[Matthew, you're Cc'd here for patches 1 and 3 which touch the mm/filemap code. Since in the meanwhile the KVM side has taken a more definitive shape, this time through review/ack is welcome! And there is a proper commit message too. - Paolo] This is the next version of the gmem common API patches, adding target-independent functionality and hooks that are needed by SEV-SNP and TDX. The code in here is mostly taken from two series: - [PATCH 00/21] TDX/SNP part 1 of n, for 6.9 https://lore.kernel.org/kvm/20240227232100.478238-1-pbonzini@xxxxxxxxxx/ - [PATCH gmem 0/6] gmem fix-ups and interfaces for populating gmem pages https://lore.kernel.org/kvm/20240329212444.395559-1-michael.roth@xxxxxxx/ 1-2: This introduces an AS_INACCESSIBLE flag that prevents unexpected accesses to hole-punched gmem pages before invalidation hooks have had a chance to make them safely accessible to the host again. 3-9: This introduces an interface for preparing gmem pages either on first use or by populating them with user data. The latter interface, kvm_gmem_populate(), alternates calls to __kvm_gmem_get_pfn() with calls to a user provided callback. This implementation simplifies the handling of races and errors, by confining filemap rollback and locking in kvm_gmem_populate(). The function's tasks are otherwise kept to the minimum so that it can be used by both SNP and TDX. 10-11: This introduces other hooks needed by SEV-SNP, and is unchanged from "[PATCH 00/21] TDX/SNP part 1 of n, for 6.9". The main changes compared to the previous posting are in patch 9; both the locking of kvm_gmem_populate() (which now takes the filemap's invalidate_lock) and the operation of the function (which now looks up the memslot, but OTOH does not do copy_from_user() anymore) are pretty new. I tested the logic slightly by adding a call to it for sw-protected VMs. Shout or post fixups if it breaks something for you. Current state: - kvm/queue has the SEV_INIT2 and some easy refactorings from the TDX series. Both are expected to move to kvm/next soon. - I have pushed this already at kvm-coco-queue, but I haven't finished the #VE series yet so tomorrow I'll post it and update kvm-coco-queue again. Paolo Michael Roth (4): mm: Introduce AS_INACCESSIBLE for encrypted/confidential memory KVM: guest_memfd: Use AS_INACCESSIBLE when creating guest_memfd inode KVM: guest_memfd: Add hook for invalidating memory KVM: x86: Add gmem hook for determining max NPT mapping level Paolo Bonzini (7): KVM: guest_memfd: pass error up from filemap_grab_folio filemap: add FGP_CREAT_ONLY KVM: guest_memfd: limit overzealous WARN KVM: guest_memfd: Add hook for initializing memory KVM: guest_memfd: extract __kvm_gmem_get_pfn() KVM: guest_memfd: extract __kvm_gmem_punch_hole() KVM: guest_memfd: Add interface for populating gmem pages with user data arch/x86/include/asm/kvm-x86-ops.h | 3 + arch/x86/include/asm/kvm_host.h | 4 + arch/x86/kvm/mmu/mmu.c | 8 + arch/x86/kvm/x86.c | 13 ++ include/linux/kvm_host.h | 35 +++++ include/linux/pagemap.h | 3 + mm/filemap.c | 4 + mm/truncate.c | 3 +- virt/kvm/Kconfig | 8 + virt/kvm/guest_memfd.c | 230 ++++++++++++++++++++++++----- 10 files changed, 277 insertions(+), 34 deletions(-) -- 2.43.0
