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

Chao Peng
2021-11-19T13:50:16Z

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.zhang@linux.intel.com>
Signed-off-by: Chao Peng <chao.p.peng@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