From patchwork Wed Jan 6 01:56:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12000783 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0A340C433E0 for ; Wed, 6 Jan 2021 01:57:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B6DE522CE3 for ; Wed, 6 Jan 2021 01:57:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726052AbhAFB5t (ORCPT ); Tue, 5 Jan 2021 20:57:49 -0500 Received: from mga02.intel.com ([134.134.136.20]:45140 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725965AbhAFB5t (ORCPT ); Tue, 5 Jan 2021 20:57:49 -0500 IronPort-SDR: fhZdGzVpGYCLlNZTJk7gDZ6/2lPQeUFoIRSFwOs8LG5qSIQFzU9yl2A+OVO0IWaxMwTajjukUe wBpvP5XpshVA== X-IronPort-AV: E=McAfee;i="6000,8403,9855"; a="164284412" X-IronPort-AV: E=Sophos;i="5.78,478,1599548400"; d="scan'208";a="164284412" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2021 17:57:03 -0800 IronPort-SDR: 6I3Ab42IN2XZ91nP3SrvKP2C+JjrmRPLo1IZFAzm9Q7fsk0IpowqxYxIYqTRRvzda05xdzgjXH x1C8iOaCZ0Mg== X-IronPort-AV: E=Sophos;i="5.78,478,1599548400"; d="scan'208";a="421993442" Received: from zhuoxuan-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.251.29.237]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Jan 2021 17:56:59 -0800 From: Kai Huang To: linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org Cc: seanjc@google.com, jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, mattson@google.com, joro@8bytes.org, vkuznets@redhat.com, wanpengli@tencent.com, Kai Huang Subject: [RFC PATCH 13/23] KVM: VMX: Convert vcpu_vmx.exit_reason to a union Date: Wed, 6 Jan 2021 14:56:43 +1300 Message-Id: X-Mailer: git-send-email 2.29.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org From: Sean Christopherson Convert vcpu_vmx.exit_reason from a u32 to a union (of size u32). The full VM_EXIT_REASON field is comprised of a 16-bit basic exit reason in bits 15:0, and single-bit modifiers in bits 31:16. Historically, KVM has only had to worry about handling the "failed VM-Entry" modifier, which could only be set in very specific flows and required dedicated handling. I.e. manually stripping the FAILED_VMENTRY bit was a somewhat viable approach. But even with only a single bit to worry about, KVM has had several bugs related to comparing a basic exit reason against the full exit reason store in vcpu_vmx. Upcoming Intel features, e.g. SGX, will add new modifier bits that can be set on more or less any VM-Exit, as opposed to the significantly more restricted FAILED_VMENTRY, i.e. correctly handling everything in one-off flows isn't scalable. Tracking exit reason in a union forces code to explicitly choose between consuming the full exit reason and the basic exit, and is a convenient way to document and access the modifiers. No functional change intended. Signed-off-by: Sean Christopherson Signed-off-by: Kai Huang --- arch/x86/kvm/vmx/nested.c | 42 +++++++++++++++--------- arch/x86/kvm/vmx/vmx.c | 68 ++++++++++++++++++++------------------- arch/x86/kvm/vmx/vmx.h | 25 +++++++++++++- 3 files changed, 86 insertions(+), 49 deletions(-) diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c index 89af692deb7e..1ae147e2c8f2 100644 --- a/arch/x86/kvm/vmx/nested.c +++ b/arch/x86/kvm/vmx/nested.c @@ -3310,7 +3310,11 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12 = get_vmcs12(vcpu); enum vm_entry_failure_code entry_failure_code; bool evaluate_pending_interrupts; - u32 exit_reason, failed_index; + u32 failed_index; + union vmx_exit_reason exit_reason = { + .basic = -1, + .failed_vmentry = 1, + }; if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu)) kvm_vcpu_flush_tlb_current(vcpu); @@ -3362,7 +3366,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, if (nested_vmx_check_guest_state(vcpu, vmcs12, &entry_failure_code)) { - exit_reason = EXIT_REASON_INVALID_STATE; + exit_reason.basic = EXIT_REASON_INVALID_STATE; vmcs12->exit_qualification = entry_failure_code; goto vmentry_fail_vmexit; } @@ -3373,7 +3377,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, vcpu->arch.tsc_offset += vmcs12->tsc_offset; if (prepare_vmcs02(vcpu, vmcs12, &entry_failure_code)) { - exit_reason = EXIT_REASON_INVALID_STATE; + exit_reason.basic = EXIT_REASON_INVALID_STATE; vmcs12->exit_qualification = entry_failure_code; goto vmentry_fail_vmexit_guest_mode; } @@ -3383,7 +3387,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, vmcs12->vm_entry_msr_load_addr, vmcs12->vm_entry_msr_load_count); if (failed_index) { - exit_reason = EXIT_REASON_MSR_LOAD_FAIL; + exit_reason.basic = EXIT_REASON_MSR_LOAD_FAIL; vmcs12->exit_qualification = failed_index; goto vmentry_fail_vmexit_guest_mode; } @@ -3451,7 +3455,7 @@ enum nvmx_vmentry_status nested_vmx_enter_non_root_mode(struct kvm_vcpu *vcpu, return NVMX_VMENTRY_VMEXIT; load_vmcs12_host_state(vcpu, vmcs12); - vmcs12->vm_exit_reason = exit_reason | VMX_EXIT_REASONS_FAILED_VMENTRY; + vmcs12->vm_exit_reason = exit_reason.full; if (enable_shadow_vmcs || vmx->nested.hv_evmcs) vmx->nested.need_vmcs12_to_shadow_sync = true; return NVMX_VMENTRY_VMEXIT; @@ -5512,7 +5516,12 @@ static int handle_vmfunc(struct kvm_vcpu *vcpu) return kvm_skip_emulated_instruction(vcpu); fail: - nested_vmx_vmexit(vcpu, vmx->exit_reason, + /* + * This is effectively a reflected VM-Exit, as opposed to a synthesized + * nested VM-Exit. Pass the original exit reason, i.e. don't hardcode + * EXIT_REASON_VMFUNC as the exit reason. + */ + nested_vmx_vmexit(vcpu, vmx->exit_reason.full, vmx_get_intr_info(vcpu), vmx_get_exit_qual(vcpu)); return 1; @@ -5580,7 +5589,8 @@ static bool nested_vmx_exit_handled_io(struct kvm_vcpu *vcpu, * MSR bitmap. This may be the case even when L0 doesn't use MSR bitmaps. */ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu, - struct vmcs12 *vmcs12, u32 exit_reason) + struct vmcs12 *vmcs12, + union vmx_exit_reason exit_reason) { u32 msr_index = kvm_rcx_read(vcpu); gpa_t bitmap; @@ -5594,7 +5604,7 @@ static bool nested_vmx_exit_handled_msr(struct kvm_vcpu *vcpu, * First we need to figure out which of the four to use: */ bitmap = vmcs12->msr_bitmap; - if (exit_reason == EXIT_REASON_MSR_WRITE) + if (exit_reason.basic == EXIT_REASON_MSR_WRITE) bitmap += 2048; if (msr_index >= 0xc0000000) { msr_index -= 0xc0000000; @@ -5731,11 +5741,12 @@ static bool nested_vmx_exit_handled_mtf(struct vmcs12 *vmcs12) * Return true if L0 wants to handle