[Devel] [PATCH 10/16] KVM: VMX: Enable and initialize VMX TSC scaling

[Roman Kagan]

From: Haozhong Zhang <haozhong.zhang at intel.com>

This patch exhances kvm-intel module to enable VMX TSC scaling and
collects information of TSC scaling ratio during initialization.

Signed-off-by: Haozhong Zhang <haozhong.zhang at intel.com>
Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
(cherry-picked from commit 64903d6195cbfb051ce339d30848cc64babdba12)
Signed-off-by: Denis Plotnikov <dplotnikov at virtuozzo.com>
Signed-off-by: Roman Kagan <rkagan at virtuozzo.com>
---
 arch/x86/include/asm/vmx.h |  4 +++-
 arch/x86/kvm/vmx.c         | 17 ++++++++++++++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 8530b93..ebe7cf9d 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -70,7 +70,7 @@
 #define SECONDARY_EXEC_ENABLE_INVPCID		0x00001000
 #define SECONDARY_EXEC_SHADOW_VMCS              0x00004000
 #define SECONDARY_EXEC_ENABLE_PML               0x00020000
-
+#define SECONDARY_EXEC_TSC_SCALING              0x02000000
 
 #define PIN_BASED_EXT_INTR_MASK                 0x00000001
 #define PIN_BASED_NMI_EXITING                   0x00000008
@@ -163,6 +163,8 @@ enum vmcs_field {
 	EOI_EXIT_BITMAP3_HIGH           = 0x00002023,
 	VMREAD_BITMAP                   = 0x00002026,
 	VMWRITE_BITMAP                  = 0x00002028,
+	TSC_MULTIPLIER                  = 0x00002032,
+	TSC_MULTIPLIER_HIGH             = 0x00002033,
 	GUEST_PHYSICAL_ADDRESS          = 0x00002400,
 	GUEST_PHYSICAL_ADDRESS_HIGH     = 0x00002401,
 	VMCS_LINK_POINTER               = 0x00002800,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f61433a..ab8a678 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -104,6 +104,8 @@ module_param(nested, bool, S_IRUGO);
 static bool __read_mostly enable_pml = 1;
 module_param_named(pml, enable_pml, bool, S_IRUGO);
 
+#define KVM_VMX_TSC_MULTIPLIER_MAX     0xffffffffffffffffULL
+
 #define KVM_GUEST_CR0_MASK (X86_CR0_NW | X86_CR0_CD)
 #define KVM_VM_CR0_ALWAYS_ON_UNRESTRICTED_GUEST (X86_CR0_WP | X86_CR0_NE)
 #define KVM_VM_CR0_ALWAYS_ON						\
@@ -1071,6 +1073,12 @@ static inline bool cpu_has_vmx_pml(void)
 	return vmcs_config.cpu_based_2nd_exec_ctrl & SECONDARY_EXEC_ENABLE_PML;
 }
 
+static inline bool cpu_has_vmx_tsc_scaling(void)
+{
+	return vmcs_config.cpu_based_2nd_exec_ctrl &
+		SECONDARY_EXEC_TSC_SCALING;
+}
+
 static inline bool report_flexpriority(void)
 {
 	return flexpriority_enabled;
@@ -2877,7 +2885,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
 			SECONDARY_EXEC_APIC_REGISTER_VIRT |
 			SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
 			SECONDARY_EXEC_SHADOW_VMCS |
-			SECONDARY_EXEC_ENABLE_PML;
+			SECONDARY_EXEC_ENABLE_PML |
+			SECONDARY_EXEC_TSC_SCALING;
 		if (adjust_vmx_controls(min2, opt2,
 					MSR_IA32_VMX_PROCBASED_CTLS2,
 					&_cpu_based_2nd_exec_control) < 0)
@@ -5840,6 +5849,12 @@ static __init int hardware_setup(void)
 	if (nested)
 		nested_vmx_setup_ctls_msrs();
 
+	if (cpu_has_vmx_tsc_scaling()) {
+		kvm_has_tsc_control = true;
+		kvm_max_tsc_scaling_ratio = KVM_VMX_TSC_MULTIPLIER_MAX;
+		kvm_tsc_scaling_ratio_frac_bits = 48;
+	}
+
 	vmx_disable_intercept_for_msr(MSR_FS_BASE, false);
 	vmx_disable_intercept_for_msr(MSR_GS_BASE, false);
 	vmx_disable_intercept_for_msr(MSR_KERNEL_GS_BASE, true);
-- 
2.7.4