[PATCH qemu-server v5 05/21] cpu flags: normalize CPU flags to QEMU's format

[Arthur Bied-Charreton <a.bied-charreton@proxmox.com>]

The QMP commands used in query_supported_cpu_flags() return some flags
multiple times in different formats, like for example 'sse4.2', 'sse4-2'
and 'sse4_2'.

In order to have a unified format, add the normalize_cpu_flag helper to
the CPUFlags module, which returns the alias QEMU has for a given flag
value. The list is sourced from x86_cpu_initfn() in
qemu/target/i386/cpu.c.

Suggested-by: Fiona Ebner <f.ebner@proxmox.com>
Signed-off-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
---
 src/PVE/QemuServer.pm          |  7 ++---
 src/PVE/QemuServer/CPUFlags.pm | 53 ++++++++++++++++++++++++++++++++++
 2 files changed, 56 insertions(+), 4 deletions(-)

diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 57123e56..af55c322 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -69,6 +69,7 @@ use PVE::QemuServer::CPUConfig qw(
     get_intel_tdx_object
     get_cvm_type
 );
+use PVE::QemuServer::CPUFlags;
 use PVE::QemuServer::Drive qw(
     is_valid_drivename
     checked_volume_format
@@ -2992,10 +2993,8 @@ sub query_supported_cpu_flags {
             my $props = $cmd_result->{model}->{props};
             foreach my $prop (keys %$props) {
                 next if $props->{$prop} ne JSON::true;
-                # QEMU returns some flags multiple times, with '_', '.' or '-'
-                # (e.g. lahf_lm and lahf-lm; sse4.2, sse4-2 and sse4_2; ...).
-                # We only keep those with underscores, to match /proc/cpuinfo
-                $prop =~ s/\.|-/_/g;
+                $prop = PVE::QemuServer::CPUFlags::normalize_cpu_flag($prop);
+
                 $flags->{$prop} = 1;
             }
         };
diff --git a/src/PVE/QemuServer/CPUFlags.pm b/src/PVE/QemuServer/CPUFlags.pm
index a681eb75..e17ed00c 100644
--- a/src/PVE/QemuServer/CPUFlags.pm
+++ b/src/PVE/QemuServer/CPUFlags.pm
@@ -14,6 +14,7 @@ our @EXPORT_OK = qw(
     supported_cpu_flags_names
     get_supported_cpu_flags
     query_understood_cpu_flags
+    normalize_cpu_flag
 );
 
 my $supported_vm_specific_cpu_flags_by_arch = {
@@ -93,6 +94,58 @@ for my $arch ($supported_vm_specific_cpu_flags_by_arch->%*) {
 
 my @supported_cpu_flags_name_sorted = sort keys $all_supported_vm_specific_cpu_flags->%*;
 
+# qemu/target/i386/cpu.c, x86_cpu_initfn()
+my $qemu_cpu_flag_alias_map = {
+    sse3 => 'pni',
+    pclmuldq => 'pclmulqdq',
+    'sse4-1' => 'sse4.1',
+    'sse4-2' => 'sse4.2',
+    xd => 'nx',
+    ffxsr => 'fxsr-opt',
+    i64 => 'lm',
+    ds_cpl => 'ds-cpl',
+    tsc_adjust => 'tsc-adjust',
+    fxsr_opt => 'fxsr-opt',
+    lahf_lm => 'lahf-lm',
+    cmp_legacy => 'cmp-legacy',
+    nodeid_msr => 'nodeid-msr',
+    perfctr_core => 'perfctr-core',
+    perfctr_nb => 'perfctr-nb',
+    kvm_nopiodelay => 'kvm-nopiodelay',
+    kvm_mmu => 'kvm-mmu',
+    kvm_asyncpf => 'kvm-asyncpf',
+    kvm_asyncpf_int => 'kvm-asyncpf-int',
+    kvm_steal_time => 'kvm-steal-time',
+    kvm_pv_eoi => 'kvm-pv-eoi',
+    kvm_pv_unhalt => 'kvm-pv-unhalt',
+    kvm_poll_control => 'kvm-poll-control',
+    svm_lock => 'svm-lock',
+    nrip_save => 'nrip-save',
+    tsc_scale => 'tsc-scale',
+    vmcb_clean => 'vmcb-clean',
+    pause_filter => 'pause-filter',
+    sse4_1 => 'sse4.1',
+    sse4_2 => 'sse4.2',
+    'hv-apicv' => 'hv-avic',
+    lbr_fmt => 'lbr-fmt',
+};
+
+=head3 normalize_cpu_flag($flag)
+
+Normalize a CPU flag to its QEMU form.
+
+QEMU defines aliases for some CPU flags (see C<x86_cpu_initfn()> in
+C<target/i386/cpu.c>). For example, C<sse4_2> and C<sse4-2> are both aliases for
+C<sse4.2>.
+
+If C<$flag> has a known alias, return that, otherwise return C<$flag> unchanged.
+
+=cut
+
+sub normalize_cpu_flag($flag) {
+    return $qemu_cpu_flag_alias_map->{$flag} // $flag;
+}
+
 # Understood CPU flags are written to a file at 'pve-qemu' compile time and
 # shipped below this directory by the pve-qemu-kvm package.
 my $understood_cpu_flag_dir = "/usr/share/kvm";
-- 
2.47.3