Re: [Xen-devel] [PATCH v2] Xen missing prompt log when exec-sp=off

[Jin Nan Wang <jnwang@xxxxxxxx>]

On 16/12/2019 7:00 pm, Jan Beulich wrote:
> On 16.12.2019 09:27, Jin Nan Wang wrote:
>> Fix a issue when user disable ETP exec-sp, xen missed a prompt
>> log in dmesg.
> Why "missed" (and why "prompt")? I think the original intention
> was to log a message only when no command line option was given
> and the system would be vulnerable without the disabling.

Yes, I guess it.

But when I test ept=exec-sp=off. I got a little confused.

Because of the "prompt" tell me it's disabled, at default.

when I add 'ept=exec-sp=off', the "prompt" is disappeared. It seems like 
it's ENABLED.


James

> Nevertheless two style remarks as well:
>
>> --- a/xen/arch/x86/hvm/vmx/vmx.c
>> +++ b/xen/arch/x86/hvm/vmx/vmx.c
>> @@ -2495,14 +2495,14 @@ const struct hvm_function_table * __init 
>> start_vmx(void)
>>       {
>>           bool cpu_has_bug_pschange_mc = has_if_pschange_mc();
>>   
>> +        /* Default to non-executable superpages on vulnerable hardware. */
>>           if ( opt_ept_exec_sp == -1 )
>> -        {
>> -            /* Default to non-executable superpages on vulnerable hardware. 
>> */
>>               opt_ept_exec_sp = !cpu_has_bug_pschange_mc;
>>   
>> -            if ( cpu_has_bug_pschange_mc )
>> -                printk("VMX: Disabling executable EPT superpages due to 
>> CVE-2018-12207\n");
>> -        }
>> +        if (opt_ept_exec_sp)
> Missing blanks inside ().
>
>> +            printk("VMX: Enable executable EPT superpages.\n");
> No full stop here please.
>
> Jan
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel