Re: [Qemu-devel] Hvmloader: Modify ACPI to only supply _EJ0 methods for PCIslots that support hotplug by runtime patching

[Fabio Fantoni <fabio.fantoni@m2r.biz>]

Il 16/10/2013 08:30, Gonglei (Arei) ha scritto:
> http://lists.xen.org/archives/html/xen-devel/2013-09/msg03113.html
> As said above, In Xen platform, after using upstream qemu, all pci devices can be unpluged in the windows guest.
> In this situation, the windows guest may occur blue screen when VM' user click the icon of pass-through Graphics card for trying to unplug the device.
>
> The kvm system doesn't have this problem for the use of seabios.
> http://www.seabios.org/pipermail/seabios/2011-September/002293.html
> The patch above in seabios solves the problem. The patch is ported in hvmloader and works well.

Thanks, I tried it but it fails to compile:
> /mnt/vm/xen/Xen/tools/firmware/hvmloader# make
> make[1]: Entering directory `/mnt/vm/xen/Xen/tools/firmware/hvmloader'
> make -C acpi all
> make[2]: Entering directory 
> `/mnt/vm/xen/Xen/tools/firmware/hvmloader/acpi'
> Makefile:59: warning: overriding commands for target 
> `dsdt_anycpu_qemu_xen.c'
> Makefile:51: warning: ignoring old commands for target 
> `dsdt_anycpu_qemu_xen.c'
> gcc   -O1 -fno-omit-frame-pointer -m32 -march=i686 -g 
> -fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes 
> -Wdeclaration-after-statement -Wno-unused-but-set-variable 
> -Wno-unused-local-typedefs   -D__XEN_TOOLS__ -MMD -MF .build.o.d 
> -D_LARGEFILE_SOURCE -D_LARGEFILE64_SOURCE -fno-optimize-sibling-calls 
> -mno-tls-direct-seg-refs  -Werror -fno-stack-protector -fno-exceptions 
> -fno-builtin -msoft-float 
> -I/mnt/vm/xen/Xen/tools/firmware/hvmloader/acpi/../../../../tools/include 
> -c -o build.o build.c
> build.c: In function âacpi_build_tablesâ:
> build.c:555:1: error: expected declaration or statement at end of input
> make[2]: *** [build.o] Error 1
> make[2]: Leaving directory `/mnt/vm/xen/Xen/tools/firmware/hvmloader/acpi'
> make[1]: *** [subdir-all-acpi] Error 2
> make[1]: Leaving directory `/mnt/vm/xen/Xen/tools/firmware/hvmloader'
> make: *** [subdirs-all] Error 2

It seems there is something incomplete.

Here are the details of dom0 where I test it:
http://lists.xen.org/archives/html/xen-devel/2013-10/msg01111.html


>
> This is done by runtime patching:
> - Rename _EJ0 methods for PCI slots in DSDT to EJ0_:
>    note that this has the same checksum, but
>    is ignored by OSPM.
> - At compile time, look for these methods in ASL source,
>    find the matching AML, and store the offsets of these methods
>    in a table named aml_ej0_data.
> - At run time, go over aml_ej0_data, check which slots
>    not support hotplug and patch the ACPI table, replacing _EJ0 with EJ0_.
