arm64/sve: Check SVE virtualisability

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Due to the way the effective SVE vector length is controlled and
trapped at different exception levels, certain mismatches in the
sets of vector lengths supported by different physical CPUs in the
system may prevent straightforward virtualisation of SVE at parity
with the host.

This patch analyses the extent to which SVE can be virtualised
safely without interfering with migration of vcpus between physical
CPUs, and rejects late secondary CPUs that would erode the
situation further.

It is left up to KVM to decide what to do with this information.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Reviewed-by: Julien Thierry <julien.thierry@arm.com>
Tested-by: zhang.lei <zhang.lei@jp.fujitsu.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

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This commit is contained in:

Dave Martin 2018-09-28 14:39:10 +01:00 • committed by Marc Zyngier

parent 8b08e8401f

commit d06b76be8d

3 changed files with 73 additions and 16 deletions

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1

arch/arm64/include/asm/fpsimd.h

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2

arch/arm64/kernel/cpufeature.c

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86

arch/arm64/kernel/fpsimd.c

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