[PATCH] kvm: x86: mmu: Drop the need_remote_flush() function

[Junaid Shahid <junaids@google.com>]

This is only used by kvm_mmu_pte_write(), which no longer actually
creates the new SPTE and instead just clears the old SPTE. So we
just need to check if the old SPTE was shadow-present instead of
calling need_remote_flush(). Hence we can drop this function. It was
incomplete anyway as it didn't take access-tracking into account.

This patch should not result in any functional change.

Signed-off-by: Junaid Shahid <junaids@google.com>
---
 arch/x86/kvm/mmu/mmu.c | 15 +--------------
 1 file changed, 1 insertion(+), 14 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f0d7193db455..39959841beee 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5333,19 +5333,6 @@ void kvm_mmu_free_obsolete_roots(struct kvm_vcpu *vcpu)
 	__kvm_mmu_free_obsolete_roots(vcpu->kvm, &vcpu->arch.guest_mmu);
 }
 
-static bool need_remote_flush(u64 old, u64 new)
-{
-	if (!is_shadow_present_pte(old))
-		return false;
-	if (!is_shadow_present_pte(new))
-		return true;
-	if ((old ^ new) & SPTE_BASE_ADDR_MASK)
-		return true;
-	old ^= shadow_nx_mask;
-	new ^= shadow_nx_mask;
-	return (old & ~new & SPTE_PERM_MASK) != 0;
-}
-
 static u64 mmu_pte_write_fetch_gpte(struct kvm_vcpu *vcpu, gpa_t *gpa,
 				    int *bytes)
 {
@@ -5491,7 +5478,7 @@ static void kvm_mmu_pte_write(struct kvm_vcpu *vcpu, gpa_t gpa,
 			mmu_page_zap_pte(vcpu->kvm, sp, spte, NULL);
 			if (gentry && sp->role.level != PG_LEVEL_4K)
 				++vcpu->kvm->stat.mmu_pde_zapped;
-			if (need_remote_flush(entry, *spte))
+			if (is_shadow_present_pte(entry))
 				flush = true;
 			++spte;
 		}

base-commit: a4850b5590d01bf3fb19fda3fc5d433f7382a974
-- 
2.37.1.359.gd136c6c3e2-goog