Re: [PATCH v9 04/13] KVM: guest_memfd: Add stub for kvm_arch_gmem_invalidate

[Ackerley Tng]

"Kalyazin, Nikita"  writes:

> From: Patrick Roy 
>
> Add a no-op stub for kvm_arch_gmem_invalidate if
> CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE=n. This allows defining
> kvm_gmem_free_folio without ifdef-ery, which allows more cleanly using
> guest_memfd's free_folio callback for non-arch-invalidation related
> code.
>
> Acked-by: David Hildenbrand (Red Hat) 
> Signed-off-by: Patrick Roy 
> Acked-by: Vlastimil Babka 
> Signed-off-by: Nikita Kalyazin 
> ---
>  include/linux/kvm_host.h | 2 ++
>  virt/kvm/guest_memfd.c   | 4 
>  2 files changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index d93f75b05ae2..27796a09d29b 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2589,6 +2589,8 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void 
> __user *src, long npages
>
>  #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
>  void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
> +#else
> +static inline void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) 
> { }
>  #endif
>
>  #ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
> diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
> index fdaea3422c30..92e7f8c1f303 100644
> --- a/virt/kvm/guest_memfd.c
> +++ b/virt/kvm/guest_memfd.c
> @@ -527,7 +527,6 @@ static int kvm_gmem_error_folio(struct address_space 
> *mapping, struct folio *fol
>   return MF_DELAYED;
>  }
>
> -#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
>  static void kvm_gmem_free_folio(struct folio *folio)
>  {
>   struct page *page = folio_page(folio, 0);
> @@ -536,15 +535,12 @@ static void kvm_gmem_free_folio(struct folio *folio)
>
>   kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order));
>  }
> -#endif
>
>  static const struct address_space_operations kvm_gmem_aops = {
>   .dirty_folio = noop_dirty_folio,
>   .migrate_folio  = kvm_gmem_migrate_folio,
>   .error_remove_folio = kvm_gmem_error_folio,
> -#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
>   .free_folio = kvm_gmem_free_folio,
> -#endif
>  };
>
>  static int kvm_gmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
> --
> 2.50.1

Like this change, thanks!

Reviewed-by: Ackerley Tng 

[PATCH v9 04/13] KVM: guest_memfd: Add stub for kvm_arch_gmem_invalidate

[Kalyazin, Nikita]

From: Patrick Roy 

Add a no-op stub for kvm_arch_gmem_invalidate if
CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE=n. This allows defining
kvm_gmem_free_folio without ifdef-ery, which allows more cleanly using
guest_memfd's free_folio callback for non-arch-invalidation related
code.

Acked-by: David Hildenbrand (Red Hat) 
Signed-off-by: Patrick Roy 
Acked-by: Vlastimil Babka 
Signed-off-by: Nikita Kalyazin 
---
 include/linux/kvm_host.h | 2 ++
 virt/kvm/guest_memfd.c   | 4 
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d93f75b05ae2..27796a09d29b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -2589,6 +2589,8 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void 
__user *src, long npages
 
 #ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
 void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
+#else
+static inline void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end) { }
 #endif
 
 #ifdef CONFIG_KVM_GENERIC_PRE_FAULT_MEMORY
diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c
index fdaea3422c30..92e7f8c1f303 100644
--- a/virt/kvm/guest_memfd.c
+++ b/virt/kvm/guest_memfd.c
@@ -527,7 +527,6 @@ static int kvm_gmem_error_folio(struct address_space 
*mapping, struct folio *fol
return MF_DELAYED;
 }
 
-#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
 static void kvm_gmem_free_folio(struct folio *folio)
 {
struct page *page = folio_page(folio, 0);
@@ -536,15 +535,12 @@ static void kvm_gmem_free_folio(struct folio *folio)
 
kvm_arch_gmem_invalidate(pfn, pfn + (1ul << order));
 }
-#endif
 
 static const struct address_space_operations kvm_gmem_aops = {
.dirty_folio = noop_dirty_folio,
.migrate_folio  = kvm_gmem_migrate_folio,
.error_remove_folio = kvm_gmem_error_folio,
-#ifdef CONFIG_HAVE_KVM_ARCH_GMEM_INVALIDATE
.free_folio = kvm_gmem_free_folio,
-#endif
 };
 
 static int kvm_gmem_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
-- 
2.50.1