Re: [PATCH V2] x86/sev: Mark the code returning to user space as syscall gap

[Lai Jiangshan]

On Tue, Apr 12, 2022 at 8:48 PM Lai Jiangshan <jiangshanlai@xxxxxxxxx> wrote:
>
> From: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>
>
> When returning to user space, the %rsp is user controlled value.
>
> If it is SNP-guest and the hypervisor decides to mess with the code-page
> for this path while a CPU is executing it.  This will cause a #VC on
> that CPU and that could hit in the syscall return path and mislead
> the #VC handler.
>
> So make ip_within_syscall_gap() return true in this case.
>
> Cc: Joerg Roedel <jroedel@xxxxxxx>
> Signed-off-by: Lai Jiangshan <jiangshan.ljs@xxxxxxxxxxxx>



Hello

Ping.

Thanks
Lai