[PATCH qemu-server v2 03/17] cpu flags: Create CPUFlags module

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

Introduce PVE::QemuServer::CPUFlags module as the new home for cpu
flags-related helpers, and move various utilities from QemuServer
and CPUConfig into it.

`query_supported_cpu_flags` is not yet moved to the new module, as it is
trickier to migrate without creating circular dependencies.

Signed-off-by: Arthur Bied-Charreton <a.bied-charreton@proxmox.com>
---
 src/PVE/QemuServer.pm           |  24 +-----
 src/PVE/QemuServer/CPUConfig.pm |  89 ++--------------------
 src/PVE/QemuServer/CPUFlags.pm  | 126 ++++++++++++++++++++++++++++++++
 src/PVE/QemuServer/Makefile     |   1 +
 4 files changed, 136 insertions(+), 104 deletions(-)
 create mode 100644 src/PVE/QemuServer/CPUFlags.pm

diff --git a/src/PVE/QemuServer.pm b/src/PVE/QemuServer.pm
index 856dc737..9cea859f 100644
--- a/src/PVE/QemuServer.pm
+++ b/src/PVE/QemuServer.pm
@@ -2917,9 +2917,10 @@ sub vga_conf_has_spice {
     return $1 || 1;
 }
 
-# To use query_supported_cpu_flags and query_understood_cpu_flags to get flags
-# to use in a QEMU command line (-cpu element), first array_intersect the result
-# of query_supported_ with query_understood_. This is necessary because:
+# To use query_supported_cpu_flags and query_understood_cpu_flags (moved to the
+# PVE::QemuServer::CPUFlags module) to get flags to use in a QEMU command line
+# (-cpu element), first array_intersect the result of query_supported_ with
+# query_understood_. This is necessary because:
 #
 # a) query_understood_ returns flags the host cannot use and
 # b) query_supported_ (rather the QMP call) doesn't actually return CPU
@@ -3026,23 +3027,6 @@ sub query_supported_cpu_flags {
     return $flags;
 }
 
-# Understood CPU flags are written to a file at 'pve-qemu' compile time
-my $understood_cpu_flag_dir = "/usr/share/kvm";
-
-sub query_understood_cpu_flags {
-    my $arch = get_host_arch();
-    my $filepath = "$understood_cpu_flag_dir/recognized-CPUID-flags-$arch";
-
-    die "Cannot query understood QEMU CPU flags for architecture: $arch (file not found)\n"
-        if !-e $filepath;
-
-    my $raw = file_get_contents($filepath);
-    $raw =~ s/^\s+|\s+$//g;
-    my @flags = split(/\s+/, $raw);
-
-    return \@flags;
-}
-
 # Since commit 277d33454f77ec1d1e0bc04e37621e4dd2424b67 in pve-qemu, smm is not off by default
 # anymore. But smm=off seems to be required when using SeaBIOS and serial display.
 my sub should_disable_smm {
diff --git a/src/PVE/QemuServer/CPUConfig.pm b/src/PVE/QemuServer/CPUConfig.pm
index 7adfdf45..0ee9b991 100644
--- a/src/PVE/QemuServer/CPUConfig.pm
+++ b/src/PVE/QemuServer/CPUConfig.pm
@@ -12,6 +12,7 @@ use PVE::RESTEnvironment qw(log_warn);
 use PVE::Tools qw(run_command);
 
 use PVE::QemuServer::Helpers qw(min_version get_host_arch);
+use PVE::QemuServer::CPUFlags qw(cpu_flag_supported_re cpu_flag_any_re supported_cpu_flags_names);
 
 use base qw(PVE::SectionConfig Exporter);
 
