From: Zhao Liu <zhao1.liu@xxxxxxxxx>
ITD (Intel Thread Director) is the extension of HFI feature. Based on
HFI, it adds 4 classes in HFI table and it provides the MSR interface to
support the OS to classify the currently running task into one of 4
classes.
As the first step of ITD support, extend the HFI table and related HFI
MSRs' emulation to support the ITD:
* More classes in HFI table
If ITD is configured in Guest's CPUID, the virtual HFI table will be
built with 4 classes.
But only when ITD is enabled in MSR_IA32_HW_FEEDBACK_CONFIG, the
virtual HFI table will update all these 4 classes, otherwise it will
only update class 0's data if HFI is enabled.
* MSR_IA32_HW_FEEDBACK_CONFIG (HW_FEEDBACK_CONFIG_ITD_ENABLE bit)
With ITD support, MSR_IA32_HW_FEEDBACK_CONFIG has 2 feature enabling
bits: HW_FEEDBACK_CONFIG_HFI_ENABLE and HW_FEEDBACK_CONFIG_ITD_ENABLE
bit. These 2 bits control whether the HFI and ITD features are enabled
or not, and also affect which class data should actually be updated in
the virtual HFI table [1].
For the MSR_IA32_HW_FEEDBACK_CONFIG's emulation, add support for
dynamically changing these two bits and the corresponding HFI update
adjustments.
[1]: SDM, vol. 3B, section 15.6.5 Hardware Feedback Interface
Configuration, Table 15-10. IA32_HW_FEEDBACK_CONFIG Control Option
Tested-by: Yanting Jiang <yanting.jiang@xxxxxxxxx>
Co-developed-by: Zhuocheng Ding <zhuocheng.ding@xxxxxxxxx>
Signed-off-by: Zhuocheng Ding <zhuocheng.ding@xxxxxxxxx>
Signed-off-by: Zhao Liu <zhao1.liu@xxxxxxxxx>
---
arch/x86/kvm/vmx/vmx.c | 68 +++++++++++++++++++++++++++++++-----------
arch/x86/kvm/vmx/vmx.h | 3 ++
2 files changed, 54 insertions(+), 17 deletions(-)
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 636f2bd68546..bdff1d424b2f 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1547,11 +1547,11 @@ static int vmx_init_hfi_table(struct kvm *kvm)
struct hfi_table *hfi_table = &kvm_vmx_hfi->hfi_table;
int nr_classes, ret = 0;
- /*
- * Currently we haven't supported ITD. HFI is the default feature
- * with 1 class.
- */
- nr_classes = 1;
+ if (guest_cpuid_has(kvm_get_vcpu(kvm, 0), X86_FEATURE_ITD))
+ nr_classes = 4;
+ else
+ nr_classes = 1;
+
ret = intel_hfi_build_virt_features(hfi_features,
nr_classes,
kvm->created_vcpus);
@@ -1579,11 +1579,11 @@ static int vmx_build_hfi_table(struct kvm *kvm)
struct kvm_vcpu *v;
unsigned long i;
- /*
- * Currently we haven't supported ITD. HFI is the default feature
- * with 1 class.
- */
- nr_classes = 1;
+ if (kvm_vmx_hfi->itd_enabled)
+ nr_classes = kvm_vmx_hfi->hfi_features.nr_classes;
+ else
+ nr_classes = 1;
+
for (int j = 0; j < nr_classes; j++) {
hfi_hdr->perf_updated = 0;
hfi_hdr->ee_updated = 0;
@@ -2575,7 +2575,7 @@ static int vmx_set_hfi_cfg_msr(struct kvm_vcpu *vcpu,
struct kvm_vmx *kvm_vmx = to_kvm_vmx(vcpu->kvm);
struct hfi_desc *kvm_vmx_hfi = &kvm_vmx->pkg_therm.hfi_desc;
u64 data = msr_info->data;
- bool hfi_enabled, hfi_changed;
+ bool hfi_enabled, hfi_changed, itd_enabled, itd_changed;
/*
* When the HFI enable bit changes (either from 0 to 1 or 1 to
@@ -2584,12 +2584,44 @@ static int vmx_set_hfi_cfg_msr(struct kvm_vcpu *vcpu,
*/
hfi_enabled = data & HW_FEEDBACK_CONFIG_HFI_ENABLE;
hfi_changed = kvm_vmx_hfi->hfi_enabled != hfi_enabled;
+ itd_enabled = data & HW_FEEDBACK_CONFIG_ITD_ENABLE;
+ itd_changed = kvm_vmx_hfi->itd_enabled != itd_enabled;
kvm_vmx->pkg_therm.msr_ia32_hfi_cfg = data;
kvm_vmx_hfi->hfi_enabled = hfi_enabled;
+ kvm_vmx_hfi->itd_enabled = itd_enabled;
+
+ if (!hfi_changed && !itd_changed)
+ return 0;
+
+ /*
+ * Refer to SDM, vol. 3B, Table 15-10. IA32_HW_FEEDBACK_CONFIG
+ * Control Option.
