Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-02 Thread Steven Rostedt
On Fri, 2012-11-02 at 14:09 +, Jan Beulich wrote: > >>subq $(5*8), %rsp > >> + CFI_ADJUST_CFA_OFFSET 5*8 > >> > >>CFI_DEF_CFA_OFFSET SS+8-RIP > >> end_repeat_nmi: > >> > > > > Is that second one even needed? Or will the CFI_DEF_CFA_OFFSET SS+8-RIP > > fix it? > > Yes it will (as

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-02 Thread Jan Beulich
>>> On 02.11.12 at 14:53, Steven Rostedt wrote: > On Fri, 2012-11-02 at 09:51 -0400, Steven Rostedt wrote: >> On Thu, 2012-11-01 at 19:53 +, Jan Beulich wrote: >> >> > There doesn't appear to be anything special about these adjustments, so I >> > don't see what help would be required here - i

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-02 Thread Steven Rostedt
On Fri, 2012-11-02 at 09:51 -0400, Steven Rostedt wrote: > On Thu, 2012-11-01 at 19:53 +, Jan Beulich wrote: > > > There doesn't appear to be anything special about these adjustments, so I > > don't see what help would be required here - it ought to be the normal use > > of CFI_ADJUST_CFA_OFFS

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-02 Thread Steven Rostedt
On Thu, 2012-11-01 at 19:53 +, Jan Beulich wrote: > There doesn't appear to be anything special about these adjustments, so I > don't see what help would be required here - it ought to be the normal use > of CFI_ADJUST_CFA_OFFSET that needs adding. This change look fine to you? diff --git a/

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-01 Thread Steven Rostedt
On Thu, 2012-11-01 at 19:53 +, Jan Beulich wrote: > >>> Steven Rostedt 11/01/12 2:04 AM >>> > >On Mon, 2012-10-01 at 17:29 -0700, Salman Qazi wrote: > >> @@ -1826,12 +1832,15 @@ repeat_nmi: > >> * is benign for the non-repeat case, where 1 was pushed just above > >> * to this very

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-11-01 Thread Jan Beulich
>>> Steven Rostedt 11/01/12 2:04 AM >>> >On Mon, 2012-10-01 at 17:29 -0700, Salman Qazi wrote: >> @@ -1826,12 +1832,15 @@ repeat_nmi: >> * is benign for the non-repeat case, where 1 was pushed just above >> * to this very stack slot). >> */ >> -movq $1, 5*8(%rsp) >> +movq

Re: [PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-10-31 Thread Steven Rostedt
On Mon, 2012-10-01 at 17:29 -0700, Salman Qazi wrote: > The nested NMI modifies the place (instruction, flags and stack) > that the first NMI will iret to. However, the copy of registers > modified is exactly the one that is the part of pt_regs in > the first NMI. This can change the behaviour of

[PATCH] [PATCH] x86: Don't clobber top of pt_regs in nested NMI

2012-10-01 Thread Salman Qazi
The nested NMI modifies the place (instruction, flags and stack) that the first NMI will iret to. However, the copy of registers modified is exactly the one that is the part of pt_regs in the first NMI. This can change the behaviour of the first NMI. In particular, Google's arch_trigger_all_cpu_