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KVM: x86/mmu: Set shadow_dirty_mask for EPT even if A/D bits disabled

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Set shadow_dirty_mask to the architectural EPT Dirty bit value even if
A/D bits are disabled at the module level, i.e. even if KVM will never
enable A/D bits in hardware.  Doing so provides consistent behavior for
Accessed and Dirty bits, i.e. doesn't leave KVM in a state where it sets
shadow_accessed_mask but not shadow_dirty_mask.

Functionally, this should be one big nop, as consumption of
shadow_dirty_mask is always guarded by a check that hardware A/D bits are
enabled.

Link: https://lore.kernel.org/r/20241011021051.1557902-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2024-10-10 19:10:43 -07:00
parent 3835819fb1
commit 53510b9125
1 changed files with 1 additions and 1 deletions
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2
arch/x86/kvm/mmu/spte.c
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@@ -420,7 +420,7 @@ void kvm_mmu_set_ept_masks(bool has_ad_bits, bool has_exec_only)
shadow_user_mask = VMX_EPT_READABLE_MASK;
shadow_accessed_mask = VMX_EPT_ACCESS_BIT;
shadow_dirty_mask = has_ad_bits ? VMX_EPT_DIRTY_BIT : 0ull;
shadow_dirty_mask = VMX_EPT_DIRTY_BIT;
shadow_nx_mask = 0ull;
shadow_x_mask = VMX_EPT_EXECUTABLE_MASK;
/* VMX_EPT_SUPPRESS_VE_BIT is needed for W or X violation. */