From: Sean Christopherson <seanjc@google.com>
Date: Fri, 22 Oct 2021 01:00:04 +0000 (-0700)
Subject: KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range()
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=e8be2a5ba86c7d6553a22d76fd21ac2cf665b165;p=linux.git

KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range()

Remove an unnecessary remote TLB flush in kvm_zap_gfn_range() now that
said function holds mmu_lock for write for its entire duration.  The
flush was added by the now-reverted commit to allow TDP MMU to flush while
holding mmu_lock for read, as the transition from write=>read required
dropping the lock and thus a pending flush needed to be serviced.

Fixes: 5a324c24b638 ("Revert "KVM: x86/mmu: Allow zap gfn range to operate under the mmu read lock"")
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Cc: Maciej S. Szmigiero <maciej.szmigiero@oracle.com>
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211022010005.1454978-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d9f1142b48923..71165a5d11635 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5743,9 +5743,6 @@ void kvm_zap_gfn_range(struct kvm *kvm, gfn_t gfn_start, gfn_t gfn_end)
 						end - 1, true, flush);
 			}
 		}
-		if (flush)
-			kvm_flush_remote_tlbs_with_address(kvm, gfn_start,
-							   gfn_end - gfn_start);
 	}
 
 	if (is_tdp_mmu_enabled(kvm)) {