diff options
| author | David Matlack <dmatlack@google.com> | 2022-01-26 02:05:15 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-02-10 21:50:32 +0300 |
| commit | 115111efd97c6c0e86f8b5904c6624fddcfe4f34 (patch) | |
| tree | e56472f8d5376879f8961fabb462c482e4015747 /arch/x86/kvm/mmu/spte.c | |
| parent | 932859a4e0b9fa12ba315e88e3d29f9d2f638916 (diff) | |
KVM: x86/mmu: Check SPTE writable invariants when setting leaf SPTEs
Check SPTE writable invariants when setting SPTEs rather than in
spte_can_locklessly_be_made_writable(). By the time KVM checks
spte_can_locklessly_be_made_writable(), the SPTE has long been since
corrupted.
Note that these invariants only apply to shadow-present leaf SPTEs (i.e.
not to MMIO SPTEs, non-leaf SPTEs, etc.). Add a comment explaining the
restriction and only instrument the code paths that set shadow-present
leaf SPTEs.
To account for access tracking, also check the SPTE writable invariants
when marking an SPTE as an access track SPTE. This also lets us remove
a redundant WARN from mark_spte_for_access_track().
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: David Matlack <dmatlack@google.com>
Message-Id: <20220125230518.1697048-3-dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/spte.c')
| -rw-r--r-- | arch/x86/kvm/mmu/spte.c | 9 |
1 files changed, 1 insertions, 8 deletions
diff --git a/arch/x86/kvm/mmu/spte.c b/arch/x86/kvm/mmu/spte.c index 73cfe62fdad1..788d9d2b5536 100644 --- a/arch/x86/kvm/mmu/spte.c +++ b/arch/x86/kvm/mmu/spte.c @@ -250,14 +250,7 @@ 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), |