[MODERATED] Re: [PATCH 4/5] SSB extra 5

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Thu, May 03, 2018 at 03:29:47PM -0700, speck for Dave Hansen wrote:
> From: Dave Hansen <dave.hansen@linux.intel.com>
> Subject:  x86, bugs: centralize SPEC_CTRL MSR mask generation
> 
> From: Dave Hansen <dave.hansen@linux.intel.com>
> 
> The KVM code manipualtes the SPEC_CTRL MSR when it enters and exits
> the guest.  It overwrites the "kernel" value when it enters the guest
> and restores the "kernel" value after leaving the guest.
> 
> Both code paths take into account the "base" (x86_spec_ctrl_base)
> value and the per-task TIF_RDS flag (on Intel).  They then see if the
> new state differs from the existing state and avoid the MSR write if
> no change is made.
> 
> But, these two paths could be a bit more unified.  Introduce a new
> function: x86_calculate_kernel_spec_ctrl() which will figure out the
> "kernel" value to contrast it with the "guest" value.  We also
> rename the arguments to the set/restore functions to make it clear
> that while the arguments are both "guest" state, they really mean
> different things to the two functions.
> 
> This will make the next step easier when we have more state to
> consult in doing the x86_calculate_kernel_spec_ctrl() calculatione
> 
> Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>