Add Xen support

2009-03-11  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/i386/vm_param.h (VM_MIN_KERNEL_ADDRESS) [MACH_XEN]: Set to
	0x20000000.
	* i386/i386/i386asm.sym (pfn_list) [VM_MIN_KERNEL_ADDRESS ==
	LINEAR_MIN_KERNEL_ADDRESS]: Define to constant PFN_LIST.

2009-02-27  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/intel/pmap.c [MACH_HYP] (INVALIDATE_TLB): Call hyp_invlpg
	instead of flush_tlb when e - s is compile-time known to be
	PAGE_SIZE.

2008-11-27  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/configfrag.ac (enable_pae): Enable by default on the Xen
	platform.

2007-11-14  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/i386at/model_dep.c (machine_relax): New function.
	(c_boot_entry): Refuse to boot as dom0.

2007-10-17  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/i386/fpu.c [MACH_XEN]: Disable unused fpintr().

2007-08-12  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* Makefile.am (clib_routines): Add _START.
	* i386/xen/xen_boothdr: Use _START for VIRT_BASE and PADDR_OFFSET. Add
	GUEST_VERSION and XEN_ELFNOTE_FEATURES.

2007-06-13  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* i386/i386/user_ldt.h (user_ldt) [MACH_XEN]: Add alloc field.
	* i386/i386/user_ldt.c (i386_set_ldt) [MACH_XEN]: Round allocation of
	LDT to a page, set back LDT pages read/write before freeing them.
	(user_ldt_free) [MACH_XEN]: Likewise.

2007-04-18  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	* device/ds_routines.c [MACH_HYP]: Add hypervisor block and net devices.

2007-02-19  Thomas Schwinge  <tschwinge@gnu.org>

	* i386/xen/Makefrag.am [PLATFORM_xen] (gnumach_LINKFLAGS): Define.

	* Makefrag.am: Include `xen/Makefrag.am'.
	* configure.ac: Include `xen/configfrag.ac'.
	(--enable-platform): Support the `xen' platform.
	* i386/configfrag.ac: Likewise.
	* i386/Makefrag.am [PLATFORM_xen]: Include `i386/xen/Makefrag.am'.

2007-02-19  Samuel Thibault  <samuel.thibault@ens-lyon.org>
	    Thomas Schwinge  <tschwinge@gnu.org>

	* i386/xen/Makefrag.am: New file.
	* xen/Makefrag.am: Likewise.
	* xen/configfrag.ac: Likewise.

