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Subject[RFC][PATCH 0/5] s390: improve speculative execution handling v2
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Version 2 of the speculative execution mitigation for s390. Changes to v1:

* The KVM patch to add the guest bpb feature already went upstream.
* Dropped the patch to introduce the gmb barrier to defend against spectre
variant 1 until the bikeshedding in regard to the naming is done.
* Switched from a system call to the PR_ISOLATE_BP process control to run
user space tasks with branch prediction isolation.

My main question is if the prctl(PR_ISOLATE_BP) makes sense.

Martin Schwidefsky (5):
prctl: add PR_ISOLATE_BP process control
s390/alternative: use a copy of the facility bit mask
s390: add options to change branch prediction behaviour for the kernel
s390: define ISOLATE_BP to run tasks with modified branch prediction
s390: scrub registers on kernel entry and KVM exit

arch/s390/Kconfig | 17 +++++
arch/s390/include/asm/facility.h | 18 +++++
arch/s390/include/asm/lowcore.h | 3 +-
arch/s390/include/asm/processor.h | 4 ++
arch/s390/include/asm/thread_info.h | 4 ++
arch/s390/kernel/alternative.c | 26 ++++++-
arch/s390/kernel/early.c | 5 ++
arch/s390/kernel/entry.S | 134 +++++++++++++++++++++++++++++++++++-
arch/s390/kernel/ipl.c | 1 +
arch/s390/kernel/processor.c | 8 +++
arch/s390/kernel/setup.c | 4 +-
arch/s390/kernel/smp.c | 6 +-
include/uapi/linux/prctl.h | 8 +++
kernel/sys.c | 6 ++
14 files changed, 238 insertions(+), 6 deletions(-)

--
2.7.4

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