[xen staging] AMD/IOMMU: walk trees upon page fault

[patchbot@xxxxxxx]

commit 0e461c2d7f45c50fcf4d26c7730cdd7cde77eb1f
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Fri May 20 12:24:11 2022 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Fri May 20 12:24:11 2022 +0200

    AMD/IOMMU: walk trees upon page fault
    
    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>
    Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/drivers/passthrough/amd/iommu.h         |  2 ++
 xen/drivers/passthrough/amd/iommu_init.c    |  3 ++
 xen/drivers/passthrough/amd/iommu_map.c     | 44 +++++++++++++++++++++++++++++
 xen/drivers/passthrough/amd/pci_amd_iommu.c |  5 ++--
 4 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu.h 
b/xen/drivers/passthrough/amd/iommu.h
index 0a19d6a662..a05dd112bc 100644
--- a/xen/drivers/passthrough/amd/iommu.h
+++ b/xen/drivers/passthrough/amd/iommu.h
@@ -259,6 +259,8 @@ int __must_check cf_check amd_iommu_flush_iotlb_pages(
     struct domain *d, dfn_t dfn, unsigned long page_count,
     unsigned int flush_flags);
 int __must_check cf_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);
diff --git a/xen/drivers/passthrough/amd/iommu_init.c 
b/xen/drivers/passthrough/amd/iommu_init.c
index 7d074ca843..e2166f534f 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -575,6 +575,9 @@ static void cf_check parse_event_log_entry(struct amd_iommu 
*iommu, u32 entry[])
                (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),
diff --git a/xen/drivers/passthrough/amd/iommu_map.c 
b/xen/drivers/passthrough/amd/iommu_map.c
index a63eec477a..5ad33340e8 100644
--- a/xen/drivers/passthrough/amd/iommu_map.c
+++ b/xen/drivers/passthrough/amd/iommu_map.c
@@ -428,6 +428,50 @@ int cf_check amd_iommu_unmap_page(
     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_SBDF(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_SBDF(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)
 {
diff --git a/xen/drivers/passthrough/amd/pci_amd_iommu.c 
b/xen/drivers/passthrough/amd/pci_amd_iommu.c
index 8c5d69a46a..4bf87e8c03 100644
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -724,10 +724,11 @@ static void amd_dump_page_table_level(struct page_info 
*pg, int level,
                 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);
--
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