BUS(bdf),
--- a/xen/drivers/passthrough/amd/iommu_map.c
+++ b/xen/drivers/passthrough/amd/iommu_map.c
@@ -363,6 +363,50 @@ int amd_iommu_unmap_page(struct domain *
     return 0;
 }
 
+void amd_iommu_print_entries(const struct amd_iommu *iommu, unsigned int 
dev_id,
+                             dfn_t dfn)
+{
+    mfn_t pt_mfn;
+    unsigned int level;
+    const struct amd_iommu_dte *dt = iommu->dev_table.buffer;
+
+    if ( !dt[dev_id].tv )
+    {
+        printk("%pp: no root\n", &PCI_SBDF2(iommu->seg, dev_id));
+        return;
+    }
+
+    pt_mfn = _mfn(dt[dev_id].pt_root);
+    level = dt[dev_id].paging_mode;
+    printk("%pp root @ %"PRI_mfn" (%u levels) dfn=%"PRI_dfn"\n",
+           &PCI_SBDF2(iommu->seg, dev_id), mfn_x(pt_mfn), level, dfn_x(dfn));
+
+    while ( level )
+    {
+        const union amd_iommu_pte *pt = map_domain_page(pt_mfn);
+        unsigned int idx = pfn_to_pde_idx(dfn_x(dfn), level);
+        union amd_iommu_pte pte = pt[idx];
+
+        unmap_domain_page(pt);
+
+        printk("  L%u[%03x] = %"PRIx64" %c%c\n", level, idx, pte.raw,
+               pte.pr ? pte.ir ? 'r' : '-' : 'n',
+               pte.pr ? pte.iw ? 'w' : '-' : 'p');
+
+        if ( !pte.pr )
+            break;
+
+        if ( pte.next_level >= level )
+        {
+            printk("  L%u[%03x]: next: %u\n", level, idx, pte.next_level);
+            break;
+        }
+
+        pt_mfn = _mfn(pte.mfn);
+        level = pte.next_level;
+    }
+}
+
 static unsigned long flush_count(unsigned long dfn, unsigned long page_count,
                                  unsigned int order)
 {
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -561,10 +561,11 @@ static void amd_dump_page_table_level(st
                 mfn_to_page(_mfn(pde->mfn)), pde->next_level,
                 address, indent + 1);
         else
-            printk("%*sdfn: %08lx  mfn: %08lx\n",
+            printk("%*sdfn: %08lx  mfn: %08lx  %c%c\n",
                    indent, "",
                    (unsigned long)PFN_DOWN(address),
-                   (unsigned long)PFN_DOWN(pfn_to_paddr(pde->mfn)));
+                   (unsigned long)PFN_DOWN(pfn_to_paddr(pde->mfn)),
+                   pde->ir ? 'r' : '-', pde->iw ? 'w' : '-');
     }
 
     unmap_domain_page(table_vaddr);