>
> The files *.py are from seabios
> diff -urN hvmloader/acpi/Makefile hvmloader_new//acpi/Makefile
> --- hvmloader/acpi/Makefile	2013-10-16 11:51:53.000000000 +0800
> +++ hvmloader_new//acpi/Makefile	2013-10-16 11:51:58.000000000 +0800
> @@ -36,18 +36,34 @@
>   
>   dsdt_anycpu_qemu_xen.asl: dsdt.asl mk_dsdt
>   	awk 'NR > 1 {print s} {s=$$0}' $< > $@
> -	./mk_dsdt --dm-version qemu-xen >> $@
> +	sed -i 's/AmlCode/dsdt_anycpu_qemu_xen/g' $@
> +	./mk_dsdt --dm-version qemu-xen >> $@	
> +	sed -i 's/aml_ej0_name/dsdt_anycpu_qemu_xen_aml_ej0_name/g' $@
> +	sed -i 's/aml_adr_dword/dsdt_anycpu_qemu_xen_aml_adr_dword/g' $@
>   
>   # NB. awk invocation is a portable alternative to 'head -n -1'
>   dsdt_%cpu.asl: dsdt.asl mk_dsdt
>   	awk 'NR > 1 {print s} {s=$$0}' $< > $@
> +	sed -i 's/AmlCode/dsdt_$*cpu/g' $@
>   	./mk_dsdt --maxcpu $*  >> $@
>   
>   $(filter dsdt_%.c,$(C_SRC)): %.c: iasl %.asl
> -	iasl -vs -p $* -tc $*.asl
> -	sed -e 's/AmlCode/$*/g' $*.hex >$@
> +	cpp -P $*.asl > $*.asl.i.orig
> +	/usr/bin/python ../tools/acpi_extract_preprocess.py $*.asl.i.orig > $*.asl.i
> +	iasl -vs -l -tc -p $* $*.asl.i
> +	/usr/bin/python ../tools/acpi_extract.py $*.lst > $@
>   	echo "int $*_len=sizeof($*);" >>$@
> -	rm -f $*.aml $*.hex
> +	rm -f $*.aml $*.hex $*.asl.i.orig $*.asl.i $*.lst
> +
> +dsdt_anycpu_qemu_xen.c:iasl dsdt_anycpu_qemu_xen.asl
> +	cpp -P $*.asl > $*.asl.i.orig
> +	/usr/bin/python ../tools/acpi_extract_preprocess.py $*.asl.i.orig > $*.asl.i
> +	iasl -vs -l -tc -p $* $*.asl.i
> +	/usr/bin/python ../tools/acpi_extract.py $*.lst > $@
> +	echo "int $*_len=sizeof($*);" >>$@
> +	echo "int $*_aml_ej0_name_len=sizeof($*_aml_ej0_name);" >>$@
> +	echo "int $*_aml_adr_dword_len=sizeof($*_aml_adr_dword);" >>$@
> +	rm -f $*.aml $*.hex $*.asl.i.orig $*.asl.i $*.lst
>   
>   iasl:
>   	@echo
> @@ -64,7 +80,7 @@
>   
>   clean:
>   	rm -rf *.a *.o $(IASL_VER) $(IASL_VER).tar.gz $(DEPS)
> -	rm -rf ssdt_*.h dsdt*.c *~ *.aml *.hex mk_dsdt dsdt_*.asl
> +	rm -rf ssdt_*.h dsdt*.c *~ *.aml *.hex mk_dsdt dsdt_*.asl *.asl.i *.asl.i.orig *.lst
>   
>   install: all
>   
> diff -urN hvmloader/acpi/acpi2_0.h hvmloader_new//acpi/acpi2_0.h
> --- hvmloader/acpi/acpi2_0.h	2013-10-16 11:54:49.000000000 +0800
> +++ hvmloader_new//acpi/acpi2_0.h	2013-10-16 11:46:52.000000000 +0800
> @@ -396,6 +396,11 @@
>       int dsdt_anycpu_len;
>       unsigned char *dsdt_15cpu;
>       int dsdt_15cpu_len;
> +    unsigned short *aml_ej0_name;
> +    unsigned short *aml_adr_dword;
> +    int aml_ej0_name_len;
> +    int aml_adr_dword_len;
> +
>   };
