summaryrefslogtreecommitdiff
path: root/arch/x86/kvm/mmu/spte.c
diff options
context:
space:
mode:
authorDavid Matlack <dmatlack@google.com>2022-01-26 02:05:15 +0300
committerPaolo Bonzini <pbonzini@redhat.com>2022-02-10 21:50:32 +0300
commit115111efd97c6c0e86f8b5904c6624fddcfe4f34 (patch)
treee56472f8d5376879f8961fabb462c482e4015747 /arch/x86/kvm/mmu/spte.c
parent932859a4e0b9fa12ba315e88e3d29f9d2f638916 (diff)
downloadlinux-115111efd97c6c0e86f8b5904c6624fddcfe4f34.tar.xz
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.c9
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),