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| author | Wei Huang <wei.huang2@amd.com> | 2021-01-26 03:18:31 -0500 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2021-02-04 05:27:28 -0500 |
| commit | 14c2bf81fcd2226ca7fb9b179320ca1ca7cb581a (patch) | |
| tree | 8fea01a324274270a98afa84ae8c0f165ee3a599 | |
| parent | 3b9c723ed7cfa4e1eef338afaa57e94be2a60d9c (diff) | |
| download | powerpc-14c2bf81fcd2226ca7fb9b179320ca1ca7cb581a.tar.gz | |
KVM: SVM: Fix #GP handling for doubly-nested virtualization
Under the case of nested on nested (L0, L1, L2 are all hypervisors),
we do not support emulation of the vVMLOAD/VMSAVE feature, the
L0 hypervisor can inject the proper #VMEXIT to inform L1 of what is
happening and L1 can avoid invoking the #GP workaround. For this
reason we turns on guest VM's X86_FEATURE_SVME_ADDR_CHK bit for KVM
running inside VM to receive the notification and change behavior.
Similarly we check if vcpu is under guest mode before emulating the
vmware-backdoor instructions. For the case of nested on nested, we
let the guest handle it.
Co-developed-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Bandan Das <bsd@redhat.com>
Signed-off-by: Wei Huang <wei.huang2@amd.com>
Tested-by: Maxim Levitsky <mlevitsk@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210126081831.570253-5-wei.huang2@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 0378d423044f6a..8d18f01b29c30a 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -933,6 +933,9 @@ static __init void svm_set_cpu_caps(void) if (npt_enabled) kvm_cpu_cap_set(X86_FEATURE_NPT); + + /* Nested VM can receive #VMEXIT instead of triggering #GP */ + kvm_cpu_cap_set(X86_FEATURE_SVME_ADDR_CHK); } /* CPUID 0x80000008 */ @@ -2202,6 +2205,11 @@ static int svm_instr_opcode(struct kvm_vcpu *vcpu) static int emulate_svm_instr(struct kvm_vcpu *vcpu, int opcode) { + const int guest_mode_exit_codes[] = { + [SVM_INSTR_VMRUN] = SVM_EXIT_VMRUN, + [SVM_INSTR_VMLOAD] = SVM_EXIT_VMLOAD, + [SVM_INSTR_VMSAVE] = SVM_EXIT_VMSAVE, + }; int (*const svm_instr_handlers[])(struct vcpu_svm *svm) = { [SVM_INSTR_VMRUN] = vmrun_interception, [SVM_INSTR_VMLOAD] = vmload_interception, @@ -2209,7 +2217,14 @@ static int emulate_svm_instr(struct kvm_vcpu *vcpu, int opcode) }; struct vcpu_svm *svm = to_svm(vcpu); - return svm_instr_handlers[opcode](svm); + if (is_guest_mode(vcpu)) { + svm->vmcb->control.exit_code = guest_mode_exit_codes[opcode]; + svm->vmcb->control.exit_info_1 = 0; + svm->vmcb->control.exit_info_2 = 0; + + return nested_svm_vmexit(svm); + } else + return svm_instr_handlers[opcode](svm); } /* @@ -2244,7 +2259,8 @@ static int gp_interception(struct vcpu_svm *svm) * VMware backdoor emulation on #GP interception only handles * IN{S}, OUT{S}, and RDPMC. */ - return kvm_emulate_instruction(vcpu, + if (!is_guest_mode(vcpu)) + return kvm_emulate_instruction(vcpu, EMULTYPE_VMWARE_GP | EMULTYPE_NO_DECODE); } else return emulate_svm_instr(vcpu, opcode); |