diff options
Diffstat (limited to 'arch/x86/kvm/mmu/spte.c')
| -rw-r--r-- | arch/x86/kvm/mmu/spte.c | 72 |
1 files changed, 62 insertions, 10 deletions
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 73cfe62fdad1..4739b53c9734 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -192,6 +192,65 @@ out: return wrprot; } +static u64 make_spte_executable(u64 spte) +{ + bool is_access_track = is_access_track_spte(spte); + + if (is_access_track) + spte = restore_acc_track_spte(spte); + + spte &= ~shadow_nx_mask; + spte |= shadow_x_mask; + + if (is_access_track) + spte = mark_spte_for_access_track(spte); + + return spte; +} + +/* + * Construct an SPTE that maps a sub-page of the given huge page SPTE where + * `index` identifies which sub-page. + * + * This is used during huge page splitting to build the SPTEs that make up the + * new page table. + */ +u64 make_huge_page_split_spte(u64 huge_spte, int huge_level, int index) +{ + u64 child_spte; + int child_level; + + if (WARN_ON_ONCE(!is_shadow_present_pte(huge_spte))) + return 0; + + if (WARN_ON_ONCE(!is_large_pte(huge_spte))) + return 0; + + child_spte = huge_spte; + child_level = huge_level - 1; + + /* + * The child_spte already has the base address of the huge page being + * split. So we just have to OR in the offset to the page at the next + * lower level for the given index. + */ + child_spte |= (index * KVM_PAGES_PER_HPAGE(child_level)) << PAGE_SHIFT; + + if (child_level == PG_LEVEL_4K) { + child_spte &= ~PT_PAGE_SIZE_MASK; + + /* + * When splitting to a 4K page, mark the page executable as the + * NX hugepage mitigation no longer applies. + */ + if (is_nx_huge_page_enabled()) + child_spte = make_spte_executable(child_spte); + } + + return child_spte; +} + + u64 make_nonleaf_spte(u64 *child_pt, bool ad_disabled) { u64 spte = SPTE_MMU_PRESENT_MASK; @@ -250,14 +309,7 @@ u64 mark_spte_for_access_track(u64 spte) if (is_access_track_spte(spte)) return spte; - /* - * Making an Access Tracking PTE will result in removal of write access - * from the PTE. So, verify that we will be able to restore the write - * access in the fast page fault path later on. - */ - WARN_ONCE((spte & PT_WRITABLE_MASK) && - !spte_can_locklessly_be_made_writable(spte), - "kvm: Writable SPTE is not locklessly dirty-trackable\n"); + check_spte_writable_invariants(spte); WARN_ONCE(spte & (SHADOW_ACC_TRACK_SAVED_BITS_MASK << SHADOW_ACC_TRACK_SAVED_BITS_SHIFT), @@ -368,8 +420,8 @@ void kvm_mmu_reset_all_pte_masks(void) shadow_acc_track_mask = 0; shadow_me_mask = sme_me_mask; - shadow_host_writable_mask = DEFAULT_SPTE_HOST_WRITEABLE; - shadow_mmu_writable_mask = DEFAULT_SPTE_MMU_WRITEABLE; + shadow_host_writable_mask = DEFAULT_SPTE_HOST_WRITABLE; + shadow_mmu_writable_mask = DEFAULT_SPTE_MMU_WRITABLE; /* * Set a reserved PA bit in MMIO SPTEs to generate page faults with |