From: Sean Christopherson <sean.j.christopherson@intel.com> To: Tao Xu <tao3.xu@intel.com> Cc: pbonzini@redhat.com, rkrcmar@redhat.com, corbet@lwn.net, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, fenghua.yu@intel.com, xiaoyao.li@linux.intel.com, jingqi.liu@intel.com Subject: Re: [PATCH v7 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE Date: Fri, 12 Jul 2019 09:03:52 -0700 Message-ID: <20190712160352.GD29659@linux.intel.com> (raw) In-Reply-To: <20190712082907.29137-4-tao3.xu@intel.com> On Fri, Jul 12, 2019 at 04:29:07PM +0800, Tao Xu wrote: > --- a/arch/x86/kvm/vmx/nested.c > +++ b/arch/x86/kvm/vmx/nested.c > @@ -5213,6 +5213,9 @@ bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason) > case EXIT_REASON_ENCLS: > /* SGX is never exposed to L1 */ > return false; > + case EXIT_REASON_UMWAIT: case EXIT_REASON_TPAUSE: Grouped case statements are usually stacked vertically, e.g.: case EXIT_REASON_UMWAIT: case EXIT_REASON_TPAUSE: > + return nested_cpu_has2(vmcs12, > + SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE); > default: > return true; > } > diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c > index 0787f140d155..e026b1313dc3 100644 > --- a/arch/x86/kvm/vmx/vmx.c > +++ b/arch/x86/kvm/vmx/vmx.c > @@ -5349,6 +5349,20 @@ static int handle_monitor(struct kvm_vcpu *vcpu) > return handle_nop(vcpu); > } > > +static int handle_umwait(struct kvm_vcpu *vcpu) > +{ > + kvm_skip_emulated_instruction(vcpu); > + WARN(1, "this should never happen\n"); Blech. I'm guessing this code was copy-pasted from handle_xsaves() and handle_xrstors(). The blurb of "this should never happen" isn't very helpful, e.g. the WARN itself makes it pretty obvious that we don't expect to reach this point. WARN_ONCE would also be preferable, no need to spam the log in the event things go completely haywire. Rather than propagate ugly code, what about defining a common helper, e.g. static int handle_unexpected_vmexit(struct kvm_vcpu *vcpu) { kvm_skip_emulated_instruction(vcpu); WARN_ONCE(1, "Unexpected VM-Exit = 0x%x", vmcs_read32(VM_EXIT_REASON)); return 1; } ... { [EXIT_REASON_XSAVES] = handle_unexpected_vmexit, [EXIT_REASON_XRSTORS] = handle_unexpected_vmexit, [EXIT_REASON_UMWAIT] = handle_unexpected_vmexit, [EXIT_REASON_TPAUSE] = handle_unexpected_vmexit, } > + return 1; > +} > + > +static int handle_tpause(struct kvm_vcpu *vcpu) > +{ > + kvm_skip_emulated_instruction(vcpu); > + WARN(1, "this should never happen\n"); > + return 1; > +} > + > static int handle_invpcid(struct kvm_vcpu *vcpu) > { > u32 vmx_instruction_info; > @@ -5559,6 +5573,8 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { > [EXIT_REASON_VMFUNC] = handle_vmx_instruction, > [EXIT_REASON_PREEMPTION_TIMER] = handle_preemption_timer, > [EXIT_REASON_ENCLS] = handle_encls, > + [EXIT_REASON_UMWAIT] = handle_umwait, > + [EXIT_REASON_TPAUSE] = handle_tpause, > }; > > static const int kvm_vmx_max_exit_handlers = > -- > 2.20.1 >
next prev parent reply index Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-07-12 8:29 [PATCH v7 0/3] KVM: x86: Enable user wait instructions Tao Xu 2019-07-12 8:29 ` [PATCH v7 1/3] KVM: x86: add support for " Tao Xu 2019-07-12 15:13 ` Sean Christopherson 2019-07-15 1:11 ` Tao Xu 2019-07-12 8:29 ` [PATCH v7 2/3] KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL Tao Xu 2019-07-12 15:52 ` Sean Christopherson 2019-07-15 1:22 ` Tao Xu 2019-07-15 14:16 ` Sean Christopherson 2019-07-16 16:03 ` Eduardo Habkost 2019-07-17 1:17 ` Tao Xu 2019-07-17 2:03 ` Tao Xu 2019-07-12 8:29 ` [PATCH v7 3/3] KVM: vmx: handle vm-exit for UMWAIT and TPAUSE Tao Xu 2019-07-12 16:03 ` Sean Christopherson [this message] 2019-07-13 14:22 ` Tao Xu
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