[PATCH 5.11 120/152] KVM: x86/mmu: Ensure TLBs are flushed for TDP MMU during NX zapping

Greg Kroah-Hartman
2021-04-05T09:21:53Z

From: Sean Christopherson <seanjc@google.com>

[ Upstream commit 048f49809c526348775425420fb5b8e84fd9a133 ]

Honor the "flush needed" return from kvm_tdp_mmu_zap_gfn_range(), which
does the flush itself if and only if it yields (which it will never do in
this particular scenario), and otherwise expects the caller to do the
flush. If pages are zapped from the TDP MMU but not the legacy MMU, then
no flush will occur.

Fixes: 29cf0f5007a2 ("kvm: x86/mmu: NX largepage recovery for TDP MMU")
Cc: stable@vger.kernel.org
Cc: Ben Gardon <bgardon@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210325200119.1359384-3-seanjc@google.com>
Reviewed-by: Ben Gardon <bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
arch/x86/kvm/mmu/mmu.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index d9901836d7aa..8643c766415a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -5985,6 +5985,8 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
struct kvm_mmu_page *sp;
unsigned int ratio;
LIST_HEAD(invalid_list);
+ bool flush = false;
+ gfn_t gfn_end;
ulong to_zap;

rcu_idx = srcu_read_lock(&kvm->srcu);
@@ -6006,19 +6008,20 @@ static void kvm_recover_nx_lpages(struct kvm *kvm)
lpage_disallowed_link);
WARN_ON_ONCE(!sp->lpage_disallowed);
if (is_tdp_mmu_page(sp)) {
- kvm_tdp_mmu_zap_gfn_range(kvm, sp->gfn,
- sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level));
+ gfn_end = sp->gfn + KVM_PAGES_PER_HPAGE(sp->role.level);
+ flush = kvm_tdp_mmu_zap_gfn_range(kvm, sp->gfn, gfn_end);
} else {
kvm_mmu_prepare_zap_page(kvm, sp, &invalid_list);
WARN_ON_ONCE(sp->lpage_disallowed);
}

if (need_resched() || spin_needbreak(&kvm->mmu_lock)) {
- kvm_mmu_commit_zap_page(kvm, &invalid_list);
+ kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);
cond_resched_lock(&kvm->mmu_lock);
+ flush = false;
}
}
- kvm_mmu_commit_zap_page(kvm, &invalid_list);
+ kvm_mmu_remote_flush_or_zap(kvm, &invalid_list, flush);

spin_unlock(&kvm->mmu_lock);
srcu_read_unlock(&kvm->srcu, rcu_idx);
--
2.30.1