2007-02-11 (and later dates)  Samuel Thibault  <samuel.thibault@ens-lyon.org>

	Xen support
	* Makefile.am (clib_routines): Add _start.
	* Makefrag.am (include_mach_HEADERS): Add include/mach/xen.h.
	* device/cons.c (cnputc): Call hyp_console_write.
	* i386/Makefrag.am (libkernel_a_SOURCES): Move non-Xen source to
	[PLATFORM_at].
	* i386/i386/debug_trace.S: Include <i386/xen.h>
	* i386/i386/fpu.c [MACH_HYP] (init_fpu): Call set_ts() and clear_ts(),
	do not enable CR0_EM.
	* i386/i386/gdt.c: Include <mach/xen.h> and <intel/pmap.h>.
	[MACH_XEN]: Make gdt array extern.
	[MACH_XEN] (gdt_init): Register gdt with hypervisor.  Request 4gb
	segments assist.  Shift la_shift.
	[MACH_PSEUDO_PHYS] (gdt_init): Shift pfn_list.
	* i386/i386/gdt.h [MACH_XEN]: Don't define KERNEL_LDT and LINEAR_DS.
	* i386/i386/i386asm.sym: Include <i386/xen.h>.
	[MACH_XEN]: Remove KERNEL_LDT, Add shared_info's CPU_CLI, CPU_PENDING,
	CPU_PENDING_SEL, PENDING, EVTMASK and CR2.
	* i386/i386/idt.c [MACH_HYP] (idt_init): Register trap table with
	hypervisor.
	* i386/i386/idt_inittab.S: Include <i386/i386asm.h>.
	[MACH_XEN]: Set IDT_ENTRY() for hypervisor. Set trap table terminator.
	* i386/i386/ktss.c [MACH_XEN] (ktss_init): Request exception task switch
	from hypervisor.
	* i386/i386/ldt.c: Include <mach/xen.h> and <intel/pmap.h>
	[MACH_XEN]: Make ldt array extern.
	[MACH_XEN] (ldt_init): Set ldt readwrite.
	[MACH_HYP] (ldt_init): Register ldt with hypervisor.
	* i386/i386/locore.S: Include <i386/xen.h>. Handle KERNEL_RING == 1
	case.
	[MACH_XEN]: Read hyp_shared_info's CR2 instead of %cr2.
	[MACH_PSEUDO_PHYS]: Add mfn_to_pfn computation.
	[MACH_HYP]: Drop Cyrix I/O-based detection.  Read cr3 instead of %cr3.
	Make hypervisor call for pte invalidation.
	* i386/i386/mp_desc.c: Include <mach/xen.h>.
	[MACH_HYP] (mp_desc_init): Panic.
	* i386/i386/pcb.c: Include <mach/xen.h>.
	[MACH_XEN] (switch_ktss): Request stack switch from hypervisor.
	[MACH_HYP] (switch_ktss): Request ldt and gdt switch from hypervisor.
	* i386/i386/phys.c: Include <mach/xen.h>
	[MACH_PSEUDO_PHYS] (kvtophys): Do page translation.
	* i386/i386/proc_reg.h [MACH_HYP] (cr3): New declaration.
	(set_cr3, get_cr3, set_ts, clear_ts): Implement macros.
	* i386/i386/seg.h [MACH_HYP]: Define KERNEL_RING macro.  Include
	<mach/xen.h>
	[MACH_XEN] (fill_descriptor): Register descriptor with hypervisor.
	* i386/i386/spl.S: Include <i386/xen.h> and <i386/i386/asm.h>
	[MACH_XEN] (pic_mask): #define to int_mask.
	[MACH_XEN] (SETMASK): Implement.
	* i386/i386/vm_param.h [MACH_XEN] (HYP_VIRT_START): New macro.
	[MACH_XEN]: Set VM_MAX_KERNEL_ADDRESS to HYP_VIRT_START-
	LINEAR_MIN_KERNEL_ADDRESS + VM_MIN_KERNEL_ADDRESS.  Increase
	KERNEL_STACK_SIZE and INTSTACK_SIZE to 4 pages.
	* i386/i386at/conf.c [MACH_HYP]: Remove hardware devices, add hypervisor
	console device.
	* i386/i386at/cons_conf.c [MACH_HYP]: Add hypervisor console device.
	* i386/i386at/model_dep.c: Include <sys/types.h>, <mach/xen.h>.
	[MACH_XEN] Include <xen/console.h>, <xen/store.h>, <xen/evt.h>,
	<xen/xen.h>.
	[MACH_PSEUDO_PHYS]: New boot_info, mfn_list, pfn_list variables.
	[MACH_XEN]: New la_shift variable.
	[MACH_HYP] (avail_next, mem_size_init): Drop BIOS skipping mecanism.
	[MACH_HYP] (machine_init): Call hyp_init(), drop hardware
	initialization.
	[MACH_HYP] (machine_idle): Call hyp_idle().
	[MACH_HYP] (halt_cpu): Call hyp_halt().
	[MACH_HYP] (halt_all_cpus): Call hyp_reboot() or hyp_halt().
	[MACH_HYP] (i386at_init): Initialize with hypervisor.
