[Xen-devel] [PATCH V2] x86/AMD-Vi: Add additional check for invalid special->handle

[<suravee.suthikulpanit@xxxxxxx>]

From: Suravee Suthikulpanit <suravee.suthikulpanit@xxxxxxx>

This patch add an additional logic to check for the often case when the
special->handle is not initialized due to firmware bugs.
but the special->usedid is correct. If users overide this using the
command line option ivrs_ioapic, then it should use the value instead.
---
This patch is supposed to follow the patches:
[Xen-devel] [PATCH RFC 2/2] AMD IOMMU: allow command line overrides for broken 
IVRS tables

Changes in V2:
        - Fix logic to match the special->used_id with the value provided by 
users.

 xen/drivers/passthrough/amd/iommu_acpi.c |   55 ++++++++++++++++++++----------
 1 file changed, 37 insertions(+), 18 deletions(-)

diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c 
b/xen/drivers/passthrough/amd/iommu_acpi.c
index 89b359c..8b14112 100644
--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -698,14 +698,16 @@ static u16 __init parse_ivhd_device_special(
         return 0;
     }
 
-    AMD_IOMMU_DEBUG("IVHD Special: %04x:%02x:%02x.%u variety %#x handle %#x\n",
+    AMD_IOMMU_DEBUG("IVHD Special: %04x:%02x:%02x.%u variety %#x handle %#x 
used_id %#x\n",
                     seg, PCI_BUS(bdf), PCI_SLOT(bdf), PCI_FUNC(bdf),
-                    special->variety, special->handle);
+                    special->variety, special->handle, special->used_id);
     add_ivrs_mapping_entry(bdf, bdf, special->header.data_setting, iommu);
 
     switch ( special->variety )
     {
     case ACPI_IVHD_IOAPIC:
+    {
+        unsigned int apic_id = 0;
         if ( !iommu_intremap )
             break;
         /*
@@ -715,29 +717,45 @@ static u16 __init parse_ivhd_device_special(
          */
         for ( apic = 0; apic < nr_ioapics; apic++ )
         {
-            if ( IO_APIC_ID(apic) != special->handle )
-                continue;
+            apic_id = special->handle;
 
-            if ( special->handle >= ARRAY_SIZE(ioapic_sbdf) )
+            if ( IO_APIC_ID(apic) != apic_id )
+            {
+                /* Some BIOSes have invalid value in the special->handle, 
+                 * but the special->used_id is correct. Here we check to see 
if 
+                 * the user is overiding the special->handle from commandline
+                 */
+                if ( (ioapic_sbdf[IO_APIC_ID(apic)].bdf == special->used_id) &&
+                     (test_bit(IO_APIC_ID(apic), ioapic_cmdline)) )
+                {
+                    apic_id = IO_APIC_ID(apic);
+                    AMD_IOMMU_DEBUG ("IVHD Special: Usinging command override "
+                        "value for IO-APIC %#x, bdf=%#x\n", 
+                        apic_id, ioapic_sbdf[apic_id].bdf);
+                }
+                else
+                    continue;
+            }
+               
+            if ( apic_id >= ARRAY_SIZE(ioapic_sbdf) )
             {
                 printk(XENLOG_ERR "IVHD Error: IO-APIC %#x entry beyond 
bounds\n",
-                       special->handle);
+                       apic_id);
                 return 0;
             }
 
-            if ( test_bit(special->handle, ioapic_cmdline) )
-                AMD_IOMMU_DEBUG("IVHD: Command line override present for 
IO-APIC %#x\n",
-                                special->handle);
-            else if ( ioapic_sbdf[special->handle].pin_2_idx )
+            if ( test_bit(apic_id, ioapic_cmdline) )
+                break;
+            else if ( ioapic_sbdf[apic_id].pin_2_idx )
             {
-                if ( ioapic_sbdf[special->handle].bdf == bdf &&
-                     ioapic_sbdf[special->handle].seg == seg )
+                if ( ioapic_sbdf[apic_id].bdf == bdf &&
+                     ioapic_sbdf[apic_id].seg == seg )
                     AMD_IOMMU_DEBUG("IVHD Warning: Duplicate IO-APIC %#x 
entries\n",
-                                    special->handle);
+                                    apic_id);
                 else
                 {
                     printk(XENLOG_ERR "IVHD Error: Conflicting IO-APIC %#x 
entries\n",
-                           special->handle);
+                           apic_id);
                     if ( amd_iommu_perdev_intremap )
                         return 0;
                 }
@@ -745,10 +763,10 @@ static u16 __init parse_ivhd_device_special(
             else
             {
                 /* set device id of ioapic */
-                ioapic_sbdf[special->handle].bdf = bdf;
-                ioapic_sbdf[special->handle].seg = seg;
+                ioapic_sbdf[apic_id].bdf = bdf;
+                ioapic_sbdf[apic_id].seg = seg;
 
-                ioapic_sbdf[special->handle].pin_2_idx = xmalloc_array(
+                ioapic_sbdf[apic_id].pin_2_idx = xmalloc_array(
                     u16, nr_ioapic_entries[apic]);
                 if ( nr_ioapic_entries[apic] &&
                      !ioapic_sbdf[IO_APIC_ID(apic)].pin_2_idx )
@@ -765,10 +783,11 @@ static u16 __init parse_ivhd_device_special(
         if ( apic == nr_ioapics )
         {
             printk(XENLOG_ERR "IVHD Error: Invalid IO-APIC %#x\n",
-                   special->handle);
+                   apic_id);
             return 0;
         }
         break;
+    }
     case ACPI_IVHD_HPET:
         /* set device id of hpet */
         if ( hpet_sbdf.iommu ||
-- 
1.7.10.4



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