x86/cpufeatures: Add virtual TSC_AUX feature bit

The TSC_AUX Virtualization feature allows AMD SEV-ES guests to securely use
TSC_AUX (auxiliary time stamp counter data) MSR in RDTSCP and RDPID
instructions.

The TSC_AUX MSR is typically initialized to APIC ID or another unique
identifier so that software can quickly associate returned TSC value
with the logical processor.

Add the feature bit and also include it in the kvm for detection.
Signed-off-by: Babu Moger <babu.moger@amd.com>
Acked-by: Borislav Petkov <bp@suse.de>
Message-Id: <165040157111.1399644.6123821125319995316.stgit@bmoger-ubuntu>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/cpufeatures.h

@@ -405,6 +405,7 @@
 #define X86_FEATURE_SEV			(19*32+ 1) /* AMD Secure Encrypted Virtualization */
 #define X86_FEATURE_VM_PAGE_FLUSH	(19*32+ 2) /* "" VM Page Flush MSR is supported */
 #define X86_FEATURE_SEV_ES		(19*32+ 3) /* AMD Secure Encrypted Virtualization - Encrypted State */
+#define X86_FEATURE_V_TSC_AUX		(19*32+ 9) /* Virtual TSC_AUX */
 #define X86_FEATURE_SME_COHERENT	(19*32+10) /* "" AMD hardware-enforced cache coherency */
 
 /*