* [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range()
@ 2014-12-11 3:02 Tiejun Chen
2014-12-11 11:29 ` Paolo Bonzini
0 siblings, 1 reply; 4+ messages in thread
From: Tiejun Chen @ 2014-12-11 3:02 UTC (permalink / raw)
To: pbonzini; +Cc: kvm
We already check 'len' above to make sure it already isn't
negative here, so indeed, (addr + len < addr) should never be happened.
Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
---
virt/kvm/coalesced_mmio.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 00d8642..60f59cd 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -30,8 +30,6 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
*/
if (len < 0)
return 0;
- if (addr + len < addr)
- return 0;
if (addr < dev->zone.addr)
return 0;
if (addr + len > dev->zone.addr + dev->zone.size)
--
1.9.1
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range()
2014-12-11 3:02 [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range() Tiejun Chen
@ 2014-12-11 11:29 ` Paolo Bonzini
2014-12-12 1:02 ` Chen, Tiejun
0 siblings, 1 reply; 4+ messages in thread
From: Paolo Bonzini @ 2014-12-11 11:29 UTC (permalink / raw)
To: Tiejun Chen; +Cc: kvm
On 11/12/2014 04:02, Tiejun Chen wrote:
> We already check 'len' above to make sure it already isn't
> negative here, so indeed, (addr + len < addr) should never be happened.
... except if there is an overflow.
Paolo
> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
> ---
> virt/kvm/coalesced_mmio.c | 2 --
> 1 file changed, 2 deletions(-)
>
> diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
> index 00d8642..60f59cd 100644
> --- a/virt/kvm/coalesced_mmio.c
> +++ b/virt/kvm/coalesced_mmio.c
> @@ -30,8 +30,6 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
> */
> if (len < 0)
> return 0;
> - if (addr + len < addr)
> - return 0;
> if (addr < dev->zone.addr)
> return 0;
> if (addr + len > dev->zone.addr + dev->zone.size)
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range()
2014-12-11 11:29 ` Paolo Bonzini
@ 2014-12-12 1:02 ` Chen, Tiejun
2014-12-12 1:24 ` Chen, Tiejun
0 siblings, 1 reply; 4+ messages in thread
From: Chen, Tiejun @ 2014-12-12 1:02 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm
On 2014/12/11 19:29, Paolo Bonzini wrote:
>
>
> On 11/12/2014 04:02, Tiejun Chen wrote:
>> We already check 'len' above to make sure it already isn't
>> negative here, so indeed, (addr + len < addr) should never be happened.
>
> ... except if there is an overflow.
Sorry, I'm confused. 'addr' is u64 and now 'len' would always be '>=0',
what's your a so-called overflow here? And we also have such a check
below, (addr + len > dev->zone.addr + dev->zone.size), so can this
guarantee an overflow?
Thanks
Tiejun
>
> Paolo
>
>> Signed-off-by: Tiejun Chen <tiejun.chen@intel.com>
>> ---
>> virt/kvm/coalesced_mmio.c | 2 --
>> 1 file changed, 2 deletions(-)
>>
>> diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
>> index 00d8642..60f59cd 100644
>> --- a/virt/kvm/coalesced_mmio.c
>> +++ b/virt/kvm/coalesced_mmio.c
>> @@ -30,8 +30,6 @@ static int coalesced_mmio_in_range(struct kvm_coalesced_mmio_dev *dev,
>> */
>> if (len < 0)
>> return 0;
>> - if (addr + len < addr)
>> - return 0;
>> if (addr < dev->zone.addr)
>> return 0;
>> if (addr + len > dev->zone.addr + dev->zone.size)
>>
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
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> More majordomo info at http://vger.kernel.org/majordomo-info.html
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range()
2014-12-12 1:02 ` Chen, Tiejun
@ 2014-12-12 1:24 ` Chen, Tiejun
0 siblings, 0 replies; 4+ messages in thread
From: Chen, Tiejun @ 2014-12-12 1:24 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: kvm
On 2014/12/12 9:02, Chen, Tiejun wrote:
> On 2014/12/11 19:29, Paolo Bonzini wrote:
>>
>>
>> On 11/12/2014 04:02, Tiejun Chen wrote:
>>> We already check 'len' above to make sure it already isn't
>>> negative here, so indeed, (addr + len < addr) should never be happened.
>>
>> ... except if there is an overflow.
>
I think now I can understand what you mean.
Thanks
Tiejun
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2014-12-12 1:24 UTC | newest]
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2014-12-11 3:02 [PATCH] kvm: coalesced_mmio: remove one redundant check inside of coalesced_mmio_in_range() Tiejun Chen
2014-12-11 11:29 ` Paolo Bonzini
2014-12-12 1:02 ` Chen, Tiejun
2014-12-12 1:24 ` Chen, Tiejun
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