| Message ID | 20240227232100.478238-20-pbonzini@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | TDX/SNP part 1 of n, for 6.9 | expand |
On Tue, Feb 27, 2024 at 06:20:58PM -0500, Paolo Bonzini wrote: > In order to be able to redo kvm_gmem_get_uninit_pfn, a hole must be punched > into the filemap, thus allowing FGP_CREAT_ONLY to succeed again. This will > be used whenever an operation that follows kvm_gmem_get_uninit_pfn fails. > > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> > --- > include/linux/kvm_host.h | 7 +++++++ > virt/kvm/guest_memfd.c | 28 ++++++++++++++++++++++++++++ > 2 files changed, 35 insertions(+) > > diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h > index 03bf616b7308..192c58116220 100644 > --- a/include/linux/kvm_host.h > +++ b/include/linux/kvm_host.h > @@ -2436,6 +2436,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > gfn_t gfn, kvm_pfn_t *pfn, int *max_order); > int kvm_gmem_get_uninit_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > gfn_t gfn, kvm_pfn_t *pfn, int *max_order); > +int kvm_gmem_undo_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > + gfn_t gfn, int order); > #else > static inline int kvm_gmem_get_pfn(struct kvm *kvm, > struct kvm_memory_slot *slot, gfn_t gfn, > @@ -2452,6 +2454,11 @@ static inline int kvm_gmem_get_uninit_pfn(struct kvm *kvm, > KVM_BUG_ON(1, kvm); > return -EIO; > } > + > +static inline int kvm_gmem_undo_get_pfn(struct kvm *kvm, > + struct kvm_memory_slot *slot, gfn_t gfn, > + int order) > +{} return -EIO; or compiler would complain that no return value. > #endif /* CONFIG_KVM_PRIVATE_MEM */ > > #ifdef CONFIG_HAVE_KVM_GMEM_PREPARE > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index 7ec7afafc960..535ef1aa34fb 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -590,3 +590,31 @@ int kvm_gmem_get_uninit_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > return __kvm_gmem_get_pfn(kvm, slot, gfn, pfn, max_order, false); > } > EXPORT_SYMBOL_GPL(kvm_gmem_get_uninit_pfn); > + > +int kvm_gmem_undo_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, > + gfn_t gfn, int order) Didn't see the caller yet, but do we need to ensure the gfn is aligned with page order? e.g. WARN_ON(gfn & ((1UL << order) - 1)); > +{ > + pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff; > + struct kvm_gmem *gmem; > + struct file *file; > + int r; > + > + file = kvm_gmem_get_file(slot); > + if (!file) > + return -EFAULT; > + > + gmem = file->private_data; > + > + if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) { > + r = -EIO; > + goto out_fput; > + } > + > + r = kvm_gmem_punch_hole(file_inode(file), index << PAGE_SHIFT, PAGE_SHIFT << order); ^ PAGE_SIZE << order Thanks, Yilun > + > +out_fput: > + fput(file); > + > + return r; > +} > +EXPORT_SYMBOL_GPL(kvm_gmem_undo_get_pfn); > -- > 2.39.0 > > >
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 03bf616b7308..192c58116220 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -2436,6 +2436,8 @@ int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, int *max_order); int kvm_gmem_get_uninit_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, kvm_pfn_t *pfn, int *max_order); +int kvm_gmem_undo_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, int order); #else static inline int kvm_gmem_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, gfn_t gfn, @@ -2452,6 +2454,11 @@ static inline int kvm_gmem_get_uninit_pfn(struct kvm *kvm, KVM_BUG_ON(1, kvm); return -EIO; } + +static inline int kvm_gmem_undo_get_pfn(struct kvm *kvm, + struct kvm_memory_slot *slot, gfn_t gfn, + int order) +{} #endif /* CONFIG_KVM_PRIVATE_MEM */ #ifdef CONFIG_HAVE_KVM_GMEM_PREPARE diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c index 7ec7afafc960..535ef1aa34fb 100644 --- a/virt/kvm/guest_memfd.c +++ b/virt/kvm/guest_memfd.c @@ -590,3 +590,31 @@ int kvm_gmem_get_uninit_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, return __kvm_gmem_get_pfn(kvm, slot, gfn, pfn, max_order, false); } EXPORT_SYMBOL_GPL(kvm_gmem_get_uninit_pfn); + +int kvm_gmem_undo_get_pfn(struct kvm *kvm, struct kvm_memory_slot *slot, + gfn_t gfn, int order) +{ + pgoff_t index = gfn - slot->base_gfn + slot->gmem.pgoff; + struct kvm_gmem *gmem; + struct file *file; + int r; + + file = kvm_gmem_get_file(slot); + if (!file) + return -EFAULT; + + gmem = file->private_data; + + if (WARN_ON_ONCE(xa_load(&gmem->bindings, index) != slot)) { + r = -EIO; + goto out_fput; + } + + r = kvm_gmem_punch_hole(file_inode(file), index << PAGE_SHIFT, PAGE_SHIFT << order); + +out_fput: + fput(file); + + return r; +} +EXPORT_SYMBOL_GPL(kvm_gmem_undo_get_pfn);
In order to be able to redo kvm_gmem_get_uninit_pfn, a hole must be punched into the filemap, thus allowing FGP_CREAT_ONLY to succeed again. This will be used whenever an operation that follows kvm_gmem_get_uninit_pfn fails. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- include/linux/kvm_host.h | 7 +++++++ virt/kvm/guest_memfd.c | 28 ++++++++++++++++++++++++++++ 2 files changed, 35 insertions(+)