[Xen-devel] [PATCH,RFC 13/17] 32-on-64 trap table setup

["Jan Beulich" <jbeulich@xxxxxxxxxx>]

Index: 2006-10-04/xen/arch/x86/x86_64/compat/entry.S
===================================================================
--- 2006-10-04.orig/xen/arch/x86/x86_64/compat/entry.S  2006-10-04 
15:20:09.000000000 +0200
+++ 2006-10-04/xen/arch/x86/x86_64/compat/entry.S       2006-10-04 
15:20:14.000000000 +0200
@@ -278,8 +278,6 @@ CFIX14:
 
 .section .rodata, "a", @progbits
 
-#define compat_set_trap_table domain_crash_synchronous
-#define compat_set_gdt domain_crash_synchronous
 #define compat_platform_op domain_crash_synchronous
 #define compat_multicall domain_crash_synchronous
 #define compat_set_timer_op domain_crash_synchronous
Index: 2006-10-04/xen/arch/x86/x86_64/compat/mm.c
===================================================================
--- 2006-10-04.orig/xen/arch/x86/x86_64/compat/mm.c     2006-10-04 
15:18:57.000000000 +0200
+++ 2006-10-04/xen/arch/x86/x86_64/compat/mm.c  2006-10-04 15:20:14.000000000 
+0200
@@ -4,6 +4,39 @@
 #include <compat/memory.h>
 #include <compat/xen.h>
 
+int compat_set_gdt(XEN_GUEST_HANDLE(uint) frame_list, unsigned int entries)
+{
+    unsigned int i, nr_pages = (entries + 511) / 512;
+    unsigned long frames[16];
+    long ret;
+
+    /* Rechecked in set_gdt, but ensures a sane limit for copy_from_user(). */
+    if ( entries > FIRST_RESERVED_GDT_ENTRY )
+        return -EINVAL;
+
+    if ( !guest_handle_okay(frame_list, nr_pages) )
+        return -EFAULT;
+
+    for ( i = 0; i < nr_pages; ++i )
+    {
+        unsigned int frame;
+
+        if ( __copy_from_guest(&frame, frame_list, 1) )
+            return -EFAULT;
+        frames[i] = frame;
+        guest_handle_add_offset(frame_list, 1);
+    }
+
+    LOCK_BIGLOCK(current->domain);
+
+    if ( (ret = set_gdt(current, frames, entries)) == 0 )
+        local_flush_tlb();
+
+    UNLOCK_BIGLOCK(current->domain);
+
+    return ret;
+}
+
 int compat_update_descriptor(u32 pa_lo, u32 pa_hi, u32 desc_lo, u32 desc_hi)
 {
     return do_update_descriptor(pa_lo | ((u64)pa_hi << 32),
Index: 2006-10-04/xen/arch/x86/x86_64/compat/traps.c
===================================================================
--- 2006-10-04.orig/xen/arch/x86/x86_64/compat/traps.c  2006-10-04 
15:11:03.000000000 +0200
+++ 2006-10-04/xen/arch/x86/x86_64/compat/traps.c       2006-10-04 
15:20:14.000000000 +0200
@@ -1,6 +1,8 @@
 #ifdef CONFIG_COMPAT
 
+#include <xen/event.h>
 #include <compat/callback.h>
+#include <compat/arch-x86_32.h>
 
 void compat_show_guest_stack(struct cpu_user_regs *regs, int debug_stack_lines)
 {
@@ -204,6 +206,53 @@ long compat_set_callbacks(unsigned long 
     return 0;
 }
 
+DEFINE_XEN_GUEST_HANDLE(trap_info_compat_t);
+
+int compat_set_trap_table(XEN_GUEST_HANDLE(trap_info_compat_t) traps)
+{
+    struct compat_trap_info cur;
+    struct trap_info *dst = current->arch.guest_context.trap_ctxt;
+    long rc = 0;
+
+    /* If no table is presented then clear the entire virtual IDT. */
+    if ( guest_handle_is_null(traps) )
+    {
+        memset(dst, 0, 256 * sizeof(*dst));
+        init_int80_direct_trap(current);
+        return 0;
+    }
+
+    for ( ; ; )
+    {
+        if ( hypercall_preempt_check() )
+        {
+            rc = hypercall_create_continuation(
+                __HYPERVISOR_set_trap_table, "h", traps);
+            break;
+        }
+
+        if ( copy_from_guest(&cur, traps, 1) )
+        {
+            rc = -EFAULT;
+            break;
+        }
+
+        if ( cur.address == 0 )
+            break;
+
+        fixup_guest_code_selector(current->domain, cur.cs);
+
+        XLAT_trap_info(dst + cur.vector, &cur);
+
+        if ( cur.vector == 0x80 )
+            init_int80_direct_trap(current);
+
+        guest_handle_add_offset(traps, 1);
+    }
+
+    return rc;
+}
+
 #endif /* CONFIG_COMPAT */
 
 static void hypercall_page_initialise_ring1_kernel(void *hypercall_page)


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