xen: arm: map memory as inner shareable.

The inner shareable domain contains all SMP processors, including different
clusters (e.g. big.LITTLE). Therefore this is the correct thing to use for Xen
memory mappings. The outer shareable domain is for devices on busses which are
coherent and barrier-aware (e.g. AMBA4 AXI with ACE). While the system domain
is for things behind bridges which are not.

One wrinkle is that Normal memory with attributes Inner Non-cacheable, Outer
Non-cacheable (which we call BUFFERABLE) must be mapped Outer Shareable on ARM
v7. Therefore change the prototype of mfn_to_xen_entry to take the attribute
index so we can DTRT. On ARMv8 the sharability is ignored and considered to
always be Outer Shareable.

Don't adjust the barriers, flushes etc, those remain as they were (which is
more than is now required).  I'll change those in a later patch.

Many thanks to Leif for explaining the difference between Inner- and
Outer-Shareable in words of two or less syllables, I hope I've replicated that
explanation properly above!

Signed-off-by: Ian Campbell <ian.campbell@citrix.com>
Acked-by: Julien Grall <julien.grall@linaro.org>

diff --git a/xen/arch/arm/arm32/head.S b/xen/arch/arm/arm32/head.S
index 72cda349cfc1dc582a8a956fb2a3eccdbf00d27b..39978cb3531a26de24bd217529579b6475549fe3 100644 (file)
--- a/xen/arch/arm/arm32/head.S
+++ b/xen/arch/arm/arm32/head.S
@@ -24,8 +24,8 @@
 
 #define ZIMAGE_MAGIC_NUMBER 0x016f2818
 
-#define PT_PT     0xe7f /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=1 P=1 */
-#define PT_MEM    0xe7d /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=0 P=1 */
+#define PT_PT     0xf7f /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=1 P=1 */
+#define PT_MEM    0xf7d /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=0 P=1 */
 #define PT_DEV    0xe71 /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=100 T=0 P=1 */
 #define PT_DEV_L3 0xe73 /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=100 T=1 P=1 */
 
@@ -224,10 +224,10 @@ cpu_init_done:
         mcr   CP32(r1, HMAIR1)
 
         /* Set up the HTCR:
-         * PT walks use Outer-Shareable accesses,
+         * PT walks use Inner-Shareable accesses,
          * PT walks are write-back, write-allocate in both cache levels,
          * Full 32-bit address space goes through this table. */
-        ldr   r0, =0x80002500
+        ldr   r0, =0x80003500
         mcr   CP32(r0, HTCR)
 
         /* Set up the HSCTLR:

diff --git a/xen/arch/arm/arm64/head.S b/xen/arch/arm/arm64/head.S
index d151724a8fd07e2b2aa8e892c53dff1bb2d04898..9547ef5fd8ab375bcd5d1d4da9443be0b0cb1200 100644 (file)
--- a/xen/arch/arm/arm64/head.S
+++ b/xen/arch/arm/arm64/head.S
@@ -25,8 +25,8 @@
 #include <asm/asm_defns.h>
 #include <asm/early_printk.h>
 
-#define PT_PT     0xe7f /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=1 P=1 */
-#define PT_MEM    0xe7d /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=111 T=0 P=1 */
+#define PT_PT     0xf7f /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=1 P=1 */
+#define PT_MEM    0xf7d /* nG=1 AF=1 SH=11 AP=01 NS=1 ATTR=111 T=0 P=1 */
 #define PT_DEV    0xe71 /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=100 T=0 P=1 */
 #define PT_DEV_L3 0xe73 /* nG=1 AF=1 SH=10 AP=01 NS=1 ATTR=100 T=1 P=1 */
 
@@ -227,10 +227,10 @@ skip_bss:
         /* Set up the HTCR:
          * PASize -- 40 bits / 1TB
          * Top byte is used
-         * PT walks use Outer-Shareable accesses,
+         * PT walks use Inner-Shareable accesses,
          * PT walks are write-back, write-allocate in both cache levels,
          * Full 64-bit address space goes through this table. */
-        ldr   x0, =0x80822500
+        ldr   x0, =0x80823500
         msr   tcr_el2, x0
 