an exit from L2 regardless of whether or not * L1 wants the exit. Only call this when in is_guest_mode (L2). */ -static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason) +static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, + union vmx_exit_reason exit_reason) { u32 intr_info; - switch ((u16)exit_reason) { + switch (exit_reason.basic) { case EXIT_REASON_EXCEPTION_NMI: intr_info = vmx_get_intr_info(vcpu); if (is_nmi(intr_info)) @@ -5791,12 +5802,13 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason) * Return 1 if L1 wants to intercept an exit from L2. Only call this when in * is_guest_mode (L2). */ -static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason) +static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, + union vmx_exit_reason exit_reason) { struct vmcs12 *vmcs12 = get_vmcs12(vcpu); u32 intr_info; - switch ((u16)exit_reason) { + switch (exit_reason.basic) { case EXIT_REASON_EXCEPTION_NMI: intr_info = vmx_get_intr_info(vcpu); if (is_nmi(intr_info)) @@ -5915,7 +5927,7 @@ static bool nested_vmx_l1_wants_exit(struct kvm_vcpu *vcpu, u32 exit_reason) bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - u32 exit_reason = vmx->exit_reason; + union vmx_exit_reason exit_reason = vmx->exit_reason; unsigned long exit_qual; u32 exit_intr_info; @@ -5934,7 +5946,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu) goto reflect_vmexit; } - trace_kvm_nested_vmexit(exit_reason, vcpu, KVM_ISA_VMX); + trace_kvm_nested_vmexit(exit_reason.full, vcpu, KVM_ISA_VMX); /* If L0 (KVM) wants the exit, it trumps L1's desires. */ if (nested_vmx_l0_wants_exit(vcpu, exit_reason)) @@ -5960,7 +5972,7 @@ bool nested_vmx_reflect_vmexit(struct kvm_vcpu *vcpu) exit_qual = vmx_get_exit_qual(vcpu); reflect_vmexit: - nested_vmx_vmexit(vcpu, exit_reason, exit_intr_info, exit_qual); + nested_vmx_vmexit(vcpu, exit_reason.full, exit_intr_info, exit_qual); return true; } diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 47b8357b9751..8b37812bbadc 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1578,7 +1578,7 @@ static int skip_emulated_instruction(struct kvm_vcpu *vcpu) * i.e. we end up advancing IP with some random value. */ if (!static_cpu_has(X86_FEATURE_HYPERVISOR) || - to_vmx(vcpu)->exit_reason != EXIT_REASON_EPT_MISCONFIG) { + to_vmx(vcpu)->exit_reason.basic != EXIT_REASON_EPT_MISCONFIG) { orig_rip = kvm_rip_read(vcpu); rip = orig_rip + vmcs_read32(VM_EXIT_INSTRUCTION_LEN); #ifdef CONFIG_X86_64 @@ -5687,7 +5687,7 @@ static void vmx_get_exit_info(struct kvm_vcpu *vcpu, u64 *info1, u64 *info2, struct vcpu_vmx *vmx = to_vmx(vcpu); *info1 = vmx_get_exit_qual(vcpu); - if (!(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) { + if (!vmx->exit_reason.failed_vmentry) { *info2 = vmx->idt_vectoring_info; *intr_info = vmx_get_intr_info(vcpu); if (is_exception_with_error_code(*intr_info)) @@ -5931,8 +5931,9 @@ void dump_vmcs(void) static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) { struct vcpu_vmx *vmx = to_vmx(vcpu); - u32 exit_reason = vmx->exit_reason; + union vmx_exit_reason exit_reason = vmx->exit_reason; u32 vectoring_info = vmx->idt_vectoring_info; + u16 