KVM: x86: Advertise PREFETCHIT0/1 CPUID to user space

mainline inclusion
from mainline-v6.2-rc1
commit 29c46979
category: feature
bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I8GYV5
CVE: N/A
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=29c46979b25d5ca867e9859bfdd088d028739cdf



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Intel-SIG: commit 29c46979 ("KVM: x86: Advertise PREFETCHIT0/1 CPUID to user space")

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KVM: x86: Advertise PREFETCHIT0/1 CPUID to user space

Latest Intel platform Granite Rapids has introduced a new instruction -
PREFETCHIT0/1, which moves code to memory (cache) closer to the
processor depending on specific hints.

The bit definition:
CPUID.(EAX=7,ECX=1):EDX[bit 14]

PREFETCHIT0/1 is on a KVM-only subleaf. Plus an x86_FEATURE definition
for this feature bit to direct it to the KVM entry.

Advertise PREFETCHIT0/1 to KVM userspace. This is safe because there are
no new VMX controls or additional host enabling required for guests to
use this feature.

Signed-off-by: Jiaxi Chen <jiaxi.chen@linux.intel.com>
Message-Id: <20221125125845.1182922-9-jiaxi.chen@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Quanxian Wang <quanxian.wang@intel.com>