linux-kernel - Re: [PATCH 08/10] KVM: SEV: define VM types for SEV and SEV-ES

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Thu, 15 Feb 2024 14:40:32 +0100
From: Paolo Bonzini <pbonzini@...hat.com>
To: Michael Roth <michael.roth@....com>
Cc: linux-kernel@...r.kernel.org, kvm@...r.kernel.org, seanjc@...gle.com,
 aik@....com, isaku.yamahata@...el.com
Subject: Re: [PATCH 08/10] KVM: SEV: define VM types for SEV and SEV-ES

On 2/15/24 02:19, Michael Roth wrote:
>>   #define KVM_X86_DEFAULT_VM	0
>>   #define KVM_X86_SW_PROTECTED_VM	(KVM_X86_DEFAULT_VM | __KVM_X86_PRIVATE_MEM_TYPE)
>> +#define KVM_X86_SEV_VM		8
> Hmm... would it make sense to decouple the VM types and their associated
> capabilities? Only bit 2 is left in the lower range after this, and using any
> bits beyond TDX's bit 4 risks overflowing check_extension ioctl's 32-bit return
> value.

Yes, the idea was to leave 0..7 for vendor independent types (with 0 and 
1 in use), 8..15 for AMD (3 of them being reserved already for 
SEV/SEV-ES/SEV-SNP), 16..23 for Intel.

> Maybe a separate lookup table instead?

The mask was nice because it can be used in relatively hot paths... 
I'll keep them but move the constants away from uapi/ headers.

Paolo