[v5,04/10] AMD/IOMMU: introduce a "valid" flag for IVRS mappings

Commit Message

Jan Beulich Aug. 6, 2019, 1:08 p.m. UTC

For us to no longer blindly allocate interrupt remapping tables for
everything the ACPI tables name, we can't use struct ivrs_mappings'
intremap_table field anymore to also have the meaning of "this entry
is valid". Add a separate boolean field instead.

Signed-off-by: Jan Beulich <[e-mail]>
---
v5: New.

Comments

Andrew Cooper Sept. 17, 2019, 12:45 p.m. UTC | #1

On 06/08/2019 14:08, Jan Beulich wrote:
> For us to no longer blindly allocate interrupt remapping tables for
> everything the ACPI tables name, we can't use struct ivrs_mappings'
> intremap_table field anymore to also have the meaning of "this entry
> is valid". Add a separate boolean field instead.
>
> Signed-off-by: Jan Beulich <[e-mail]>

Acked-by: Andrew Cooper <[e-mail]>

Patch

--- a/xen/drivers/passthrough/amd/iommu_acpi.c
+++ b/xen/drivers/passthrough/amd/iommu_acpi.c
@@ -88,6 +88,8 @@  static void __init add_ivrs_mapping_entr
           }
      }
  
+    ivrs_mappings[alias_id].valid = true;
+
      /* Assign IOMMU hardware. */
      ivrs_mappings[bdf].iommu = iommu;
  }
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -1244,7 +1244,6 @@  static int __init amd_iommu_setup_device
      u16 seg, struct ivrs_mappings *ivrs_mappings)
  {
      unsigned int bdf;
-    void *intr_tb, *dte;
  
      BUG_ON( (ivrs_bdf_entries == 0) );
  
@@ -1264,16 +1263,17 @@  static int __init amd_iommu_setup_device
      /* Add device table entries */
      for ( bdf = 0; bdf < ivrs_bdf_entries; bdf++ )
      {
-        intr_tb = ivrs_mappings[bdf].intremap_table;
-
-        if ( intr_tb )
+        if ( ivrs_mappings[bdf].valid )
          {
+            void *dte;
+
              /* add device table entry */
              dte = device_table.buffer + (bdf * IOMMU_DEV_TABLE_ENTRY_SIZE);
              iommu_dte_add_device_entry(dte, &ivrs_mappings[bdf]);
  
              amd_iommu_set_intremap_table(
-                dte, (u64)virt_to_maddr(intr_tb), iommu_intremap);
+                dte, virt_to_maddr(ivrs_mappings[bdf].intremap_table),
+                iommu_intremap);
          }
      }
  
--- a/xen/drivers/passthrough/amd/pci_amd_iommu.c
+++ b/xen/drivers/passthrough/amd/pci_amd_iommu.c
@@ -69,8 +69,8 @@  struct amd_iommu *find_iommu_for_device(
   * table and I/O page table respectively. Such devices will have
   * both alias entry and select entry in IVRS structure.
   *
- * Return original device id, if device has valid interrupt remapping
- * table setup for both select entry and alias entry.
+ * Return original device id if both the specific entry and the alias entry
+ * have been marked valid.
   */
  int get_dma_requestor_id(uint16_t seg, uint16_t bdf)
  {
@@ -79,8 +79,7 @@  int get_dma_requestor_id(uint16_t seg, u
  
      BUG_ON ( bdf >= ivrs_bdf_entries );
      req_id = ivrs_mappings[bdf].dte_requestor_id;
-    if ( (ivrs_mappings[bdf].intremap_table != NULL) &&
-         (ivrs_mappings[req_id].intremap_table != NULL) )
+    if ( ivrs_mappings[bdf].valid && ivrs_mappings[req_id].valid )
          req_id = bdf;
  
      return req_id;
--- a/xen/include/asm-x86/amd-iommu.h
+++ b/xen/include/asm-x86/amd-iommu.h
@@ -111,6 +111,7 @@  struct ivrs_mappings {
      u8 unity_map_enable;
      u8 write_permission;
      u8 read_permission;
+    bool valid;
      unsigned long addr_range_start;
      unsigned long addr_range_length;
      struct amd_iommu *iommu;