[pve-devel] [PATCH qemu-server v4 2/4] Convert policy calculation

[Philipp Giersfeld <philipp.giersfeld@canarybit.eu>]

Convert policy calculation to use shift operators and OR operation
instead of binary numbers and addition.

Signed-off-by: Philipp Giersfeld <philipp.giersfeld@canarybit.eu>
Reviewed-by: Daniel Kral <d.kral@proxmox.com>
Reviewed-by: Fiona Ebner <f.ebner@proxmox.com>
Tested-by: Markus Frank <m.frank@proxmox.com>
---

 changes since v3: https://lists.proxmox.com/pipermail/pve-devel/2025-February/068578.html
  * Fix typo in commit description

 PVE/QemuServer/CPUConfig.pm | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/PVE/QemuServer/CPUConfig.pm b/PVE/QemuServer/CPUConfig.pm
index e65d8c26..ad0be16e 100644
--- a/PVE/QemuServer/CPUConfig.pm
+++ b/PVE/QemuServer/CPUConfig.pm
@@ -846,12 +846,12 @@ sub get_amd_sev_object {
 
     # guest policy bit calculation as described here:
     # https://documentation.suse.com/sles/15-SP5/html/SLES-amd-sev/article-amd-sev.html#table-guestpolicy
-    my $policy = 0b0000;
-    $policy += 0b0001 if $amd_sev_conf->{'no-debug'};
-    $policy += 0b0010 if $amd_sev_conf->{'no-key-sharing'};
-    $policy += 0b0100 if $amd_sev_conf->{type} eq 'es';
+    my $policy = 0;
+    $policy |= 1 << 0 if $amd_sev_conf->{'no-debug'};
+    $policy |= 1 << 1 if $amd_sev_conf->{'no-key-sharing'};
+    $policy |= 1 << 2 if $amd_sev_conf->{type} eq 'es';
     # disable migration with bit 3 nosend to prevent amd-sev-migration-attack
-    $policy += 0b1000;
+    $policy |= 1 << 3;
 
     $sev_mem_object .= ',policy='.sprintf("%#x", $policy);
     $sev_mem_object .= ',kernel-hashes=on' if ($amd_sev_conf->{'kernel-hashes'});
-- 
2.39.5


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