xen: add PV/PVH kernel entry point

Add the PV/PVH entry point and the low level functions for PVH
early initialization.

Approved by: gibbs
Sponsored by: Citrix Systems R&D

amd64/amd64/genassym.c:
 - Add __FreeBSD_version define to assym.s so it can be used for the
   Xen notes.

amd64/amd64/locore.S:
 - Make bootstack global so it can be used from Xen kernel entry
   point.

amd64/amd64/xen-locore.S:
 - Add Xen notes to the kernel.
 - Add the Xen PV entry point, that is going to call hammer_time_xen.

amd64/include/asmacros.h:
 - Add ELFNOTE macros.

i386/xen/xen_machdep.c:
 - Define HYPERVISOR_start_info for the XEN i386 PV port, which is
   going to be used in some shared code between PV and PVH.

x86/xen/hvm.c:
 - Define HYPERVISOR_start_info for the PVH port.

x86/xen/pv.c:
 - Introduce hammer_time_xen which is going to perform early setup for
   Xen PVH:
    - Setup shared Xen variables start_info, shared_info and
      xen_store.
    - Set guest type.
    - Create initial page tables as FreeBSD expects to find them.
    - Call into native init function (hammer_time).

xen/xen-os.h:
 - Declare HYPERVISOR_start_info.

conf/files.amd64:
 - Add amd64/amd64/locore.S and x86/xen/pv.c to the list of files.

9 files changed, 240 insertions, 0 deletions

diff --git a/sys/amd64/amd64/genassym.c b/sys/amd64/amd64/genassym.c
index 028a2cd..ff1f282 100644
--- a/sys/amd64/amd64/genassym.c
+++ b/sys/amd64/amd64/genassym.c
@@ -248,6 +248,8 @@ ASSYM(TSSSEL, GSEL(GPROC0_SEL, SEL_KPL));
 ASSYM(LDTSEL, GSEL(GUSERLDT_SEL, SEL_KPL));
 ASSYM(SEL_RPL_MASK, SEL_RPL_MASK);
 
+ASSYM(__FreeBSD_version, __FreeBSD_version);
+
 #ifdef	HWPMC_HOOKS
 ASSYM(PMC_FN_USER_CALLCHAIN, PMC_FN_USER_CALLCHAIN);
 #endif
diff --git a/sys/amd64/amd64/locore.S b/sys/amd64/amd64/locore.S
index 55cda3a..4acef97 100644
--- a/sys/amd64/amd64/locore.S
+++ b/sys/amd64/amd64/locore.S
@@ -84,5 +84,6 @@ NON_GPROF_ENTRY(btext)
 
 	.bss
 	ALIGN_DATA			/* just to be sure */
+	.globl	bootstack
 	.space	0x1000			/* space for bootstack - temporary stack */
 bootstack:
diff --git a/sys/amd64/amd64/xen-locore.S b/sys/amd64/amd64/xen-locore.S
new file mode 100644
index 0000000..0142e6b
--- /dev/null
+++ b/sys/amd64/amd64/xen-locore.S
@@ -0,0 +1,83 @@
+/*-
+ * Copyright (c) 2003 Peter Wemm <peter@FreeBSD.org>
+ * Copyright (c) 2013 Roger Pau Monne <royger@FreeBSD.org>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ *
+ * $FreeBSD$
+ */
+
+#include <machine/asmacros.h>
+#include <machine/psl.h>
+#include <machine/pmap.h>
+#include <machine/specialreg.h>
+
+#include <xen/xen-os.h>
+#define __ASSEMBLY__
+#include <xen/interface/elfnote.h>
+
+#include "assym.s"
+
+.section __xen_guest
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_OS,       .asciz, "FreeBSD")
+	ELFNOTE(Xen, XEN_ELFNOTE_GUEST_VERSION,  .asciz, __XSTRING(__FreeBSD_version))
+	ELFNOTE(Xen, XEN_ELFNOTE_XEN_VERSION,    .asciz, "xen-3.0")
+	ELFNOTE(Xen, XEN_ELFNOTE_VIRT_BASE,      .quad,  KERNBASE)
+	ELFNOTE(Xen, XEN_ELFNOTE_PADDR_OFFSET,   .quad,  KERNBASE) /* Xen honours elf->p_paddr; compensate for this */
+	ELFNOTE(Xen, XEN_ELFNOTE_ENTRY,          .quad,  xen_start)
+	ELFNOTE(Xen, XEN_ELFNOTE_HYPERCALL_PAGE, .quad,	 hypercall_page)
+	ELFNOTE(Xen, XEN_ELFNOTE_HV_START_LOW,   .quad,  HYPERVISOR_VIRT_START)
+	ELFNOTE(Xen, XEN_ELFNOTE_FEATURES,       .asciz, "writable_descriptor_tables|auto_translated_physmap|supervisor_mode_kernel|hvm_callback_vector")
+	ELFNOTE(Xen, XEN_ELFNOTE_PAE_MODE,       .asciz, "yes")
+	ELFNOTE(Xen, XEN_ELFNOTE_L1_MFN_VALID,   .long,  PG_V, PG_V)
+	ELFNOTE(Xen, XEN_ELFNOTE_LOADER,         .asciz, "generic")
+	ELFNOTE(Xen, XEN_ELFNOTE_SUSPEND_CANCEL, .long,  0)
+	ELFNOTE(Xen, XEN_ELFNOTE_BSD_SYMTAB,	 .asciz, "yes")
+
+	.text
+.p2align PAGE_SHIFT, 0x90	/* Hypercall_page needs to be PAGE aligned */
+
+NON_GPROF_ENTRY(hypercall_page)
+	.skip	0x1000, 0x90	/* Fill with "nop"s */
+
+NON_GPROF_ENTRY(xen_start)
+	/* Don't trust what the loader gives for rflags. */
+	pushq	$PSL_KERNEL
+	popfq
+
+	/* Parameters for the xen init function */
+	movq	%rsi, %rdi		/* shared_info (arg 1) */
+	movq	%rsp, %rsi		/* xenstack    (arg 2) */
+
+	/* Use our own stack */
+	movq	$bootstack,%rsp
+	xorl	%ebp, %ebp
+
+	/* u_int64_t hammer_time_xen(start_info_t *si, u_int64_t xenstack); */
+	call	hammer_time_xen
+	movq	%rax, %rsp		/* set up kstack for mi_startup() */
+	call	mi_startup		/* autoconfiguration, mountroot etc */
+
+	/* NOTREACHED */
+0:	hlt
+	jmp 	0b
diff --git a/sys/amd64/include/asmacros.h b/sys/amd64/include/asmacros.h
index 1fb592a..ce8dce4 100644
--- a/sys/amd64/include/asmacros.h
+++ b/sys/amd64/include/asmacros.h
@@ -201,4 +201,30 @@
 
