diff options
| author | Lai Jiangshan <jiangshan.ljs@antgroup.com> | 2022-12-12 17:01:06 +0800 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-12-29 15:33:13 -0500 |
| commit | c4a488685b84ad94f099aa6be066bf1488e4b73c (patch) | |
| tree | e16689f6042ccd98d05c886f3017785e70dff47f /arch/x86/kvm/mmu/mmu.c | |
| parent | 80edc49f6a7544fa0fac122e177ffb63af60651e (diff) | |
| download | lwn-c4a488685b84ad94f099aa6be066bf1488e4b73c.tar.gz lwn-c4a488685b84ad94f099aa6be066bf1488e4b73c.zip | |
kvm: x86/mmu: Warn on linking when sp->unsync_children
Since the commit 65855ed8b034 ("KVM: X86: Synchronize the shadow
pagetable before link it"), no sp would be linked with
sp->unsync_children = 1.
So make it WARN if it is the case.
Signed-off-by: Lai Jiangshan <jiangshan.ljs@antgroup.com>
Message-Id: <20221212090106.378206-1-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/mmu/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 4736d7849c60..26b32ae6b526 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -2355,7 +2355,16 @@ static void __link_shadow_page(struct kvm *kvm, mmu_page_add_parent_pte(cache, sp, sptep); - if (sp->unsync_children || sp->unsync) + /* + * The non-direct sub-pagetable must be updated before linking. For + * L1 sp, the pagetable is updated via kvm_sync_page() in + * kvm_mmu_find_shadow_page() without write-protecting the gfn, + * so sp->unsync can be true or false. For higher level non-direct + * sp, the pagetable is updated/synced via mmu_sync_children() in + * FNAME(fetch)(), so sp->unsync_children can only be false. + * WARN_ON_ONCE() if anything happens unexpectedly. + */ + if (WARN_ON_ONCE(sp->unsync_children) || sp->unsync) mark_unsync(sptep); } |