From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Maxim Levitsky <mlevitsk@redhat.com>,
"Maciej S . Szmigiero" <maciej.szmigiero@oracle.com>,
Ben Gardon <bgardon@google.com>
Subject: [PATCH 2/3] KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range()
Date: Thu, 21 Oct 2021 18:00:04 -0700 [thread overview]
Message-ID: <20211022010005.1454978-3-seanjc@google.com> (raw)
In-Reply-To: <20211022010005.1454978-1-seanjc@google.com>
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>
---
arch/x86/kvm/mmu/mmu.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index f82b192bba0b..e8b8a665e2e9 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5700,9 +5700,6 @@ 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)) {
--
2.33.0.1079.g6e70778dc9-goog
next prev parent reply other threads:[~2021-10-22 1:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-22 1:00 [PATCH 0/3] KVM: x86/mmu: Clean up kvm_zap_gfn_range() Sean Christopherson
2021-10-22 1:00 ` [PATCH 1/3] KVM: x86/mmu: Drop a redundant, broken remote TLB flush Sean Christopherson
2021-10-22 2:58 ` Lai Jiangshan
2021-10-22 3:03 ` Lai Jiangshan
2021-10-22 15:39 ` Maxim Levitsky
2021-10-22 1:00 ` Sean Christopherson [this message]
2021-10-22 11:44 ` [PATCH 2/3] KVM: x86/mmu: Drop a redundant remote TLB flush in kvm_zap_gfn_range() Maciej S. Szmigiero
2021-10-25 15:39 ` Sean Christopherson
2021-10-26 14:22 ` Maciej S. Szmigiero
2021-10-22 1:00 ` [PATCH 3/3] KVM: x86/mmu: Extract zapping of rmaps for gfn range to separate helper Sean Christopherson
2021-10-22 15:11 ` [PATCH 0/3] KVM: x86/mmu: Clean up kvm_zap_gfn_range() Paolo Bonzini
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