>   
>   void acpi_build_tables(struct acpi_config *config, unsigned int physical);
> diff -urN hvmloader/acpi/build.c hvmloader_new//acpi/build.c
> --- hvmloader/acpi/build.c	2013-10-16 11:55:55.000000000 +0800
> +++ hvmloader_new//acpi/build.c	2013-10-16 11:46:52.000000000 +0800
> @@ -30,6 +30,9 @@
>   #define align16(sz)        (((sz) + 15) & ~15)
>   #define fixed_strcpy(d, s) strncpy((d), (s), sizeof(d))
>   
> +
> +#define PCI_RMV_BASE 0xae0c
> +
>   extern struct acpi_20_rsdp Rsdp;
>   extern struct acpi_20_rsdt Rsdt;
>   extern struct acpi_20_xsdt Xsdt;
> @@ -404,6 +407,7 @@
>       unsigned char       *dsdt;
>       unsigned long        secondary_tables[ACPI_MAX_SECONDARY_TABLES];
>       int                  nr_secondaries, i;
> +    unsigned int rmvc_pcrm = 0;
>   
>       /* Allocate and initialise the acpi info area. */
>       mem_hole_populate_ram(ACPI_INFO_PHYSICAL_ADDRESS >> PAGE_SHIFT, 1);
> @@ -438,9 +442,26 @@
>           dsdt = mem_alloc(config->dsdt_anycpu_len, 16);
>           if (!dsdt) goto oom;
>           memcpy(dsdt, config->dsdt_anycpu, config->dsdt_anycpu_len);
> -        nr_processor_objects = HVM_MAX_VCPUS;
> +    if(config->aml_adr_dword_len && config->aml_ej0_name_len &&
> +        (config->aml_adr_dword_len/sizeof(config->aml_adr_dword[0]) == config->aml_ej0_name_len/sizeof(config->aml_ej0_name[0])))
> +    {
> +         rmvc_pcrm = inl(PCI_RMV_BASE);
> +	  printf("rmvc_pcrm is %x\n", rmvc_pcrm);
> +        for(i = 0;  i < config->aml_adr_dword_len/sizeof(config->aml_adr_dword[0]); i ++)
> +        {
> +            /* Slot is in byte 2 in _ADR */
> +            unsigned char slot = dsdt[config->aml_adr_dword[i] + 2] & 0x1F;
> +            /* Sanity check */
> +            if (memcmp(dsdt + config->aml_ej0_name[i], "_EJ0", 4)) {
> +                goto oom;
> +            }
> +            if (!(rmvc_pcrm & (0x1 << slot))) {
> +                memcpy(dsdt + config->aml_ej0_name[i], "EJ0_", 4);
> +            }
> +        }
>       }
>   
> +    nr_processor_objects = HVM_MAX_VCPUS;
>       /*
>        * N.B. ACPI 1.0 operating systems may not handle FADT with revision 2
>        * or above properly, notably Windows 2000, which tries to copy FADT
> diff -urN hvmloader/acpi/dsdt.asl hvmloader_new//acpi/dsdt.asl
> --- hvmloader/acpi/dsdt.asl	2013-10-16 11:56:20.000000000 +0800
> +++ hvmloader_new//acpi/dsdt.asl	2013-10-16 11:46:52.000000000 +0800
> @@ -16,6 +16,7 @@
>    * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
>    * Place - Suite 330, Boston, MA 02111-1307 USA.
