[14/14] KVM: x86: nSVM: support PAUSE filter threshold and count

Commit Message

Maxim Levitsky Sept. 14, 2021, 3:48 p.m. UTC

Allow L1 to use these settings if L0 disables PAUSE interception
(AKA cpu_pm=on)

Signed-off-by: Maxim Levitsky <[e-mail]>
---
 arch/x86/kvm/svm/nested.c |  6 ++++++
 arch/x86/kvm/svm/svm.c    | 18 ++++++++++++++++++
 arch/x86/kvm/svm/svm.h    |  2 ++
 3 files changed, 26 insertions(+)

Patch

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 4c26417f36b8..b47c745ec659 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -602,6 +602,12 @@  static void nested_vmcb02_prepare_control(struct vcpu_svm *svm)
 	if (!nested_vmcb_needs_vls_intercept(svm))
 		svm->vmcb->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
 
+	if (svm->pause_filter_enabled)
+		svm->vmcb->control.pause_filter_count = svm->nested.ctl.pause_filter_count;
+
+	if (svm->pause_threshold_enabled)
+		svm->vmcb->control.pause_filter_thresh = svm->nested.ctl.pause_filter_thresh;
+
 	nested_svm_transition_tlb_flush(vcpu);
 
 	/* Enter Guest-Mode */
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 0b797351cfb9..95125cd2e666 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1026,6 +1026,13 @@  static __init void svm_set_cpu_caps(void)
 		if (tsc_scaling)
 			kvm_cpu_cap_set(X86_FEATURE_TSCRATEMSR);
 
+		if (pause_filter_count)
+			kvm_cpu_cap_set(X86_FEATURE_PAUSEFILTER);
+
+		if (pause_filter_thresh)
+			kvm_cpu_cap_set(X86_FEATURE_PFTHRESHOLD);
+
+
 		/* Nested VM can receive #VMEXIT instead of triggering #GP */
 		kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
 	}
@@ -4133,6 +4140,17 @@  static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 
 	svm->tsc_scaling_enabled = tsc_scaling && guest_cpuid_has(vcpu, X86_FEATURE_TSCRATEMSR);
 
+	if (kvm_pause_in_guest(vcpu->kvm)) {
+		svm->pause_filter_enabled = pause_filter_count > 0 &&
+					    guest_cpuid_has(vcpu, X86_FEATURE_PAUSEFILTER);
+
+		svm->pause_threshold_enabled = pause_filter_thresh > 0 &&
+					    guest_cpuid_has(vcpu, X86_FEATURE_PFTHRESHOLD);
+	} else {
+		svm->pause_filter_enabled = false;
+		svm->pause_threshold_enabled = false;
+	}
+
 	svm_recalc_instruction_intercepts(vcpu, svm);
 
 	/* For sev guests, the memory encryption bit is not reserved in CR3.  */
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c8ea3b14da73..7e679dd7a6e4 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -166,6 +166,8 @@  struct vcpu_svm {
 	bool lbrv_enabled                 : 1;
 	bool v_vmload_vmsave_enabled      : 1;
 	bool tsc_scaling_enabled          : 1;
+	bool pause_filter_enabled         : 1;
+	bool pause_threshold_enabled      : 1;
 
 	u32 ldr_reg;
 	u32 dfr_reg;