	[MACH_XEN] (c_boot_entry): Add Xen-specific initialization.
	[MACH_HYP] (init_alloc_aligned, pmap_valid_page): Drop zones skipping
	mecanism.
	* i386/intel/pmap.c: Include <mach/xen.h>.
	[MACH_PSEUDO_PHYS] (WRITE_PTE): Do page translation.
	[MACH_HYP] (INVALIDATE_TLB): Request invalidation from hypervisor.
	[MACH_XEN] (pmap_map_bd, pmap_create, pmap_destroy, pmap_remove_range)
	(pmap_page_protect, pmap_protect, pmap_enter, pmap_change_wiring)
	(pmap_attribute_clear, pmap_unmap_page_zero, pmap_collect): Request MMU
	update from hypervisor.
	[MACH_XEN] (pmap_bootstrap): Request pagetable initialization from
	hypervisor.
	[MACH_XEN] (pmap_set_page_readwrite, pmap_set_page_readonly)
	(pmap_set_page_readonly_init, pmap_clear_bootstrap_pagetable)
	(pmap_map_mfn): New functions.
	* i386/intel/pmap.h [MACH_XEN] (INTEL_PTE_GLOBAL): Disable global page
	support.
	[MACH_PSEUDO_PHYS] (pte_to_pa): Do page translation.
	[MACH_XEN] (pmap_set_page_readwrite, pmap_set_page_readonly)
	(pmap_set_page_readonly_init, pmap_clear_bootstrap_pagetable)
	(pmap_map_mfn): Declare functions.
	* i386/i386/xen.h: New file.
	* i386/xen/xen.c: New file.
	* i386/xen/xen_boothdr.S: New file.
	* i386/xen/xen_locore.S: New file.
	* include/mach/xen.h: New file.
	* kern/bootstrap.c [MACH_XEN] (boot_info): Declare variable.
	[MACH_XEN] (bootstrap_create): Rebase multiboot header.
	* kern/debug.c: Include <mach/xen.h>.
	[MACH_HYP] (panic): Call hyp_crash() without delay.
	* linux/dev/include/asm-i386/segment.h [MACH_HYP] (KERNEL_CS)
	(KERNEL_DS): Use ring 1.
	* xen/block.c: New file.
	* xen/block.h: Likewise.
	* xen/console.c: Likewise.
	* xen/console.h: Likewise.
	* xen/evt.c: Likewise.
	* xen/evt.h: Likewise.
	* xen/grant.c: Likewise.
	* xen/grant.h: Likewise.
	* xen/net.c: Likewise.
	* xen/net.h: Likewise.
	* xen/ring.c: Likewise.
	* xen/ring.h: Likewise.
	* xen/store.c: Likewise.
	* xen/store.h: Likewise.
	* xen/time.c: Likewise.
	* xen/time.h: Likewise.
	* xen/xen.c: Likewise.
	* xen/xen.h: Likewise.
	* xen/public/COPYING: Import file from Xen.
	* xen/public/callback.h: Likewise.
	* xen/public/dom0_ops.h: Likewise.
	* xen/public/domctl.h: Likewise.
	* xen/public/elfnote.h: Likewise.
	* xen/public/elfstructs.h: Likewise.
	* xen/public/event_channel.h: Likewise.
	* xen/public/features.h: Likewise.
	* xen/public/grant_table.h: Likewise.
	* xen/public/kexec.h: Likewise.
	* xen/public/libelf.h: Likewise.
	* xen/public/memory.h: Likewise.
	* xen/public/nmi.h: Likewise.
	* xen/public/physdev.h: Likewise.
	* xen/public/platform.h: Likewise.
	* xen/public/sched.h: Likewise.
	* xen/public/sysctl.h: Likewise.
	* xen/public/trace.h: Likewise.
	* xen/public/vcpu.h: Likewise.
	* xen/public/version.h: Likewise.
	* xen/public/xen-compat.h: Likewise.
	* xen/public/xen.h: Likewise.
	* xen/public/xencomm.h: Likewise.
	* xen/public/xenoprof.h: Likewise.
	* xen/public/arch-x86/xen-mca.h: Likewise.
	* xen/public/arch-x86/xen-x86_32.h: Likewise.
	* xen/public/arch-x86/xen-x86_64.h: Likewise.
	* xen/public/arch-x86/xen.h: Likewise.
	* xen/public/arch-x86_32.h: Likewise.
	* xen/public/arch-x86_64.h: Likewise.
	* xen/public/io/blkif.h: Likewise.
	* xen/public/io/console.h: Likewise.
	* xen/public/io/fbif.h: Likewise.
	* xen/public/io/fsif.h: Likewise.
	* xen/public/io/kbdif.h: Likewise.
	* xen/public/io/netif.h: Likewise.
	* xen/public/io/pciif.h: Likewise.
	* xen/public/io/protocols.h: Likewise.
	* xen/public/io/ring.h: Likewise.
	* xen/public/io/tpmif.h: Likewise.
	* xen/public/io/xenbus.h: Likewise.
	* xen/public/io/xs_wire.h: Likewise.