>    */
> +ACPI_EXTRACT_ALL_CODE AmlCode
>   
>   DefinitionBlock ("DSDT.aml", "DSDT", 2, "Xen", "HVM", 0)
>   {
> diff -urN hvmloader/acpi/mk_dsdt.c hvmloader_new//acpi/mk_dsdt.c
> --- hvmloader/acpi/mk_dsdt.c	2013-10-16 11:56:32.000000000 +0800
> +++ hvmloader_new//acpi/mk_dsdt.c	2013-10-16 11:46:52.000000000 +0800
> @@ -368,7 +368,9 @@
>           /* hotplug_slot */
>           for (slot = 1; slot <= 31; slot++) {
>               push_block("Device", "S%i", slot); {
> +                printf("ACPI_EXTRACT_NAME_DWORD_CONST aml_adr_dword\n");
>                   stmt("Name", "_ADR, %#06x0000", slot);
> +                printf("ACPI_EXTRACT_METHOD_STRING aml_ej0_name\n");
>                   push_block("Method", "_EJ0,1"); {
>                       stmt("Store", "ShiftLeft(1, %#06x), B0EJ", slot);
>                       stmt("Return", "0x0");
> @@ -453,7 +455,7 @@
>   /*
>    * Local variables:
>    * mode: C
> - * c-file-style: "BSD"
> + * c-set-style: "BSD"
>    * c-basic-offset: 4
>    * tab-width: 4
>    * indent-tabs-mode: nil
> diff -urN hvmloader/ovmf.c hvmloader_new//ovmf.c
> --- hvmloader/ovmf.c	2013-10-16 11:57:15.000000000 +0800
> +++ hvmloader_new//ovmf.c	2013-10-16 11:57:48.000000000 +0800
> @@ -79,7 +79,11 @@
>           .dsdt_anycpu = dsdt_anycpu,
>           .dsdt_anycpu_len = dsdt_anycpu_len,
>           .dsdt_15cpu = NULL,
> -        .dsdt_15cpu_len = 0
> +        .dsdt_15cpu_len = 0,
> +        .aml_ej0_name = NULL,
> +        .aml_adr_dword = NULL,
> +        .aml_ej0_name_len = 0,
> +        .aml_adr_dword_len = 0,
>       };
>   
>       acpi_build_tables(&config, ACPI_PHYSICAL_ADDRESS);
> diff -urN hvmloader/rombios.c hvmloader_new//rombios.c
> --- hvmloader/rombios.c	2013-10-16 11:57:15.000000000 +0800
> +++ hvmloader_new//rombios.c	2013-10-16 11:57:48.000000000 +0800
> @@ -179,6 +179,10 @@
>           .dsdt_anycpu_len = dsdt_anycpu_len,
>           .dsdt_15cpu = dsdt_15cpu,
>           .dsdt_15cpu_len = dsdt_15cpu_len,
> +        .aml_ej0_name = NULL,
> +        .aml_adr_dword = NULL,
> +        .aml_ej0_name_len = 0,
> +        .aml_adr_dword_len = 0,
>       };
>   
>       acpi_build_tables(&config, ACPI_PHYSICAL_ADDRESS);
> diff -urN hvmloader/seabios.c hvmloader_new//seabios.c
> --- hvmloader/seabios.c	2013-10-16 11:57:15.000000000 +0800
> +++ hvmloader_new//seabios.c	2013-10-16 11:57:48.000000000 +0800
> @@ -33,6 +33,10 @@
>   
>   extern unsigned char dsdt_anycpu_qemu_xen[];
>   extern int dsdt_anycpu_qemu_xen_len;
> +extern unsigned short dsdt_anycpu_qemu_xen_aml_ej0_name[];
> +extern unsigned short dsdt_anycpu_qemu_xen_aml_adr_dword[];
> +extern int dsdt_anycpu_qemu_xen_aml_ej0_name_len;
> +extern int dsdt_anycpu_qemu_xen_aml_adr_dword_len;
>   
>   struct seabios_info {
>       char signature[14]; /* XenHVMSeaBIOS\0 */
> @@ -99,6 +103,10 @@
>           .dsdt_anycpu_len = dsdt_anycpu_qemu_xen_len,
>           .dsdt_15cpu = NULL,
>           .dsdt_15cpu_len = 0,
> +        .aml_ej0_name = dsdt_anycpu_qemu_xen_aml_ej0_name,
> +        .aml_adr_dword = dsdt_anycpu_qemu_xen_aml_adr_dword,
> +        .aml_ej0_name_len = dsdt_anycpu_qemu_xen_aml_ej0_name_len,
> +        .aml_adr_dword_len = dsdt_anycpu_qemu_xen_aml_adr_dword_len,
>       };
>   
>       acpi_build_tables(&config, rsdp);
> diff -urN hvmloader/tools/acpi_extract.py hvmloader_new//tools/acpi_extract.py
> --- hvmloader/tools/acpi_extract.py	1970-01-01 08:00:00.000000000 +0800
> +++ hvmloader_new//tools/acpi_extract.py	2013-10-16 11:46:52.000000000 +0800
> @@ -0,0 +1,308 @@
> +#!/usr/bin/python
> +# Copyright (C) 2011 Red Hat, Inc., Michael S. Tsirkin<mst@redhat.com>
> +#
> +# This file may be distributed under the terms of the GNU GPLv3 license.
