Re: [PATCH v8 07/46] KVM: Rename memory attribute APIs to prepare for in-place gmem conversion

[Fuad Tabba]

On Fri, 19 Jun 2026 at 01:31, Ackerley Tng via B4 Relay
<devnull+ackerleytng.google.com@xxxxxxxxxx> wrote:
>
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> Rename memory attribute APIs to add a "vm_" in the name in anticipation of
> moving PRIVATE tracking into guest_memfd, to allow in-place conversion
> between SHARED and PRIVATE.  At that point, there will effectively be two
> (potential) sources of memory attributes: the VM and guest_memfd.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>

Missing SoB (other patches as well, I won't mention it again). But for
this (and other patches I review with a missing SoB fixed):

Reviewed-by: Fuad Tabba <tabba@xxxxxxxxxx>

Cheers,
/fuad
> ---
>  arch/x86/kvm/mmu/mmu.c   |  6 +++---
>  include/linux/kvm_host.h | 15 +++++++++++----
>  virt/kvm/guest_memfd.c   |  6 +++---
>  virt/kvm/kvm_main.c      | 16 ++++++++--------
>  4 files changed, 25 insertions(+), 18 deletions(-)
>
> diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
> index e0005a21b6e22..cbc50aef801fb 100644
> --- a/arch/x86/kvm/mmu/mmu.c
> +++ b/arch/x86/kvm/mmu/mmu.c
> @@ -8087,11 +8087,11 @@ static bool hugepage_has_attrs(struct kvm *kvm, struct kvm_memory_slot *slot,
>         const unsigned long end = start + KVM_PAGES_PER_HPAGE(level);
>
>         if (level == PG_LEVEL_2M)
> -               return kvm_range_has_memory_attributes(kvm, start, end, ~0, attrs);
> +               return kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attrs);
>
>         for (gfn = start; gfn < end; gfn += KVM_PAGES_PER_HPAGE(level - 1)) {
>                 if (hugepage_test_mixed(slot, gfn, level - 1) ||
> -                   attrs != kvm_get_memory_attributes(kvm, gfn))
> +                   attrs != kvm_get_vm_memory_attributes(kvm, gfn))
>                         return false;
>         }
>         return true;
> @@ -8191,7 +8191,7 @@ void kvm_mmu_init_memslot_memory_attributes(struct kvm *kvm,
>                  * be manually checked as the attributes may already be mixed.
>                  */
>                 for (gfn = start; gfn < end; gfn += nr_pages) {
> -                       unsigned long attrs = kvm_get_memory_attributes(kvm, gfn);
> +                       unsigned long attrs = kvm_get_vm_memory_attributes(kvm, gfn);
>
>                         if (hugepage_has_attrs(kvm, slot, gfn, level, attrs))
>                                 hugepage_clear_mixed(slot, gfn, level);
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index d370e834d619e..eb26d4ea8945a 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2534,13 +2534,13 @@ static inline bool kvm_memslot_is_gmem_only(const struct kvm_memory_slot *slot)
>  }
>
>  #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> -static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
> +static inline unsigned long kvm_get_vm_memory_attributes(struct kvm *kvm, gfn_t gfn)
>  {
>         return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
>  }
>
> -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> -                                    unsigned long mask, unsigned long attrs);
> +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> +                                       unsigned long mask, unsigned long attrs);
>  bool kvm_arch_pre_set_memory_attributes(struct kvm *kvm,
>                                         struct kvm_gfn_range *range);
>  bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
> @@ -2548,7 +2548,14 @@ bool kvm_arch_post_set_memory_attributes(struct kvm *kvm,
>
>  static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
>  {
> -       return kvm_get_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +       return kvm_get_vm_memory_attributes(kvm, gfn) & KVM_MEMORY_ATTRIBUTE_PRIVATE;
> +}
> +static inline bool kvm_mem_range_is_private(struct kvm *kvm, gfn_t start,
> +                                           gfn_t end)
> +{
> +       return kvm_range_has_vm_memory_attributes(kvm, start, end,
