Avoid compat_arg_xlat to be a large per-CPU object

Signed-off-by: Jan Beulich <jbeulich@novell.com>

7 files changed, 38 insertions, 11 deletions

diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index 64b55ebc86..976fba89bd 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -878,6 +878,9 @@ static int __devinit do_boot_cpu(int apicid, int cpu)
 		per_cpu(doublefault_tss, cpu) = alloc_xenheap_page();
 		memset(per_cpu(doublefault_tss, cpu), 0, PAGE_SIZE);
 	}
+#else
+	if (!per_cpu(compat_arg_xlat, cpu))
+		setup_compat_arg_xlat(cpu, apicid_to_node[apicid]);
 #endif
 
 	if (!idt_tables[cpu]) {
diff --git a/xen/arch/x86/x86_64/compat/mm.c b/xen/arch/x86/x86_64/compat/mm.c
index 4ececde057..8cfe95a25e 100644
--- a/xen/arch/x86/x86_64/compat/mm.c
+++ b/xen/arch/x86/x86_64/compat/mm.c
@@ -58,7 +58,7 @@ int compat_arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
     case XENMEM_add_to_physmap:
     {
         struct compat_add_to_physmap cmp;
-        struct xen_add_to_physmap *nat = (void *)COMPAT_ARG_XLAT_VIRT_BASE;
+        struct xen_add_to_physmap *nat = COMPAT_ARG_XLAT_VIRT_BASE;
 
         if ( copy_from_guest(&cmp, arg, 1) )
             return -EFAULT;
@@ -72,7 +72,7 @@ int compat_arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
     case XENMEM_set_memory_map:
     {
         struct compat_foreign_memory_map cmp;
-        struct xen_foreign_memory_map *nat = (void *)COMPAT_ARG_XLAT_VIRT_BASE;
+        struct xen_foreign_memory_map *nat = COMPAT_ARG_XLAT_VIRT_BASE;
 
         if ( copy_from_guest(&cmp, arg, 1) )
             return -EFAULT;
@@ -91,7 +91,7 @@ int compat_arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
     case XENMEM_machine_memory_map:
     {
         struct compat_memory_map cmp;
-        struct xen_memory_map *nat = (void *)COMPAT_ARG_XLAT_VIRT_BASE;
+        struct xen_memory_map *nat = COMPAT_ARG_XLAT_VIRT_BASE;
 
         if ( copy_from_guest(&cmp, arg, 1) )
             return -EFAULT;
@@ -118,7 +118,7 @@ int compat_arch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
     case XENMEM_get_pod_target:
     {
         struct compat_pod_target cmp;
-        struct xen_pod_target *nat = (void *)COMPAT_ARG_XLAT_VIRT_BASE;
+        struct xen_pod_target *nat = COMPAT_ARG_XLAT_VIRT_BASE;
 
         if ( copy_from_guest(&cmp, arg, 1) )
             return -EFAULT;
@@ -212,7 +212,7 @@ int compat_mmuext_op(XEN_GUEST_HANDLE(mmuext_op_compat_t) cmp_uops,
     if ( unlikely(!guest_handle_okay(cmp_uops, count)) )
         return -EFAULT;
 
-    set_xen_guest_handle(nat_ops, (void *)COMPAT_ARG_XLAT_VIRT_BASE);
+    set_xen_guest_handle(nat_ops, COMPAT_ARG_XLAT_VIRT_BASE);
 
     for ( ; count; count -= i )
     {
diff --git a/xen/arch/x86/x86_64/mm.c b/xen/arch/x86/x86_64/mm.c
index f2e27b9b89..06d59077d4 100644
--- a/xen/arch/x86/x86_64/mm.c
+++ b/xen/arch/x86/x86_64/mm.c
@@ -22,6 +22,7 @@
 #include <xen/init.h>
 #include <xen/mm.h>
 #include <xen/sched.h>
+#include <xen/numa.h>
 #include <xen/guest_access.h>
 #include <asm/current.h>
 #include <asm/asm_defns.h>
@@ -30,14 +31,13 @@
 #include <asm/fixmap.h>
 #include <asm/hypercall.h>
 #include <asm/msr.h>
-#include <asm/numa.h>
 #include <public/memory.h>
 
 #ifdef CONFIG_COMPAT
 unsigned int m2p_compat_vstart = __HYPERVISOR_COMPAT_VIRT_START;
 #endif
 
-DEFINE_PER_CPU(char, compat_arg_xlat[COMPAT_ARG_XLAT_SIZE]);
+DEFINE_PER_CPU(void *, compat_arg_xlat);
 