4 files changed, 387 insertions, 0 deletions

diff --git a/i386/xen/Makefrag.am b/i386/xen/Makefrag.am
new file mode 100644
index 0000000..b15b7db
--- /dev/null
+++ b/i386/xen/Makefrag.am
@@ -0,0 +1,33 @@
+# Makefile fragment for the ix86 specific part of the Xen platform.
+
+# Copyright (C) 2007 Free Software Foundation, Inc.
+
+# This program is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by the
+# Free Software Foundation; either version 2, or (at your option) any later
+# version.
+# 
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+# or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+# for more details.
+# 
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+#
+# Xen support.
+#
+
+libkernel_a_SOURCES += \
+	i386/xen/xen.c \
+	i386/xen/xen_locore.S \
+	i386/xen/xen_boothdr.S
+
+
+if PLATFORM_xen
+gnumach_LINKFLAGS += \
+	--defsym _START=0x20000000 \
+	-T '$(srcdir)'/i386/ldscript
+endif
diff --git a/i386/xen/xen.c b/i386/xen/xen.c
new file mode 100644
index 0000000..aa3c2cc
--- /dev/null
+++ b/i386/xen/xen.c
@@ -0,0 +1,77 @@
+/*
+ *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *
+ * This program is free software ; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY ; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <kern/printf.h>
+#include <kern/debug.h>
+
+#include <mach/machine/eflags.h>
+#include <machine/thread.h>
+#include <machine/ipl.h>
+
+#include <machine/model_dep.h>
+
+unsigned long cr3;
+
+struct failsafe_callback_regs {
+	unsigned int ds;
+	unsigned int es;
+	unsigned int fs;
+	unsigned int gs;
+	unsigned int ip;
+	unsigned int cs_and_mask;
+	unsigned int flags;
+};
+
+void hyp_failsafe_c_callback(struct failsafe_callback_regs *regs) {
+	printf("Fail-Safe callback!\n");
+	printf("IP: %08X CS: %4X DS: %4X ES: %4X FS: %4X GS: %4X FLAGS %08X MASK %04X\n", regs->ip, regs->cs_and_mask & 0xffff, regs->ds, regs->es, regs->fs, regs->gs, regs->flags, regs->cs_and_mask >> 16);
+	panic("failsafe");
+}
+
+extern void clock_interrupt();
+extern void return_to_iret;
+
+void hypclock_machine_intr(int old_ipl, void *ret_addr, struct i386_interrupt_state *regs, unsigned64_t delta) {
+	if (ret_addr == &return_to_iret) {
+		clock_interrupt(delta/1000,		/* usec per tick */
+			(regs->efl & EFL_VM) ||		/* user mode */ 
+			((regs->cs & 0x02) != 0),	/* user mode */ 
+			old_ipl == SPL0);		/* base priority */
+	} else
+		clock_interrupt(delta/1000, FALSE, FALSE);
+}
+
+void hyp_p2m_init(void) {
+	unsigned long nb_pfns = atop(phys_last_addr);
+#ifdef MACH_PSEUDO_PHYS
+#define P2M_PAGE_ENTRIES (PAGE_SIZE / sizeof(unsigned long))
+	unsigned long *l3 = (unsigned long *)phystokv(pmap_grab_page()), *l2 = NULL;
+	unsigned long i;
+
+	for (i = 0; i < (nb_pfns + P2M_PAGE_ENTRIES) / P2M_PAGE_ENTRIES; i++) {
+		if (!(i % P2M_PAGE_ENTRIES)) {
+			l2 = (unsigned long *) phystokv(pmap_grab_page());
+			l3[i / P2M_PAGE_ENTRIES] = kv_to_mfn(l2);
+		}
+		l2[i % P2M_PAGE_ENTRIES] = kv_to_mfn(&mfn_list[i * P2M_PAGE_ENTRIES]);
+	}
+
+	hyp_shared_info.arch.pfn_to_mfn_frame_list_list = kv_to_mfn(l3);
+#endif
+	hyp_shared_info.arch.max_pfn = nb_pfns;
+}
diff --git a/i386/xen/xen_boothdr.S b/i386/xen/xen_boothdr.S
new file mode 100644
index 0000000..3d84e0c
--- /dev/null
+++ b/i386/xen/xen_boothdr.S
@@ -0,0 +1,167 @@
+/*
