* [PATCH 0/3] nvram: at24c: fix problems related to "rom-size"
@ 2018-03-12 21:42 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, 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, mostly related to "rom-size". It fixes a segfault.
Wolfram Sang (3):
nvram: at24c: remove doubled prefix for ERR
nvram: at24c: prevent segfault by checking "rom-size"
nvram: at24c: use a sane default for "rom-size"
hw/nvram/eeprom_at24c.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
--
2.11.0
^ permalink raw reply [flat|nested] 16+ messages in thread
* [Qemu-devel] [PATCH 0/3] nvram: at24c: fix problems related to "rom-size"
@ 2018-03-12 21:42 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, 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, mostly related to "rom-size". It fixes a segfault.
Wolfram Sang (3):
nvram: at24c: remove doubled prefix for ERR
nvram: at24c: prevent segfault by checking "rom-size"
nvram: at24c: use a sane default for "rom-size"
hw/nvram/eeprom_at24c.c | 18 ++++++++++--------
1 file changed, 10 insertions(+), 8 deletions(-)
--
2.11.0
^ permalink raw reply [flat|nested] 16+ messages in thread
* [PATCH 1/3] nvram: at24c: remove doubled prefix for ERR
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
@ 2018-03-12 21:42 ` Wolfram Sang
-1 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, Wolfram Sang
The ERR macro already has the TYPE_AT24C_EE prefix, no need to repeat in
the error message.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
hw/nvram/eeprom_at24c.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index 5494351976..8507516b7e 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -60,8 +60,7 @@ 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");
+ ERR("failed to write backing file\n");
}
DPRINTK("Wrote to backing file\n");
}
@@ -127,7 +126,7 @@ 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",
+ ERR("Backing file size %lu != %u\n",
(unsigned long)len, (unsigned)ee->rsize);
exit(1);
}
@@ -135,8 +134,7 @@ 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");
+ ERR("Backing file incorrect permission\n");
exit(1);
}
}
@@ -158,8 +156,7 @@ 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");
+ ERR("Failed initial sync with backing file\n");
}
DPRINTK("Reset read backing file\n");
}
--
2.11.0
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [Qemu-devel] [PATCH 1/3] nvram: at24c: remove doubled prefix for ERR
@ 2018-03-12 21:42 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, Wolfram Sang
The ERR macro already has the TYPE_AT24C_EE prefix, no need to repeat in
the error message.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
hw/nvram/eeprom_at24c.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index 5494351976..8507516b7e 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -60,8 +60,7 @@ 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");
+ ERR("failed to write backing file\n");
}
DPRINTK("Wrote to backing file\n");
}
@@ -127,7 +126,7 @@ 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",
+ ERR("Backing file size %lu != %u\n",
(unsigned long)len, (unsigned)ee->rsize);
exit(1);
}
@@ -135,8 +134,7 @@ 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");
+ ERR("Backing file incorrect permission\n");
exit(1);
}
}
@@ -158,8 +156,7 @@ 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");
+ ERR("Failed initial sync with backing file\n");
}
DPRINTK("Reset read backing file\n");
}
--
2.11.0
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH 2/3] nvram: at24c: prevent segfault by checking "rom-size"
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
@ 2018-03-12 21:42 ` Wolfram Sang
-1 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, 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 as well.
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 8507516b7e..d82710e1df 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -120,6 +120,11 @@ 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
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [Qemu-devel] [PATCH 2/3] nvram: at24c: prevent segfault by checking "rom-size"
@ 2018-03-12 21:42 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, 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 as well.
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 8507516b7e..d82710e1df 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -120,6 +120,11 @@ 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
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
@ 2018-03-12 21:42 ` Wolfram Sang
-1 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, Wolfram Sang
0 as "rom-size" doesn't make much sense, let's use the smallest 24cXX
which has 128 byte.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
hw/nvram/eeprom_at24c.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index d82710e1df..de988f8d07 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -168,7 +168,7 @@ 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, 128),
DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
DEFINE_PROP_END_OF_LIST()
--
2.11.0
^ permalink raw reply related [flat|nested] 16+ messages in thread
* [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
@ 2018-03-12 21:42 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-12 21:42 UTC (permalink / raw)
To: qemu-devel; +Cc: Michael Davidsaver, linux-renesas-soc, Wolfram Sang
0 as "rom-size" doesn't make much sense, let's use the smallest 24cXX
which has 128 byte.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
hw/nvram/eeprom_at24c.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
index d82710e1df..de988f8d07 100644
--- a/hw/nvram/eeprom_at24c.c
+++ b/hw/nvram/eeprom_at24c.c
@@ -168,7 +168,7 @@ 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, 128),
DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
DEFINE_PROP_END_OF_LIST()
--
2.11.0
^ permalink raw reply related [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
(?)
