diff options
author | Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp> | 2015-11-20 17:45:44 +0900 |
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committer | Paolo Bonzini <pbonzini@redhat.com> | 2015-11-25 17:26:47 +0100 |
commit | 77fbbbd2f09fae486190bb2bd7142647dc2a6e8b (patch) | |
tree | 540f568e2226e1cfe370c3ed7cf0bd4544b03c22 /arch/x86/kvm | |
parent | afd28fe1c901429eba8957f54bdb4a13cc15ae44 (diff) | |
download | linux-77fbbbd2f09fae486190bb2bd7142647dc2a6e8b.tar.bz2 |
KVM: x86: MMU: Consolidate BUG_ON checks for reverse-mapped sptes
At some call sites of rmap_get_first() and rmap_get_next(), BUG_ON is
placed right after the call to detect unrelated sptes which must not be
found in the reverse-mapping list.
Move this check in rmap_get_first/next() so that all call sites, not
just the users of the for_each_rmap_spte() macro, will be checked the
same way.
One thing to keep in mind is that kvm_mmu_unlink_parents() also uses
rmap_get_first() to handle parent sptes. The change will not break it
because parent sptes are present, at least until drop_parent_pte()
actually unlinks them, and not mmio-sptes.
Signed-off-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r-- | arch/x86/kvm/mmu.c | 26 |
1 files changed, 17 insertions, 9 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 3104748eeb48..5b249d4f4da1 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -1098,17 +1098,23 @@ struct rmap_iterator { static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head, struct rmap_iterator *iter) { + u64 *sptep; + if (!rmap_head->val) return NULL; if (!(rmap_head->val & 1)) { iter->desc = NULL; - return (u64 *)rmap_head->val; + sptep = (u64 *)rmap_head->val; + goto out; } iter->desc = (struct pte_list_desc *)(rmap_head->val & ~1ul); iter->pos = 0; - return iter->desc->sptes[iter->pos]; + sptep = iter->desc->sptes[iter->pos]; +out: + BUG_ON(!is_shadow_present_pte(*sptep)); + return sptep; } /* @@ -1118,14 +1124,14 @@ static u64 *rmap_get_first(struct kvm_rmap_head *rmap_head, */ static u64 *rmap_get_next(struct rmap_iterator *iter) { + u64 *sptep; + if (iter->desc) { if (iter->pos < PTE_LIST_EXT - 1) { - u64 *sptep; - ++iter->pos; sptep = iter->desc->sptes[iter->pos]; if (sptep) - return sptep; + goto out; } iter->desc = iter->desc->more; @@ -1133,17 +1139,20 @@ static u64 *rmap_get_next(struct rmap_iterator *iter) if (iter->desc) { iter->pos = 0; /* desc->sptes[0] cannot be NULL */ - return iter->desc->sptes[iter->pos]; + sptep = iter->desc->sptes[iter->pos]; + goto out; } } return NULL; +out: + BUG_ON(!is_shadow_present_pte(*sptep)); + return sptep; } #define for_each_rmap_spte(_rmap_head_, _iter_, _spte_) \ for (_spte_ = rmap_get_first(_rmap_head_, _iter_); \ - _spte_ && ({BUG_ON(!is_shadow_present_pte(*_spte_)); 1;}); \ - _spte_ = rmap_get_next(_iter_)) + _spte_; _spte_ = rmap_get_next(_iter_)) static void drop_spte(struct kvm *kvm, u64 *sptep) { @@ -1358,7 +1367,6 @@ static bool kvm_zap_rmapp(struct kvm *kvm, struct kvm_rmap_head *rmap_head) bool flush = false; while ((sptep = rmap_get_first(rmap_head, &iter))) { - BUG_ON(!(*sptep & PT_PRESENT_MASK)); rmap_printk("%s: spte %p %llx.\n", __func__, sptep, *sptep); drop_spte(kvm, sptep); |