+ */
+
+ /* Invalid option; quietly ignored by the hardware. */
+ if (!hfi_changed && itd_changed && !hfi_enabled && itd_enabled) {
+ /* No action (no update in the table). */
+ return 0;
+ }
- if (!hfi_changed)
+ /* No action; keep HFI and Intel Thread Director disabled. */
+ if (!hfi_changed && itd_changed && !hfi_enabled && !itd_enabled) {
+ /* No action (no update in the table). */
return 0;
+ }
+
+ /* No action; keep HFI enabled. */
+ if (!hfi_changed && itd_changed && hfi_enabled && !itd_enabled) {
+ /* No action (no update in the table). */
+ return 0;
+ }
+
+ /* Disable HFI and Intel Thread Director whether ITD changed. */
+ if (hfi_changed && !hfi_enabled && itd_enabled) {
+ kvm_vmx_hfi->hfi_enabled = false;
+ kvm_vmx_hfi->itd_enabled = false;
+ }
if (!hfi_enabled) {
/*
@@ -3006,12 +3038,14 @@ static int vmx_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
if (!msr_info->host_initiated &&
!guest_cpuid_has(vcpu, X86_FEATURE_HFI))
return 1;
- /*
- * Unsupported and reserved bits. ITD is not supported
- * (CPUID.06H:EAX[19]) yet.
- */
+ /* Unsupported bit: generate the exception. */
+ if (!msr_info->host_initiated &&
+ !guest_cpuid_has(vcpu, X86_FEATURE_ITD) &&
+ (data & HW_FEEDBACK_CONFIG_ITD_ENABLE))
+ return 1;
+ /* Reserved bits: generate the exception. */
if (!msr_info->host_initiated &&
- data & ~(HW_FEEDBACK_CONFIG_HFI_ENABLE))
+ data & ~(HW_FEEDBACK_CONFIG_HFI_ENABLE | HW_FEEDBACK_CONFIG_ITD_ENABLE))
return 1;
mutex_lock(&kvm_vmx->pkg_therm.pkg_therm_lock);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index d9db8bf3726f..0ef767d63def 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -377,6 +377,8 @@ struct vcpu_vmx {
* struct hfi_desc - Representation of an HFI instance (i.e., a table)
* @hfi_enabled: Flag to indicate whether HFI is enabled at runtime.
* Parsed from the Guest's MSR_IA32_HW_FEEDBACK_CONFIG.
+ * @itd_enabled: Flag to indicate whether ITD is enabled at runtime.
+ * Parsed from the Guest's MSR_IA32_HW_FEEDBACK_CONFIG.
* @hfi_int_enabled: Flag to indicate whether HFI is enabled at runtime.
* Parsed from Guest's MSR_IA32_PACKAGE_THERM_INTERRUPT[bit 25].
* @table_ptr_valid: Flag to indicate whether the memory of Guest HFI table is ready.
@@ -407,6 +409,7 @@ struct vcpu_vmx {
struct hfi_desc {
bool hfi_enabled;
+ bool itd_enabled;
bool hfi_int_enabled;
bool table_ptr_valid;
bool hfi_update_status;
--
2.34.1
