Back in the mists of time, well, prior to 4.14.9, you could put clearcpuid=N
several times on the command line to clear several CPUID bits. Unfortunately,
there was a problem with the way that this was done which meant XSAVE, in
particular, wasn't cleared early enough. This was fixed in 0c2a3913d6f5
("x86/fpu: Parse clearcpuid= as early XSAVE argument"). Unfortunately that
also meant that only one bit could be cleared.
This patch mostly fixes that. Gone is the old, anachronistic, multiple
clearcpuid= arguments to be replaced by a single clearcpuid=BITNUM[,BITNUM,...]
argument. It's no longer possible to clear perhaps dozens of flags with a very
long kernel command line, but you can clear up to about eight bits now instead
of just one.
jch
John Haxby (1):
x86/fpu: Allow clearcpuid= to clear several bits
.../admin-guide/kernel-parameters.txt | 24 ++++++++++---------
arch/x86/kernel/fpu/init.c | 18 ++++++++------
2 files changed, 24 insertions(+), 18 deletions(-)
--
2.25.3