         /* Set up the SCTLR_EL2:

diff --git a/xen/arch/arm/mm.c b/xen/arch/arm/mm.c
index 305879fd642808af255bcb9c8ed51b6d5047af8f..b7360b655b0aedfc75ef69f94a9d989125220ff0 100644 (file)
--- a/xen/arch/arm/mm.c
+++ b/xen/arch/arm/mm.c
@@ -212,9 +212,8 @@ void dump_hyp_walk(vaddr_t addr)
 /* Map a 4k page in a fixmap entry */
 void set_fixmap(unsigned map, unsigned long mfn, unsigned attributes)
 {
-    lpae_t pte = mfn_to_xen_entry(mfn);
+    lpae_t pte = mfn_to_xen_entry(mfn, attributes);
     pte.pt.table = 1; /* 4k mappings always have this bit set */
-    pte.pt.ai = attributes;
     pte.pt.xn = 1;
     write_pte(xen_fixmap + third_table_offset(FIXMAP_ADDR(map)), pte);
     flush_xen_data_tlb_range_va(FIXMAP_ADDR(map), PAGE_SIZE);
@@ -270,7 +269,7 @@ void *map_domain_page(unsigned long mfn)
         else if ( map[slot].pt.avail == 0 )
         {
             /* Commandeer this 2MB slot */
-            pte = mfn_to_xen_entry(slot_mfn);
+            pte = mfn_to_xen_entry(slot_mfn, WRITEALLOC);
             pte.pt.avail = 1;
             write_pte(map + slot, pte);
             break;
@@ -397,7 +396,7 @@ static inline lpae_t pte_of_xenaddr(vaddr_t va)
 {
     paddr_t ma = va + phys_offset;
     unsigned long mfn = ma >> PAGE_SHIFT;
-    return mfn_to_xen_entry(mfn);
+    return mfn_to_xen_entry(mfn, WRITEALLOC);
 }
 
 void __init remove_early_mappings(void)
@@ -418,6 +417,12 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
     lpae_t pte, *p;
     int i;
 
+    /* Map the destination in the boot misc area. */
+    dest_va = BOOT_RELOC_VIRT_START;
+    pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT, WRITEALLOC);
+    write_pte(xen_second + second_table_offset(dest_va), pte);
+    flush_xen_data_tlb_range_va(dest_va, SECOND_SIZE);
+
     /* Calculate virt-to-phys offset for the new location */
     phys_offset = xen_paddr - (unsigned long) _start;
 
@@ -451,7 +456,7 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
     /* Initialise xen second level entries ... */
     /* ... Xen's text etc */
 
-    pte = mfn_to_xen_entry(xen_paddr>>PAGE_SHIFT);
+    pte = mfn_to_xen_entry(xen_paddr>>PAGE_SHIFT, WRITEALLOC);
     pte.pt.xn = 0;/* Contains our text mapping! */
     xen_second[second_table_offset(XEN_VIRT_START)] = pte;
 
