From 8f383ab9eaebb03f7bc4001f71cbf83bf12473cf Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Sat, 26 Feb 2022 00:15:26 +0000 Subject: [PATCH] KVM: x86/mmu: Batch TLB flushes from TDP MMU for MMU notifier change_spte Batch TLB flushes (with other MMUs) when handling ->change_spte() notifications in the TDP MMU. The MMU notifier path in question doesn't allow yielding and correcty flushes before dropping mmu_lock. Signed-off-by: Sean Christopherson Reviewed-by: Ben Gardon Message-Id: <20220226001546.360188-9-seanjc@google.com> Reviewed-by: Mingwei Zhang Signed-off-by: Paolo Bonzini --- arch/x86/kvm/mmu/tdp_mmu.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c index 53c7987198b7a..9b1d64468d95a 100644 --- a/arch/x86/kvm/mmu/tdp_mmu.c +++ b/arch/x86/kvm/mmu/tdp_mmu.c @@ -1226,13 +1226,12 @@ static bool set_spte_gfn(struct kvm *kvm, struct tdp_iter *iter, */ bool kvm_tdp_mmu_set_spte_gfn(struct kvm *kvm, struct kvm_gfn_range *range) { - bool flush = kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn); - - /* FIXME: return 'flush' instead of flushing here. */ - if (flush) - kvm_flush_remote_tlbs_with_address(kvm, range->start, 1); - - return false; + /* + * No need to handle the remote TLB flush under RCU protection, the + * target SPTE _must_ be a leaf SPTE, i.e. cannot result in freeing a + * shadow page. See the WARN on pfn_changed in __handle_changed_spte(). + */ + return kvm_tdp_mmu_handle_gfn(kvm, range, set_spte_gfn); } /* -- 2.39.5