KVM: x86: Update vCPU's runtime CPUID on write to MSR_IA32_XSS

stable inclusion
from stable-v5.10.96
commit e92cac1dd803aca5bc326ec22bdcd4f56855d7ce
bugzilla: https://gitee.com/openeuler/kernel/issues/I55NWB

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=e92cac1dd803aca5bc326ec22bdcd4f56855d7ce



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commit 4c282e51 upstream.

Do a runtime CPUID update for a vCPU if MSR_IA32_XSS is written, as the
size in bytes of the XSAVE area is affected by the states enabled in XSS.

Fixes: 20300099 ("kvm: vmx: add MSR logic for XSAVES")
Cc: stable@vger.kernel.org
Signed-off-by: Like Xu <likexu@tencent.com>
[sean: split out as a separate patch, adjust Fixes tag]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20220126172226.2298529-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Yu Liao <liaoyu15@huawei.com>
Reviewed-by: Wei Li <liwei391@huawei.com>
Signed-off-by: Zheng Zengkai <zhengzengkai@huawei.com>