@@ -261,89 +262,9 @@ sub get_all_cpu_models {
     return $all_cpu_models;
 }
 
-my $supported_cpu_flags_by_arch = {
-    x86_64 => [
-        {
-            name => 'nested-virt',
-            description =>
-                "Controls nested virtualization, namely 'svm' for AMD CPUs and 'vmx' for"
-                . " Intel CPUs. Live migration still only works if it's the same flag on both sides."
-                . " Use a CPU model similar to the host, with the same vendor, not x86-64-vX!",
-        },
-        {
-            name => 'md-clear',
-            description => "Required to let the guest OS know if MDS is mitigated correctly.",
-        },
-        {
-            name => 'pcid',
-            description =>
-                "Meltdown fix cost reduction on Westmere, Sandy-, and IvyBridge Intel CPUs.",
-        },
-        {
-            name => 'spec-ctrl',
-            description => "Allows improved Spectre mitigation with Intel CPUs.",
-        },
-        {
-            name => 'ssbd',
-            description => "Protection for 'Speculative Store Bypass' for Intel models.",
-        },
-        {
-            name => 'ibpb',
-            description => "Allows improved Spectre mitigation with AMD CPUs.",
-        },
-        {
-            name => 'virt-ssbd',
-            description => "Basis for 'Speculative Store Bypass' protection for AMD models.",
-        },
-        {
-            name => 'amd-ssbd',
-            description =>
-                "Improves Spectre mitigation performance with AMD CPUs, best used with"
-                . " 'virt-ssbd'.",
-        },
-        {
-            name => 'amd-no-ssb',
-            description =>
-                "Notifies guest OS that host is not vulnerable for Spectre on AMD CPUs.",
-        },
-        {
-            name => 'pdpe1gb',
-            description => "Allow guest OS to use 1GB size pages, if host HW supports it.",
-        },
-        {
-            name => 'hv-tlbflush',
-            description =>
-                "Improve performance in overcommitted Windows guests. May lead to guest"
-                . " bluescreens on old CPUs.",
-        },
-        {
-            name => 'hv-evmcs',
-            description =>
-                "Improve performance for nested virtualization. Only supported on Intel" . " CPUs.",
-        },
-        {
-            name => 'aes',
-            description => "Activate AES instruction set for HW acceleration.",
-        },
-    ],
-    aarch64 => [],
-};
-
-sub get_supported_cpu_flags {
-    my ($arch) = @_;
-    $arch = get_host_arch() if !defined($arch);
-    return $supported_cpu_flags_by_arch->{$arch};
-}
-
-my $all_supported_cpu_flags = {};
-for my $arch ($supported_cpu_flags_by_arch->%*) {
-    for my $flag ($supported_cpu_flags_by_arch->{$arch}->@*) {
-        $all_supported_cpu_flags->{ $flag->{name} } = 1;
-    }
-}
-my @supported_cpu_flags_names = sort keys $all_supported_cpu_flags->%*;
-my $cpu_flag_supported_re = qr/([+-])(@{[join('|', @supported_cpu_flags_names)]})/;
-my $cpu_flag_any_re = qr/([+-])([a-zA-Z0-9\-_\.]+)/;
+my $cpu_flag_supported_re = cpu_flag_supported_re();
+my $cpu_flag_any_re = cpu_flag_any_re();
+my @supported_cpu_flags_names = (supported_cpu_flags_names());
 
 our $qemu_cmdline_cpu_re = qr/^((?>[+-]?[\w\-\._=]+,?)+)$/;
 