@ 2018-03-13 10:53 ` Philippe Mathieu-Daudé
2018-03-13 20:16 ` Wolfram Sang
-1 siblings, 1 reply; 16+ messages in thread
From: Philippe Mathieu-Daudé @ 2018-03-13 10:53 UTC (permalink / raw)
To: Wolfram Sang, qemu-devel; +Cc: linux-renesas-soc, Michael Davidsaver
Hi Wolfram,
On 03/12/2018 10:42 PM, Wolfram Sang wrote:
> 0 as "rom-size" doesn't make much sense, let's use the smallest 24cXX
> which has 128 byte.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> hw/nvram/eeprom_at24c.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
> index d82710e1df..de988f8d07 100644
> --- a/hw/nvram/eeprom_at24c.c
> +++ b/hw/nvram/eeprom_at24c.c
> @@ -168,7 +168,7 @@ 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, 128),
This patch should goes before your 2/3 in your series.
Can you add a #define for this value? Such AT24C_ROMSIZE_MIN.
With a #define you can add:
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> DEFINE_PROP_BOOL("writable", EEPROMState, writable, true),
> DEFINE_PROP_DRIVE("drive", EEPROMState, blk),
> DEFINE_PROP_END_OF_LIST()
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 1/3] nvram: at24c: remove doubled prefix for ERR
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
(?)
@ 2018-03-13 10:57 ` Philippe Mathieu-Daudé
2018-03-13 20:10 ` Wolfram Sang
-1 siblings, 1 reply; 16+ messages in thread
From: Philippe Mathieu-Daudé @ 2018-03-13 10:57 UTC (permalink / raw)
To: Wolfram Sang, qemu-devel; +Cc: linux-renesas-soc, Michael Davidsaver
Hi Wolfram,
On 03/12/2018 10:42 PM, Wolfram Sang wrote:
> The ERR macro already has the TYPE_AT24C_EE prefix, no need to repeat in
> the error message.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> ---
> hw/nvram/eeprom_at24c.c | 11 ++++-------
> 1 file changed, 4 insertions(+), 7 deletions(-)
>
> diff --git a/hw/nvram/eeprom_at24c.c b/hw/nvram/eeprom_at24c.c
> index 5494351976..8507516b7e 100644
> --- a/hw/nvram/eeprom_at24c.c
> +++ b/hw/nvram/eeprom_at24c.c
> @@ -60,8 +60,7 @@ 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");
> + ERR("failed to write backing file\n");
printf/fprintf are deprecated, since you are modifying this file can you
use a newer API, "qemu/error-report.h" for example.
> }
> DPRINTK("Wrote to backing file\n");
DPRINTK() can be converted to tracepoint.
> }
> @@ -127,7 +126,7 @@ 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",
> + ERR("Backing file size %lu != %u\n",
> (unsigned long)len, (unsigned)ee->rsize);
> exit(1);
> }
> @@ -135,8 +134,7 @@ 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");
> + ERR("Backing file incorrect permission\n");
> exit(1);
> }
> }
> @@ -158,8 +156,7 @@ 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");
> + ERR("Failed initial sync with backing file\n");
> }
> DPRINTK("Reset read backing file\n");
> }
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 2/3] nvram: at24c: prevent segfault by checking "rom-size"
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
(?)
@ 2018-03-13 10:59 ` Philippe Mathieu-Daudé
-1 siblings, 0 replies; 16+ messages in thread
From: Philippe Mathieu-Daudé @ 2018-03-13 10:59 UTC (permalink / raw)
To: Wolfram Sang, qemu-devel; +Cc: linux-renesas-soc, Michael Davidsaver
On 03/12/2018 10:42 PM, Wolfram Sang wrote:
> 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 as well.
