Re: [PATCH v16 05/22] KVM: Rename CONFIG_KVM_GENERIC_PRIVATE_MEM to CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE

[Xiaoyao Li <xiaoyao.li@intel.com>]

On 7/23/2025 6:46 PM, Fuad Tabba wrote:
> The original name was vague regarding its functionality. This Kconfig
> option specifically enables and gates the kvm_gmem_populate() function,
> which is responsible for populating a GPA range with guest data.
> 
> The new name, HAVE_KVM_ARCH_GMEM_POPULATE, describes the purpose of the
> option: to enable arch-specific guest_memfd population mechanisms. It
> also follows the same pattern as the other HAVE_KVM_ARCH_* configuration
> options.
> 
> This improves clarity for developers and ensures the name accurately
> reflects the functionality it controls, especially as guest_memfd
> support expands beyond purely "private" memory scenarios.
> 
> Note that the vm type KVM_X86_SW_PROTECTED_VM does not need the populate
> function. Therefore, ensure that the correct configuration is selected
> when KVM_SW_PROTECTED_VM is enabled.

the changelog needs to be enhanced. At least it doesn't talk about 
KVM_X86_PRIVATE_MEM at all.

If Sean is going to queue this version, I think he can help refine it 
when queuing.

> Reviewed-by: Ira Weiny <ira.weiny@intel.com>
> Reviewed-by: Gavin Shan <gshan@redhat.com>
> Reviewed-by: Shivank Garg <shivankg@amd.com>
> Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
> Co-developed-by: David Hildenbrand <david@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> Co-developed-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> Signed-off-by: Fuad Tabba <tabba@google.com>

Reviewed-by: Xiaoyao Li <xiaoyao.li@intel.com>

> ---
>   arch/x86/kvm/Kconfig     | 14 ++++++++++----
>   include/linux/kvm_host.h |  2 +-
>   virt/kvm/Kconfig         |  9 ++++-----
>   virt/kvm/guest_memfd.c   |  2 +-
>   4 files changed, 16 insertions(+), 11 deletions(-)
> 
> diff --git a/arch/x86/kvm/Kconfig b/arch/x86/kvm/Kconfig
> index 13ab7265b505..c763446d9b9f 100644
> --- a/arch/x86/kvm/Kconfig
> +++ b/arch/x86/kvm/Kconfig
> @@ -79,11 +79,16 @@ config KVM_WERROR
>   
>   	  If in doubt, say "N".
>   
> +config KVM_X86_PRIVATE_MEM
> +	select KVM_GENERIC_MEMORY_ATTRIBUTES
> +	select KVM_GUEST_MEMFD
> +	bool
> +
>   config KVM_SW_PROTECTED_VM
>   	bool "Enable support for KVM software-protected VMs"
>   	depends on EXPERT
>   	depends on KVM_X86 && X86_64
> -	select KVM_GENERIC_PRIVATE_MEM
> +	select KVM_X86_PRIVATE_MEM
>   	help
>   	  Enable support for KVM software-protected VMs.  Currently, software-
>   	  protected VMs are purely a development and testing vehicle for
> @@ -133,8 +138,8 @@ config KVM_INTEL_TDX
>   	bool "Intel Trust Domain Extensions (TDX) support"
>   	default y
>   	depends on INTEL_TDX_HOST
> -	select KVM_GENERIC_PRIVATE_MEM
> -	select KVM_GENERIC_MEMORY_ATTRIBUTES
> +	select KVM_X86_PRIVATE_MEM
> +	select HAVE_KVM_ARCH_GMEM_POPULATE
>   	help
>   	  Provides support for launching Intel Trust Domain Extensions (TDX)
>   	  confidential VMs on Intel processors.
> @@ -157,9 +162,10 @@ config KVM_AMD_SEV
>   	depends on KVM_AMD && X86_64
>   	depends on CRYPTO_DEV_SP_PSP && !(KVM_AMD=y && CRYPTO_DEV_CCP_DD=m)
>   	select ARCH_HAS_CC_PLATFORM
> -	select KVM_GENERIC_PRIVATE_MEM
> +	select KVM_X86_PRIVATE_MEM
>   	select HAVE_KVM_ARCH_GMEM_PREPARE
>   	select HAVE_KVM_ARCH_GMEM_INVALIDATE
> +	select HAVE_KVM_ARCH_GMEM_POPULATE
>   	help
>   	  Provides support for launching encrypted VMs which use Secure
>   	  Encrypted Virtualization (SEV), Secure Encrypted Virtualization with
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 8cdc0b3cc1b1..ddfb6cfe20a6 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2534,7 +2534,7 @@ static inline int kvm_gmem_get_pfn(struct kvm *kvm,
>   int kvm_arch_gmem_prepare(struct kvm *kvm, gfn_t gfn, kvm_pfn_t pfn, int max_order);
>   #endif
>   
> -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
> +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
>   /**
>    * kvm_gmem_populate() - Populate/prepare a GPA range with guest data
>    *
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index e4b400feff94..1b7d5be0b6c4 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -116,11 +116,6 @@ config KVM_GUEST_MEMFD
>          select XARRAY_MULTI
>          bool
>   
> -config KVM_GENERIC_PRIVATE_MEM
> -       select KVM_GENERIC_MEMORY_ATTRIBUTES
> -       select KVM_GUEST_MEMFD
> -       bool
> -
>   config HAVE_KVM_ARCH_GMEM_PREPARE
>          bool
>          depends on KVM_GUEST_MEMFD
> @@ -128,3 +123,7 @@ config HAVE_KVM_ARCH_GMEM_PREPARE
>   config HAVE_KVM_ARCH_GMEM_INVALIDATE
>          bool
>          depends on KVM_GUEST_MEMFD
> +
> +config HAVE_KVM_ARCH_GMEM_POPULATE
> +       bool
> +       depends on KVM_GUEST_MEMFD
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index 7d85cc33c0bb..b2b50560e80e 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -627,7 +627,7 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot,
>   }
>   EXPORT_SYMBOL_GPL(kvm_gmem_get_pfn);
>   
> -#ifdef CONFIG_KVM_GENERIC_PRIVATE_MEM
> +#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_POPULATE
>   long kvm_gmem_populate(struct kvm *kvm, gfn_t start_gfn, void __user *src, long npages,
>   		       kvm_gmem_populate_cb post_populate, void *opaque)
>   {