Re: [PATCH v12 8/8] x86: Disallow vsyscall emulation when CET is enabled

[Yu, Yu-cheng]

On 9/23/2020 3:08 PM, Dave Hansen wrote:
> On 9/23/20 3:06 PM, Yu, Yu-cheng wrote:
> > I think I'll add a check here for (r + 8) >= TASK_SIZE_MAX.  It is
> > better than getting a fault.
>
> There's also wrmsr_safe().
Yes, thanks.

Since I am going to change this to:

fpu__prepare_write(), then write to the XSAVES area.

The kernel does not expect XRSTORS to fail ("Bad FPU state detected..." 
message).  So maybe still check the address first.