From 136a55c054ca03b44b74efe03f136d495dd84ec8 Mon Sep 17 00:00:00 2001 From: Maxim Levitsky Date: Wed, 22 Sep 2021 10:28:43 -0400 Subject: [PATCH] KVM: x86: nSVM: refactor svm_leave_smm and smm_enter_smm Use return statements instead of nested if, and fix error path to free all the maps that were allocated. Suggested-by: Sean Christopherson Signed-off-by: Maxim Levitsky Message-Id: <20210913140954.165665-2-mlevitsk@redhat.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm/svm.c | 135 +++++++++++++++++++++++++------------------------ 1 file changed, 69 insertions(+), 66 deletions(-) diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index ffdde86..196bb3d 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -4285,43 +4285,44 @@ static int svm_enter_smm(struct kvm_vcpu *vcpu, char *smstate) struct kvm_host_map map_save; int ret; - if (is_guest_mode(vcpu)) { - /* FED8h - SVM Guest */ - put_smstate(u64, smstate, 0x7ed8, 1); - /* FEE0h - SVM Guest VMCB Physical Address */ - put_smstate(u64, smstate, 0x7ee0, svm->nested.vmcb12_gpa); + if (!is_guest_mode(vcpu)) + return 0; - svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX]; - svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP]; - svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP]; + /* FED8h - SVM Guest */ + put_smstate(u64, smstate, 0x7ed8, 1); + /* FEE0h - SVM Guest VMCB Physical Address */ + put_smstate(u64, smstate, 0x7ee0, svm->nested.vmcb12_gpa); - ret = nested_svm_vmexit(svm); - if (ret) - return ret; + svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX]; + svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP]; + svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP]; - /* - * KVM uses VMCB01 to store L1 host state while L2 runs but - * VMCB01 is going to be used during SMM and thus the state will - * be lost. Temporary save non-VMLOAD/VMSAVE state to the host save - * area pointed to by MSR_VM_HSAVE_PA. APM guarantees that the - * format of the area is identical to guest save area offsetted - * by 0x400 (matches the offset of 'struct vmcb_save_area' - * within 'struct vmcb'). Note: HSAVE area may also be used by - * L1 hypervisor to save additional host context (e.g. KVM does - * that, see svm_prepare_guest_switch()) which must be - * preserved. - */ - if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), - &map_save) == -EINVAL) - return 1; + ret = nested_svm_vmexit(svm); + if (ret) + return ret; + + /* + * KVM uses VMCB01 to store L1 host state while L2 runs but + * VMCB01 is going to be used during SMM and thus the state will + * be lost. Temporary save non-VMLOAD/VMSAVE state to the host save + * area pointed to by MSR_VM_HSAVE_PA. APM guarantees that the + * format of the area is identical to guest save area offsetted + * by 0x400 (matches the offset of 'struct vmcb_save_area' + * within 'struct vmcb'). Note: HSAVE area may also be used by + * L1 hypervisor to save additional host context (e.g. KVM does + * that, see svm_prepare_guest_switch()) which must be + * preserved. + */ + if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), + &map_save) == -EINVAL) + return 1; - BUILD_BUG_ON(offsetof(struct vmcb, save) != 0x400); + BUILD_BUG_ON(offsetof(struct vmcb, save) != 0x400); - svm_copy_vmrun_state(map_save.hva + 0x400, - &svm->vmcb01.ptr->save); + svm_copy_vmrun_state(map_save.hva + 0x400, + &svm->vmcb01.ptr->save); - kvm_vcpu_unmap(vcpu, &map_save, true); - } + kvm_vcpu_unmap(vcpu, &map_save, true); return 0; } @@ -4329,52 +4330,54 @@ static int svm_leave_smm(struct kvm_vcpu *vcpu, const char *smstate) { struct vcpu_svm *svm = to_svm(vcpu); struct kvm_host_map map, map_save; - int ret = 0; + u64 saved_efer, vmcb12_gpa; + struct vmcb *vmcb12; + int ret; - if (guest_cpuid_has(vcpu, X86_FEATURE_LM)) { - u64 saved_efer = GET_SMSTATE(u64, smstate, 0x7ed0); - u64 guest = GET_SMSTATE(u64, smstate, 0x7ed8); - u64 vmcb12_gpa = GET_SMSTATE(u64, smstate, 0x7ee0); - struct vmcb *vmcb12; + if (!guest_cpuid_has(vcpu, X86_FEATURE_LM)) + return 0; - if (guest) { - if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM)) - return 1; + /* Non-zero if SMI arrived while vCPU was in guest mode. */ + if (!GET_SMSTATE(u64, smstate, 0x7ed8)) + return 0; - if (!(saved_efer & EFER_SVME)) - return 1; + if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM)) + return 1; - if (kvm_vcpu_map(vcpu, - gpa_to_gfn(vmcb12_gpa), &map) == -EINVAL) - return 1; + saved_efer = GET_SMSTATE(u64, smstate, 0x7ed0); + if (!(saved_efer & EFER_SVME)) + return 1; - if (svm_allocate_nested(svm)) - return 1; + vmcb12_gpa = GET_SMSTATE(u64, smstate, 0x7ee0); + if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcb12_gpa), &map) == -EINVAL) + return 1; - kvm_vcpu_unmap(vcpu, &map, true); + ret = 1; + if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), &map_save) == -EINVAL) + goto unmap_map; - /* - * Restore L1 host state from L1 HSAVE area as VMCB01 was - * used during SMM (see svm_enter_smm()) - */ - if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), - &map_save) == -EINVAL) - return 1; + if (svm_allocate_nested(svm)) + goto unmap_save; - svm_copy_vmrun_state(&svm->vmcb01.ptr->save, - map_save.hva + 0x400); + /* + * Restore L1 host state from L1 HSAVE area as VMCB01 was + * used during SMM (see svm_enter_smm()) + */ - /* - * Enter the nested guest now - */ - vmcb12 = map.hva; - nested_load_control_from_vmcb12(svm, &vmcb12->control); - ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12, false); + svm_copy_vmrun_state(&svm->vmcb01.ptr->save, map_save.hva + 0x400); - kvm_vcpu_unmap(vcpu, &map_save, true); - } - } + /* + * Enter the nested guest now + */ + vmcb12 = map.hva; + nested_load_control_from_vmcb12(svm, &vmcb12->control); + ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12, false); + +unmap_save: + kvm_vcpu_unmap(vcpu, &map_save, true); +unmap_map: + kvm_vcpu_unmap(vcpu, &map, true); return ret; } -- 2.7.4