> +
> +# Process mixed ASL/AML listing (.lst file) produced by iasl -l
> +# Locate and execute ACPI_EXTRACT directives, output offset info
> +#
> +# Documentation of ACPI_EXTRACT_* directive tags:
> +#
> +# These directive tags output offset information from AML for BIOS runtime
> +# table generation.
> +# Each directive is of the form:
> +# ACPI_EXTRACT_<TYPE> <array_name> <Operator> (...)
> +# and causes the extractor to create an array
> +# named <array_name> with offset, in the generated AML,
> +# of an object of a given type in the following <Operator>.
> +#
> +# A directive must fit on a single code line.
> +#
> +# Object type in AML is verified, a mismatch causes a build failure.
> +#
> +# Directives and operators currently supported are:
> +# ACPI_EXTRACT_NAME_DWORD_CONST - extract a Dword Const object from Name()
> +# ACPI_EXTRACT_NAME_WORD_CONST - extract a Word Const object from Name()
> +# ACPI_EXTRACT_NAME_BYTE_CONST - extract a Byte Const object from Name()
> +# ACPI_EXTRACT_METHOD_STRING - extract a NameString from Method()
> +# ACPI_EXTRACT_NAME_STRING - extract a NameString from Name()
> +# ACPI_EXTRACT_PROCESSOR_START - start of Processor() block
> +# ACPI_EXTRACT_PROCESSOR_STRING - extract a NameString from Processor()
> +# ACPI_EXTRACT_PROCESSOR_END - offset at last byte of Processor() + 1
> +# ACPI_EXTRACT_PKG_START - start of Package block
> +#
> +# ACPI_EXTRACT_ALL_CODE - create an array storing the generated AML bytecode
> +#
> +# ACPI_EXTRACT is not allowed anywhere else in code, except in comments.
> +
> +import re;
> +import sys;
> +import fileinput;
> +
> +aml = []
> +asl = []
> +output = {}
> +debug = ""
> +
> +class asl_line:
> +    line = None
> +    lineno = None
> +    aml_offset = None
> +
> +def die(diag):
> +    sys.stderr.write("Error: %s; %s\n" % (diag, debug))
> +    sys.exit(1)
> +
> +#Store an ASL command, matching AML offset, and input line (for debugging)
> +def add_asl(lineno, line):
> +    l = asl_line()
> +    l.line = line
> +    l.lineno = lineno
> +    l.aml_offset = len(aml)
> +    asl.append(l)
> +
> +#Store an AML byte sequence
> +#Verify that offset output by iasl matches # of bytes so far
> +def add_aml(offset, line):
> +    o = int(offset, 16);
> +    # Sanity check: offset must match size of code so far
> +    if (o != len(aml)):
> +        die("Offset 0x%x != 0x%x" % (o, len(aml)))
> +    # Strip any trailing dots and ASCII dump after "
> +    line = re.sub(r'\s*\.*\s*".*$',"", line)
> +    # Strip traling whitespace
> +    line = re.sub(r'\s+$',"", line)
> +    # Strip leading whitespace
> +    line = re.sub(r'^\s+',"", line)
> +    # Split on whitespace
> +    code = re.split(r'\s+', line)
> +    for c in code:
> +        # Require a legal hex number, two digits
> +        if (not(re.search(r'^[0-9A-Fa-f][0-9A-Fa-f]$', c))):
> +            die("Unexpected octet %s" % c);
> +        aml.append(int(c, 16));
> +
> +# Process aml bytecode array, decoding AML
> +def aml_pkglen_bytes(offset):
> +    # PkgLength can be multibyte. Bits 8-7 give the # of extra bytes.