>
> 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 8507516b7e..d82710e1df 100644
> --- a/hw/nvram/eeprom_at24c.c
> +++ b/hw/nvram/eeprom_at24c.c
> @@ -120,6 +120,11 @@ int at24c_eeprom_init(I2CSlave *i2c)
> {
> EEPROMState *ee = AT24C_EE(i2c);
>
> + if (!ee->rsize) {
> + ERR("rom-size not allowed to be 0\n");
This might be more useful:
error_report("Minimum rom-size is %u", AT24C_ROMSIZE_MIN);
> + exit(1);
> + }
> +
> ee->mem = g_malloc0(ee->rsize);
>
> if (ee->blk) {
>
^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 1/3] nvram: at24c: remove doubled prefix for ERR
2018-03-13 10:57 ` Philippe Mathieu-Daudé
@ 2018-03-13 20:10 ` Wolfram Sang
0 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-13 20:10 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: Wolfram Sang, qemu-devel, linux-renesas-soc, Michael Davidsaver
[-- Attachment #1: Type: text/plain, Size: 510 bytes --]
> > - ERR(TYPE_AT24C_EE
> > - " : failed to write backing file\n");
> > + ERR("failed to write backing file\n");
>
> printf/fprintf are deprecated, since you are modifying this file can you
> use a newer API, "qemu/error-report.h" for example.
Sure, I'll have a look.
> > }
> > DPRINTK("Wrote to backing file\n");
>
> DPRINTK() can be converted to tracepoint.
I'd leave that for another incremental change.
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
2018-03-13 10:53 ` Philippe Mathieu-Daudé
@ 2018-03-13 20:16 ` Wolfram Sang
2018-03-18 23:50 ` Philippe Mathieu-Daudé
0 siblings, 1 reply; 16+ messages in thread
From: Wolfram Sang @ 2018-03-13 20:16 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: Wolfram Sang, qemu-devel, linux-renesas-soc, Michael Davidsaver
[-- Attachment #1: Type: text/plain, Size: 772 bytes --]
Hi Philippe,
> > static Property at24c_eeprom_props[] = {
> > - DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
> > + DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 128),
>
> This patch should goes before your 2/3 in your series.
I don't mind much, but why? My reasoning was "let's first fix the cause
and then the symptom"?
> Can you add a #define for this value? Such AT24C_ROMSIZE_MIN.
Can do, of course. But won't that give room for regressions because
people are already using it with lower values?
Ideally, we would have a "model" variable. The model type would define
the size of the memory. The "rom-size" variable could then be kept as is
(except for the 0 bugfix) or deprecated?
Thanks for the review,
Wolfram
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
2018-03-13 20:16 ` Wolfram Sang
@ 2018-03-18 23:50 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 16+ messages in thread
From: Philippe Mathieu-Daudé @ 2018-03-18 23:50 UTC (permalink / raw)
To: Wolfram Sang
Cc: Wolfram Sang, qemu-devel, linux-renesas-soc, Michael Davidsaver
[-- Attachment #1.1: Type: text/plain, Size: 1375 bytes --]
Hi Wolfram,
On 03/13/2018 09:16 PM, Wolfram Sang wrote:
> Hi Philippe,
>
>>> static Property at24c_eeprom_props[] = {
>>> - DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
>>> + DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 128),
>>
>> This patch should goes before your 2/3 in your series.
>
> I don't mind much, but why? My reasoning was "let's first fix the cause
> and then the symptom"?
The '0' case is worst than incorrect, it segfaults, so you are right :)
>
>> Can you add a #define for this value? Such AT24C_ROMSIZE_MIN.
>
> Can do, of course. But won't that give room for regressions because
> people are already using it with lower values?
Your patch already introduce the regression :)
I prefer self-explanatory #defines than magic value, but I see your
point, so if we can not decide a value, can you add a comment to explain
the magic value? I think the clearer is to add a #define with a comment.
>
> Ideally, we would have a "model" variable. The model type would define
> the size of the memory. The "rom-size" variable could then be kept as is
> (except for the 0 bugfix) or deprecated?
IMO there are too many AT24C eeproms to model, so the "rom-size"
variable is the easiest way. Your patch #2 is simple enough to avoid the
#DIV/0!
>
> Thanks for the review,
>
> Wolfram
>
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
@ 2018-03-18 23:50 ` Philippe Mathieu-Daudé
0 siblings, 0 replies; 16+ messages in thread
From: Philippe Mathieu-Daudé @ 2018-03-18 23:50 UTC (permalink / raw)
To: Wolfram Sang
Cc: Wolfram Sang, qemu-devel, linux-renesas-soc, Michael Davidsaver
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Hi Wolfram,
On 03/13/2018 09:16 PM, Wolfram Sang wrote:
> Hi Philippe,
>
>>> static Property at24c_eeprom_props[] = {
>>> - DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 0),
>>> + DEFINE_PROP_UINT32("rom-size", EEPROMState, rsize, 128),
>>
>> This patch should goes before your 2/3 in your series.
>
> I don't mind much, but why? My reasoning was "let's first fix the cause
> and then the symptom"?
The '0' case is worst than incorrect, it segfaults, so you are right :)
>
>> Can you add a #define for this value? Such AT24C_ROMSIZE_MIN.
>
> Can do, of course. But won't that give room for regressions because
> people are already using it with lower values?
Your patch already introduce the regression :)
I prefer self-explanatory #defines than magic value, but I see your
point, so if we can not decide a value, can you add a comment to explain
the magic value? I think the clearer is to add a #define with a comment.
>
> Ideally, we would have a "model" variable. The model type would define
> the size of the memory. The "rom-size" variable could then be kept as is
> (except for the 0 bugfix) or deprecated?
IMO there are too many AT24C eeproms to model, so the "rom-size"
variable is the easiest way. Your patch #2 is simple enough to avoid the
#DIV/0!
>
> Thanks for the review,
>
> Wolfram
>
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^ permalink raw reply [flat|nested] 16+ messages in thread
* Re: [Qemu-devel] [PATCH 3/3] nvram: at24c: use a sane default for "rom-size"
2018-03-18 23:50 ` Philippe Mathieu-Daudé
(?)
@ 2018-03-19 8:33 ` Wolfram Sang
-1 siblings, 0 replies; 16+ messages in thread
From: Wolfram Sang @ 2018-03-19 8:33 UTC (permalink / raw)
To: Philippe Mathieu-Daudé
Cc: Wolfram Sang, qemu-devel, linux-renesas-soc, Michael Davidsaver
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Hi Philippe,
> > I don't mind much, but why? My reasoning was "let's first fix the cause
> > and then the symptom"?
>
> The '0' case is worst than incorrect, it segfaults, so you are right :)
Ok, thanks.
> >> Can you add a #define for this value? Such AT24C_ROMSIZE_MIN.
> >
> > Can do, of course. But won't that give room for regressions because
> > people are already using it with lower values?
>
> Your patch already introduce the regression :)
Not really. The current default setting (0) segfaults. This is how I
discovered it. So, there can't be any active user of that.
> I prefer self-explanatory #defines than magic value, but I see your
> point, so if we can not decide a value, can you add a comment to explain
> the magic value? I think the clearer is to add a #define with a comment.
I wouldn't mind a macro AT24C_ROMSIZE_DEFAULT and a comment explaining
why we chose this value. This is totally fine with me.
It was just the MIN value I saw potential usage regressions with.
> IMO there are too many AT24C eeproms to model, so the "rom-size"
> variable is the easiest way. Your patch #2 is simple enough to avoid the
> #DIV/0!
Fine with me, too. I will update my series accordingly.
Thanks,
Wolfram
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^ permalink raw reply [flat|nested] 16+ messages in thread
end of thread, other threads:[~2018-03-19 8:33 UTC | newest]
Thread overview: 16+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-03-12 21:42 [PATCH 0/3] nvram: at24c: fix problems related to "rom-size" Wolfram Sang
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
2018-03-12 21:42 ` [PATCH 1/3] nvram: at24c: remove doubled prefix for ERR Wolfram Sang
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
2018-03-13 10:57 ` Philippe Mathieu-Daudé
2018-03-13 20:10 ` Wolfram Sang
2018-03-12 21:42 ` [PATCH 2/3] nvram: at24c: prevent segfault by checking "rom-size" Wolfram Sang
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
2018-03-13 10:59 ` Philippe Mathieu-Daudé
2018-03-12 21:42 ` [PATCH 3/3] nvram: at24c: use a sane default for "rom-size" Wolfram Sang
2018-03-12 21:42 ` [Qemu-devel] " Wolfram Sang
2018-03-13 10:53 ` Philippe Mathieu-Daudé
2018-03-13 20:16 ` Wolfram Sang
2018-03-18 23:50 ` Philippe Mathieu-Daudé
2018-03-18 23:50 ` Philippe Mathieu-Daudé
2018-03-19 8:33 ` Wolfram Sang
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