/* Bits which may be returned by set_spte() */
#define SET_SPTE_WRITE_PROTECTED_PT BIT(0)
#define SET_SPTE_NEED_REMOTE_TLB_FLUSH BIT(1)
+#define SET_SPTE_SPURIOUS BIT(2)
static int set_spte(struct kvm_vcpu *vcpu, u64 *sptep,
unsigned int pte_access, int level,
spte = mark_spte_for_access_track(spte);
set_pte:
- if (mmu_spte_update(sptep, spte))
+ if (*sptep == spte)
+ ret |= SET_SPTE_SPURIOUS;
+ else if (mmu_spte_update(sptep, spte))
ret |= SET_SPTE_NEED_REMOTE_TLB_FLUSH;
return ret;
}
if (unlikely(is_mmio_spte(*sptep)))
ret = RET_PF_EMULATE;
+ /*
+ * The fault is fully spurious if and only if the new SPTE and old SPTE
+ * are identical, and emulation is not required.
+ */
+ if ((set_spte_ret & SET_SPTE_SPURIOUS) && ret == RET_PF_FIXED) {
+ WARN_ON_ONCE(!was_rmapped);
+ return RET_PF_SPURIOUS;
+ }
+
pgprintk("%s: setting spte %llx\n", __func__, *sptep);
trace_kvm_mmu_set_spte(level, gfn, sptep);
if (!was_rmapped && is_large_pte(*sptep))
ret = mmu_set_spte(vcpu, it.sptep, ACC_ALL,
write, level, base_gfn, pfn, prefault,
map_writable);
+ if (ret == RET_PF_SPURIOUS)
+ return ret;
+
direct_pte_prefetch(vcpu, it.sptep);
++vcpu->stat.pf_fixed;
return ret;
ret = mmu_set_spte(vcpu, it.sptep, gw->pte_access, write_fault,
it.level, base_gfn, pfn, prefault, map_writable);
+ if (ret == RET_PF_SPURIOUS)
+ return ret;
+
FNAME(pte_prefetch)(vcpu, gw, it.sptep);
++vcpu->stat.pf_fixed;
return ret;