 #endif /* LOCORE */
 
+#ifdef __STDC__
+#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
+#else /* !__STDC__, i.e. -traditional */
+#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
+#endif /* __STDC__ */
+
 #endif /* !_MACHINE_ASMACROS_H_ */
diff --git a/sys/conf/files.amd64 b/sys/conf/files.amd64
index f4b3c4c..a6eb12a 100644
--- a/sys/conf/files.amd64
+++ b/sys/conf/files.amd64
@@ -108,6 +108,7 @@ amd64/amd64/in_cksum.c		optional	inet | inet6
 amd64/amd64/initcpu.c		standard
 amd64/amd64/io.c		optional	io
 amd64/amd64/locore.S		standard	no-obj
+amd64/amd64/xen-locore.S	optional	xenhvm
 amd64/amd64/machdep.c		standard
 amd64/amd64/mem.c		optional	mem
 amd64/amd64/minidump_machdep.c	standard
@@ -555,3 +556,4 @@ x86/x86/nexus.c			standard
 x86/x86/tsc.c			standard
 x86/xen/hvm.c			optional	xenhvm
 x86/xen/xen_intr.c		optional	xen | xenhvm
+x86/xen/pv.c			optional	xenhvm
diff --git a/sys/i386/xen/xen_machdep.c b/sys/i386/xen/xen_machdep.c
index 7049be6..fd575ee 100644
--- a/sys/i386/xen/xen_machdep.c
+++ b/sys/i386/xen/xen_machdep.c
@@ -89,6 +89,7 @@ IDTVEC(div), IDTVEC(dbg), IDTVEC(nmi), IDTVEC(bpt), IDTVEC(ofl),
 
 int xendebug_flags; 
 start_info_t *xen_start_info;
+start_info_t *HYPERVISOR_start_info;
 shared_info_t *HYPERVISOR_shared_info;
 xen_pfn_t *xen_machine_phys = machine_to_phys_mapping;
 xen_pfn_t *xen_phys_machine;
@@ -927,6 +928,7 @@ initvalues(start_info_t *startinfo)
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments_notify);	
 #endif	
 	xen_start_info = startinfo;
+	HYPERVISOR_start_info = startinfo;
 	xen_phys_machine = (xen_pfn_t *)startinfo->mfn_list;
 
 	IdlePTD = (pd_entry_t *)((uint8_t *)startinfo->pt_base + PAGE_SIZE);
diff --git a/sys/x86/xen/hvm.c b/sys/x86/xen/hvm.c
index 9f4c6be..6977d56 100644
--- a/sys/x86/xen/hvm.c
+++ b/sys/x86/xen/hvm.c
@@ -149,6 +149,7 @@ DPCPU_DEFINE(xen_intr_handle_t, ipi_handle[nitems(xen_ipis)]);
 /** Hypercall table accessed via HYPERVISOR_*_op() methods. */
 char *hypercall_stubs;
 shared_info_t *HYPERVISOR_shared_info;
+start_info_t *HYPERVISOR_start_info;
 
