{
return ACCESS_ONCE(*sptep);
}
+
+static bool __check_direct_spte_mmio_pf(u64 spte)
+{
+ /* It is valid if the spte is zapped. */
+ return spte == 0ull;
+}
#else
union split_spte {
struct {
return spte.spte;
}
+
+static bool __check_direct_spte_mmio_pf(u64 spte)
+{
+ union split_spte sspte = (union split_spte)spte;
+ u32 high_mmio_mask = shadow_mmio_mask >> 32;
+
+ /* It is valid if the spte is zapped. */
+ if (spte == 0ull)
+ return true;
+
+ /* It is valid if the spte is being zapped. */
+ if (sspte.spte_low == 0ull &&
+ (sspte.spte_high & high_mmio_mask) == high_mmio_mask)
+ return true;
+
+ return false;
+}
#endif
static bool spte_has_volatile_bits(u64 spte)
return vcpu_match_mmio_gva(vcpu, addr);
}
+
+/*
+ * On direct hosts, the last spte is only allows two states
+ * for mmio page fault:
+ * - It is the mmio spte
+ * - It is zapped or it is being zapped.
+ *
+ * This function completely checks the spte when the last spte
+ * is not the mmio spte.
+ */
+static bool check_direct_spte_mmio_pf(u64 spte)
+{
+ return __check_direct_spte_mmio_pf(spte);
+}
+
static u64 walk_shadow_page_get_mmio_spte(struct kvm_vcpu *vcpu, u64 addr)
{
struct kvm_shadow_walk_iterator iterator;
return 1;
}
+ /*
+ * It's ok if the gva is remapped by other cpus on shadow guest,
+ * it's a BUG if the gfn is not a mmio page.
+ */
+ if (direct && !check_direct_spte_mmio_pf(spte))
+ return -1;
+
/*
* If the page table is zapped by other cpus, let CPU fault again on
* the address.