"David Hildenbrand (Arm)" <[email protected]> writes:
> On 8/7/26 23:52, Ackerley Tng via B4 Relay wrote:
>> From: Ackerley Tng <[email protected]>
>>
>>
>> [...snip...]
>>
>> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
>> index abb108886733a..2c3c22aeafa54 100644
>> --- a/arch/x86/kvm/Kconfig
>> +++ b/arch/x86/kvm/Kconfig
>> @@ -81,13 +81,21 @@ config KVM_WERROR
>> If in doubt, say "N".
>>
>> config KVM_VM_MEMORY_ATTRIBUTES
>> - bool
>> + bool "Enable per-VM PRIVATE vs. SHARED attributes (for CoCo VMs)"
>> + depends on KVM_SW_PROTECTED_VM || KVM_INTEL_TDX || KVM_AMD_SEV
>> + help
>> + Enable support for tracking PRIVATE vs. SHARED memory using per-VM
>> + memory attributes. Using per-VM attributes is deprecated in favor of
>> + tracking PRIVATE state in guest_memfd. Select this if you need to run
>> + CoCo VMs using a VMM that doesn't support guest_memfd memory
>> + attributes.
>> +
>> + If unsure, say N.
>
> Hm, does that imply that a distribution that must support both, cannot ship a
> single kernel?
>
Did you mean this as a documentation comment? Should the above read:
help
Enable support for tracking PRIVATE vs. SHARED memory using per-VM
memory attributes. Using per-VM attributes is deprecated in favor of
tracking PRIVATE state in guest_memfd. Select this if you need to run
CoCo VMs using a VMM that doesn't support guest_memfd memory
- attributes.
+ attributes. Select this to defer selection of where PRIVATE vs. SHARED
+ attributes are tracked to KVM module load time, where
+ gmem_in_place_conversion can be specified as a module parameter.
If unsure, say N.
I think we should do _without_ the above clarification since using VM
memory attributes for shared/private status is intended to be
deprecated.
Is it fair to say distributions should not support both, and if they
_must_ support both, they need to read code to figure this out?
> --
> Cheers,
>
> David
