Re: [PATCH v7 45/72] x86/entry/64: Add entry code for #VC handler

2021-01-28 Thread Joerg Roedel
Hello Lai, On Sun, Jan 24, 2021 at 10:11:14PM +0800, Lai Jiangshan wrote: > > + > > + /* > > +* No need to switch back to the IST stack. The current stack is > > either > > +* identical to the stack in the IRET frame or the VC fall-back > > stack, > > +* so it is

Re: [PATCH v7 45/72] x86/entry/64: Add entry code for #VC handler

2021-01-24 Thread Lai Jiangshan
> + > + /* > +* No need to switch back to the IST stack. The current stack is > either > +* identical to the stack in the IRET frame or the VC fall-back stack, > +* so it is definitly mapped even with PTI enabled. > +*/ > + jmp paranoid_exit > + >

[PATCH v7 45/72] x86/entry/64: Add entry code for #VC handler

2020-09-07 Thread Joerg Roedel
From: Joerg Roedel The #VC handler needs special entry code because: 1. It runs on an IST stack 2. It needs to be able to handle nested #VC exceptions To make this work the entry code is implemented to pretend it doesn't use an IST stack. When entered from user-mode or early