@@ -466,7 +471,7 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
 
     /* Map the destination in the boot misc area. */
     dest_va = BOOT_RELOC_VIRT_START;
-    pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT);
+    pte = mfn_to_xen_entry(xen_paddr >> PAGE_SHIFT, WRITEALLOC);
     write_pte(boot_second + second_table_offset(dest_va), pte);
     flush_xen_data_tlb_range_va(dest_va, SECOND_SIZE);
 #ifdef CONFIG_ARM_64
@@ -495,7 +500,7 @@ void __init setup_pagetables(unsigned long boot_phys_offset, paddr_t xen_paddr)
         unsigned long va = XEN_VIRT_START + (i << PAGE_SHIFT);
         if ( !is_kernel(va) )
             break;
-        pte = mfn_to_xen_entry(mfn);
+        pte = mfn_to_xen_entry(mfn, WRITEALLOC);
         pte.pt.table = 1; /* 4k mappings always have this bit set */
         if ( is_kernel_text(va) || is_kernel_inittext(va) )
         {
@@ -565,7 +570,7 @@ int init_secondary_pagetables(int cpu)
      * domheap mapping pages. */
     for ( i = 0; i < DOMHEAP_SECOND_PAGES; i++ )
     {
-        pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES));
+        pte = mfn_to_xen_entry(virt_to_mfn(domheap+i*LPAE_ENTRIES), WRITEALLOC);
         pte.pt.table = 1;
         write_pte(&first[first_table_offset(DOMHEAP_VIRT_START+i*FIRST_SIZE)], pte);
     }
@@ -610,7 +615,7 @@ static void __init create_32mb_mappings(lpae_t *second,
 
     count = nr_mfns / LPAE_ENTRIES;
     p = second + second_linear_offset(virt_offset);
-    pte = mfn_to_xen_entry(base_mfn);
+    pte = mfn_to_xen_entry(base_mfn, WRITEALLOC);
     pte.pt.contig = 1;  /* These maps are in 16-entry contiguous chunks. */
     for ( i = 0; i < count; i++ )
     {
@@ -682,13 +687,13 @@ void __init setup_xenheap_mappings(unsigned long base_mfn,
         else
         {
             unsigned long first_mfn = alloc_boot_pages(1, 1);
-            pte = mfn_to_xen_entry(first_mfn);
+            pte = mfn_to_xen_entry(first_mfn, WRITEALLOC);
             pte.pt.table = 1;
             write_pte(p, pte);
             first = mfn_to_virt(first_mfn);
         }
 
-        pte = mfn_to_xen_entry(base_mfn);
+        pte = mfn_to_xen_entry(base_mfn, WRITEALLOC);
         /* TODO: Set pte.pt.contig when appropriate. */
         write_pte(&first[first_table_offset(vaddr)], pte);
 
@@ -724,7 +729,7 @@ void __init setup_frametable_mappings(paddr_t ps, paddr_t pe)
     second = mfn_to_virt(second_base);
     for ( i = 0; i < nr_second; i++ )
     {
-        pte = mfn_to_xen_entry(second_base + i);
+        pte = mfn_to_xen_entry(second_base + i, WRITEALLOC);
         pte.pt.table = 1;
         write_pte(&xen_first[first_table_offset(FRAMETABLE_VIRT_START)+i], pte);
     }
@@ -776,7 +781,7 @@ static int create_xen_table(lpae_t *entry)
     if ( p == NULL )
         return -ENOMEM;
     clear_page(p);
-    pte = mfn_to_xen_entry(virt_to_mfn(p));
+    pte = mfn_to_xen_entry(virt_to_mfn(p), WRITEALLOC);
     pte.pt.table = 1;
     write_pte(entry, pte);
     return 0;
@@ -822,9 +827,8 @@ static int create_xen_entries(enum xenmap_operation op,
                            addr, mfn);
                     return -EINVAL;
                 }
-                pte = mfn_to_xen_entry(mfn);
+                pte = mfn_to_xen_entry(mfn, ai);
                 pte.pt.table = 1;
-                pte.pt.ai = ai;
                 write_pte(&third[third_table_offset(addr)], pte);
                 break;
             case REMOVE:

diff --git a/xen/arch/arm/p2m.c b/xen/arch/arm/p2m.c
index d00c8825d7357866e7762bd36e6bce830224dcef..b9d8ca6ebefc718f5cc41a4db76cfd44d53b1fc2 100644 (file)
--- a/xen/arch/arm/p2m.c
+++ b/xen/arch/arm/p2m.c
@@ -145,10 +145,10 @@ static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr,
                                p2m_type_t t)
 {
     paddr_t pa = ((paddr_t) mfn) << PAGE_SHIFT;
-    /* xn and write bit will be defined in the switch */
+    /* sh, xn and write bit will be defined in the following switches
+     * based on mattr and t. */
     lpae_t e = (lpae_t) {
         .p2m.af = 1,
-        .p2m.sh = LPAE_SH_OUTER,
         .p2m.read = 1,
         .p2m.mattr = mattr,
         .p2m.table = 1,
@@ -158,6 +158,20 @@ static lpae_t mfn_to_p2m_entry(unsigned long mfn, unsigned int mattr,
 