@@ -388,7 +309,7 @@ my $cpu_fmt = {
             . " controls nested virtualization for the current CPU ('svm' for AMD and 'vmx' for"
             . " Intel). Custom CPU models can specify any flag supported by QEMU/KVM, VM-specific"
             . " flags must be from the following set for security reasons: "
-            . join(', ', @supported_cpu_flags_names),
+            . join(', ', PVE::QemuServer::CPUFlags::supported_cpu_flags_names()),
         format_description => '+FLAG[;-FLAG...]',
         type => 'string',
         pattern => qr/$cpu_flag_any_re(;$cpu_flag_any_re)*/,
diff --git a/src/PVE/QemuServer/CPUFlags.pm b/src/PVE/QemuServer/CPUFlags.pm
new file mode 100644
index 00000000..51d7753e
--- /dev/null
+++ b/src/PVE/QemuServer/CPUFlags.pm
@@ -0,0 +1,126 @@
+package PVE::QemuServer::CPUFlags;
+
+use v5.36;
+
+use Exporter qw(import);
+
+use PVE::Cluster;
+use PVE::Tools;
+use PVE::QemuServer::Helpers qw(get_host_arch);
+
+our @EXPORT_OK = qw(
+    cpu_flag_supported_re
+    cpu_flag_any_re
+    supported_cpu_flags_names
+    get_supported_cpu_flags
+    query_understood_cpu_flags
+);
+
+my $supported_vm_specific_cpu_flags_by_arch = {
+    x86_64 => [
+        {
+            name => 'nested-virt',
+            description =>
+                "Controls nested virtualization, namely 'svm' for AMD CPUs and 'vmx' for"
+                . " Intel CPUs. Live migration still only works if it's the same flag on both sides."
+                . " Use a CPU model similar to the host, with the same vendor, not x86-64-vX!",
+        },
+        {
+            name => 'md-clear',
+            description => "Required to let the guest OS know if MDS is mitigated correctly.",
+        },
+        {
+            name => 'pcid',
+            description =>
+                "Meltdown fix cost reduction on Westmere, Sandy-, and IvyBridge Intel CPUs.",
+        },
+        {
+            name => 'spec-ctrl',
+            description => "Allows improved Spectre mitigation with Intel CPUs.",
+        },
+        {
+            name => 'ssbd',
+            description => "Protection for 'Speculative Store Bypass' for Intel models.",
+        },
+        {
+            name => 'ibpb',
+            description => "Allows improved Spectre mitigation with AMD CPUs.",
+        },
+        {
+            name => 'virt-ssbd',
+            description => "Basis for 'Speculative Store Bypass' protection for AMD models.",
+        },
+        {
+            name => 'amd-ssbd',
+            description =>
+                "Improves Spectre mitigation performance with AMD CPUs, best used with"
+                . " 'virt-ssbd'.",
+        },
+        {
+            name => 'amd-no-ssb',
+            description =>
+                "Notifies guest OS that host is not vulnerable for Spectre on AMD CPUs.",
+        },
+        {
+            name => 'pdpe1gb',
+            description => "Allow guest OS to use 1GB size pages, if host HW supports it.",
+        },
+        {
+            name => 'hv-tlbflush',
+            description =>
+                "Improve performance in overcommitted Windows guests. May lead to guest"
+                . " bluescreens on old CPUs.",
+        },
+        {
+            name => 'hv-evmcs',
+            description =>
+                "Improve performance for nested virtualization. Only supported on Intel" . " CPUs.",
+        },
+        {
+            name => 'aes',
+            description => "Activate AES instruction set for HW acceleration.",
+        },
+    ],
+    aarch64 => [],
+};
+
+my $all_supported_vm_specific_cpu_flags = {};
+for my $arch ($supported_vm_specific_cpu_flags_by_arch->%*) {
+    for my $flag ($supported_vm_specific_cpu_flags_by_arch->{$arch}->@*) {
+        $all_supported_vm_specific_cpu_flags->{ $flag->{name} } = 1;
+    }
+}
+
+# Understood CPU flags are written to a file at 'pve-qemu' compile time
+my $understood_cpu_flag_dir = "/usr/share/kvm";
+
+sub supported_cpu_flags_names() {
+    return sort keys $all_supported_vm_specific_cpu_flags->%*;
+}
+
+sub cpu_flag_supported_re() {
+    return qr/([+-])(@{[join('|', supported_cpu_flags_names())]})/;
+}
+
+sub cpu_flag_any_re() {
+    return qr/([+-])([a-zA-Z0-9\-_\.]+)/;
+}
+
+# Return supported VM-specific CPU flags.
+sub get_supported_cpu_flags($arch) {
+    return $supported_vm_specific_cpu_flags_by_arch->{$arch};
+}
+
+sub query_understood_cpu_flags($arch) {
+    my $filepath = "$understood_cpu_flag_dir/recognized-CPUID-flags-$arch";
+
+    die "Cannot query understood QEMU CPU flags for architecture: $arch (file not found)\n"
+        if !-e $filepath;
+
+    my $raw = PVE::Tools::file_get_contents($filepath);
+    $raw =~ s/^\s+|\s+$//g;
+    my @flags = split(/\s+/, $raw);
+
+    return \@flags;
+}
+1;
diff --git a/src/PVE/QemuServer/Makefile b/src/PVE/QemuServer/Makefile
index 7e48c388..c26bdec4 100644
--- a/src/PVE/QemuServer/Makefile
+++ b/src/PVE/QemuServer/Makefile
@@ -9,6 +9,7 @@ SOURCES=Agent.pm	\
 	CGroup.pm	\
 	Cloudinit.pm	\
 	CPUConfig.pm	\
+	CPUFlags.pm	\
 	DBusVMState.pm	\
 	Drive.pm	\
 	DriveDevice.pm	\
-- 
2.47.3