diff mbox series

[v3,25/28] tcg: Round the tb_size default from qemu_get_host_physmem

Message ID 20210502231844.1977630-26-richard.henderson@linaro.org
State Superseded
Headers show
Series tcg: Clean up code_gen_buffer allocation | expand

Commit Message

Richard Henderson May 2, 2021, 11:18 p.m. UTC 
If qemu_get_host_physmem returns an odd number of pages,
then physmem / 8 will not be a multiple of the page size.

The following was observed on a gitlab runner:

ERROR qtest-arm/boot-serial-test - Bail out!
ERROR:../util/osdep.c:80:qemu_mprotect__osdep: \
  assertion failed: (!(size & ~qemu_real_host_page_mask))

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

---
 tcg/region.c | 47 +++++++++++++++++++++--------------------------
 1 file changed, 21 insertions(+), 26 deletions(-)

-- 
2.25.1

Comments

Alex Bennée June 9, 2021, 10:36 a.m. UTC | #1 
Richard Henderson <richard.henderson@linaro.org> writes:

> If qemu_get_host_physmem returns an odd number of pages,

> then physmem / 8 will not be a multiple of the page size.

>

> The following was observed on a gitlab runner:

>

> ERROR qtest-arm/boot-serial-test - Bail out!

> ERROR:../util/osdep.c:80:qemu_mprotect__osdep: \

>   assertion failed: (!(size & ~qemu_real_host_page_mask))

>

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>


Reviewed-by: Alex Bennée <alex.bennee@linaro.org>


-- 
Alex Bennée
Luis Fernando Fujita Pires June 9, 2021, 2:59 p.m. UTC | #2 
From: Richard Henderson <richard.henderson@linaro.org>

> If qemu_get_host_physmem returns an odd number of pages, then physmem / 8

> will not be a multiple of the page size.

> 

> The following was observed on a gitlab runner:

> 

> ERROR qtest-arm/boot-serial-test - Bail out!

> ERROR:../util/osdep.c:80:qemu_mprotect__osdep: \

>   assertion failed: (!(size & ~qemu_real_host_page_mask))

> 

> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

> ---

>  tcg/region.c | 47 +++++++++++++++++++++--------------------------

>  1 file changed, 21 insertions(+), 26 deletions(-)


Reviewed-by: Luis Pires <luis.pires@eldorado.org.br>


--
Luis Pires
Instituto de Pesquisas ELDORADO
Aviso Legal - Disclaimer <https://www.eldorado.org.br/disclaimer.html>
diff mbox series

Patch

diff --git a/tcg/region.c b/tcg/region.c
index b3f0b9bda5..49764b40dc 100644
--- a/tcg/region.c
+++ b/tcg/region.c
@@ -469,26 +469,6 @@  static size_t tcg_n_regions(size_t tb_size, unsigned max_cpus)
   (DEFAULT_CODE_GEN_BUFFER_SIZE_1 < MAX_CODE_GEN_BUFFER_SIZE \
    ? DEFAULT_CODE_GEN_BUFFER_SIZE_1 : MAX_CODE_GEN_BUFFER_SIZE)
 
-static size_t size_code_gen_buffer(size_t tb_size)
-{
-    /* Size the buffer.  */
-    if (tb_size == 0) {
-        size_t phys_mem = qemu_get_host_physmem();
-        if (phys_mem == 0) {
-            tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
-        } else {
-            tb_size = MIN(DEFAULT_CODE_GEN_BUFFER_SIZE, phys_mem / 8);
-        }
-    }
-    if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {
-        tb_size = MIN_CODE_GEN_BUFFER_SIZE;
-    }
-    if (tb_size > MAX_CODE_GEN_BUFFER_SIZE) {
-        tb_size = MAX_CODE_GEN_BUFFER_SIZE;
-    }
-    return tb_size;
-}
-
 #ifdef __mips__
 /* In order to use J and JAL within the code_gen_buffer, we require
    that the buffer not cross a 256MB boundary.  */
@@ -836,13 +816,29 @@  static int alloc_code_gen_buffer(size_t size, int splitwx, Error **errp)
  */
 void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
 {
-    size_t page_size;
+    const size_t page_size = qemu_real_host_page_size;
     size_t region_size;
     size_t i;
     int have_prot;
 
-    have_prot = alloc_code_gen_buffer(size_code_gen_buffer(tb_size),
-                                      splitwx, &error_fatal);
+    /* Size the buffer.  */
+    if (tb_size == 0) {
+        size_t phys_mem = qemu_get_host_physmem();
+        if (phys_mem == 0) {
+            tb_size = DEFAULT_CODE_GEN_BUFFER_SIZE;
+        } else {
+            tb_size = QEMU_ALIGN_DOWN(phys_mem / 8, page_size);
+            tb_size = MIN(DEFAULT_CODE_GEN_BUFFER_SIZE, tb_size);
+        }
+    }
+    if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {
+        tb_size = MIN_CODE_GEN_BUFFER_SIZE;
+    }
+    if (tb_size > MAX_CODE_GEN_BUFFER_SIZE) {
+        tb_size = MAX_CODE_GEN_BUFFER_SIZE;
+    }
+
+    have_prot = alloc_code_gen_buffer(tb_size, splitwx, &error_fatal);
     assert(have_prot >= 0);
 
     /* Request large pages for the buffer and the splitwx.  */
@@ -857,9 +853,8 @@  void tcg_region_init(size_t tb_size, int splitwx, unsigned max_cpus)
      * As a result of this we might end up with a few extra pages at the end of
      * the buffer; we will assign those to the last region.
      */
-    region.n = tcg_n_regions(region.total_size, max_cpus);
-    page_size = qemu_real_host_page_size;
-    region_size = region.total_size / region.n;
+    region.n = tcg_n_regions(tb_size, max_cpus);
+    region_size = tb_size / region.n;
     region_size = QEMU_ALIGN_DOWN(region_size, page_size);
 
     /* A region must have at least 2 pages; one code, one guard */