[Qemu-devel] [PATCH v3 RESEND 0/3] nvram: at24c: fix problems related to "rom-size"

[Qemu-devel] [PATCH v3 RESEND 0/3] nvram: at24c: fix problems related to "rom-size"

[Wolfram Sang]

I used this driver as a template for a custom one. While hacking on my own, I
noticed some problems in this driver, too. This series fixes the first set of
them, related to the "rom-size" parameter. It fixes a segfault.

I think the first patch is clearly suitable for stable. I think the second one,
too, but not as clearly. The third one is a cleanup and not for stable. Still,
I am open for opinions about these thoughts.

Thanks,

   Wolfram

This is the same v3 as last time. Rebased to current master, but that produced
no diff.

Changes since v2:

* removed '\n' from error_report-strings
* made sure checkpatch is happy
* added tags from Philippe (thanks!)

Changes since v1:

* reordered patches according to significance for stable
* use AT24C_ROMSIZE_DEFAULT instead of magic value
* patch 3 doesn't improve the ERR macro anymore but replaces
  it completely with error_report().


Wolfram Sang (3):
  nvram: at24c: prevent segfault by checking "rom-size"
  nvram: at24c: use a sane default for "rom-size"
  nvram: at24c: use standard error reporting

 hw/nvram/eeprom_at24c.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

-- 
2.11.0

[Qemu-devel] [PATCH v3 RESEND 1/3] nvram: at24c: prevent segfault by checking "rom-size"

[Wolfram Sang]

The value for "rom-size" is used as a divisor, so it must not be 0 or it
will segfault. A size of 0 wouldn't make sense anyhow.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 hw/nvram/eeprom_at24c.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index 22183f5360..ccf78b25e4 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -121,6 +121,11 @@ int at24c_eeprom_init(I2CSlave *i2c)
 {
     EEPROMState *ee = AT24C_EE(i2c);
 
+    if (!ee->rsize) {
+        ERR("rom-size not allowed to be 0\n");
+        exit(1);
+    }
+
     ee->mem = g_malloc0(ee->rsize);
 
     if (ee->blk) {
-- 
2.11.0

[Qemu-devel] [PATCH v3 RESEND 2/3] nvram: at24c: use a sane default for "rom-size"

[Wolfram Sang]

0 as "rom-size" will lead to an error message. Let's use the size of a
small 24c01 which has 128 byte.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 hw/nvram/eeprom_at24c.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index ccf78b25e4..ab1ef686e2 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -28,6 +28,9 @@
 #define TYPE_AT24C_EE "at24c-eeprom"
 #define AT24C_EE(obj) OBJECT_CHECK(EEPROMState, (obj), TYPE_AT24C_EE)
 
+/* default is the size of a 24c01 EEPROM */
+#define AT24C_ROMSIZE_DEFAULT 128
+
 typedef struct EEPROMState {
     I2CSlave parent_obj;
 
@@ -171,7 +174,7 @@ void at24c_eeprom_reset(DeviceState *state)
 }
 
 static Property at24c_eeprom_props[] = {
-    DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
+    DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, AT24C_ROMSIZE_DEFAULT),
     DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
     DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
     DEFINE_PROP_END_OF_LIST()
-- 
2.11.0

[Qemu-devel] [PATCH v3 RESEND 3/3] nvram: at24c: use standard error reporting

[Wolfram Sang]

Replace the ERR macro with error_report() because fprintf is deprecated.
This also fixes the prefix printed out twice.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
 hw/nvram/eeprom_at24c.c | 17 ++++++-----------
 1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index ab1ef686e2..c35b29e503 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -13,6 +13,7 @@
 #include "hw/hw.h"
 #include "hw/i2c/i2c.h"
 #include "sysemu/block-backend.h"
+#include "qemu/error-report.h"
 
 /* #define DEBUG_AT24C */
 
@@ -22,9 +23,6 @@
 #define DPRINTK(FMT, ...) do {} while (0)
 #endif
 
-#define ERR(FMT, ...) fprintf(stderr, TYPE_AT24C_EE " : " FMT, \
-                            ## __VA_ARGS__)
-
 #define TYPE_AT24C_EE "at24c-eeprom"
 #define AT24C_EE(obj) OBJECT_CHECK(EEPROMState, (obj), TYPE_AT24C_EE)
 
