tcg: Use Error with alloc_code_gen_buffer

Report better error messages than just "could not allocate".
Let alloc_code_gen_buffer set ctx->code_gen_buffer_size
and ctx->code_gen_buffer, and simply return bool.

Reviewed-by: Joelle van Dyne <j@getutm.app>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

accel/tcg/translate-all.c

@@ -59,6 +59,7 @@
 #include "sysemu/cpus.h"
 #include "sysemu/cpu-timers.h"
 #include "sysemu/tcg.h"
+#include "qapi/error.h"
 
 /* #define DEBUG_TB_INVALIDATE */
 /* #define DEBUG_TB_FLUSH */
@@ -963,7 +964,7 @@ static void page_lock_pair(PageDesc **ret_p1, tb_page_addr_t phys1,
   (DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \
    ? DEFAULT_CODE_GEN_BUFFER_SIZE_1 : MAX_CODE_GEN_BUFFER_SIZE)
 
-static inline size_t size_code_gen_buffer(size_t tb_size)
+static size_t size_code_gen_buffer(size_t tb_size)
 {
     /* Size the buffer.  */
     if (tb_size == 0) {
@@ -1014,7 +1015,7 @@ static inline void *split_cross_256mb(void *buf1, size_t size1)
 static uint8_t static_code_gen_buffer[DEFAULT_CODE_GEN_BUFFER_SIZE]
     __attribute__((aligned(CODE_GEN_ALIGN)));
 
-static inline void *alloc_code_gen_buffer(void)
+static bool alloc_code_gen_buffer(size_t tb_size, Error **errp)
 {
     void *buf = static_code_gen_buffer;
     void *end = static_code_gen_buffer + sizeof(static_code_gen_buffer);
@@ -1027,9 +1028,8 @@ static inline void *alloc_code_gen_buffer(void)
     size = end - buf;
 
     /* Honor a command-line option limiting the size of the buffer.  */
-    if (size > tcg_ctx->code_gen_buffer_size) {
-        size = QEMU_ALIGN_DOWN(tcg_ctx->code_gen_buffer_size,
-                               qemu_real_host_page_size);
+    if (size > tb_size) {
+        size = QEMU_ALIGN_DOWN(tb_size, qemu_real_host_page_size);
     }
     tcg_ctx->code_gen_buffer_size = size;
 
@@ -1041,31 +1041,43 @@ static inline void *alloc_code_gen_buffer(void)
 #endif
 
     if (qemu_mprotect_rwx(buf, size)) {
-        abort();
+        error_setg_errno(errp, errno, "mprotect of jit buffer");
+        return false;
     }
     qemu_madvise(buf, size, QEMU_MADV_HUGEPAGE);
 
-    return buf;
+    tcg_ctx->code_gen_buffer = buf;
+    return true;
 }
 #elif defined(_WIN32)
-static inline void *alloc_code_gen_buffer(void)
+static bool alloc_code_gen_buffer(size_t size, Error **errp)
 {
-    size_t size = tcg_ctx->code_gen_buffer_size;
-    return VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
-                        PAGE_EXECUTE_READWRITE);
+    void *buf = VirtualAlloc(NULL, size, MEM_RESERVE | MEM_COMMIT,
+                             PAGE_EXECUTE_READWRITE);
+    if (buf == NULL) {
+        error_setg_win32(errp, GetLastError(),
+                         "allocate %zu bytes for jit buffer", size);
+        return false;
+    }
+
+    tcg_ctx->code_gen_buffer = buf;
+    tcg_ctx->code_gen_buffer_size = size;
+    return true;
 }
 #else
-static inline void *alloc_code_gen_buffer(void)
+static bool alloc_code_gen_buffer(size_t size, Error **errp)
 {
     int prot = PROT_WRITE | PROT_READ | PROT_EXEC;
     int flags = MAP_PRIVATE | MAP_ANONYMOUS;
-    size_t size = tcg_ctx->code_gen_buffer_size;
     void *buf;
 
     buf = mmap(NULL, size, prot, flags, -1, 0);
     if (buf == MAP_FAILED) {
-        return NULL;
+        error_setg_errno(errp, errno,
+                         "allocate %zu bytes for jit buffer", size);
+        return false;
     }
+    tcg_ctx->code_gen_buffer_size = size;
 
 #ifdef __mips__
     if (cross_256mb(buf, size)) {
@@ -1104,20 +1116,11 @@ static inline void *alloc_code_gen_buffer(void)
     /* Request large pages for the buffer.  */
     qemu_madvise(buf, size, QEMU_MADV_HUGEPAGE);
 
-    return buf;
+    tcg_ctx->code_gen_buffer = buf;
+    return true;
 }
 #endif /* USE_STATIC_CODE_GEN_BUFFER, WIN32, POSIX */
 
-static inline void code_gen_alloc(size_t tb_size)
-{
-    tcg_ctx->code_gen_buffer_size = size_code_gen_buffer(tb_size);
-    tcg_ctx->code_gen_buffer = alloc_code_gen_buffer();
-    if (tcg_ctx->code_gen_buffer == NULL) {
-        fprintf(stderr, "Could not allocate dynamic translator buffer\n");
-        exit(1);
-    }
-}
-
 static bool tb_cmp(const void *ap, const void *bp)
 {
     const TranslationBlock *a = ap;
@@ -1144,11 +1147,16 @@ static void tb_htable_init(void)
    size. */
 void tcg_exec_init(unsigned long tb_size)
 {
+    bool ok;
+
     tcg_allowed = true;
     cpu_gen_init();
     page_init();
     tb_htable_init();
-    code_gen_alloc(tb_size);
+
+    ok = alloc_code_gen_buffer(size_code_gen_buffer(tb_size), &error_fatal);
+    assert(ok);
+
 #if defined(CONFIG_SOFTMMU)
     /* There's no guest base to take into account, so go ahead and
        initialize the prologue now.  */