[RFC v2 PATCH 12/13] KVM: Introduce kvm_memfd_fallocate_range

[Chao Peng]

It reuses the same code for kvm_memfd_invalidate_range, except using
kvm_map_gfn_range as its handler.

Signed-off-by: Yu Zhang <yu.c.zh...@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.p...@linux.intel.com>
---
 include/linux/kvm_host.h |  2 ++
 virt/kvm/kvm_main.c      | 28 +++++++++++++++++++++++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index d841ed877b4b..f1d7856be05b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1887,5 +1887,7 @@ static inline void kvm_handle_signal_exit(struct kvm_vcpu 
*vcpu)
 
 int kvm_memfd_invalidate_range(struct kvm *kvm, struct inode *inode,
                               unsigned long start, unsigned long end);
+int kvm_memfd_fallocate_range(struct kvm *kvm, struct inode *inode,
+                             unsigned long start, unsigned long end);
 
 #endif
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 492c1a99ec63..7eaafc0ae6ab 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -828,8 +828,10 @@ static int kvm_init_mmu_notifier(struct kvm *kvm)
        return mmu_notifier_register(&kvm->mmu_notifier, current->mm);
 }
 
-int kvm_memfd_invalidate_range(struct kvm *kvm, struct inode *inode,
-                              unsigned long start, unsigned long end)
+int kvm_memfd_handle_range(struct kvm *kvm, struct inode *inode,
+                          unsigned long start, unsigned long end,
+                          gfn_handler_t handler)
+
 {
        int ret;
        const struct kvm_useraddr_range useraddr_range = {
@@ -837,7 +839,7 @@ int kvm_memfd_invalidate_range(struct kvm *kvm, struct 
inode *inode,
                .end            = end,
                .inode          = inode,
                .pte            = __pte(0),
-               .handler        = kvm_unmap_gfn_range,
+               .handler        = handler,
                .on_lock        = (void *)kvm_null_fn,
                .flush_on_ret   = true,
                .may_block      = false,
@@ -858,6 +860,20 @@ int kvm_memfd_invalidate_range(struct kvm *kvm, struct 
inode *inode,
        return ret;
 }
 
+int kvm_memfd_invalidate_range(struct kvm *kvm, struct inode *inode,
+                              unsigned long start, unsigned long end)
+{
+       return kvm_memfd_handle_range(kvm, inode, start, end,
+                                     kvm_unmap_gfn_range);
+}
+
+int kvm_memfd_fallocate_range(struct kvm *kvm, struct inode *inode,
+                             unsigned long start, unsigned long end)
+{
+       return kvm_memfd_handle_range(kvm, inode, start, end,
+                                     kvm_map_gfn_range);
+}
+
 #else  /* !(CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER) */
 
 static int kvm_init_mmu_notifier(struct kvm *kvm)
@@ -871,6 +887,12 @@ int kvm_memfd_invalidate_range(struct kvm *kvm, struct 
inode *inode,
        return 0;
 }
 
+int kvm_memfd_fallocate_range(struct kvm *kvm, struct inode *inode,
+                             unsigned long start, unsigned long end)
+{
+       return 0;
+}
+
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */
 
 #ifdef CONFIG_HAVE_KVM_PM_NOTIFIER
-- 
2.17.1