> +    pkglenbytes = aml[offset] >> 6;
> +    return pkglenbytes + 1
> +
> +def aml_pkglen(offset):
> +    pkgstart = offset
> +    pkglenbytes = aml_pkglen_bytes(offset)
> +    pkglen = aml[offset] & 0x3F
> +    # If multibyte, first nibble only uses bits 0-3
> +    if ((pkglenbytes > 0) and (pkglen & 0x30)):
> +        die("PkgLen bytes 0x%x but first nibble 0x%x expected 0x0X" %
> +            (pkglen, pkglen))
> +    offset += 1
> +    pkglenbytes -= 1
> +    for i in range(pkglenbytes):
> +        pkglen |= aml[offset + i] << (i * 8 + 4)
> +    if (len(aml) < pkgstart + pkglen):
> +        die("PckgLen 0x%x at offset 0x%x exceeds AML size 0x%x" %
> +            (pkglen, offset, len(aml)))
> +    return pkglen
> +
> +# Given method offset, find its NameString offset
> +def aml_method_string(offset):
> +    #0x14 MethodOp PkgLength NameString MethodFlags TermList
> +    if (aml[offset] != 0x14):
> +        die( "Method offset 0x%x: expected 0x14 actual 0x%x" %
> +             (offset, aml[offset]));
> +    offset += 1;
> +    pkglenbytes = aml_pkglen_bytes(offset)
> +    offset += pkglenbytes;
> +    return offset;
> +
> +# Given name offset, find its NameString offset
> +def aml_name_string(offset):
> +    #0x08 NameOp NameString DataRef
> +    if (aml[offset] != 0x08):
> +        die( "Name offset 0x%x: expected 0x08 actual 0x%x" %
> +             (offset, aml[offset]));
> +    offset += 1
> +    # Block Name Modifier. Skip it.
> +    if (aml[offset] == 0x5c or aml[offset] == 0x5e):
> +        offset += 1
> +    return offset;
> +
> +# Given data offset, find dword const offset
> +def aml_data_dword_const(offset):
> +    #0x08 NameOp NameString DataRef
> +    if (aml[offset] != 0x0C):
> +        die( "Name offset 0x%x: expected 0x0C actual 0x%x" %
> +             (offset, aml[offset]));
> +    return offset + 1;
> +
> +# Given data offset, find word const offset
> +def aml_data_word_const(offset):
> +    #0x08 NameOp NameString DataRef
> +    if (aml[offset] != 0x0B):
> +        die( "Name offset 0x%x: expected 0x0B actual 0x%x" %
> +             (offset, aml[offset]));
> +    return offset + 1;
> +
> +# Given data offset, find byte const offset
> +def aml_data_byte_const(offset):
> +    #0x08 NameOp NameString DataRef
> +    if (aml[offset] != 0x0A):
> +        die( "Name offset 0x%x: expected 0x0A actual 0x%x" %
> +             (offset, aml[offset]));
> +    return offset + 1;
> +
> +# Given name offset, find dword const offset
> +def aml_name_dword_const(offset):
> +    return aml_data_dword_const(aml_name_string(offset) + 4)
> +
> +# Given name offset, find word const offset
> +def aml_name_word_const(offset):
> +    return aml_data_word_const(aml_name_string(offset) + 4)
> +
> +# Given name offset, find byte const offset
> +def aml_name_byte_const(offset):
> +    return aml_data_byte_const(aml_name_string(offset) + 4)
> +
> +def aml_processor_start(offset):
> +    #0x5B 0x83 ProcessorOp PkgLength NameString ProcID
> +    if ((aml[offset] != 0x5B) or (aml[offset + 1] != 0x83)):
> +        die( "Name offset 0x%x: expected 0x5B 0x83 actual 0x%x 0x%x" %
> +             (offset, aml[offset], aml[offset + 1]));
> +    return offset
> +
> +def aml_processor_string(offset):
> +    #0x5B 0x83 ProcessorOp PkgLength NameString ProcID
> +    start = aml_processor_start(offset)
