diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h
index 49384bb66a..43ddcf024c 100644
--- a/include/exec/cpu-all.h
+++ b/include/exec/cpu-all.h
@@ -328,7 +328,18 @@ CPUArchState *cpu_copy(CPUArchState *env);
      | CPU_INTERRUPT_TGT_EXT_3   \
      | CPU_INTERRUPT_TGT_EXT_4)
 
-#if !defined(CONFIG_USER_ONLY)
+#ifdef CONFIG_USER_ONLY
+
+/*
+ * Allow some level of source compatibility with softmmu.  We do not
+ * support any of the more exotic features, so only invalid pages may
+ * be signaled by probe_access_flags().
+ */
+#define TLB_INVALID_MASK    (1 << (TARGET_PAGE_BITS_MIN - 1))
+#define TLB_MMIO            0
+#define TLB_WATCHPOINT      0
+
+#else
 
 /*
  * Flags stored in the low bits of the TLB virtual address.
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index d656a1f05c..8792bea07a 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -362,6 +362,28 @@ static inline void *probe_read(CPUArchState *env, target_ulong addr, int size,
     return probe_access(env, addr, size, MMU_DATA_LOAD, mmu_idx, retaddr);
 }
 
+/**
+ * probe_access_flags:
+ * @env: CPUArchState
+ * @addr: guest virtual address to look up
+ * @access_type: read, write or execute permission
+ * @mmu_idx: MMU index to use for lookup
+ * @nonfault: suppress the fault
+ * @phost: return value for host address
+ * @retaddr: return address for unwinding
+ *
+ * Similar to probe_access, loosely returning the TLB_FLAGS_MASK for
+ * the page, and storing the host address for RAM in @phost.
+ *
+ * If @nonfault is set, do not raise an exception but return TLB_INVALID_MASK.
+ * Do not handle watchpoints, but include TLB_WATCHPOINT in the returned flags.
+ * Do handle clean pages, so exclude TLB_NOTDIRY from the returned flags.
+ * For simplicity, all "mmio-like" flags are folded to TLB_MMIO.
+ */
+int probe_access_flags(CPUArchState *env, target_ulong addr,
+                       MMUAccessType access_type, int mmu_idx,
+                       bool nonfault, void **phost, uintptr_t retaddr);
+
 #define CODE_GEN_ALIGN           16 /* must be >= of the size of a icache line */
 
 /* Estimated block size for TB allocation.  */
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index e3b5750c3b..bbe265ce28 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1231,86 +1231,16 @@ static void notdirty_write(CPUState *cpu, vaddr mem_vaddr, unsigned size,
     }
 }
 
-/*
- * Probe for whether the specified guest access is permitted. If it is not
- * permitted then an exception will be taken in the same way as if this
- * were a real access (and we will not return).
- * If the size is 0 or the page requires I/O access, returns NULL; otherwise,
- * returns the address of the host page similar to tlb_vaddr_to_host().
- */
-void *probe_access(CPUArchState *env, target_ulong addr, int size,
-                   MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
+static int probe_access_internal(CPUArchState *env, target_ulong addr,
+                                 int fault_size, MMUAccessType access_type,
+                                 int mmu_idx, bool nonfault,
+                                 void **phost, uintptr_t retaddr)
 {
     uintptr_t index = tlb_index(env, mmu_idx, addr);
     CPUTLBEntry *entry = tlb_entry(env, mmu_idx, addr);
-    target_ulong tlb_addr;
-    size_t elt_ofs;
-    int wp_access;
-
-    g_assert(-(addr | TARGET_PAGE_MASK) >= size);
-
-    switch (access_type) {
-    case MMU_DATA_LOAD:
-        elt_ofs = offsetof(CPUTLBEntry, addr_read);
-        wp_access = BP_MEM_READ;
-        break;
-    case MMU_DATA_STORE:
-        elt_ofs = offsetof(CPUTLBEntry, addr_write);
-        wp_access = BP_MEM_WRITE;
-        break;
-    case MMU_INST_FETCH:
-        elt_ofs = offsetof(CPUTLBEntry, addr_code);
-        wp_access = BP_MEM_READ;
-        break;
-    default:
-        g_assert_not_reached();
-    }
-    tlb_addr = tlb_read_ofs(entry, elt_ofs);
-
-    if (unlikely(!tlb_hit(tlb_addr, addr))) {
-        if (!victim_tlb_hit(env, mmu_idx, index, elt_ofs,
-                            addr & TARGET_PAGE_MASK)) {
-            tlb_fill(env_cpu(env), addr, size, access_type, mmu_idx, retaddr);
-            /* TLB resize via tlb_fill may have moved the entry. */
-            index = tlb_index(env, mmu_idx, addr);
-            entry = tlb_entry(env, mmu_idx, addr);
-        }
-        tlb_addr = tlb_read_ofs(entry, elt_ofs);
-    }
-
-    if (!size) {
-        return NULL;
-    }
-
-    if (unlikely(tlb_addr & TLB_FLAGS_MASK)) {
-        CPUIOTLBEntry *iotlbentry = &env_tlb(env)->d[mmu_idx].iotlb[index];
-
-        /* Reject I/O access, or other required slow-path.  */
-        if (tlb_addr & (TLB_MMIO | TLB_BSWAP | TLB_DISCARD_WRITE)) {
-            return NULL;
-        }
-
-        /* Handle watchpoints.  */
-        if (tlb_addr & TLB_WATCHPOINT) {
-            cpu_check_watchpoint(env_cpu(env), addr, size,
-                                 iotlbentry->attrs, wp_access, retaddr);
-        }
-
-        /* Handle clean RAM pages.  */
-        if (tlb_addr & TLB_NOTDIRTY) {
-            notdirty_write(env_cpu(env), addr, size, iotlbentry, retaddr);
-        }
-    }
-
-    return (void *)((uintptr_t)addr + entry->addend);
-}
-
-void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
-                        MMUAccessType access_type, int mmu_idx)
-{
-    CPUTLBEntry *entry = tlb_entry(env, mmu_idx, addr);
-    target_ulong tlb_addr, page;
+    target_ulong tlb_addr, page_addr;
     size_t elt_ofs;
+    int flags;
 