@@ -63,8 +61,7 @@ int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
         if (ee->blk && ee->changed) {
             int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0);
             if (len != ee->rsize) {
-                ERR(TYPE_AT24C_EE
-                        " : failed to write backing file\n");
+                error_report("failed to write backing file");
             }
             DPRINTK("Wrote to backing file\n");
         }
@@ -125,7 +122,7 @@ int at24c_eeprom_init(I2CSlave *i2c)
     EEPROMState *ee = AT24C_EE(i2c);
 
     if (!ee->rsize) {
-        ERR("rom-size not allowed to be 0\n");
+        error_report("rom-size not allowed to be 0");
         exit(1);
     }
 
@@ -135,7 +132,7 @@ int at24c_eeprom_init(I2CSlave *i2c)
         int64_t len = blk_getlength(ee->blk);
 
         if (len != ee->rsize) {
-            ERR(TYPE_AT24C_EE " : Backing file size %lu != %u\n",
+            error_report("Backing file size %lu != %u",
                     (unsigned long)len, (unsigned)ee->rsize);
             exit(1);
         }
@@ -143,8 +140,7 @@ int at24c_eeprom_init(I2CSlave *i2c)
         if (blk_set_perm(ee->blk, BLK_PERM_CONSISTENT_READ | BLK_PERM_WRITE,
                          BLK_PERM_ALL, &error_fatal) < 0)
         {
-            ERR(TYPE_AT24C_EE
-                    " : Backing file incorrect permission\n");
+            error_report("Backing file incorrect permission");
             exit(1);
         }
     }
@@ -166,8 +162,7 @@ void at24c_eeprom_reset(DeviceState *state)
         int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize);
 
         if (len != ee->rsize) {
-            ERR(TYPE_AT24C_EE
-                    " : Failed initial sync with backing file\n");
+            error_report("Failed initial sync with backing file");
         }
         DPRINTK("Reset read backing file\n");
     }
-- 
2.11.0

Re: [Qemu-devel] [PATCH v3 RESEND 3/3] nvram: at24c: use standard error reporting

[Peter Maydell]

On 20 May 2018 at 08:00, Wolfram Sang <wsa+renesas@sang-engineering.com> wrote:
> Replace the ERR macro with error_report() because fprintf is deprecated.
> This also fixes the prefix printed out twice.
>
> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
>  hw/nvram/eeprom_at24c.c | 17 ++++++-----------
>  1 file changed, 6 insertions(+), 11 deletions(-)
> @@ -63,8 +61,7 @@ int at24c_eeprom_event(I2CSlave *s, enum i2c_event event)
>          if (ee->blk && ee->changed) {
>              int len = blk_pwrite(ee->blk, 0, ee->mem, ee->rsize, 0);
>              if (len != ee->rsize) {
> -                ERR(TYPE_AT24C_EE
> -                        " : failed to write backing file\n");
> +                error_report("failed to write backing file");
>              }
>              DPRINTK("Wrote to backing file\n");
>          }
> @@ -125,7 +122,7 @@ int at24c_eeprom_init(I2CSlave *i2c)
>      EEPROMState *ee = AT24C_EE(i2c);
>
>      if (!ee->rsize) {
> -        ERR("rom-size not allowed to be 0\n");
> +        error_report("rom-size not allowed to be 0");
>          exit(1);
>      }

Hi; if we're going to overhaul the error handling for this
device, I think we might as well do it properly, by moving
the code in this init function which can fail into a new
device realize method. The realize method takes an Error**
and can report failures that way rather than by causing
QEMU to exit.

> @@ -166,8 +162,7 @@ void at24c_eeprom_reset(DeviceState *state)
>          int len = blk_pread(ee->blk, 0, ee->mem, ee->rsize);
>
>          if (len != ee->rsize) {
> -            ERR(TYPE_AT24C_EE
> -                    " : Failed initial sync with backing file\n");
> +            error_report("Failed initial sync with backing file");
>          }
>          DPRINTK("Reset read backing file\n");
>      }

Errors in reset and event methods are a bit more awkward;
error_report is an improvement in those cases.

thanks
-- PMM