Ackerley Tng <[email protected]> writes: > Tarun Sahu <[email protected]> writes: > >> >> [...snip...] >> >> +static bool kvm_gmem_luo_can_preserve(struct liveupdate_file_handler >> *handler, struct file *file) >> +{ >> + struct inode *inode = file_inode(file); >> + struct gmem_file *gmem_file; >> + struct kvm *kvm; >> + >> + if (inode->i_sb->s_magic != GUEST_MEMFD_MAGIC) >> + return false; >> + >> + gmem_file = file->private_data; >> + if (!gmem_file) >> + return false; >> + >> + /* >> + * Only Fully-shared guest_memfd preservation is supported >> + */ >> + if (!(GMEM_I(inode)->flags & GUEST_MEMFD_FLAG_INIT_SHARED)) >> + return false; >> + > > The above check can probably be removed. I think the core thing about > this series is "we can preserve any memory that doesn't have any > encryption state that goes along with it", and so the check for > kvm_arch_has_private_mem() below would be sufficient to gate that.
Sounds Good. Will remove it in next version. I will rephrase the Line: "Support only fully shared guest_memfd" => "Support only guest_memfd that does not support private pages and also can not be converted to private" > >> + /* >> + * It makes sure that no memory can be converted to private >> + * even if it was initially fully shared (in-place conversions are >> + * prevented). >> + */ >> + kvm = gmem_file->kvm; >> + if (kvm_arch_has_private_mem(kvm)) >> + return false; >> + > > For now, has_private_mem == has some encryption state that we can't > preserve yet. > > This also gates off KVM_X86_SW_PROTECTED_VM, but I guess that is > intended, since when work is done for preserving encryption state, we > can then test using KVM_X86_SW_PROTECTED_VM, and only then, remove this > check? Yes, It will be enabled when private memory preservation will be supported. > >> + if (mapping_large_folio_support(inode->i_mapping)) >> + return false; >> + >> + return true; >> +} >> + >> >> [...snip...] >>
