diff options
Diffstat (limited to 'arch/x86/kvm/mmu.c')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 28 |
1 files changed, 21 insertions, 7 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index fbdca08b8d8c..ba2efcf2b86e 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -288,6 +288,21 @@ static void __set_spte(u64 *sptep, u64 spte) #endif } +static u64 __xchg_spte(u64 *sptep, u64 new_spte) +{ +#ifdef CONFIG_X86_64 + return xchg(sptep, new_spte); +#else + u64 old_spte; + + do { + old_spte = *sptep; + } while (cmpxchg64(sptep, old_spte, new_spte) != old_spte); + + return old_spte; +#endif +} + static int mmu_topup_memory_cache(struct kvm_mmu_memory_cache *cache, struct kmem_cache *base_cache, int min) { @@ -653,18 +668,17 @@ static void rmap_remove(struct kvm *kvm, u64 *spte) static void drop_spte(struct kvm *kvm, u64 *sptep, u64 new_spte) { pfn_t pfn; + u64 old_spte; - if (!is_rmap_spte(*sptep)) { - __set_spte(sptep, new_spte); + old_spte = __xchg_spte(sptep, new_spte); + if (!is_rmap_spte(old_spte)) return; - } - pfn = spte_to_pfn(*sptep); - if (*sptep & shadow_accessed_mask) + pfn = spte_to_pfn(old_spte); + if (old_spte & shadow_accessed_mask) kvm_set_pfn_accessed(pfn); - if (is_writable_pte(*sptep)) + if (is_writable_pte(old_spte)) kvm_set_pfn_dirty(pfn); rmap_remove(kvm, sptep); - __set_spte(sptep, new_spte); } static u64 *rmap_next(struct kvm *kvm, unsigned long *rmapp, u64 *spte) |
