Re: [PATCH v8 13/46] KVM: guest_memfd: Add base support for KVM_SET_MEMORY_ATTRIBUTES2

[Binbin Wu]

On 6/19/2026 8:31 AM, Ackerley Tng via B4 Relay wrote:
> From: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> 
> Introduce base support for KVM_SET_MEMORY_ATTRIBUTES2 in guest_memfd, which
> just updates attributes tracked by guest_memfd.
> 
> Validate input fields in general. Guard usage of KVM_SET_MEMORY_ATTRIBUTES2
> by making sure requested attributes are supported for this instance of kvm.
> 
> A new KVM_SET_MEMORY_ATTRIBUTES2 is defined to support writes (unlike
> KVM_SET_MEMORY_ATTRIBUTES) in addition to reads so it can provide error
> details to userspace. This will be used in a later patch.
> 
> The two ioctls use their corresponding structs with no overlap, but
> backward compatibility is baked in for future support of
> KVM_SET_MEMORY_ATTRIBUTES2 and struct kvm_memory_attributes2 in the VM
> ioctl.
> 
> The process of setting memory attributes is set up such that the later half
> will not fail due to allocation. Any necessary checks are performed before
> the point of no return.
> 
> Co-developed-by: Vishal Annapurve <vannapurve@xxxxxxxxxx>
> Signed-off-by: Vishal Annapurve <vannapurve@xxxxxxxxxx>
> Co-developed-by: Sean Christoperson <seanjc@xxxxxxxxxx>
> Signed-off-by: Sean Christoperson <seanjc@xxxxxxxxxx>

s/Christoperson /Christopherson

> Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>
> Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
> ---
>  include/uapi/linux/kvm.h |  13 ++++++
>  virt/kvm/Kconfig         |   1 +
>  virt/kvm/guest_memfd.c   | 116 +++++++++++++++++++++++++++++++++++++++++++++++
>  virt/kvm/kvm_main.c      |  12 +++++
>  4 files changed, 142 insertions(+)
> 
>

[...]

> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index 297e4399fbd49..cfa2c78ba5fb9 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -102,6 +102,7 @@ config KVM_MMU_LOCKLESS_AGING
>  
>  config KVM_GUEST_MEMFD
>         select XARRAY_MULTI
> +       select KVM_MEMORY_ATTRIBUTES

What's this?
This config is gone.

>         bool
>