[PATCH 1/3] x86/AMD-Vi: Overrides special->handle in IVRS IOAPIC

[<suravee.suthikulpanit@amd.com>]

From: Jan Beulich <JBeulich@suse.com>

This patch handles the case when IVRS IOAPIC contains invalid
special->handle, which mainly caused by firmware bugs.
This allows users to override the invalid handle with command option
ivrs_ioapic[<handle>]=<sbdf>.

Acked-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
---
 xen/drivers/passthrough/amd/iommu_acpi.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/xen/drivers/passthrough/amd/iommu_acpi.c b/xen/drivers/passthrough/amd/iommu_acpi.c
index 89b359c..50b4a44 100644
--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -708,6 +708,26 @@ static u16 __init parse_ivhd_device_special(
     case ACPI_IVHD_IOAPIC:
         if ( !iommu_intremap )
             break;
+
+        /* Handling the ivrs_ioapic overriding */
+        apic = find_first_bit(ioapic_cmdline, ARRAY_SIZE(ioapic_sbdf));
+        while ( apic < ARRAY_SIZE(ioapic_sbdf) )
+        {
+            if ( ioapic_sbdf[apic].bdf == bdf &&
+                 ioapic_sbdf[apic].seg == seg )
+                break;
+            apic = find_next_bit(ioapic_cmdline, ARRAY_SIZE(ioapic_sbdf),
+                                 apic + 1);
+        }
+        if ( apic < ARRAY_SIZE(ioapic_sbdf) )
+        {
+            AMD_IOMMU_DEBUG("IVHD: Command line override present for IO-APIC %#x "
+                            "(IVRS: %#x devID %04x:%02x:%02x.%u)\n",
+                            apic, special->handle, seg, PCI_BUS(bdf),
+                            PCI_SLOT(bdf), PCI_FUNC(bdf));
+            break;
+        }
+
         /*
          * Some BIOSes have IOAPIC broken entries so we check for IVRS
          * consistency here --- whether entry's IOAPIC ID is valid and
-- 
1.8.1.2