+ *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *
+ * This program is free software ; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY ; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <xen/public/elfnote.h>
+
+.section __xen_guest
+	.ascii	"GUEST_OS=GNU Mach"
+	.ascii  ",GUEST_VERSION=1.3"
+	.ascii	",XEN_VER=xen-3.0"
+	.ascii  ",VIRT_BASE=0x20000000"
+	.ascii  ",ELF_PADDR_OFFSET=0x20000000"
+	.ascii	",HYPERCALL_PAGE=0x2"
+#if PAE
+	.ascii  ",PAE=yes"
+#else
+	.ascii  ",PAE=no"
+#endif
+	.ascii	",LOADER=generic"
+#ifndef	MACH_PSEUDO_PHYS
+	.ascii	",FEATURES=!auto_translated_physmap"
+#endif
+	.byte	0
+
+/* Macro taken from linux/include/linux/elfnote.h */
+#define ELFNOTE(name, type, desctype, descdata)	\
+.pushsection .note.name			;	\
+  .align 4				;	\
+  .long 2f - 1f		/* namesz */	;	\
+  .long 4f - 3f		/* descsz */	;	\
+  .long type				;	\
+1:.asciz "name"				;	\
+2:.align 4				;	\
+3:desctype descdata			;	\
+4:.align 4				;	\
+.popsection				;
+
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,		.asciz, "GNU Mach")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,		.asciz, "1.3")
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,		.asciz, "xen-3.0")
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,		.long,  _START)
+	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,		.long,  _START)
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,			.long,  start)
+	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE,	.long,  hypcalls)
+#if PAE
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,		.asciz, "yes")
+#else
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,		.asciz, "no")
+#endif
+	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,		.asciz, "generic")
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,              .asciz, ""
+#ifndef MACH_PSEUDO_PHYS
+						"!auto_translated_physmap"
+#endif
+	)
+
+#include <mach/machine/asm.h>
+
+#include <i386/i386/i386asm.h>
+
+	.text
+	.globl	gdt, ldt
+	.globl	start, _start, gdt
+start:
+_start:
+
+	/* Switch to our own interrupt stack.  */
+	movl	$(_intstack+INTSTACK_SIZE),%eax
+	movl	%eax,%esp
+
+	/* Reset EFLAGS to a known state.  */
+	pushl	$0
+	popf
+
+	/* Push the start_info pointer to be the second argument.  */
+	subl    $KERNELBASE,%esi
+	pushl	%esi
+
+	/* Jump into C code.  */
+	call	EXT(c_boot_entry)
+
+/* Those need to be aligned on page boundaries.  */
+.global hyp_shared_info, hypcalls
+
+	.org	(start + 0x1000)
+hyp_shared_info:
+	.org	hyp_shared_info + 0x1000
+
+/* Labels just for debuggers */
+#define hypcall(name, n) \
+	.org	hypcalls + n*32 ; \
+__hyp_##name:
+
+hypcalls:
+	hypcall(set_trap_table, 0)
+	hypcall(mmu_update, 1)
+	hypcall(set_gdt, 2)
+	hypcall(stack_switch, 3)
+	hypcall(set_callbacks, 4)
+	hypcall(fpu_taskswitch, 5)
+	hypcall(sched_op_compat, 6)
+	hypcall(platform_op, 7)
+	hypcall(set_debugreg, 8)
+	hypcall(get_debugreg, 9)
+	hypcall(update_descriptor, 10)
+	hypcall(memory_op, 12)
+	hypcall(multicall, 13)
+	hypcall(update_va_mapping, 14)
+	hypcall(set_timer_op, 15)
+	hypcall(event_channel_op_compat, 16)
+	hypcall(xen_version, 17)
+	hypcall(console_io, 18)
+	hypcall(physdev_op_compat, 19)
+	hypcall(grant_table_op, 20)
+	hypcall(vm_assist, 21)
+	hypcall(update_va_mapping_otherdomain, 22)
+	hypcall(iret, 23)
+	hypcall(vcpu_op, 24)
+	hypcall(set_segment_base, 25)