> +    offset += 2
> +    pkglenbytes = aml_pkglen_bytes(offset)
> +    offset += pkglenbytes
> +    return offset
> +
> +def aml_processor_end(offset):
> +    start = aml_processor_start(offset)
> +    offset += 2
> +    pkglenbytes = aml_pkglen_bytes(offset)
> +    pkglen = aml_pkglen(offset)
> +    return offset + pkglen
> +
> +def aml_package_start(offset):
> +    offset = aml_name_string(offset) + 4
> +    # 0x12 PkgLength NumElements PackageElementList
> +    if (aml[offset] != 0x12):
> +        die( "Name offset 0x%x: expected 0x12 actual 0x%x" %
> +             (offset, aml[offset]));
> +    offset += 1
> +    return offset + aml_pkglen_bytes(offset) + 1
> +
> +lineno = 0
> +for line in fileinput.input():
> +    # Strip trailing newline
> +    line = line.rstrip();
> +    # line number and debug string to output in case of errors
> +    lineno = lineno + 1
> +    debug = "input line %d: %s" % (lineno, line)
> +    #ASL listing: space, then line#, then ...., then code
> +    pasl = re.compile('^\s+([0-9]+)\.\.\.\.\s*')
> +    m = pasl.search(line)
> +    if (m):
> +        add_asl(lineno, pasl.sub("", line));
> +    # AML listing: offset in hex, then ...., then code
> +    paml = re.compile('^([0-9A-Fa-f]+)\.\.\.\.\s*')
> +    m = paml.search(line)
> +    if (m):
> +        add_aml(m.group(1), paml.sub("", line))
> +
> +# Now go over code
> +# Track AML offset of a previous non-empty ASL command
> +prev_aml_offset = -1
> +for i in range(len(asl)):
> +    debug = "input line %d: %s" % (asl[i].lineno, asl[i].line)
> +
> +    l = asl[i].line
> +
> +    # skip if not an extract directive
> +    a = len(re.findall(r'ACPI_EXTRACT', l))
> +    if (not a):
> +        # If not empty, store AML offset. Will be used for sanity checks
> +        # IASL seems to put {}. at random places in the listing.
> +        # Ignore any non-words for the purpose of this test.
> +        m = re.search(r'\w+', l)
> +        if (m):
> +                prev_aml_offset = asl[i].aml_offset
> +        continue
> +
> +    if (a > 1):
> +        die("Expected at most one ACPI_EXTRACT per line, actual %d" % a)
> +
> +    mext = re.search(r'''
> +                      ^\s* # leading whitespace
> +                      /\*\s* # start C comment
> +                      (ACPI_EXTRACT_\w+) # directive: group(1)
> +                      \s+ # whitspace separates directive from array name
> +                      (\w+) # array name: group(2)
> +                      \s*\*/ # end of C comment
> +                      \s*$ # trailing whitespace
> +                      ''', l, re.VERBOSE)
> +    if (not mext):
> +        die("Stray ACPI_EXTRACT in input")
> +
> +    # previous command must have produced some AML,
> +    # otherwise we are in a middle of a block
> +    if (prev_aml_offset == asl[i].aml_offset):
> +        die("ACPI_EXTRACT directive in the middle of a block")
> +
> +    directive = mext.group(1)
> +    array = mext.group(2)
> +    offset = asl[i].aml_offset
> +
> +    if (directive == "ACPI_EXTRACT_ALL_CODE"):
> +        if array in output:
> +            die("%s directive used more than once" % directive)
> +        output[array] = aml
> +        continue
> +    if (directive == "ACPI_EXTRACT_NAME_DWORD_CONST"):
> +        offset = aml_name_dword_const(offset)
> +    elif (directive == "ACPI_EXTRACT_NAME_WORD_CONST"):