 /* Top-level master (and idle-domain) page directory. */
 l4_pgentry_t __attribute__ ((__section__ (".bss.page_aligned")))
@@ -293,6 +293,25 @@ void __init zap_low_mappings(void)
                      0x10, __PAGE_HYPERVISOR);
 }
 
+int __cpuinit setup_compat_arg_xlat(unsigned int cpu, int node)
+{
+    unsigned int order = get_order_from_bytes(COMPAT_ARG_XLAT_SIZE);
+    unsigned long sz = PAGE_SIZE << order;
+    unsigned int memflags = node != NUMA_NO_NODE ? MEMF_node(node) : 0;
+    struct page_info *pg;
+
+    pg = alloc_domheap_pages(NULL, order, memflags);
+    if ( !pg )
+        return -ENOMEM;
+
+    for ( ; (sz -= PAGE_SIZE) >= COMPAT_ARG_XLAT_SIZE; ++pg )
+        free_domheap_page(pg);
+
+    per_cpu(compat_arg_xlat, cpu) = page_to_virt(pg);
+
+    return 0;
+}
+
 void __init subarch_init_memory(void)
 {
     unsigned long i, n, v, m2p_start_mfn;
@@ -350,6 +369,10 @@ void __init subarch_init_memory(void)
             share_xen_page_with_privileged_guests(page, XENSHARE_readonly);
         }
     }
+
+    if ( setup_compat_arg_xlat(smp_processor_id(),
+                               apicid_to_node[boot_cpu_physical_apicid]) )
+        panic("Could not setup argument translation area");
 }
 
 long subarch_memory_op(int op, XEN_GUEST_HANDLE(void) arg)
diff --git a/xen/common/compat/domain.c b/xen/common/compat/domain.c
index 48173decc6..67e0e5e316 100644
--- a/xen/common/compat/domain.c
+++ b/xen/common/compat/domain.c
@@ -87,7 +87,7 @@ int compat_vcpu_op(int cmd, int vcpuid, XEN_GUEST_HANDLE(void) arg)
 
         if ( copy_from_guest(&cmp, arg, 1) )
             return -EFAULT;
-        nat = (void *)COMPAT_ARG_XLAT_VIRT_BASE;
+        nat = COMPAT_ARG_XLAT_VIRT_BASE;
         XLAT_vcpu_set_singleshot_timer(nat, &cmp);
         rc = do_vcpu_op(cmd, vcpuid, guest_handle_from_ptr(nat, void));
         break;
diff --git a/xen/common/compat/grant_table.c b/xen/common/compat/grant_table.c
index f3a6d93776..5f0dc2db57 100644
--- a/xen/common/compat/grant_table.c
+++ b/xen/common/compat/grant_table.c
@@ -97,7 +97,7 @@ int compat_grant_table_op(unsigned int cmd,
             struct compat_gnttab_copy copy;
         } cmp;
 
-        set_xen_guest_handle(nat.uop, (void *)COMPAT_ARG_XLAT_VIRT_BASE);
+        set_xen_guest_handle(nat.uop, COMPAT_ARG_XLAT_VIRT_BASE);
         switch ( cmd )
         {
         case GNTTABOP_setup_table:
diff --git a/xen/common/compat/memory.c b/xen/common/compat/memory.c
index 779cad9f26..99467db8a8 100644
--- a/xen/common/compat/memory.c
+++ b/xen/common/compat/memory.c
@@ -25,7 +25,7 @@ int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE(void) compat)
             struct compat_memory_exchange xchg;
         } cmp;
 
-        set_xen_guest_handle(nat.hnd, (void *)COMPAT_ARG_XLAT_VIRT_BASE);
+        set_xen_guest_handle(nat.hnd, COMPAT_ARG_XLAT_VIRT_BASE);
         split = 0;
         switch ( op )
         {
diff --git a/xen/include/asm-x86/x86_64/uaccess.h b/xen/include/asm-x86/x86_64/uaccess.h
index 4433fd0b69..f76be30d3e 100644
--- a/xen/include/asm-x86/x86_64/uaccess.h
+++ b/xen/include/asm-x86/x86_64/uaccess.h
@@ -3,7 +3,8 @@
 
 #define COMPAT_ARG_XLAT_VIRT_BASE this_cpu(compat_arg_xlat)
 #define COMPAT_ARG_XLAT_SIZE      PAGE_SIZE
-DECLARE_PER_CPU(char, compat_arg_xlat[COMPAT_ARG_XLAT_SIZE]);
+DECLARE_PER_CPU(void *, compat_arg_xlat);
+int setup_compat_arg_xlat(unsigned int cpu, int node);
 #define is_compat_arg_xlat_range(addr, size) ({                               \
     unsigned long __off;                                                      \
     __off = (unsigned long)(addr) - (unsigned long)COMPAT_ARG_XLAT_VIRT_BASE; \