[pve-devel] [PATCH v3 qemu-server] Prevent starting a 32-bit VM using a 64-bit OVMF BIOS

[pve-devel] [PATCH v3 qemu-server] Prevent starting a 32-bit VM using a 64-bit OVMF BIOS

[Filip Schauer]

Instead of starting a VM with a 32-bit CPU type and a 64-bit OVMF image,
throw an error before starting the VM telling the user that OVMF is not
supported on 32-bit CPU types.

Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
---
Changes since v2:
* Simplify the check whether a 32-bit CPU type is used in combination
  with OVMF

 PVE/QemuServer.pm | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
index 2063e66..b25a3cd 100644
--- a/PVE/QemuServer.pm
+++ b/PVE/QemuServer.pm
@@ -3570,6 +3570,16 @@ my sub print_ovmf_drive_commandlines {
     return ("if=pflash,unit=0,format=raw,readonly=on,file=$ovmf_code", $var_drive_str);
 }
 
+my @cputypes_32bit = (
+    '486',
+    'pentium',
+    'pentium2',
+    'pentium3',
+    'coreduo',
+    'athlon',
+    'kvm32',
+    'qemu32',
+);
 sub config_to_command {
     my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
         $pbs_backing) = @_;
@@ -3689,6 +3699,9 @@ sub config_to_command {
     }
 
     if ($conf->{bios} && $conf->{bios} eq 'ovmf') {
+	die "OVMF (UEFI) BIOS is not supported on 32-bit CPU types\n"
+	    if ($conf->{cpu} && first {$_ eq $conf->{cpu}} @cputypes_32bit);
+
 	my ($code_drive_str, $var_drive_str) =
 	    print_ovmf_drive_commandlines($conf, $storecfg, $vmid, $arch, $q35, $version_guard);
 	push $cmd->@*, '-drive', $code_drive_str;
-- 
2.39.2

Re: [pve-devel] [PATCH v3 qemu-server] Prevent starting a 32-bit VM using a 64-bit OVMF BIOS

[Fiona Ebner]

Am 12.12.23 um 11:58 schrieb Filip Schauer:
> Instead of starting a VM with a 32-bit CPU type and a 64-bit OVMF image,
> throw an error before starting the VM telling the user that OVMF is not
> supported on 32-bit CPU types.
> 
> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
> ---
> Changes since v2:
> * Simplify the check whether a 32-bit CPU type is used in combination
>   with OVMF
> 

Yes, it's much nicer than extending the EFI-related functions with new
parameters :)

>  PVE/QemuServer.pm | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
> index 2063e66..b25a3cd 100644
> --- a/PVE/QemuServer.pm
> +++ b/PVE/QemuServer.pm
> @@ -3570,6 +3570,16 @@ my sub print_ovmf_drive_commandlines {
>      return ("if=pflash,unit=0,format=raw,readonly=on,file=$ovmf_code", $var_drive_str);
>  }
>  
> +my @cputypes_32bit = (
> +    '486',
> +    'pentium',
> +    'pentium2',
> +    'pentium3',
> +    'coreduo',
> +    'athlon',
> +    'kvm32',
> +    'qemu32',
> +);

I'd like to put this list in CPUConfig.pm and have a small helper
function there. The QemuServer.pm module already has way too many
functions and variables ;) And since it's only used for lookup, maybe
using a hash is better?

A short comment in the commit message about how you got the list would
be nice too (I just checked for absence of CPUID_EXT2_LM in
target/i386/cpu.c to verify your list).

>  sub config_to_command {
>      my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
>          $pbs_backing) = @_;
> @@ -3689,6 +3699,9 @@ sub config_to_command {
>      }
>  
>      if ($conf->{bios} && $conf->{bios} eq 'ovmf') {
> +	die "OVMF (UEFI) BIOS is not supported on 32-bit CPU types\n"
> +	    if ($conf->{cpu} && first {$_ eq $conf->{cpu}} @cputypes_32bit);

Style nit: usually we don't have parentheses for post-if

Re: [pve-devel] [PATCH v3 qemu-server] Prevent starting a 32-bit VM using a 64-bit OVMF BIOS

[Filip Schauer]

Patch v5 is available:

https://lists.proxmox.com/pipermail/pve-devel/2023-December/061079.html

On 12/12/2023 12:12, Fiona Ebner wrote:
> Am 12.12.23 um 11:58 schrieb Filip Schauer:
>> Instead of starting a VM with a 32-bit CPU type and a 64-bit OVMF image,
>> throw an error before starting the VM telling the user that OVMF is not
>> supported on 32-bit CPU types.
>>
>> Signed-off-by: Filip Schauer <f.schauer@proxmox.com>
>> ---
>> Changes since v2:
>> * Simplify the check whether a 32-bit CPU type is used in combination
>>    with OVMF
>>
> Yes, it's much nicer than extending the EFI-related functions with new
> parameters :)
>
>>   PVE/QemuServer.pm | 13 +++++++++++++
>>   1 file changed, 13 insertions(+)
>>
>> diff --git a/PVE/QemuServer.pm b/PVE/QemuServer.pm
>> index 2063e66..b25a3cd 100644
>> --- a/PVE/QemuServer.pm
>> +++ b/PVE/QemuServer.pm
>> @@ -3570,6 +3570,16 @@ my sub print_ovmf_drive_commandlines {
>>       return ("if=pflash,unit=0,format=raw,readonly=on,file=$ovmf_code", $var_drive_str);
>>   }
>>   
>> +my @cputypes_32bit = (
>> +    '486',
>> +    'pentium',
>> +    'pentium2',
>> +    'pentium3',
>> +    'coreduo',
>> +    'athlon',
>> +    'kvm32',
>> +    'qemu32',
>> +);
> I'd like to put this list in CPUConfig.pm and have a small helper
> function there. The QemuServer.pm module already has way too many
> functions and variables ;) And since it's only used for lookup, maybe
> using a hash is better?
>
> A short comment in the commit message about how you got the list would
> be nice too (I just checked for absence of CPUID_EXT2_LM in
> target/i386/cpu.c to verify your list).
>
>>   sub config_to_command {
>>       my ($storecfg, $vmid, $conf, $defaults, $forcemachine, $forcecpu,
>>           $pbs_backing) = @_;
>> @@ -3689,6 +3699,9 @@ sub config_to_command {
>>       }
>>   
>>       if ($conf->{bios} && $conf->{bios} eq 'ovmf') {
>> +	die "OVMF (UEFI) BIOS is not supported on 32-bit CPU types\n"
>> +	    if ($conf->{cpu} && first {$_ eq $conf->{cpu}} @cputypes_32bit);
> Style nit: usually we don't have parentheses for post-if