exit_handler_index; /* * Flush logged GPAs PML buffer, this will make dirty_bitmap more @@ -5974,11 +5975,11 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) return 1; } - if (exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY) { + if (exit_reason.failed_vmentry) { dump_vmcs(); vcpu->run->exit_reason = KVM_EXIT_FAIL_ENTRY; vcpu->run->fail_entry.hardware_entry_failure_reason - = exit_reason; + = exit_reason.full; vcpu->run->fail_entry.cpu = vcpu->arch.last_vmentry_cpu; return 0; } @@ -6000,18 +6001,18 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) * will cause infinite loop. */ if ((vectoring_info & VECTORING_INFO_VALID_MASK) && - (exit_reason != EXIT_REASON_EXCEPTION_NMI && - exit_reason != EXIT_REASON_EPT_VIOLATION && - exit_reason != EXIT_REASON_PML_FULL && - exit_reason != EXIT_REASON_APIC_ACCESS && - exit_reason != EXIT_REASON_TASK_SWITCH)) { + (exit_reason.basic != EXIT_REASON_EXCEPTION_NMI && + exit_reason.basic != EXIT_REASON_EPT_VIOLATION && + exit_reason.basic != EXIT_REASON_PML_FULL && + exit_reason.basic != EXIT_REASON_APIC_ACCESS && + exit_reason.basic != EXIT_REASON_TASK_SWITCH)) { vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_DELIVERY_EV; vcpu->run->internal.ndata = 3; vcpu->run->internal.data[0] = vectoring_info; - vcpu->run->internal.data[1] = exit_reason; + vcpu->run->internal.data[1] = exit_reason.full; vcpu->run->internal.data[2] = vcpu->arch.exit_qualification; - if (exit_reason == EXIT_REASON_EPT_MISCONFIG) { + if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG) { vcpu->run->internal.ndata++; vcpu->run->internal.data[3] = vmcs_read64(GUEST_PHYSICAL_ADDRESS); @@ -6043,38 +6044,39 @@ static int vmx_handle_exit(struct kvm_vcpu *vcpu, fastpath_t exit_fastpath) if (exit_fastpath != EXIT_FASTPATH_NONE) return 1; - if (exit_reason >= kvm_vmx_max_exit_handlers) + if (exit_reason.basic >= kvm_vmx_max_exit_handlers) goto unexpected_vmexit; #ifdef CONFIG_RETPOLINE - if (exit_reason == EXIT_REASON_MSR_WRITE) + if (exit_reason.basic == EXIT_REASON_MSR_WRITE) return kvm_emulate_wrmsr(vcpu); - else if (exit_reason == EXIT_REASON_PREEMPTION_TIMER) + else if (exit_reason.basic == EXIT_REASON_PREEMPTION_TIMER) return handle_preemption_timer(vcpu); - else if (exit_reason == EXIT_REASON_INTERRUPT_WINDOW) + else if (exit_reason.basic == EXIT_REASON_INTERRUPT_WINDOW) return handle_interrupt_window(vcpu); - else if (exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) + else if (exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT) return handle_external_interrupt(vcpu); - else if (exit_reason == EXIT_REASON_HLT) + else if (exit_reason.basic == EXIT_REASON_HLT) return kvm_emulate_halt(vcpu); - else if (exit_reason == EXIT_REASON_EPT_MISCONFIG) + else if (exit_reason.basic == EXIT_REASON_EPT_MISCONFIG) return handle_ept_misconfig(vcpu); #endif - exit_reason = array_index_nospec(exit_reason, - kvm_vmx_max_exit_handlers); - if (!kvm_vmx_exit_handlers[exit_reason]) + exit_handler_index = array_index_nospec((u16)exit_reason.basic, + kvm_vmx_max_exit_handlers); + if (!kvm_vmx_exit_handlers[exit_handler_index]) goto unexpected_vmexit; - return kvm_vmx_exit_handlers[exit_reason](vcpu); + return