     switch (access_type) {
     case MMU_DATA_LOAD:
@@ -1325,20 +1255,19 @@ void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
     default:
         g_assert_not_reached();
     }
-
-    page = addr & TARGET_PAGE_MASK;
     tlb_addr = tlb_read_ofs(entry, elt_ofs);
 
-    if (!tlb_hit_page(tlb_addr, page)) {
-        uintptr_t index = tlb_index(env, mmu_idx, addr);
-
-        if (!victim_tlb_hit(env, mmu_idx, index, elt_ofs, page)) {
+    page_addr = addr & TARGET_PAGE_MASK;
+    if (!tlb_hit_page(tlb_addr, page_addr)) {
+        if (!victim_tlb_hit(env, mmu_idx, index, elt_ofs, page_addr)) {
             CPUState *cs = env_cpu(env);
             CPUClass *cc = CPU_GET_CLASS(cs);
 
-            if (!cc->tlb_fill(cs, addr, 0, access_type, mmu_idx, true, 0)) {
+            if (!cc->tlb_fill(cs, addr, fault_size, access_type,
+                              mmu_idx, nonfault, retaddr)) {
                 /* Non-faulting page table read failed.  */
-                return NULL;
+                *phost = NULL;
+                return TLB_INVALID_MASK;
             }
 
             /* TLB resize via tlb_fill may have moved the entry.  */
@@ -1346,15 +1275,89 @@ void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
         }
         tlb_addr = tlb_read_ofs(entry, elt_ofs);
     }
+    flags = tlb_addr & TLB_FLAGS_MASK;
 
-    if (tlb_addr & ~TARGET_PAGE_MASK) {
-        /* IO access */
+    /* Fold all "mmio-like" bits into TLB_MMIO.  This is not RAM.  */
+    if (unlikely(flags & ~(TLB_WATCHPOINT | TLB_NOTDIRTY))) {
+        *phost = NULL;
+        return TLB_MMIO;
+    }
+
+    /* Everything else is RAM. */
+    *phost = (void *)((uintptr_t)addr + entry->addend);
+    return flags;
+}
+
+int probe_access_flags(CPUArchState *env, target_ulong addr,
+                       MMUAccessType access_type, int mmu_idx,
+                       bool nonfault, void **phost, uintptr_t retaddr)
+{
+    int flags;
+
+    flags = probe_access_internal(env, addr, 0, access_type, mmu_idx,
+                                  nonfault, phost, retaddr);
+
+    /* Handle clean RAM pages.  */
+    if (unlikely(flags & TLB_NOTDIRTY)) {
+        uintptr_t index = tlb_index(env, mmu_idx, addr);
+        CPUIOTLBEntry *iotlbentry = &env_tlb(env)->d[mmu_idx].iotlb[index];
+
+        notdirty_write(env_cpu(env), addr, 1, iotlbentry, retaddr);
+        flags &= ~TLB_NOTDIRTY;
+    }
+
+    return flags;
+}
+
+void *probe_access(CPUArchState *env, target_ulong addr, int size,
+                   MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
+{
+    void *host;
+    int flags;
+
+    g_assert(-(addr | TARGET_PAGE_MASK) >= size);
+
+    flags = probe_access_internal(env, addr, size, access_type, mmu_idx,
+                                  false, &host, retaddr);
+
+    /* Per the interface, size == 0 merely faults the access. */
+    if (size == 0) {
         return NULL;
     }
 
