accel/tcg: Return bool from page_check_range

Replace the 0/-1 result with true/false.
Invert the sense of the test of all callers.
Document the function.

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20230707204054.8792-25-richard.henderson@linaro.org>

accel/tcg/ldst_atomicity.c.inc

@@ -159,7 +159,7 @@ static uint64_t load_atomic8_or_exit(CPUArchState *env, uintptr_t ra, void *pv)
      * another process, because the fallback start_exclusive solution
      * provides no protection across processes.
      */
-    if (!page_check_range(h2g(pv), 8, PAGE_WRITE_ORG)) {
+    if (page_check_range(h2g(pv), 8, PAGE_WRITE_ORG)) {
         uint64_t *p = __builtin_assume_aligned(pv, 8);
         return *p;
     }
@@ -194,7 +194,7 @@ static Int128 load_atomic16_or_exit(CPUArchState *env, uintptr_t ra, void *pv)
      * another process, because the fallback start_exclusive solution
      * provides no protection across processes.
      */
-    if (!page_check_range(h2g(p), 16, PAGE_WRITE_ORG)) {
+    if (page_check_range(h2g(p), 16, PAGE_WRITE_ORG)) {
         return *p;
     }
 #endif

accel/tcg/user-exec.c

@@ -520,19 +520,19 @@ void page_set_flags(target_ulong start, target_ulong last, int flags)
     }
 }
 
-int page_check_range(target_ulong start, target_ulong len, int flags)
+bool page_check_range(target_ulong start, target_ulong len, int flags)
 {
     target_ulong last;
     int locked;  /* tri-state: =0: unlocked, +1: global, -1: local */
-    int ret;
+    bool ret;
 
     if (len == 0) {
-        return 0;  /* trivial length */
+        return true;  /* trivial length */
     }
 
     last = start + len - 1;
     if (last < start) {
-        return -1; /* wrap around */
+        return false; /* wrap around */
     }
 
     locked = have_mmap_lock();
@@ -551,33 +551,33 @@ int page_check_range(target_ulong start, target_ulong len, int flags)
                 p = pageflags_find(start, last);
             }
             if (!p) {
-                ret = -1; /* entire region invalid */
+                ret = false; /* entire region invalid */
                 break;
             }
         }
         if (start < p->itree.start) {
-            ret = -1; /* initial bytes invalid */
+            ret = false; /* initial bytes invalid */
             break;
         }
 
         missing = flags & ~p->flags;
         if (missing & ~PAGE_WRITE) {
-            ret = -1; /* page doesn't match */
+            ret = false; /* page doesn't match */
             break;
         }
         if (missing & PAGE_WRITE) {
             if (!(p->flags & PAGE_WRITE_ORG)) {
-                ret = -1; /* page not writable */
+                ret = false; /* page not writable */
                 break;
             }
             /* Asking about writable, but has been protected: undo. */
             if (!page_unprotect(start, 0)) {
-                ret = -1;
+                ret = false;
                 break;
             }
             /* TODO: page_unprotect should take a range, not a single page. */
             if (last - start < TARGET_PAGE_SIZE) {
-                ret = 0; /* ok */
+                ret = true; /* ok */
                 break;
             }
             start += TARGET_PAGE_SIZE;
@@ -585,7 +585,7 @@ int page_check_range(target_ulong start, target_ulong len, int flags)
         }
 
         if (last <= p->itree.last) {
-            ret = 0; /* ok */
+            ret = true; /* ok */
             break;
         }
         start = p->itree.last + 1;

bsd-user/qemu.h

@@ -267,7 +267,7 @@ abi_long do_freebsd_sysarch(void *cpu_env, abi_long arg1, abi_long arg2);
 
 static inline bool access_ok(int type, abi_ulong addr, abi_ulong size)
 {
-    return page_check_range((target_ulong)addr, size, type) == 0;
+    return page_check_range((target_ulong)addr, size, type);
 }
 
 /*

include/exec/cpu-all.h

@@ -222,7 +222,18 @@ int walk_memory_regions(void *, walk_memory_regions_fn);
 int page_get_flags(target_ulong address);
 void page_set_flags(target_ulong start, target_ulong last, int flags);
 void page_reset_target_data(target_ulong start, target_ulong last);
-int page_check_range(target_ulong start, target_ulong len, int flags);
+
+/**
+ * page_check_range
+ * @start: first byte of range
+ * @len: length of range
+ * @flags: flags required for each page
+ *
+ * Return true if every page in [@start, @start+@len) has @flags set.
+ * Return false if any page is unmapped.  Thus testing flags == 0 is
+ * equivalent to testing for flags == PAGE_VALID.
+ */
+bool page_check_range(target_ulong start, target_ulong last, int flags);
 
 /**
  * page_check_range_empty:

linux-user/qemu.h

@@ -182,7 +182,7 @@ static inline bool access_ok_untagged(int type, abi_ulong addr, abi_ulong size)
         : !guest_range_valid_untagged(addr, size)) {
         return false;
     }
-    return page_check_range((target_ulong)addr, size, type) == 0;
+    return page_check_range((target_ulong)addr, size, type);
 }
 
 static inline bool access_ok(CPUState *cpu, int type,

linux-user/syscall.c

@@ -8122,7 +8122,7 @@ static int open_self_maps_1(CPUArchState *cpu_env, int fd, bool smaps)
             max = h2g_valid(max - 1) ?
                 max : (uintptr_t) g2h_untagged(GUEST_ADDR_MAX) + 1;
 
-            if (page_check_range(h2g(min), max - min, flags) == -1) {
+            if (!page_check_range(h2g(min), max - min, flags)) {
                 continue;
             }
 

target/hppa/op_helper.c

@@ -168,7 +168,7 @@ target_ureg HELPER(probe)(CPUHPPAState *env, target_ulong addr,
                           uint32_t level, uint32_t want)
 {
 #ifdef CONFIG_USER_ONLY
-    return (page_check_range(addr, 1, want) == 0) ? 1 : 0;
+    return page_check_range(addr, 1, want);
 #else
     int prot, excp;
     hwaddr phys;

target/riscv/vector_helper.c

@@ -583,7 +583,7 @@ vext_ldff(void *vd, void *v0, target_ulong base,
                                          cpu_mmu_index(env, false));
                 if (host) {
 #ifdef CONFIG_USER_ONLY
-                    if (page_check_range(addr, offset, PAGE_READ) < 0) {
+                    if (page_check_range(addr, offset, PAGE_READ)) {
                         vl = i;
                         goto ProbeSuccess;
                     }

target/sparc/ldst_helper.c

@@ -1191,7 +1191,7 @@ uint64_t helper_ld_asi(CPUSPARCState *env, target_ulong addr,
     case ASI_PNFL: /* Primary no-fault LE */
     case ASI_SNF:  /* Secondary no-fault */
     case ASI_SNFL: /* Secondary no-fault LE */
-        if (page_check_range(addr, size, PAGE_READ) == -1) {
+        if (!page_check_range(addr, size, PAGE_READ)) {
             ret = 0;
             break;
         }