> +        offset = aml_name_word_const(offset)
> +    elif (directive == "ACPI_EXTRACT_NAME_BYTE_CONST"):
> +        offset = aml_name_byte_const(offset)
> +    elif (directive == "ACPI_EXTRACT_NAME_STRING"):
> +        offset = aml_name_string(offset)
> +    elif (directive == "ACPI_EXTRACT_METHOD_STRING"):
> +        offset = aml_method_string(offset)
> +    elif (directive == "ACPI_EXTRACT_PROCESSOR_START"):
> +        offset = aml_processor_start(offset)
> +    elif (directive == "ACPI_EXTRACT_PROCESSOR_STRING"):
> +        offset = aml_processor_string(offset)
> +    elif (directive == "ACPI_EXTRACT_PROCESSOR_END"):
> +        offset = aml_processor_end(offset)
> +    elif (directive == "ACPI_EXTRACT_PKG_START"):
> +        offset = aml_package_start(offset)
> +    else:
> +        die("Unsupported directive %s" % directive)
> +
> +    if array not in output:
> +        output[array] = []
> +    output[array].append(offset)
> +
> +debug = "at end of file"
> +
> +def get_value_type(maxvalue):
> +    #Use type large enough to fit the table
> +    if (maxvalue >= 0x10000):
> +            return "int"
> +    elif (maxvalue >= 0x100):
> +            return "short"
> +    else:
> +            return "char"
> +
> +# Pretty print output
> +for array in output.keys():
> +    otype = get_value_type(max(output[array]))
> +    odata = []
> +    for value in output[array]:
> +        odata.append("0x%x" % value)
> +    sys.stdout.write("unsigned %s %s[] = {\n" % (otype, array))
> +    sys.stdout.write(",\n".join(odata))
> +    sys.stdout.write('\n};\n');
> diff -urN hvmloader/tools/acpi_extract_preprocess.py hvmloader_new//tools/acpi_extract_preprocess.py
> --- hvmloader/tools/acpi_extract_preprocess.py	1970-01-01 08:00:00.000000000 +0800
> +++ hvmloader_new//tools/acpi_extract_preprocess.py	2013-10-16 11:46:53.000000000 +0800
> @@ -0,0 +1,41 @@
> +#!/usr/bin/python
> +# Copyright (C) 2011 Red Hat, Inc., Michael S. Tsirkin<mst@redhat.com>
> +#
> +# This file may be distributed under the terms of the GNU GPLv3 license.
> +
> +# Read a preprocessed ASL listing and put each ACPI_EXTRACT
> +# directive in a comment, to make iasl skip it.
> +# We also put each directive on a new line, the machinery
> +# in tools/acpi_extract.py requires this.
> +
> +import re;
> +import sys;
> +import fileinput;
> +
> +def die(diag):
> +    sys.stderr.write("Error: %s\n" % (diag))
> +    sys.exit(1)
> +
> +# Note: () around pattern make split return matched string as part of list
> +psplit = re.compile(r''' (
> +                          \b # At word boundary
> +                          ACPI_EXTRACT_\w+ # directive
> +                          \s+ # some whitespace
> +                          \w+ # array name
> +                         )''', re.VERBOSE);
> +
> +lineno = 0
> +for line in fileinput.input():
> +    # line number and debug string to output in case of errors
> +    lineno = lineno + 1
> +    debug = "input line %d: %s" % (lineno, line.rstrip())
> +
> +    s = psplit.split(line);
> +    # The way split works, each odd item is the matching ACPI_EXTRACT directive.
> +    # Put each in a comment, and on a line by itself.
> +    for i in range(len(s)):
> +        if (i % 2):
> +            sys.stdout.write("\n/* %s */\n" % s[i])
> +        else:
> +            sys.stdout.write(s[i])
> +