     BUILD_BUG_ON(p2m_max_real_type > (1 << 4));
 
+    switch (mattr)
+    {
+    case MATTR_MEM:
+        e.p2m.sh = LPAE_SH_INNER;
+        break;
+
+    case MATTR_DEV:
+        e.p2m.sh = LPAE_SH_OUTER;
+        break;
+    default:
+        BUG();
+        break;
+    }
+
     switch (t)
     {
     case p2m_ram_rw:

diff --git a/xen/include/asm-arm/page.h b/xen/include/asm-arm/page.h
index 905beb83d268abb41ccf928cb7bfbfb26a07cdb5..fd2299326f8fc7481b9e6a09874d69259acc0dda 100644 (file)
--- a/xen/include/asm-arm/page.h
+++ b/xen/include/asm-arm/page.h
@@ -185,7 +185,7 @@ typedef union {
 /* Standard entry type that we'll use to build Xen's own pagetables.
  * We put the same permissions at every level, because they're ignored
  * by the walker in non-leaf entries. */
-static inline lpae_t mfn_to_xen_entry(unsigned long mfn)
+static inline lpae_t mfn_to_xen_entry(unsigned long mfn, unsigned attr)
 {
     paddr_t pa = ((paddr_t) mfn) << PAGE_SHIFT;
     lpae_t e = (lpae_t) {
@@ -193,10 +193,9 @@ static inline lpae_t mfn_to_xen_entry(unsigned long mfn)
             .xn = 1,              /* No need to execute outside .text */
             .ng = 1,              /* Makes TLB flushes easier */
             .af = 1,              /* No need for access tracking */
-            .sh = LPAE_SH_OUTER,  /* Xen mappings are globally coherent */
             .ns = 1,              /* Hyp mode is in the non-secure world */
             .user = 1,            /* See below */
-            .ai = WRITEALLOC,
+            .ai = attr,
             .table = 0,           /* Set to 1 for links and 4k maps */
             .valid = 1,           /* Mappings are present */
         }};;
@@ -205,6 +204,38 @@ static inline lpae_t mfn_to_xen_entry(unsigned long mfn)
      * pagetables un User mode it's OK.  If this changes, remember
      * to update the hard-coded values in head.S too */
 
+    switch ( attr )
+    {
+    case BUFFERABLE:
+        /*
+         * ARM ARM: Overlaying the shareability attribute (DDI
+         * 0406C.b B3-1376 to 1377)
+         *
+         * A memory region with a resultant memory type attribute of Normal,
+         * and a resultant cacheability attribute of Inner Non-cacheable,
+         * Outer Non-cacheable, must have a resultant shareability attribute
+         * of Outer Shareable, otherwise shareability is UNPREDICTABLE.
+         *
+         * On ARMv8 sharability is ignored and explicitly treated as Outer
+         * Shareable for Normal Inner Non_cacheable, Outer Non-cacheable.
+         */
+        e.pt.sh = LPAE_SH_OUTER;
+        break;
+    case UNCACHED:
+    case DEV_SHARED:
+        /* Shareability is ignored for non-Normal memory, Outer is as
+         * good as anything.
+         *
+         * On ARMv8 sharability is ignored and explicitly treated as Outer
+         * Shareable for any device memory type.
+         */
+        e.pt.sh = LPAE_SH_OUTER;
+        break;
+    default:
+        e.pt.sh = LPAE_SH_INNER;  /* Xen mappings are SMP coherent */
+        break;
+    }
+
     ASSERT(!(pa & ~PAGE_MASK));
     ASSERT(!(pa & ~PADDR_MASK));