[RFC 12/26] KVM: VMX: Introduce HFI table index for vCPU

[Zhao Liu <zhao1.liu@linux.intel.com>]

From: Zhao Liu <zhao1.liu@intel.com>

The HFI table contains a table header and many table entries. Each table
entry is identified by an HFI table index, and each CPU corresponds to
one of the HFI table indexes [1].

Add hfi_table_idx in vcpu_vmx, and this will be used to build virtual
HFI table.

This HFI index is initialized to 0, but in the following patch the VMM
can be allowed to configure this index with a custom value (CPUID.0x06.
edx[bits 16-31]).

[1]: SDM, vol. 3B, section 15.6.1 Hardware Feedback Interface Table
     Structure

Tested-by: Yanting Jiang <yanting.jiang@intel.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 arch/x86/kvm/vmx/vmx.c | 6 ++++++
 arch/x86/kvm/vmx/vmx.h | 3 +++
 2 files changed, 9 insertions(+)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 48f304683d6f..96f0f768939d 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7648,6 +7648,12 @@ static int vmx_vcpu_create(struct kvm_vcpu *vcpu)
 			tsx_ctrl->mask = ~(u64)TSX_CTRL_CPUID_CLEAR;
 	}
 
+	/*
+	 * hfi_table_idx is initialized to 0, but later it may be changed according
+	 * to the value in the Guest's CPUID.0x06.edx[bits 16-31].
+	 */
+	vmx->hfi_table_idx = 0;
+
 	err = alloc_loaded_vmcs(&vmx->vmcs01);
 	if (err < 0)
 		goto free_pml;
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index 4bf4ca6ac1c0..63874aad7ae3 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -362,6 +362,9 @@ struct vcpu_vmx {
 	struct pt_desc pt_desc;
 	struct lbr_desc lbr_desc;
 
+	/* Should be extracted from Guest's CPUID.0x06.edx[bits 16-31]. */
+	int hfi_table_idx;
+
 	/* Save desired MSR intercept (read: pass-through) state */
 #define MAX_POSSIBLE_PASSTHROUGH_MSRS	16
 	struct {
-- 
2.34.1