KVM: x86/mmu: Fix TLB flush range when handling disconnected pt

When recursively clearing out disconnected pts, the range based TLB
flush in handle_removed_tdp_mmu_page uses the wrong starting GFN,
resulting in the flush mostly missing the affected range. Fix this by
using base_gfn for the flush.

In response to feedback from David Matlack on the RFC version of this
patch, also move a few definitions into the for loop in the function to
prevent unintended references to them in the future.

Fixes: a066e61f13 ("KVM: x86/mmu: Factor out handling of removed page tables")
CC: stable@vger.kernel.org
Signed-off-by: Ben Gardon <bgardon@google.com>
Message-Id: <20211115211704.2621644-1-bgardon@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Ben Gardon 2021-11-15 13:17:04 -08:00 committed by Paolo Bonzini
parent 2845e7353b
commit 574c3c55e9

View File

@ -317,9 +317,6 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt)); struct kvm_mmu_page *sp = sptep_to_sp(rcu_dereference(pt));
int level = sp->role.level; int level = sp->role.level;
gfn_t base_gfn = sp->gfn; gfn_t base_gfn = sp->gfn;
u64 old_child_spte;
u64 *sptep;
gfn_t gfn;
int i; int i;
trace_kvm_mmu_prepare_zap_page(sp); trace_kvm_mmu_prepare_zap_page(sp);
@ -327,8 +324,9 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
tdp_mmu_unlink_page(kvm, sp, shared); tdp_mmu_unlink_page(kvm, sp, shared);
for (i = 0; i < PT64_ENT_PER_PAGE; i++) { for (i = 0; i < PT64_ENT_PER_PAGE; i++) {
sptep = rcu_dereference(pt) + i; u64 *sptep = rcu_dereference(pt) + i;
gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level); gfn_t gfn = base_gfn + i * KVM_PAGES_PER_HPAGE(level);
u64 old_child_spte;
if (shared) { if (shared) {
/* /*
@ -374,7 +372,7 @@ static void handle_removed_tdp_mmu_page(struct kvm *kvm, tdp_ptep_t pt,
shared); shared);
} }
kvm_flush_remote_tlbs_with_address(kvm, gfn, kvm_flush_remote_tlbs_with_address(kvm, base_gfn,
KVM_PAGES_PER_HPAGE(level + 1)); KVM_PAGES_PER_HPAGE(level + 1));
call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback); call_rcu(&sp->rcu_head, tdp_mmu_free_sp_rcu_callback);