-    return (void *)((uintptr_t)addr + entry->addend);
+    if (unlikely(flags & (TLB_NOTDIRTY | TLB_WATCHPOINT))) {
+        uintptr_t index = tlb_index(env, mmu_idx, addr);
+        CPUIOTLBEntry *iotlbentry = &env_tlb(env)->d[mmu_idx].iotlb[index];
+
+        /* Handle clean RAM pages.  */
+        if (flags & TLB_NOTDIRTY) {
+            notdirty_write(env_cpu(env), addr, 1, iotlbentry, retaddr);
+        }
+
+        /* Handle watchpoints.  */
+        if (flags & TLB_WATCHPOINT) {
+            int wp_access = (access_type == MMU_DATA_STORE
+                             ? BP_MEM_WRITE : BP_MEM_READ);
+            cpu_check_watchpoint(env_cpu(env), addr, size,
+                                 iotlbentry->attrs, wp_access, retaddr);
+        }
+    }
+
+    return host;
 }
 
+void *tlb_vaddr_to_host(CPUArchState *env, abi_ptr addr,
+                        MMUAccessType access_type, int mmu_idx)
+{
+    void *host;
+    int flags;
+
+    flags = probe_access_internal(env, addr, 0, access_type,
+                                  mmu_idx, true, &host, 0);
+
+    /* No combination of flags are expected by the caller. */
+    return flags ? NULL : host;
+}
 
 #ifdef CONFIG_PLUGIN
 /*
diff --git a/accel/tcg/user-exec.c b/accel/tcg/user-exec.c
index 4be78eb9b3..91c2dc46dd 100644
--- a/accel/tcg/user-exec.c
+++ b/accel/tcg/user-exec.c
@@ -190,13 +190,12 @@ static inline int handle_cpu_signal(uintptr_t pc, siginfo_t *info,
     g_assert_not_reached();
 }
 
-void *probe_access(CPUArchState *env, target_ulong addr, int size,
-                   MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
+int probe_access_flags(CPUArchState *env, target_ulong addr,
+                       MMUAccessType access_type, int mmu_idx,
+                       bool nonfault, void **phost, uintptr_t ra)
 {
     int flags;
 
-    g_assert(-(addr | TARGET_PAGE_MASK) >= size);
-
     switch (access_type) {
     case MMU_DATA_STORE:
         flags = PAGE_WRITE;
@@ -211,15 +210,30 @@ void *probe_access(CPUArchState *env, target_ulong addr, int size,
         g_assert_not_reached();
     }
 
-    if (!guest_addr_valid(addr) || page_check_range(addr, size, flags) < 0) {
-        CPUState *cpu = env_cpu(env);
-        CPUClass *cc = CPU_GET_CLASS(cpu);
-        cc->tlb_fill(cpu, addr, size, access_type, MMU_USER_IDX, false,
-                     retaddr);
-        g_assert_not_reached();
+    if (!guest_addr_valid(addr) || page_check_range(addr, 1, flags) < 0) {
+        if (nonfault) {
+            *phost = NULL;
+            return TLB_INVALID_MASK;
+        } else {
+            CPUState *cpu = env_cpu(env);
+            CPUClass *cc = CPU_GET_CLASS(cpu);
+            cc->tlb_fill(cpu, addr, 0, access_type, MMU_USER_IDX, false, ra);
+            g_assert_not_reached();
+        }
     }
 
-    return size ? g2h(addr) : NULL;
+    *phost = g2h(addr);
+    return 0;
+}
+
+void *probe_access(CPUArchState *env, target_ulong addr, int size,
+                   MMUAccessType access_type, int mmu_idx, uintptr_t retaddr)
+{
+    void *host;
+
+    g_assert(-(addr | TARGET_PAGE_MASK) >= size);
+    probe_access_flags(env, addr, access_type, mmu_idx, false, &host, retaddr);
+    return host;
 }
 
 #if defined(__i386__)