 #ifdef SMP
 /*---------------------------- XEN PV IPI Handlers ---------------------------*/
diff --git a/sys/x86/xen/pv.c b/sys/x86/xen/pv.c
new file mode 100644
index 0000000..6805baa
--- /dev/null
+++ b/sys/x86/xen/pv.c
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2004 Christian Limpach.
+ * Copyright (c) 2004-2006,2008 Kip Macy
+ * Copyright (c) 2013 Roger Pau Monné <roger.pau@citrix.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/bus.h>
+#include <sys/kernel.h>
+#include <sys/reboot.h>
+#include <sys/systm.h>
+#include <sys/lock.h>
+#include <sys/rwlock.h>
+
+#include <vm/vm.h>
+#include <vm/vm_extern.h>
+#include <vm/vm_kern.h>
+#include <vm/vm_page.h>
+#include <vm/vm_map.h>
+#include <vm/vm_object.h>
+#include <vm/vm_pager.h>
+#include <vm/vm_param.h>
+
+#include <xen/xen-os.h>
+#include <xen/hypervisor.h>
+
+/* Native initial function */
+extern u_int64_t hammer_time(u_int64_t, u_int64_t);
+/* Xen initial function */
+uint64_t hammer_time_xen(start_info_t *, uint64_t);
+
+/*
+ * First function called by the Xen PVH boot sequence.
+ *
+ * Set some Xen global variables and prepare the environment so it is
+ * as similar as possible to what native FreeBSD init function expects.
+ */
+uint64_t
+hammer_time_xen(start_info_t *si, uint64_t xenstack)
+{
+	uint64_t physfree;
+	uint64_t *PT4 = (u_int64_t *)xenstack;
+	uint64_t *PT3 = (u_int64_t *)(xenstack + PAGE_SIZE);
+	uint64_t *PT2 = (u_int64_t *)(xenstack + 2 * PAGE_SIZE);
+	int i;
+
+	xen_domain_type = XEN_PV_DOMAIN;
+	vm_guest = VM_GUEST_XEN;
+
+	if ((si == NULL) || (xenstack == 0)) {
+		HYPERVISOR_shutdown(SHUTDOWN_crash);
+	}
+
+	/* We use 3 pages of xen stack for the boot pagetables */
+	physfree = xenstack + 3 * PAGE_SIZE - KERNBASE;
+
+	/* Setup Xen global variables */
+	HYPERVISOR_start_info = si;
+	HYPERVISOR_shared_info =
+	    (shared_info_t *)(si->shared_info + KERNBASE);
+
+	/*
+	 * Setup some misc global variables for Xen devices
+	 *
+	 * XXX: Devices that need these specific variables should
+	 *      be rewritten to fetch this info by themselves from the
+	 *      start_info page.
+	 */
+	xen_store = (struct xenstore_domain_interface *)
+	    (ptoa(si->store_mfn) + KERNBASE);
+
+	/*
+	 * Use the stack Xen gives us to build the page tables
+	 * as native FreeBSD expects to find them (created
+	 * by the boot trampoline).
+	 */
+	for (i = 0; i < (PAGE_SIZE / sizeof(uint64_t)); i++) {
+		/* Each slot of the level 4 pages points to the same level 3 page */
+		PT4[i] = ((uint64_t)&PT3[0]) - KERNBASE;
+		PT4[i] |= PG_V | PG_RW | PG_U;
+
+		/* Each slot of the level 3 pages points to the same level 2 page */
+		PT3[i] = ((uint64_t)&PT2[0]) - KERNBASE;
+		PT3[i] |= PG_V | PG_RW | PG_U;
+
+		/* The level 2 page slots are mapped with 2MB pages for 1GB. */
+		PT2[i] = i * (2 * 1024 * 1024);
+		PT2[i] |= PG_V | PG_RW | PG_PS | PG_U;
+	}
+	load_cr3(((uint64_t)&PT4[0]) - KERNBASE);
+
+	/* Now we can jump into the native init function */
+	return (hammer_time(0, physfree));
+}
diff --git a/sys/xen/xen-os.h b/sys/xen/xen-os.h
index 87644e9..c7474d8 100644
--- a/sys/xen/xen-os.h
+++ b/sys/xen/xen-os.h
@@ -51,6 +51,10 @@
 void force_evtchn_callback(void);
 
 extern shared_info_t *HYPERVISOR_shared_info;
+extern start_info_t *HYPERVISOR_start_info;
+
+/* XXX: we need to get rid of this and use HYPERVISOR_start_info directly */
+extern struct xenstore_domain_interface *xen_store;
 
 enum xen_domain_type {
 	XEN_NATIVE,             /* running on bare hardware    */