AMD/IOMMU: convert amd_iommu_pte from struct to union

This is to add a "raw" counterpart to the bitfield equivalent. Take the
opportunity and
 - convert fields to bool / unsigned int,
 - drop the naming of the reserved field,
 - shorten the names of the ignored ones.

This is part of XSA-347.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Paul Durrant <paul@xen.org>
master commit: 73f62c7380
master date: 2020-10-20 14:22:26 +0200

xen/drivers/passthrough/amd/iommu_map.c

@@ -38,7 +38,7 @@ static unsigned int pfn_to_pde_idx(unsigned long pfn, unsigned int level)
 static unsigned int clear_iommu_pte_present(unsigned long l1_mfn,
                                             unsigned long dfn)
 {
-    struct amd_iommu_pte *table, *pte;
+    union amd_iommu_pte *table, *pte;
     unsigned int flush_flags;
 
     table = map_domain_page(_mfn(l1_mfn));
@@ -52,7 +52,7 @@ static unsigned int clear_iommu_pte_present(unsigned long l1_mfn,
     return flush_flags;
 }
 
-static unsigned int set_iommu_pde_present(struct amd_iommu_pte *pte,
+static unsigned int set_iommu_pde_present(union amd_iommu_pte *pte,
                                           unsigned long next_mfn,
                                           unsigned int next_level, bool iw,
                                           bool ir)
@@ -87,7 +87,7 @@ static unsigned int set_iommu_pte_present(unsigned long pt_mfn,
                                           int pde_level,
                                           bool iw, bool ir)
 {
-    struct amd_iommu_pte *table, *pde;
+    union amd_iommu_pte *table, *pde;
     unsigned int flush_flags;
 
     table = map_domain_page(_mfn(pt_mfn));
@@ -178,7 +178,7 @@ void iommu_dte_set_guest_cr3(struct amd_iommu_dte *dte, uint16_t dom_id,
 static int iommu_pde_from_dfn(struct domain *d, unsigned long dfn,
                               unsigned long pt_mfn[], bool map)
 {
-    struct amd_iommu_pte *pde, *next_table_vaddr;
+    union amd_iommu_pte *pde, *next_table_vaddr;
     unsigned long  next_table_mfn;
     unsigned int level;
     struct page_info *table;
@@ -458,7 +458,7 @@ int __init amd_iommu_quarantine_init(struct domain *d)
     unsigned long end_gfn =
         1ul << (DEFAULT_DOMAIN_ADDRESS_WIDTH - PAGE_SHIFT);
     unsigned int level = amd_iommu_get_paging_mode(end_gfn);
-    struct amd_iommu_pte *table;
+    union amd_iommu_pte *table;
 
     if ( hd->arch.root_table )
     {
@@ -489,7 +489,7 @@ int __init amd_iommu_quarantine_init(struct domain *d)
 
         for ( i = 0; i < PTE_PER_TABLE_SIZE; i++ )
         {
-            struct amd_iommu_pte *pde = &table[i];
+            union amd_iommu_pte *pde = &table[i];
 
             /*
              * PDEs are essentially a subset of PTEs, so this function

xen/drivers/passthrough/amd/pci_amd_iommu.c

@@ -390,7 +390,7 @@ static void deallocate_next_page_table(struct page_info *pg, int level)
 
 static void deallocate_page_table(struct page_info *pg)
 {
-    struct amd_iommu_pte *table_vaddr;
+    union amd_iommu_pte *table_vaddr;
     unsigned int index, level = PFN_ORDER(pg);
 
     PFN_ORDER(pg) = 0;
@@ -405,7 +405,7 @@ static void deallocate_page_table(struct page_info *pg)
 
     for ( index = 0; index < PTE_PER_TABLE_SIZE; index++ )
     {
-        struct amd_iommu_pte *pde = &table_vaddr[index];
+        union amd_iommu_pte *pde = &table_vaddr[index];
 
         if ( pde->mfn && pde->next_level && pde->pr )
         {
@@ -557,7 +557,7 @@ static void amd_dump_p2m_table_level(struct page_info* pg, int level,
                                      paddr_t gpa, int indent)
 {
     paddr_t address;
-    struct amd_iommu_pte *table_vaddr;
+    const union amd_iommu_pte *table_vaddr;
     int index;
 
     if ( level < 1 )
@@ -573,7 +573,7 @@ static void amd_dump_p2m_table_level(struct page_info* pg, int level,
 
     for ( index = 0; index < PTE_PER_TABLE_SIZE; index++ )
     {
-        struct amd_iommu_pte *pde = &table_vaddr[index];
+        const union amd_iommu_pte *pde = &table_vaddr[index];
 
         if ( !(index % 2) )
             process_pending_softirqs();

xen/include/asm-x86/hvm/svm/amd-iommu-defs.h

@@ -465,20 +465,23 @@ union amd_iommu_x2apic_control {
 #define IOMMU_PAGE_TABLE_U32_PER_ENTRY	(IOMMU_PAGE_TABLE_ENTRY_SIZE / 4)
 #define IOMMU_PAGE_TABLE_ALIGNMENT	4096
 
-struct amd_iommu_pte {
-    uint64_t pr:1;
-    uint64_t ignored0:4;
-    uint64_t a:1;
-    uint64_t d:1;
-    uint64_t ignored1:2;
-    uint64_t next_level:3;
-    uint64_t mfn:40;
-    uint64_t reserved:7;
-    uint64_t u:1;
-    uint64_t fc:1;
-    uint64_t ir:1;
-    uint64_t iw:1;
-    uint64_t ignored2:1;
+union amd_iommu_pte {
+    uint64_t raw;
+    struct {
+        bool pr:1;
+        unsigned int ign0:4;
+        bool a:1;
+        bool d:1;
+        unsigned int ign1:2;
+        unsigned int next_level:3;
+        uint64_t mfn:40;
+        unsigned int :7;
+        bool u:1;
+        bool fc:1;
+        bool ir:1;
+        bool iw:1;
+        unsigned int ign2:1;
+    };
 };
 
 /* Paging modes */