Re: [PATCH] cpu_map: Add libcpuinfo as optional data source

This adds an option to use libcpuinfo [1] as data source for libvirt's list of x86 cpu features. This is purely optional and does not change the script's behavior if libcpuinfo is not installed. libcpuinfo is a cross-vendor, cross-architecture source for CPU related information that has the capability to replace libvirt's dependence on qemu's cpu feature list. [1] https://gitlab.com/twiederh/libcpuinfo Signed-off-by: Tim Wiederhake <twiederh(a)redhat.com&gt; ---  src/cpu_map/libcpuinfo_aliases.xml     | 75 +++++++++++++++++++++++++  src/cpu_map/sync_qemu_features_i386.py | 77 +++++++++++++++++++++++- --  2 files changed, 145 insertions(+), 7 deletions(-)  create mode 100644 src/cpu_map/libcpuinfo_aliases.xml diff --git a/src/cpu_map/libcpuinfo_aliases.xml b/src/cpu_map/libcpuinfo_aliases.xml new file mode 100644 index 0000000000..75d243fead --- /dev/null +++ b/src/cpu_map/libcpuinfo_aliases.xml @@ -0,0 +1,75 @@ +<!-- +    libvirt uses slightly different names for some cpu features than other +    software does. Install this file into libcpuinfo's alias directory +    (e.g. /usr/share/libcpuinfo/aliases/libvirt.xml) to have libcpuinfo +    automatically translate feature names into the names libvirt uses. +--> + +<external_aliases> +    <external_alias> +        <type>feature</type> +        <canonical>pclmulqdq</canonical> +        <name>pclmuldq</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>ds-cpl</canonical> +        <name>ds_cpl</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>sse4-1</canonical> +        <name>sse4.1</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>sse4-2</canonical> +        <name>sse4.2</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>tsc-adjust</canonical> +        <name>tsc_adjust</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>lahf-lm</canonical> +        <name>lahf_lm</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>cmp-legacy</canonical> +        <name>cmp_legacy</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>nodeid-msr</canonical> +        <name>nodeid_msr</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>perfctr-core</canonical> +        <name>perfctr_core</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>perfctr-nb</canonical> +        <name>perfctr_nb</name> +        <domain>libvirt</domain> +    </external_alias> +    <external_alias> +        <type>feature</type> +        <canonical>fxsr-opt</canonical> +        <name>fxsr_opt</name> +        <domain>libvirt</domain> +    </external_alias> +</external_aliases> diff --git a/src/cpu_map/sync_qemu_features_i386.py b/src/cpu_map/sync_qemu_features_i386.py index e4b1f7275a..3b3ad5a643 100755 --- a/src/cpu_map/sync_qemu_features_i386.py +++ b/src/cpu_map/sync_qemu_features_i386.py @@ -4,6 +4,11 @@ import argparse  import os  import re   +try: +    import pycpuinfo +except ImportError: +    pycpuinfo = None +    # features in qemu that we do not want in libvirt  FEATURES_IGNORE = ( @@ -22,6 +27,7 @@ FEATURES_IGNORE = (      "kvm-steal-time",      "kvmclock",      "kvmclock-stable-bit", +    "kvmclock2",        "xstore",      "xstore-en", @@ -295,6 +301,53 @@ def add_feature_qemu(query, data):              add_feature_cpuid(eax, ecx, reg, bit, name)     +def add_features_cpuinfo(): +    def decode_bit(value): +        for i in range(0, 64): +            if value == (1 << i): +                return i + +    def decode_cpuid(v): +        if v[0] != 0 and v[1] == 0 and v[2] == 0 and v[3] == 0: +            reg, val = "eax", v[0] +        if v[0] == 0 and v[1] != 0 and v[2] == 0 and v[3] == 0: +            reg, val = "ebx", v[1] +        if v[0] == 0 and v[1] == 0 and v[2] != 0 and v[3] == 0: +            reg, val = "ecx", v[2] +        if v[0] == 0 and v[1] == 0 and v[2] == 0 and v[3] != 0: +            reg, val = "edx", v[3] + +        return reg, decode_bit(val) + +    x86 = pycpuinfo.Family.find("x86", "") + +    for feature in pycpuinfo.features(): +        if feature.family() != x86: +            continue + +        if list(feature.features()): +            continue + +        name = feature.name("libvirt") +        if name in FEATURES_IGNORE: +            continue + +        cpuid = feature.extra_x86_cpuid() +        if cpuid: +            eax = cpuid[0] +            ecx = cpuid[1] +            if ecx == pycpuinfo.x86.CPUINFO_X86_CPUID_ECX_NONE: +                ecx = None +            reg, bit = decode_cpuid(cpuid[2:]) +            add_feature_cpuid(eax, ecx, reg, bit, name) + +        msr = feature.extra_x86_msr() +        if msr: +            index = msr[0] +            bit = decode_bit(msr[1] | (msr[2] << 32)) +            add_feature_msr(index, bit, name) + +  # read the `feature_word_info` struct from qemu's cpu.c into a list of strings  def read_cpu_c(path):      pattern_comment = re.compile("/\\*.*?\\*/") @@ -450,6 +503,12 @@ def main():          nargs="?",          type=os.path.realpath,      ) +    if pycpuinfo: +        parser.add_argument( +            "--libcpuinfo", +            help="Use libcpuinfo as data source instead", +            action="store_true", +        )      parser.add_argument(          "--output",          "-o", @@ -459,14 +518,18 @@ def main():      )      args = parser.parse_args()   -    if not os.path.isdir(args.qemu): -        parser.print_help() -        exit("qemu source directory not found") +    if pycpuinfo and args.libcpuinfo: +        add_features_cpuinfo() +    else: +        if not os.path.isdir(args.qemu): +            parser.print_help() +            exit("qemu source directory not found") + +        read_headers(args.qemu) +        lines = read_cpu_c(args.qemu) +        parse_feature_words(lines) +        add_extra_features()   -    read_headers(args.qemu) -    lines = read_cpu_c(args.qemu) -    parse_feature_words(lines) -    add_extra_features()      write_output(args.output)        print(