Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm updates from Paolo Bonzini:
 "The bulk of the changes here is a largish change to guest_memfd,
  delaying the clearing and encryption of guest-private pages until they
  are actually added to guest page tables. This started as "let's make
  it impossible to misuse the API" for SEV-SNP; but then it ballooned a
  bit.

  The new logic is generally simpler and more ready for hugepage support
  in guest_memfd.

  Summary:

   - fix latent bug in how usage of large pages is determined for
     confidential VMs

   - fix "underline too short" in docs

   - eliminate log spam from limited APIC timer periods

   - disallow pre-faulting of memory before SEV-SNP VMs are initialized

   - delay clearing and encrypting private memory until it is added to
     guest page tables

   - this change also enables another small cleanup: the checks in
     SNP_LAUNCH_UPDATE that limit it to non-populated, private pages can
     now be moved in the common kvm_gmem_populate() function

   - fix compilation error that the RISC-V merge introduced in selftests"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86/mmu: fix determination of max NPT mapping level for private pages
  KVM: riscv: selftests: Fix compile error
  KVM: guest_memfd: abstract how prepared folios are recorded
  KVM: guest_memfd: let kvm_gmem_populate() operate only on private gfns
  KVM: extend kvm_range_has_memory_attributes() to check subset of attributes
  KVM: cleanup and add shortcuts to kvm_range_has_memory_attributes()
  KVM: guest_memfd: move check for already-populated page to common code
  KVM: remove kvm_arch_gmem_prepare_needed()
  KVM: guest_memfd: make kvm_gmem_prepare_folio() operate on a single struct kvm
  KVM: guest_memfd: delay kvm_gmem_prepare_folio() until the memory is passed to the guest
  KVM: guest_memfd: return locked folio from __kvm_gmem_get_pfn
  KVM: rename CONFIG_HAVE_KVM_GMEM_* to CONFIG_HAVE_KVM_ARCH_GMEM_*
  KVM: guest_memfd: do not go through struct page
  KVM: guest_memfd: delay folio_mark_uptodate() until after successful preparation
  KVM: guest_memfd: return folio from __kvm_gmem_get_pfn()
  KVM: x86: disallow pre-fault for SNP VMs before initialization
  KVM: Documentation: Fix title underline too short warning
  KVM: x86: Eliminate log spam from limited APIC timer periods

1 files changed, 9 insertions, 8 deletions

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index a16c873b3232..532df12b43c5 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -2279,18 +2279,11 @@ static int sev_gmem_post_populate(struct kvm *kvm, gfn_t gfn_start, kvm_pfn_t pf
 		bool assigned;
 		int level;
 
-		if (!kvm_mem_is_private(kvm, gfn)) {
-			pr_debug("%s: Failed to ensure GFN 0x%llx has private memory attribute set\n",
-				 __func__, gfn);
-			ret = -EINVAL;
-			goto err;
-		}
-
 		ret = snp_lookup_rmpentry((u64)pfn + i, &assigned, &level);
 		if (ret || assigned) {
 			pr_debug("%s: Failed to ensure GFN 0x%llx RMP entry is initial shared state, ret: %d assigned: %d\n",
 				 __func__, gfn, ret, assigned);
-			ret = -EINVAL;
+			ret = ret ? -EINVAL : -EEXIST;
 			goto err;
 		}
 
@@ -2549,6 +2542,14 @@ static int snp_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	data->gctx_paddr = __psp_pa(sev->snp_context);
 	ret = sev_issue_cmd(kvm, SEV_CMD_SNP_LAUNCH_FINISH, data, &argp->error);
 
+	/*
+	 * Now that there will be no more SNP_LAUNCH_UPDATE ioctls, private pages
+	 * can be given to the guest simply by marking the RMP entry as private.
+	 * This can happen on first access and also with KVM_PRE_FAULT_MEMORY.
+	 */
+	if (!ret)
+		kvm->arch.pre_fault_allowed = true;
+
 	kfree(id_auth);
 
 e_free_id_block: