[Qemu-devel] [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Qemu-devel] [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Jes.Sorensen]

From: Jes Sorensen <Jes.Sorensen@redhat.com>

There is no need to check for dest < 0 or vector >= 0 as both are
uint16_t.

This should fix problems with broken build with aggressive compiler
flags. Reported by Xudong Hao <xudong.hao@intel.com>

Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
---
 hw/ivshmem.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/ivshmem.c b/hw/ivshmem.c
index bbb5cba..afebbc3 100644
--- a/hw/ivshmem.c
+++ b/hw/ivshmem.c
@@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque, target_phys_addr_t addr,
 
         case DOORBELL:
             /* check that dest VM ID is reasonable */
-            if ((dest < 0) || (dest > s->max_peer)) {
+            if (dest > s->max_peer) {
                 IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
                 break;
             }
 
             /* check doorbell range */
-            if ((vector >= 0) && (vector < s->peers[dest].nb_eventfds)) {
+            if (vector < s->peers[dest].nb_eventfds) {
                 IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on vector %d\n",
                                                     write_one, dest, vector);
                 if (write(s->peers[dest].eventfds[vector],
-- 
1.7.2.2

[Qemu-devel] RE: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Hao, Xudong]

Jes.Sorensen@redhat.com wrote:
> From: Jes Sorensen <Jes.Sorensen@redhat.com>
> 
> There is no need to check for dest < 0 or vector >= 0 as both are
> uint16_t.
> 
> This should fix problems with broken build with aggressive compiler
> flags. Reported by Xudong Hao <xudong.hao@intel.com>
> 
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  hw/ivshmem.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index bbb5cba..afebbc3 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque,
> target_phys_addr_t addr, 
> 
>          case DOORBELL:
>              /* check that dest VM ID is reasonable */
> -            if ((dest < 0) || (dest > s->max_peer)) {
> +            if (dest > s->max_peer) {
>                  IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n",
>                  dest); break;
>              }
> 
>              /* check doorbell range */
> -            if ((vector >= 0) && (vector <
> s->peers[dest].nb_eventfds)) { +            if (vector <
>                  s->peers[dest].nb_eventfds) {
>                                                     
>                  IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on
> vector %d\n", write_one, dest, vector); if
> (write(s->peers[dest].eventfds[vector],  

This patch works for me.


Thanks,
Xudong

[Qemu-devel] RE: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Hao, Xudong]

Hao, Xudong wrote:
> Jes.Sorensen@redhat.com wrote:
>> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>> 
>> There is no need to check for dest < 0 or vector >= 0 as both are
>> uint16_t. 
>> 
>> This should fix problems with broken build with aggressive compiler
>> flags. Reported by Xudong Hao <xudong.hao@intel.com>
>> 
>> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> ---
>>  hw/ivshmem.c |    4 ++--
>>  1 files changed, 2 insertions(+), 2 deletions(-)
>> 
>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
>> index bbb5cba..afebbc3 100644
>> --- a/hw/ivshmem.c
>> +++ b/hw/ivshmem.c
>> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque,
>> target_phys_addr_t addr, 
>> 
>>          case DOORBELL:
>>              /* check that dest VM ID is reasonable */
>> -            if ((dest < 0) || (dest > s->max_peer)) {
>> +            if (dest > s->max_peer) {
>>                  IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n",
>>                  dest); break;
>>              }
>> 
>>              /* check doorbell range */
>> -            if ((vector >= 0) && (vector <
>> s->peers[dest].nb_eventfds)) { +            if (vector <
>>                  s->peers[dest].nb_eventfds) {
>> 
>>                  IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on
>> vector %d\n", write_one, dest, vector); if
>> (write(s->peers[dest].eventfds[vector],
> 
> This patch works for me.
> 

Jes, correct result is this patch works for me on x86_64 system. However, in i386 system, there is another bug:

...
  CC    x86_64-softmmu/ivshmem.o
  CC    x86_64-softmmu/fpu/softfloat-native.o
  CC    x86_64-softmmu/op_helper.o
cc1: warnings being treated as errors
/home/build/gitrepo/qemu/hw/ivshmem.c: In function 'check_shm_size.
/home/build/gitrepo/qemu/hw/ivshmem.c:357: warning: format '%ld' expects type 'long int', but argt 5 has type '__off64_t
make[1]: *** [ivshmem.o] Error 1
make[1]: *** Waiting for unfinished jobs....
make: *** [subdir-x86_64-softmmu] Error 2


Thanks,
Xudong

[Qemu-devel] Re: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Cam Macdonell]

On Mon, Aug 30, 2010 at 4:31 AM,  <Jes.Sorensen@redhat.com> wrote:
> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>
> There is no need to check for dest < 0 or vector >= 0 as both are
> uint16_t.
>
> This should fix problems with broken build with aggressive compiler
> flags. Reported by Xudong Hao <xudong.hao@intel.com>
>
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  hw/ivshmem.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index bbb5cba..afebbc3 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque, target_phys_addr_t addr,
>
>         case DOORBELL:
>             /* check that dest VM ID is reasonable */
> -            if ((dest < 0) || (dest > s->max_peer)) {
> +            if (dest > s->max_peer) {
>                 IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
>                 break;
>             }
>
>             /* check doorbell range */
> -            if ((vector >= 0) && (vector < s->peers[dest].nb_eventfds)) {
> +            if (vector < s->peers[dest].nb_eventfds) {
>                 IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on vector %d\n",
>                                                     write_one, dest, vector);
>                 if (write(s->peers[dest].eventfds[vector],
> --
> 1.7.2.2
>
>

Acked-by: Cam Macdonell <cam@cs.ualberta.ca>

I sent a patch yesterday that addressed it, but it is probably better
to remove the tests that switched to signed 16-bit ints.

Anthony, please apply this one.

Cam

[Qemu-devel] Re: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Cam Macdonell]

On Tue, Aug 31, 2010 at 6:51 PM, Hao, Xudong <xudong.hao@intel.com> wrote:
> Hao, Xudong wrote:
>> Jes.Sorensen@redhat.com wrote:
>>> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>>>
>>> There is no need to check for dest < 0 or vector >= 0 as both are
>>> uint16_t.
>>>
>>> This should fix problems with broken build with aggressive compiler
>>> flags. Reported by Xudong Hao <xudong.hao@intel.com>
>>>
>>> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> ---
>>>  hw/ivshmem.c |    4 ++--
>>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
>>> index bbb5cba..afebbc3 100644
>>> --- a/hw/ivshmem.c
>>> +++ b/hw/ivshmem.c
>>> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque,
>>> target_phys_addr_t addr,
>>>
>>>          case DOORBELL:
>>>              /* check that dest VM ID is reasonable */
>>> -            if ((dest < 0) || (dest > s->max_peer)) {
>>> +            if (dest > s->max_peer) {
>>>                  IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n",
>>>                  dest); break;
>>>              }
>>>
>>>              /* check doorbell range */
>>> -            if ((vector >= 0) && (vector <
>>> s->peers[dest].nb_eventfds)) { +            if (vector <
>>>                  s->peers[dest].nb_eventfds) {
>>>
>>>                  IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on
>>> vector %d\n", write_one, dest, vector); if
>>> (write(s->peers[dest].eventfds[vector],
>>
>> This patch works for me.
>>
>
> Jes, correct result is this patch works for me on x86_64 system. However, in i386 system, there is another bug:
>
> ...
>  CC    x86_64-softmmu/ivshmem.o
>  CC    x86_64-softmmu/fpu/softfloat-native.o
>  CC    x86_64-softmmu/op_helper.o
> cc1: warnings being treated as errors
> /home/build/gitrepo/qemu/hw/ivshmem.c: In function 'check_shm_size.
> /home/build/gitrepo/qemu/hw/ivshmem.c:357: warning: format '%ld' expects type 'long int', but argt 5 has type '__off64_t
> make[1]: *** [ivshmem.o] Error 1
> make[1]: *** Waiting for unfinished jobs....
> make: *** [subdir-x86_64-softmmu] Error 2

Hmm, that was causing problems on 32-bit systems, not 64-bit.  Is this
with gcc 4.1.2?  Please the try the following patch from Avi that
should add the necessary cast.

http://www.mail-archive.com/qemu-devel@nongnu.org/msg40715.html

Cam

[Qemu-devel] Re: [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Cam Macdonell]

On Tue, Aug 31, 2010 at 9:56 PM, Cam Macdonell <cam@cs.ualberta.ca> wrote:
> On Tue, Aug 31, 2010 at 6:51 PM, Hao, Xudong <xudong.hao@intel.com> wrote:
>> Hao, Xudong wrote:
>>> Jes.Sorensen@redhat.com wrote:
>>>> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>>>>
>>>> There is no need to check for dest < 0 or vector >= 0 as both are
>>>> uint16_t.
>>>>
>>>> This should fix problems with broken build with aggressive compiler
>>>> flags. Reported by Xudong Hao <xudong.hao@intel.com>
>>>>
>>>> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com> ---
>>>>  hw/ivshmem.c |    4 ++--
>>>>  1 files changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
>>>> index bbb5cba..afebbc3 100644
>>>> --- a/hw/ivshmem.c
>>>> +++ b/hw/ivshmem.c
>>>> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque,
>>>> target_phys_addr_t addr,
>>>>
>>>>          case DOORBELL:
>>>>              /* check that dest VM ID is reasonable */
>>>> -            if ((dest < 0) || (dest > s->max_peer)) {
>>>> +            if (dest > s->max_peer) {
>>>>                  IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n",
>>>>                  dest); break;
>>>>              }
>>>>
>>>>              /* check doorbell range */
>>>> -            if ((vector >= 0) && (vector <
>>>> s->peers[dest].nb_eventfds)) { +            if (vector <
>>>>                  s->peers[dest].nb_eventfds) {
>>>>
>>>>                  IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on
>>>> vector %d\n", write_one, dest, vector); if
>>>> (write(s->peers[dest].eventfds[vector],
>>>
>>> This patch works for me.
>>>
>>
>> Jes, correct result is this patch works for me on x86_64 system. However, in i386 system, there is another bug:
>>
>> ...
>>  CC    x86_64-softmmu/ivshmem.o
>>  CC    x86_64-softmmu/fpu/softfloat-native.o
>>  CC    x86_64-softmmu/op_helper.o
>> cc1: warnings being treated as errors
>> /home/build/gitrepo/qemu/hw/ivshmem.c: In function 'check_shm_size.
>> /home/build/gitrepo/qemu/hw/ivshmem.c:357: warning: format '%ld' expects type 'long int', but argt 5 has type '__off64_t
>> make[1]: *** [ivshmem.o] Error 1
>> make[1]: *** Waiting for unfinished jobs....
>> make: *** [subdir-x86_64-softmmu] Error 2
>
> Hmm, that was causing problems on 32-bit systems, not 64-bit.  Is this
> with gcc 4.1.2?

Oh sorry, I read too fast, you did say it was on 32-bit.  Avi's patch
will do the trick.

Cam

Re: [Qemu-devel] [PATCH] hw/ivshmem.c don't check for negative values on unsigned data types

[Blue Swirl]

Thanks, applied.

On Mon, Aug 30, 2010 at 10:31 AM,  <Jes.Sorensen@redhat.com> wrote:
> From: Jes Sorensen <Jes.Sorensen@redhat.com>
>
> There is no need to check for dest < 0 or vector >= 0 as both are
> uint16_t.
>
> This should fix problems with broken build with aggressive compiler
> flags. Reported by Xudong Hao <xudong.hao@intel.com>
>
> Signed-off-by: Jes Sorensen <Jes.Sorensen@redhat.com>
> ---
>  hw/ivshmem.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/hw/ivshmem.c b/hw/ivshmem.c
> index bbb5cba..afebbc3 100644
> --- a/hw/ivshmem.c
> +++ b/hw/ivshmem.c
> @@ -199,13 +199,13 @@ static void ivshmem_io_writel(void *opaque, target_phys_addr_t addr,
>
>         case DOORBELL:
>             /* check that dest VM ID is reasonable */
> -            if ((dest < 0) || (dest > s->max_peer)) {
> +            if (dest > s->max_peer) {
>                 IVSHMEM_DPRINTF("Invalid destination VM ID (%d)\n", dest);
>                 break;
>             }
>
>             /* check doorbell range */
> -            if ((vector >= 0) && (vector < s->peers[dest].nb_eventfds)) {
> +            if (vector < s->peers[dest].nb_eventfds) {
>                 IVSHMEM_DPRINTF("Writing %" PRId64 " to VM %d on vector %d\n",
>                                                     write_one, dest, vector);
>                 if (write(s->peers[dest].eventfds[vector],
> --
> 1.7.2.2
>
>
>