From 1476b99fe929ab33fa2cd55d594bbc67aee4789f Mon Sep 17 00:00:00 2001
From: Dominik Csapak <d.csapak@proxmox.com>
Date: Tue, 13 Aug 2019 15:19:07 +0200
Subject: [PATCH] rework kvm_user_version cache mechanism

we now also save the mtime of the binary and cache per binary (for each
arch; this is done so we have it already when we sometime decide
that we want to split the qemu package for each arch)
so that we get the real version if only pve-qemu-kvm was updated

Signed-off-by: Dominik Csapak <d.csapak@proxmox.com>
---
 PVE/QemuServer.pm | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 8c519b5..220af73 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -1471,25 +1471,33 @@ sub kvm_version {
     return $kvm_api_version;
 }
 
-my $kvm_user_version;
+my $kvm_user_version = {};
+my $kvm_mtime = {};
 
 sub kvm_user_version {
+    my ($binary) = @_;
 
-    return $kvm_user_version if $kvm_user_version;
+    $binary //= get_command_for_arch(get_host_arch()); # get the native arch by default
+    my $st = stat($binary);
 
-    $kvm_user_version = 'unknown';
+    my $cachedmtime = $kvm_mtime->{$binary} // -1;
+    return $kvm_user_version->{$binary} if $kvm_user_version->{$binary} &&
+	$cachedmtime == $st->mtime;
+
+    $kvm_user_version->{$binary} = 'unknown';
+    $kvm_mtime->{$binary} = $st->mtime;
 
     my $code = sub {
 	my $line = shift;
 	if ($line =~ m/^QEMU( PC)? emulator version (\d+\.\d+(\.\d+)?)(\.\d+)?[,\s]/) {
-	    $kvm_user_version = $2;
+	    $kvm_user_version->{$binary} = $2;
 	}
     };
 
-    eval { run_command("kvm -version", outfunc => $code); };
+    eval { run_command([$binary, '--version'], outfunc => $code); };
     warn $@ if $@;
 
-    return $kvm_user_version;
+    return $kvm_user_version->{$binary};
 
 }
 
@@ -3566,13 +3574,14 @@ sub config_to_command {
     my $devices = [];
     my $pciaddr = '';
     my $bridges = {};
-    my $kvmver = kvm_user_version();
     my $vernum = 0; # unknown
     my $ostype = $conf->{ostype};
     my $winversion = windows_version($ostype);
     my $kvm = $conf->{kvm};
 
     my ($arch, $machine_type) = get_basic_machine_info($conf, $forcemachine);
+    my $kvm_binary = get_command_for_arch($arch);
+    my $kvmver = kvm_user_version($kvm_binary);
     $kvm //= 1 if is_native($arch);
 
     if ($kvm) {
@@ -3598,7 +3607,7 @@ sub config_to_command {
     my $cpuunits = defined($conf->{cpuunits}) ?
             $conf->{cpuunits} : $defaults->{cpuunits};
 
-    push @$cmd, get_command_for_arch($arch);
+    push @$cmd, $kvm_binary;
 
     push @$cmd, '-id', $vmid;
 
-- 
2.39.2