[CRIU] [PATCH] xsave: check for X86_FEATURE_OSXSAVE rather than for X86_FEATURE_XSAVE

[Cyrill Gorcunov]

On Thu, Dec 15, 2016 at 03:30:44PM +0100, Adrian Reber wrote:
> From: Adrian Reber <areber at redhat.com>
> 
> Migrating a process between a system with the 'xsave' CPU flag and
> another system without the 'xsave' CPU flags is not possible and
> fails during restore. To avoid this situation it is possible to boot
> the source system of the migration with 'noxsave' kernel command-line.
> 
> Unfortunately criu currently tries to detect the presence of 'xsave'
> with the macro X86_FEATURE_XSAVE which represents the features of
> the CPU without taking into account if the operating system has
> disabled 'xsave'. Checking for 'xsave' availability with the macro
> X86_FEATURE_OSXSAVE detects correctly if Linux has been booted
> with disabled 'xsave' and thus migrating processes between hosts
> with and without 'xsave' is possible if the kernel uses the flag
> 'noxsave'.
> 
> Signed-off-by: Adrian Reber <areber at redhat.com>
Reviewed-by: Cyrill Gorcunov <gorcunov at openvz.org>

Thanks a lot!