> +                                                 KVM_MEMORY_ATTRIBUTE_PRIVATE,
> +                                                 KVM_MEMORY_ATTRIBUTE_PRIVATE);
>  }
>  #else
>  static inline bool kvm_mem_is_private(struct kvm *kvm, gfn_t gfn)
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index b4c24fdf159f6..8101f64e0366f 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -915,9 +915,9 @@ static long __kvm_gmem_populate(struct kvm *kvm, struct kvm_memory_slot *slot,
>
>         folio_unlock(folio);
>
> -       if (!kvm_range_has_memory_attributes(kvm, gfn, gfn + 1,
> -                                            KVM_MEMORY_ATTRIBUTE_PRIVATE,
> -                                            KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
> +       if (!kvm_range_has_vm_memory_attributes(kvm, gfn, gfn + 1,
> +                                               KVM_MEMORY_ATTRIBUTE_PRIVATE,
> +                                               KVM_MEMORY_ATTRIBUTE_PRIVATE)) {
>                 ret = -EINVAL;
>                 goto out_put_folio;
>         }
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 7b989b659cf82..6669f1477013c 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -2419,7 +2419,7 @@ static int kvm_vm_ioctl_clear_dirty_log(struct kvm *kvm,
>  #endif /* CONFIG_KVM_GENERIC_DIRTYLOG_READ_PROTECT */
>
>  #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
> -static u64 kvm_supported_mem_attributes(struct kvm *kvm)
> +static u64 kvm_supported_vm_mem_attributes(struct kvm *kvm)
>  {
>  #ifdef kvm_arch_has_private_mem
>         if (!kvm || kvm_arch_has_private_mem(kvm))
> @@ -2433,19 +2433,19 @@ static u64 kvm_supported_mem_attributes(struct kvm *kvm)
>   * Returns true if _all_ gfns in the range [@start, @end) have attributes
>   * such that the bits in @mask match @attrs.
>   */
> -bool kvm_range_has_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> -                                    unsigned long mask, unsigned long attrs)
> +bool kvm_range_has_vm_memory_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
> +                                       unsigned long mask, unsigned long attrs)
>  {
>         XA_STATE(xas, &kvm->mem_attr_array, start);
>         unsigned long index;
>         void *entry;
>
> -       mask &= kvm_supported_mem_attributes(kvm);
> +       mask &= kvm_supported_vm_mem_attributes(kvm);
>         if (attrs & ~mask)
>                 return false;
>
>         if (end == start + 1)
> -               return (kvm_get_memory_attributes(kvm, start) & mask) == attrs;
> +               return (kvm_get_vm_memory_attributes(kvm, start) & mask) == attrs;
>
>         guard(rcu)();
>         if (!attrs)
> @@ -2567,7 +2567,7 @@ static int kvm_vm_set_mem_attributes(struct kvm *kvm, gfn_t start, gfn_t end,
>         mutex_lock(&kvm->slots_lock);
>
>         /* Nothing to do if the entire range has the desired attributes. */
> -       if (kvm_range_has_memory_attributes(kvm, start, end, ~0, attributes))
> +       if (kvm_range_has_vm_memory_attributes(kvm, start, end, ~0, attributes))
>                 goto out_unlock;
>
>         /*
> @@ -2606,7 +2606,7 @@ static int kvm_vm_ioctl_set_mem_attributes(struct kvm *kvm,
>         /* flags is currently not used. */
>         if (attrs->flags)
>                 return -EINVAL;
> -       if (attrs->attributes & ~kvm_supported_mem_attributes(kvm))
> +       if (attrs->attributes & ~kvm_supported_vm_mem_attributes(kvm))
>                 return -EINVAL;
>         if (attrs->size == 0 || attrs->address + attrs->size < attrs->address)
>                 return -EINVAL;
> @@ -4926,7 +4926,7 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
>                 return 1;
>  #ifdef CONFIG_KVM_VM_MEMORY_ATTRIBUTES
>         case KVM_CAP_MEMORY_ATTRIBUTES:
> -               return kvm_supported_mem_attributes(kvm);
> +               return kvm_supported_vm_mem_attributes(kvm);
>  #endif
>  #ifdef CONFIG_KVM_GUEST_MEMFD
>         case KVM_CAP_GUEST_MEMFD:
>
> --
> 2.55.0.rc0.738.g0c8ab3ebcc-goog
>
>