amd iommu: Cleanup iommu pci capabilites detection

* Define new structure to represent capability block.
* Remove unnecessary read for unused information.
* Add sanity check into get_iommu_capabilities.
* iommu capability offset is 16 bit not 8 bit, fix that.

Signed-off-by: Wei Wang <wei.wang2@amd.com>
Committed-by: Jan Beulich <jbeulich@suse.com>

1 files changed, 10 insertions, 4 deletions

diff --git a/xen/include/asm-x86/amd-iommu.h b/xen/include/asm-x86/amd-iommu.h
index 5dc97c6766..df36fe25ac 100644
--- a/xen/include/asm-x86/amd-iommu.h
+++ b/xen/include/asm-x86/amd-iommu.h
@@ -36,16 +36,22 @@ struct table_struct {
     unsigned long alloc_size;
 };
 
+typedef struct iommu_cap {
+    uint32_t header;                    /* offset 00h */
+    uint32_t base_low;                  /* offset 04h */
+    uint32_t base_hi;                   /* offset 08h */
+    uint32_t range;                     /* offset 0Ch */
+    uint32_t misc;                      /* offset 10h */
+} iommu_cap_t;
+
 struct amd_iommu {
     struct list_head list;
     spinlock_t lock; /* protect iommu */
 
     u16 seg;
     u16 bdf;
-    u8  cap_offset;
-    u8  revision;
-    u8  unit_id;
-    u8  msi_number;
+    u16 cap_offset;
+    iommu_cap_t cap;
 
     u8 pte_not_present_cached;
     u8 ht_tunnel_support;