Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 200 insertions, 0 deletions

diff --git a/pc-bios/optionrom/pvh.S b/pc-bios/optionrom/pvh.S
new file mode 100644
index 000000000..e1d7f4a7a
--- /dev/null
+++ b/pc-bios/optionrom/pvh.S
@@ -0,0 +1,200 @@
+/*
+ * PVH Option ROM
+ *
+ * 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 this program; if not, see <http://www.gnu.org/licenses/>.
+ *
+ * Copyright Novell Inc, 2009
+ *   Authors: Alexander Graf <agraf@suse.de>
+ *
+ * Copyright (c) 2019 Red Hat Inc.
+ *   Authors: Stefano Garzarella <sgarzare@redhat.com>
+ */
+
+#include "optionrom.h"
+
+#define BOOT_ROM_PRODUCT "PVH loader"
+
+#define GS_PROT_JUMP		0
+#define GS_GDT_DESC		6
+
+#ifdef OPTION_ROM_START
+#undef OPTION_ROM_START
+#endif
+#ifdef OPTION_ROM_END
+#undef OPTION_ROM_END
+#endif
+
+/*
+ * Redefine OPTION_ROM_START and OPTION_ROM_END, because this rom is produced
+ * linking multiple objects.
+ * signrom.py will add padding.
+ */
+#define OPTION_ROM_START                                \
+    .code16;						\
+    .text;						\
+	.global 	_start;				\
+    _start:;						\
+	.short		0xaa55;				\
+	.byte		3; /* desired size in 512 units */
+
+#define OPTION_ROM_END					\
+    _end:
+
+BOOT_ROM_START
+
+run_pvhboot:
+
+	cli
+	cld
+
+	mov		%cs, %eax
+	shl		$0x4, %eax
+
+	/* set up a long jump descriptor that is PC relative */
+
+	/* move stack memory to %gs */
+	mov		%ss, %ecx
+	shl		$0x4, %ecx
+	mov		%esp, %ebx
+	add		%ebx, %ecx
+	sub		$0x20, %ecx
+	sub		$0x30, %esp
+	shr		$0x4, %ecx
+	mov		%cx, %gs
+
+	/* now push the indirect jump descriptor there */
+	mov		(prot_jump), %ebx
+	add		%eax, %ebx
+	movl		%ebx, %gs:GS_PROT_JUMP
+	mov		$8, %bx
+	movw		%bx, %gs:GS_PROT_JUMP + 4
+
+	/* fix the gdt descriptor to be PC relative */
+	movw		(gdt_desc), %bx
+	movw		%bx, %gs:GS_GDT_DESC
+	movl		(gdt_desc+2), %ebx
+	add		%eax, %ebx
+	movl		%ebx, %gs:GS_GDT_DESC + 2
+
+	/* initialize HVM memmap table using int 0x15(e820) */
+
+	/* ES = pvh_e820 struct */
+	mov 		$pvh_e820, %eax
+	shr		$4, %eax
+	mov		%ax, %es
+
+	/* start storing memmap table at %es:8 (pvh_e820.table) */
+	mov 		$8,%edi
+	xor		%ebx, %ebx
+	jmp 		memmap_loop
+
+memmap_loop_check:
+	/* pvh_e820 can contains up to 128 entries */
+	cmp 		$128, %ebx
+	je 		memmap_done
+
+memmap_loop:
+	/* entry size (hvm_memmap_table_entry) & max buffer size (int15) */
+	movl		$24, %ecx
+	/* e820 */
+	movl		$0x0000e820, %eax
+	/* 'SMAP' magic */
+	movl		$0x534d4150, %edx
+	/* store counter value at %es:0 (pvh_e820.entries) */
+	movl 		%ebx, %es:0
+
+	int		$0x15
+	/* error or last entry already done? */
+	jb		memmap_err
+
+	/* %edi += entry size (hvm_memmap_table_entry) */
+	add		$24, %edi
+
+	/* continuation value 0 means last entry */
+	test		%ebx, %ebx
+	jnz		memmap_loop_check
+
+	/* increase pvh_e820.entries to save the last entry */
+	movl 		%es:0, %ebx
+	inc 		%ebx
+
+memmap_done:
+	movl 		%ebx, %es:0
+
+memmap_err:
+
+	/* load the GDT before going into protected mode */
+lgdt:
+	data32 lgdt	%gs:GS_GDT_DESC
+
+	/* get us to protected mode now */
+	movl		$1, %eax
+	movl		%eax, %cr0
+
+	/* the LJMP sets CS for us and gets us to 32-bit */
+ljmp:
+	data32 ljmp	*%gs:GS_PROT_JUMP
+
+prot_mode:
+.code32
+
+	/* initialize all other segments */
+	movl		$0x10, %eax
+	movl		%eax, %ss
+	movl		%eax, %ds
+	movl		%eax, %es
+	movl		%eax, %fs
+	movl		%eax, %gs
+
+	jmp pvh_load_kernel
+
+/* Variables */
+.align 4, 0
+prot_jump:	.long prot_mode
+		.short 8
+
+.align 4, 0
+gdt:
+	/* 0x00 */
+.byte	0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
+
+	/*
+	 * 0x08: code segment
+	 * (base=0, limit=0xfffff, type=32bit code exec/read, DPL=0, 4k)
+	 */
+.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x9a, 0xcf, 0x00
+
+	/*
+	 * 0x10: data segment
+	 * (base=0, limit=0xfffff, type=32bit data read/write, DPL=0, 4k)
+	 */
+.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0xcf, 0x00
+
+	/*
+	 * 0x18: code segment
+	 * (base=0, limit=0x0ffff, type=16bit code exec/read/conf, DPL=0, 1b)
+	 */
+.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x9e, 0x00, 0x00
+
+	/*
+	 * 0x20: data segment
+	 * (base=0, limit=0x0ffff, type=16bit data read/write, DPL=0, 1b)
+	 */
+.byte	0xff, 0xff, 0x00, 0x00, 0x00, 0x92, 0x00, 0x00
+
+gdt_desc:
+.short	(5 * 8) - 1
+.long	gdt
+
+BOOT_ROM_END