[PATCH 13/13] KVM: x86: nSVM: Implement support for nested IBS virtualization

[Manali Shukla <manali.shukla@amd.com>]

To handle the case where IBS is enabled for L1 and L2, IBS MSRs are
copied from vmcb12 to vmcb02 during vmentry and vice-versa during
vmexit.

To handle the case where IBS is enabled for L1 but _not_ for L2, IBS
MSRs are copied from vmcb01 to vmcb02 during vmentry and vice-versa
during vmexit.

Signed-off-by: Manali Shukla <manali.shukla@amd.com>
---
 arch/x86/kvm/governed_features.h |  1 +
 arch/x86/kvm/svm/nested.c        | 23 +++++++++++++++++++++++
 arch/x86/kvm/svm/svm.c           | 18 ++++++++++++++++++
 arch/x86/kvm/svm/svm.h           |  1 +
 4 files changed, 43 insertions(+)

diff --git a/arch/x86/kvm/governed_features.h b/arch/x86/kvm/governed_features.h
index 423a73395c10..101c819f3876 100644
--- a/arch/x86/kvm/governed_features.h
+++ b/arch/x86/kvm/governed_features.h
@@ -16,6 +16,7 @@ KVM_GOVERNED_X86_FEATURE(PAUSEFILTER)
 KVM_GOVERNED_X86_FEATURE(PFTHRESHOLD)
 KVM_GOVERNED_X86_FEATURE(VGIF)
 KVM_GOVERNED_X86_FEATURE(VNMI)
+KVM_GOVERNED_X86_FEATURE(VIBS)
 
 #undef KVM_GOVERNED_X86_FEATURE
 #undef KVM_GOVERNED_FEATURE
diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index dd496c9e5f91..a1bb32779b3e 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -616,6 +616,16 @@ static void nested_vmcb02_prepare_save(struct vcpu_svm *svm, struct vmcb *vmcb12
 	} else if (unlikely(vmcb01->control.virt_ext & LBR_CTL_ENABLE_MASK)) {
 		svm_copy_lbrs(vmcb02, vmcb01);
 	}
+
+	if (guest_can_use(vcpu, X86_FEATURE_VIBS) &&
+	    !(vmcb12->control.virt_ext & VIRTUAL_IBS_ENABLE_MASK))
+		vmcb02->control.virt_ext = vmcb12->control.virt_ext & ~VIRTUAL_IBS_ENABLE_MASK;
+
+	if (unlikely(guest_can_use(vcpu, X86_FEATURE_VIBS) &&
+		     (svm->nested.ctl.virt_ext & VIRTUAL_IBS_ENABLE_MASK)))
+		svm_copy_ibs(vmcb02, vmcb12);
+	else if (unlikely(vmcb01->control.virt_ext & VIRTUAL_IBS_ENABLE_MASK))
+		svm_copy_ibs(vmcb02, vmcb01);
 }
 
 static inline bool is_evtinj_soft(u32 evtinj)
@@ -741,6 +751,13 @@ static void nested_vmcb02_prepare_control(struct vcpu_svm *svm,
 		vmcb02->control.virt_ext  |=
 			(svm->nested.ctl.virt_ext & LBR_CTL_ENABLE_MASK);
 
+	vmcb02->control.virt_ext            = vmcb01->control.virt_ext & VIRTUAL_IBS_ENABLE_MASK;
+
+	if (guest_can_use(vcpu, X86_FEATURE_VIBS))
+		vmcb02->control.virt_ext  |= (svm->nested.ctl.virt_ext & VIRTUAL_IBS_ENABLE_MASK);
+	else
+		vmcb02->control.virt_ext &= ~VIRTUAL_IBS_ENABLE_MASK;
+
 	if (!nested_vmcb_needs_vls_intercept(svm))
 		vmcb02->control.virt_ext |= VIRTUAL_VMLOAD_VMSAVE_ENABLE_MASK;
 
@@ -1083,6 +1100,12 @@ int nested_svm_vmexit(struct vcpu_svm *svm)
 		svm_update_lbrv(vcpu);
 	}
 
+	if (unlikely(guest_can_use(vcpu, X86_FEATURE_VIBS) &&
+		     (svm->nested.ctl.virt_ext & VIRTUAL_IBS_ENABLE_MASK)))
+		svm_copy_ibs(vmcb12, vmcb02);
+	else if (unlikely(vmcb01->control.virt_ext & VIRTUAL_IBS_ENABLE_MASK))
+		svm_copy_ibs(vmcb01, vmcb02);
+
 	if (vnmi) {
 		if (vmcb02->control.int_ctl & V_NMI_BLOCKING_MASK)
 			vmcb01->control.int_ctl |= V_NMI_BLOCKING_MASK;
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index b85120f0d3ac..7925bfa0b4ce 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1084,6 +1084,20 @@ void svm_ibs_msr_interception(struct vcpu_svm *svm, bool intercept)
 	set_msr_interception(&svm->vcpu, svm->msrpm, MSR_AMD64_ICIBSEXTDCTL, !intercept, !intercept);
 }
 
+void svm_copy_ibs(struct vmcb *to_vmcb, struct vmcb *from_vmcb)
+{
+	to_vmcb->save.ibs_fetch_ctl		= from_vmcb->save.ibs_fetch_ctl;
+	to_vmcb->save.ibs_fetch_linear_addr	= from_vmcb->save.ibs_fetch_linear_addr;
+	to_vmcb->save.ibs_op_ctl		= from_vmcb->save.ibs_op_ctl;
+	to_vmcb->save.ibs_op_rip		= from_vmcb->save.ibs_op_rip;
+	to_vmcb->save.ibs_op_data		= from_vmcb->save.ibs_op_data;
+	to_vmcb->save.ibs_op_data2		= from_vmcb->save.ibs_op_data2;
+	to_vmcb->save.ibs_op_data3		= from_vmcb->save.ibs_op_data3;
+	to_vmcb->save.ibs_dc_linear_addr	= from_vmcb->save.ibs_dc_linear_addr;
+	to_vmcb->save.ibs_br_target		= from_vmcb->save.ibs_br_target;
+	to_vmcb->save.ibs_fetch_extd_ctl	= from_vmcb->save.ibs_fetch_extd_ctl;
+}
+
 static void grow_ple_window(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
@@ -4441,6 +4455,7 @@ static void svm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
 	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_PFTHRESHOLD);
 	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VGIF);
 	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VNMI);
+	kvm_governed_feature_check_and_set(vcpu, X86_FEATURE_VIBS);
 
 	svm_recalc_instruction_intercepts(vcpu, svm);
 
@@ -5225,6 +5240,9 @@ static __init void svm_set_cpu_caps(void)
 		if (vnmi)
 			kvm_cpu_cap_set(X86_FEATURE_VNMI);
 
+		if (vibs)
+			kvm_cpu_cap_set(X86_FEATURE_VIBS);
+
 		/* Nested VM can receive #VMEXIT instead of triggering #GP */
 		kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK);
 	}
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index c2a02629a1d1..f607dc690d94 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -584,6 +584,7 @@ void svm_vcpu_init_msrpm(struct kvm_vcpu *vcpu, u32 *msrpm);
 void svm_vcpu_free_msrpm(u32 *msrpm);
 void svm_copy_lbrs(struct vmcb *to_vmcb, struct vmcb *from_vmcb);
 void svm_update_lbrv(struct kvm_vcpu *vcpu);
+void svm_copy_ibs(struct vmcb *to_vmcb, struct vmcb *from_vmcb);
 
 int svm_set_efer(struct kvm_vcpu *vcpu, u64 efer);
 void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0);
-- 
2.34.1