From: Hou Wenlong houwenlong.hwl@antgroup.com
commit 8d5678a76689acbf91245a3791fe853ab773090f upstream.
Before Commit c3e5e415bc1e6 ("KVM: X86: Change kvm_sync_page() to return true when remote flush is needed"), the return value of kvm_sync_page() indicates whether the page is synced, and kvm_mmu_get_page() would rebuild page when the sync fails. But now, kvm_sync_page() returns false when the page is synced and no tlb flushing is required, which leads to rebuild page in kvm_mmu_get_page(). So return the return value of mmu->sync_page() directly and check it in kvm_mmu_get_page(). If the sync fails, the page will be zapped and the invalid_list is not empty, so set flush as true is accepted in mmu_sync_children().
Cc: stable@vger.kernel.org Fixes: c3e5e415bc1e6 ("KVM: X86: Change kvm_sync_page() to return true when remote flush is needed") Signed-off-by: Hou Wenlong houwenlong.hwl@antgroup.com Acked-by: Lai Jiangshan jiangshanlai@gmail.com Message-Id: 0dabeeb789f57b0d793f85d073893063e692032d.1647336064.git.houwenlong.hwl@antgroup.com [mmu_sync_children should not flush if the page is zapped. - Paolo] Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/x86/kvm/mmu/mmu.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-)
--- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -1843,17 +1843,14 @@ static void kvm_mmu_commit_zap_page(stru &(_kvm)->arch.mmu_page_hash[kvm_page_table_hashfn(_gfn)]) \ if ((_sp)->gfn != (_gfn) || (_sp)->role.direct) {} else
-static bool kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, +static int kvm_sync_page(struct kvm_vcpu *vcpu, struct kvm_mmu_page *sp, struct list_head *invalid_list) { int ret = vcpu->arch.mmu->sync_page(vcpu, sp);
- if (ret < 0) { + if (ret < 0) kvm_mmu_prepare_zap_page(vcpu->kvm, sp, invalid_list); - return false; - } - - return !!ret; + return ret; }
static bool kvm_mmu_remote_flush_or_zap(struct kvm *kvm, @@ -1975,7 +1972,7 @@ static int mmu_sync_children(struct kvm_
for_each_sp(pages, sp, parents, i) { kvm_unlink_unsync_page(vcpu->kvm, sp); - flush |= kvm_sync_page(vcpu, sp, &invalid_list); + flush |= kvm_sync_page(vcpu, sp, &invalid_list) > 0; mmu_pages_clear_parents(&parents); } if (need_resched() || rwlock_needbreak(&vcpu->kvm->mmu_lock)) { @@ -2016,6 +2013,7 @@ static struct kvm_mmu_page *kvm_mmu_get_ struct hlist_head *sp_list; unsigned quadrant; struct kvm_mmu_page *sp; + int ret; int collisions = 0; LIST_HEAD(invalid_list);
@@ -2068,11 +2066,13 @@ static struct kvm_mmu_page *kvm_mmu_get_ * If the sync fails, the page is zapped. If so, break * in order to rebuild it. */ - if (!kvm_sync_page(vcpu, sp, &invalid_list)) + ret = kvm_sync_page(vcpu, sp, &invalid_list); + if (ret < 0) break;
WARN_ON(!list_empty(&invalid_list)); - kvm_flush_remote_tlbs(vcpu->kvm); + if (ret > 0) + kvm_flush_remote_tlbs(vcpu->kvm); }
__clear_sp_write_flooding_count(sp);