linux-kernel - [PATCH 14/14] KVM: x86: nSVM: support PAUSE filter threshold and count

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Message-Id: <20210914154825.104886-15-mlevitsk@redhat.com>
Date:   Tue, 14 Sep 2021 18:48:25 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Borislav Petkov <bp@...en8.de>, Bandan Das <bsd@...hat.com>,
        linux-kernel@...r.kernel.org (open list),
        Joerg Roedel <joro@...tes.org>, Ingo Molnar <mingo@...hat.com>,
        Wei Huang <wei.huang2@....com>,
        Sean Christopherson <seanjc@...gle.com>,
        linux-kselftest@...r.kernel.org (open list:KERNEL SELFTEST FRAMEWORK),
        Maxim Levitsky <mlevitsk@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Jim Mattson <jmattson@...gle.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        Shuah Khan <shuah@...nel.org>,
        Wanpeng Li <wanpengli@...cent.com>
Subject: [PATCH 14/14] KVM: x86: nSVM: support PAUSE filter threshold and count

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

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 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(+)

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;
-- 
2.26.3