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Message-Id: <20210913140954.165665-2-mlevitsk@redhat.com>
Date: Mon, 13 Sep 2021 17:09:48 +0300
From: Maxim Levitsky <mlevitsk@...hat.com>
To: kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>, linux-kernel@...r.kernel.org,
Jim Mattson <jmattson@...gle.com>,
Wanpeng Li <wanpengli@...cent.com>,
Thomas Gleixner <tglx@...utronix.de>,
"H. Peter Anvin" <hpa@...or.com>,
Sean Christopherson <seanjc@...gle.com>,
Borislav Petkov <bp@...en8.de>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Maxim Levitsky <mlevitsk@...hat.com>,
Ingo Molnar <mingo@...hat.com>,
x86@...nel.org (maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)),
Joerg Roedel <joro@...tes.org>
Subject: [PATCH v3 1/7] 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 <seanjc@...gle.com>
Signed-off-by: Maxim Levitsky <mlevitsk@...hat.com>
---
arch/x86/kvm/svm/svm.c | 129 +++++++++++++++++++++--------------------
1 file changed, 65 insertions(+), 64 deletions(-)
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1a70e11f0487..a75dafbfa4a6 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -4284,43 +4284,44 @@ 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;
}
@@ -4328,50 +4329,50 @@ 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;
-
- 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;
+ u64 saved_efer, vmcb12_gpa;
+ struct vmcb *vmcb12;
+ int ret;
- if (guest) {
- if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM))
- return 1;
+ if (!guest_cpuid_has(vcpu, X86_FEATURE_LM))
+ return 0;
- if (!(saved_efer & EFER_SVME))
- return 1;
+ /* Non-zero if SMI arrived while vCPU was in guest mode. */
+ if (!GET_SMSTATE(u64, smstate, 0x7ed8))
+ return 0;
- if (kvm_vcpu_map(vcpu,
- gpa_to_gfn(vmcb12_gpa), &map) == -EINVAL)
- return 1;
+ if (!guest_cpuid_has(vcpu, X86_FEATURE_SVM))
+ return 1;
- if (svm_allocate_nested(svm))
- return 1;
+ saved_efer = GET_SMSTATE(u64, smstate, 0x7ed0);
+ if (!(saved_efer & EFER_SVME))
+ return 1;
- vmcb12 = map.hva;
+ vmcb12_gpa = GET_SMSTATE(u64, smstate, 0x7ee0);
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(vmcb12_gpa), &map) == -EINVAL)
+ return 1;
- nested_load_control_from_vmcb12(svm, &vmcb12->control);
+ ret = 1;
+ if (kvm_vcpu_map(vcpu, gpa_to_gfn(svm->nested.hsave_msr), &map_save) == -EINVAL)
+ goto unmap_map;
- ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
- kvm_vcpu_unmap(vcpu, &map, true);
+ if (svm_allocate_nested(svm))
+ goto unmap_save;
- /*
- * 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;
+ vmcb12 = map.hva;
+ nested_load_control_from_vmcb12(svm, &vmcb12->control);
+ ret = enter_svm_guest_mode(vcpu, vmcb12_gpa, vmcb12);
- 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())
+ */
- kvm_vcpu_unmap(vcpu, &map_save, true);
- }
- }
+ svm_copy_vmrun_state(&svm->vmcb01.ptr->save, map_save.hva + 0x400);
+unmap_save:
+ kvm_vcpu_unmap(vcpu, &map_save, true);
+unmap_map:
+ kvm_vcpu_unmap(vcpu, &map, true);
return ret;
}
--
2.26.3
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