Re: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
On 03/23/2010 01:21 PM, Jan Kiszka wrote: A 44-byte TSS has a limit of 43 (just like a 4GB segment has a limit of 0x), so there is an off-by-one here. Right - you just found an (harmless) off-by-one in our legacy OS as well (I blindly copied its limit). It's a very common error. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
Avi Kivity wrote:
> On 03/23/2010 12:25 PM, Avi Kivity wrote:
>>> This should be stable material as well. I can provide a patch that
>>> applies on .32 and .33, or what will be the procedure?
>>
>> I'd like to drop the Cc: stable and maintain stable queues explicitly
>> (in kvm-updates/2.6.3[23]). I'll fast-forward these to current
>> -stable, please send patches against them. These branches will be
>> autotested before submission, a step that is missing in the current
>> scheme of things.
>
> kvm.git now has these branches updated.
>
6c1535244cc930a0307ea0708a2063e4f4b34158 ("Add
KVM_CAP_X86_ROBUST_SINGLESTEP") in the 2.6.33 branch is damaged. "Update
instruction length on intercepted BP" is missing in the 2.6.32 queue,
but Greg should have queued this up already.
Jan
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Re: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
Avi Kivity wrote:
> On 03/22/2010 12:29 PM, Jan Kiszka wrote:
>> A 16-bit TSS is only 44 bytes long. So make sure to test for the correct
>> size on task switch.
>>
>
>> This should be stable material as well. I can provide a patch that
>> applies on .32 and .33, or what will be the procedure?
>>
>
> I'd like to drop the Cc: stable and maintain stable queues explicitly
> (in kvm-updates/2.6.3[23]). I'll fast-forward these to current -stable,
> please send patches against them. These branches will be autotested
> before submission, a step that is missing in the current scheme of things.
>
>>
>> -if (!next_tss_desc.p || desc_limit_scaled(&next_tss_desc)< 0x67) {
>> +desc_limit = desc_limit_scaled(&next_tss_desc);
>> +if (!next_tss_desc.p ||
>> +((desc_limit< 0x67&& (next_tss_desc.type& 8)) ||
>> + desc_limit< 0x2c)) {
>>
>
> A 44-byte TSS has a limit of 43 (just like a 4GB segment has a limit of
> 0x), so there is an off-by-one here.
>
Right - you just found an (harmless) off-by-one in our legacy OS as well
(I blindly copied its limit).
Jan
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Re: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
On 03/23/2010 12:25 PM, Avi Kivity wrote: This should be stable material as well. I can provide a patch that applies on .32 and .33, or what will be the procedure? I'd like to drop the Cc: stable and maintain stable queues explicitly (in kvm-updates/2.6.3[23]). I'll fast-forward these to current -stable, please send patches against them. These branches will be autotested before submission, a step that is missing in the current scheme of things. kvm.git now has these branches updated. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH] KVM: x86: Fix TSS size check for 16-bit tasks
On 03/22/2010 12:29 PM, Jan Kiszka wrote:
A 16-bit TSS is only 44 bytes long. So make sure to test for the correct
size on task switch.
This should be stable material as well. I can provide a patch that
applies on .32 and .33, or what will be the procedure?
I'd like to drop the Cc: stable and maintain stable queues explicitly
(in kvm-updates/2.6.3[23]). I'll fast-forward these to current -stable,
please send patches against them. These branches will be autotested
before submission, a step that is missing in the current scheme of things.
- if (!next_tss_desc.p || desc_limit_scaled(&next_tss_desc)< 0x67) {
+ desc_limit = desc_limit_scaled(&next_tss_desc);
+ if (!next_tss_desc.p ||
+ ((desc_limit< 0x67&& (next_tss_desc.type& 8)) ||
+desc_limit< 0x2c)) {
A 44-byte TSS has a limit of 43 (just like a 4GB segment has a limit of
0x), so there is an off-by-one here.
--
error compiling committee.c: too many arguments to function
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