linux-kernel - [PATCH v2 3/3] KVM: nSVM: call KVM_REQ_GET_NESTED_STATE

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Date:   Mon, 23 Aug 2021 14:46:18 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Joerg Roedel <joro@...tes.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Jim Mattson <jmattson@...gle.com>,
        x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
        linux-kernel@...r.kernel.org (open list:X86 ARCHITECTURE (32-BIT AND
        64-BIT)), Wanpeng Li <wanpengli@...cent.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Borislav Petkov <bp@...en8.de>,
        Sean Christopherson <seanjc@...gle.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Ingo Molnar <mingo@...hat.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>
Subject: [PATCH v2 3/3] KVM: nSVM: call KVM_REQ_GET_NESTED_STATE_PAGES on exit from SMM mode

This allows nested SVM code to be more similar to nested VMX code.

Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
 arch/x86/kvm/svm/nested.c | 9 ++++++---
 arch/x86/kvm/svm/svm.c    | 8 +++++++-
 arch/x86/kvm/svm/svm.h    | 3 ++-
 3 files changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
index 5e13357da21e..678fd21f6077 100644
--- a/arch/x86/kvm/svm/nested.c
+++ b/arch/x86/kvm/svm/nested.c
@@ -572,7 +572,7 @@ static void nested_svm_copy_common_state(struct vmcb *from_vmcb, struct vmcb *to
 }
 
 int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa,
-			 struct vmcb *vmcb12)
+			 struct vmcb *vmcb12, bool from_entry)
 {
 	struct vcpu_svm *svm = to_svm(vcpu);
 	int ret;
@@ -602,13 +602,16 @@ int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb12_gpa,
 	nested_vmcb02_prepare_save(svm, vmcb12);
 
 	ret = nested_svm_load_cr3(&svm->vcpu, vmcb12->save.cr3,
-				  nested_npt_enabled(svm), true);
+				  nested_npt_enabled(svm), from_entry);
 	if (ret)
 		return ret;
 
 	if (!npt_enabled)
 		vcpu->arch.mmu->inject_page_fault = svm_inject_page_fault_nested;
 
+	if (!from_entry)
+		kvm_make_request(KVM_REQ_GET_NESTED_STATE_PAGES, vcpu);
+
 	svm_set_gif(svm, true);
 
 	return 0;
@@ -674,7 +677,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
 
 	svm->nested.nested_run_pending = 1;
 
-	if (enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12))
+	if (enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12, true))
 		goto out_exit_err;
 
 	if (nested_svm_vmrun_msrpm(svm))
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index ea7a4dacd42f..76ee15af8c48 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4354,6 +4354,12 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
 			if (svm_allocate_nested(svm))
 				return 1;
 
+			/* Exit from the SMM to the non root mode also uses
+			 * the KVM_REQ_GET_NESTED_STATE_PAGES request,
+			 * but in this case the pdptrs must be always reloaded
+			 */
+			vcpu->arch.pdptrs_from_userspace = false;
+
 			/*
 			 * Restore L1 host state from L1 HSAVE area as VMCB01 was
 			 * used during SMM (see svm_enter_smm())
@@ -4368,7 +4374,7 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate)
 
 			vmcb12 = map.hva;
 			nested_load_control_from_vmcb12(svm, &vmcb12->control);
-			ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
+			ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12, false);
 
 			kvm_vcpu_unmap(vcpu, &map, true);
 			kvm_vcpu_unmap(vcpu, &map_save, true);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 524d943f3efc..51ffa46ab257 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -459,7 +459,8 @@ static inline bool nested_exit_on_nmi(struct vcpu_svm *svm)
 	return vmcb_is_intercept(&svm->nested.ctl, INTERCEPT_NMI);
 }
 
-int enter_svm_guest_mode(struct kvm_vcpu *vcpu, u64 vmcb_gpa, struct vmcb *vmcb12);
+int enter_svm_guest_mode(struct kvm_vcpu *vcpu,
+		u64 vmcb_gpa, struct vmcb *vmcb12, bool from_entry);
 void svm_leave_nested(struct vcpu_svm *svm);
 void svm_free_nested(struct vcpu_svm *svm);
 int svm_allocate_nested(struct vcpu_svm *svm);
-- 
2.26.3