+	hypcall(mmuext_op, 26)
+	hypcall(acm_op, 27)
+	hypcall(nmi_op, 28)
+	hypcall(sched_op, 29)
+	hypcall(callback_op, 30)
+	hypcall(xenoprof_op, 31)
+	hypcall(event_channel_op, 32)
+	hypcall(physdev_op, 33)
+	hypcall(hvm_op, 34)
+	hypcall(sysctl, 35)
+	hypcall(domctl, 36)
+	hypcall(kexec_op, 37)
+
+	hypcall(arch_0, 48)
+	hypcall(arch_1, 49)
+	hypcall(arch_2, 50)
+	hypcall(arch_3, 51)
+	hypcall(arch_4, 52)
+	hypcall(arch_5, 53)
+	hypcall(arch_6, 54)
+	hypcall(arch_7, 55)
+
+	.org	hypcalls + 0x1000
+
+gdt:
+	.org	gdt + 0x1000
+
+ldt:
+	.org	ldt + 0x1000
+
+stack:
+	.long	_intstack+INTSTACK_SIZE,0xe021
+	.comm	_intstack,INTSTACK_SIZE
+
diff --git a/i386/xen/xen_locore.S b/i386/xen/xen_locore.S
new file mode 100644
index 0000000..51f823f
--- /dev/null
+++ b/i386/xen/xen_locore.S
@@ -0,0 +1,110 @@
+/*
+ *  Copyright (C) 2006 Samuel Thibault <samuel.thibault@ens-lyon.org>
+ *
+ * This program is free software ; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation ; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY ; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with the program ; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <mach/machine/asm.h>
+
+#include <i386/i386asm.h>
+#include <i386/cpu_number.h>
+#include <i386/xen.h>
+
+	.data	2
+int_active:
+	.long	0
+	
+
+	.text
+	.globl	hyp_callback, hyp_failsafe_callback
+	P2ALIGN(TEXT_ALIGN)
+hyp_callback:
+	pushl	%eax
+	jmp	EXT(all_intrs)
+
+ENTRY(interrupt)
+	incl	int_active		/* currently handling interrupts */
+	call	EXT(hyp_c_callback)	/* call generic interrupt routine */
+	decl	int_active		/* stopped handling interrupts */
+	sti
+	ret
+
+/* FIXME: if we're _very_ unlucky, we may be re-interrupted, filling stack
+ *
+ * Far from trivial, see mini-os. That said, maybe we could just, before poping
+ * everything (which is _not_ destructive), save sp into a known place and use
+ * it+jmp back?
+ *
+ * Mmm, there seems to be an iret hypcall that does exactly what we want:
+ * perform iret, and if IF is set, clear the interrupt mask.
+ */
+
+/* Pfff, we have to check pending interrupts ourselves. Some other DomUs just make an hypercall for retriggering the irq. Not sure it's really easier/faster */
+ENTRY(hyp_sti)
+	pushl	%ebp
+	movl	%esp, %ebp
+_hyp_sti:
+	movb	$0,hyp_shared_info+CPU_CLI /* Enable interrupts */
+	cmpl	$0,int_active		/* Check whether we were already checking pending interrupts */
+	jz	0f
+	popl	%ebp
+	ret				/* Already active, just return */
+0:
+	/* Not active, check pending interrupts by hand */
+	/* no memory barrier needed on x86 */
+	cmpb	$0,hyp_shared_info+CPU_PENDING
+	jne	0f
+	popl	%ebp
+	ret
+0:
+	movb	$0xff,hyp_shared_info+CPU_CLI
+1:
+	pushl	%eax
+	pushl	%ecx
+	pushl	%edx
+	incl	int_active		/* currently handling interrupts */
+
+	pushl	$0
+	pushl	$0
+	call	EXT(hyp_c_callback)
+	popl	%edx
+	popl	%edx
+
+	popl	%edx
+	popl	%ecx
+	popl	%eax
+	decl	int_active		/* stopped handling interrupts */
+	cmpb	$0,hyp_shared_info+CPU_PENDING
+	jne	1b
+	jmp	_hyp_sti
+
+/* Hypervisor failed to reload segments. Dump them.  */
+hyp_failsafe_callback:
+#if 1
+	/* load sane segments */
+	mov	%ss, %ax
+	mov	%ax, %ds
+	mov	%ax, %es
+	mov	%ax, %fs
+	mov	%ax, %gs
+	push	%esp
+	call	EXT(hyp_failsafe_c_callback)
+#else
+	popl	%ds
+	popl	%es
+	popl	%fs
+	popl	%gs
+	iret
+#endif