KVM: x86: Expose AVX512_FP16 for supported CPUID

mainline inclusion
from mainline-v5.11-rc1
commit 2224fc9e
category: feature
feature: SPR New Instructions Virtualization
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I5O6WB
CVE: N/A
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/


commit/?id=2224fc9e

Intel-SIG: commit 2224fc9e ("KVM: x86: Expose AVX512_FP16 for supported CPUID")

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KVM: x86: Expose AVX512_FP16 for supported CPUID

AVX512_FP16 is supported by Intel processors, like Sapphire Rapids.
It could gain better performance for it's faster compared to FP32
if the precision or magnitude requirements are met. It's availability
is indicated by CPUID.(EAX=7,ECX=0):EDX[bit 23].

Expose it in KVM supported CPUID, then guest could make use of it; no
new registers are used, only new instructions.

Signed-off-by: Cathy Zhang <cathy.zhang@intel.com>
Signed-off-by: Kyung Min Park <kyung.min.park@intel.com>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Message-Id: <20201208033441.28207-3-kyung.min.park@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Aichun Shi <aichun.shi@intel.com>