kvm_vmx_exit_handlers[exit_handler_index](vcpu); unexpected_vmexit: - vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", exit_reason); + vcpu_unimpl(vcpu, "vmx: unexpected exit reason 0x%x\n", + exit_reason.full); dump_vmcs(); vcpu->run->exit_reason = KVM_EXIT_INTERNAL_ERROR; vcpu->run->internal.suberror = KVM_INTERNAL_ERROR_UNEXPECTED_EXIT_REASON; vcpu->run->internal.ndata = 2; - vcpu->run->internal.data[0] = exit_reason; + vcpu->run->internal.data[0] = exit_reason.full; vcpu->run->internal.data[1] = vcpu->arch.last_vmentry_cpu; return 0; } @@ -6393,9 +6395,9 @@ static void vmx_handle_exit_irqoff(struct kvm_vcpu *vcpu) { struct vcpu_vmx *vmx = to_vmx(vcpu); - if (vmx->exit_reason == EXIT_REASON_EXTERNAL_INTERRUPT) + if (vmx->exit_reason.basic == EXIT_REASON_EXTERNAL_INTERRUPT) handle_external_interrupt_irqoff(vcpu); - else if (vmx->exit_reason == EXIT_REASON_EXCEPTION_NMI) + else if (vmx->exit_reason.basic == EXIT_REASON_EXCEPTION_NMI) handle_exception_nmi_irqoff(vmx); } @@ -6583,7 +6585,7 @@ void noinstr vmx_update_host_rsp(struct vcpu_vmx *vmx, unsigned long host_rsp) static fastpath_t vmx_exit_handlers_fastpath(struct kvm_vcpu *vcpu) { - switch (to_vmx(vcpu)->exit_reason) { + switch (to_vmx(vcpu)->exit_reason.basic) { case EXIT_REASON_MSR_WRITE: return handle_fastpath_set_msr_irqoff(vcpu); case EXIT_REASON_PREEMPTION_TIMER: @@ -6782,17 +6784,17 @@ static fastpath_t vmx_vcpu_run(struct kvm_vcpu *vcpu) vmx->idt_vectoring_info = 0; if (unlikely(vmx->fail)) { - vmx->exit_reason = 0xdead; + vmx->exit_reason.full = 0xdead; return EXIT_FASTPATH_NONE; } - vmx->exit_reason = vmcs_read32(VM_EXIT_REASON); - if (unlikely((u16)vmx->exit_reason == EXIT_REASON_MCE_DURING_VMENTRY)) + vmx->exit_reason.full = vmcs_read32(VM_EXIT_REASON); + if (unlikely(vmx->exit_reason.basic == EXIT_REASON_MCE_DURING_VMENTRY)) kvm_machine_check(); - trace_kvm_exit(vmx->exit_reason, vcpu, KVM_ISA_VMX); + trace_kvm_exit(vmx->exit_reason.full, vcpu, KVM_ISA_VMX); - if (unlikely(vmx->exit_reason & VMX_EXIT_REASONS_FAILED_VMENTRY)) + if (unlikely(vmx->exit_reason.failed_vmentry)) return EXIT_FASTPATH_NONE; vmx->loaded_vmcs->launched = 1; diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h index f6f66e5c6510..c8ad47ea8445 100644 --- a/arch/x86/kvm/vmx/vmx.h +++ b/arch/x86/kvm/vmx/vmx.h @@ -70,6 +70,29 @@ struct pt_desc { struct pt_ctx guest; }; +union vmx_exit_reason { + struct { + u32 basic : 16; + u32 reserved16 : 1; + u32 reserved17 : 1; + u32 reserved18 : 1; + u32 reserved19 : 1; + u32 reserved20 : 1; + u32 reserved21 : 1; + u32 reserved22 : 1; + u32 reserved23 : 1; + u32 reserved24 : 1; + u32 reserved25 : 1; + u32 reserved26 : 1; + u32 sgx_enclave_mode : 1; + u32 smi_pending_mtf : 1; + u32 smi_from_vmx_root : 1; + u32 reserved30 : 1; + u32 failed_vmentry : 1; + }; + u32 full; +}; + /* * The nested_vmx structure is part of vcpu_vmx, and holds information we need * for correct emulation of VMX (i.e., nested VMX) on this vcpu. @@ -244,7 +267,7 @@ struct vcpu_vmx { int vpid; bool emulation_required; - u32 exit_reason; + union vmx_exit_reason exit_reason; /* Posted interrupt descriptor */ struct pi_desc pi_desc;