From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jun Nakajima Subject: [PATCH v3 10/13] nEPT: Nested INVEPT Date: Sat, 18 May 2013 21:52:29 -0700 Message-ID: <1368939152-11406-10-git-send-email-jun.nakajima@intel.com> References: <1368939152-11406-1-git-send-email-jun.nakajima@intel.com> Cc: Gleb Natapov , Paolo Bonzini To: kvm@vger.kernel.org Return-path: Received: from mail-da0-f49.google.com ([209.85.210.49]:33547 "EHLO mail-da0-f49.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751371Ab3ESExA (ORCPT ); Sun, 19 May 2013 00:53:00 -0400 Received: by mail-da0-f49.google.com with SMTP id p5so3152717dak.8 for ; Sat, 18 May 2013 21:52:59 -0700 (PDT) In-Reply-To: <1368939152-11406-1-git-send-email-jun.nakajima@intel.com> Sender: kvm-owner@vger.kernel.org List-ID: From: Nadav Har'El If we let L1 use EPT, we should probably also support the INVEPT instruction. In our current nested EPT implementation, when L1 changes its EPT table for L2 (i.e., EPT12), L0 modifies the shadow EPT table (EPT02), and in the course of this modification already calls INVEPT. Therefore, when L1 calls INVEPT, we don't really need to do anything. In particular we *don't* need to call the real INVEPT again. All we do in our INVEPT is verify the validity of the call, and its parameters, and then do nothing. In KVM Forum 2010, Dong et al. presented "Nested Virtualization Friendly KVM" and classified our current nested EPT implementation as "shadow-like virtual EPT". He recommended instead a different approach, which he called "VTLB-like virtual EPT". If we had taken that alternative approach, INVEPT would have had a bigger role: L0 would only rebuild the shadow EPT table when L1 calls INVEPT. Signed-off-by: Nadav Har'El Signed-off-by: Jun Nakajima Signed-off-by: Xinhao Xu --- arch/x86/include/uapi/asm/vmx.h | 1 + arch/x86/kvm/vmx.c | 83 +++++++++++++++++++++++++++++++++++++++++ 2 files changed, 84 insertions(+) diff --git a/arch/x86/include/uapi/asm/vmx.h b/arch/x86/include/uapi/asm/vmx.h index d651082..7a34e8f 100644 --- a/arch/x86/include/uapi/asm/vmx.h +++ b/arch/x86/include/uapi/asm/vmx.h @@ -65,6 +65,7 @@ #define EXIT_REASON_EOI_INDUCED 45 #define EXIT_REASON_EPT_VIOLATION 48 #define EXIT_REASON_EPT_MISCONFIG 49 +#define EXIT_REASON_INVEPT 50 #define EXIT_REASON_PREEMPTION_TIMER 52 #define EXIT_REASON_WBINVD 54 #define EXIT_REASON_XSETBV 55 diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 1cf8a41..d9d991d 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -6251,6 +6251,87 @@ static int handle_vmptrst(struct kvm_vcpu *vcpu) return 1; } +/* Emulate the INVEPT instruction */ +static int handle_invept(struct kvm_vcpu *vcpu) +{ + u32 vmx_instruction_info; + unsigned long type; + gva_t gva; + struct x86_exception e; + struct { + u64 eptp, gpa; + } operand; + + if (!(nested_vmx_secondary_ctls_high & SECONDARY_EXEC_ENABLE_EPT) || + !(nested_vmx_ept_caps & VMX_EPT_INVEPT_BIT)) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + if (!nested_vmx_check_permission(vcpu)) + return 1; + + if (!kvm_read_cr0_bits(vcpu, X86_CR0_PE)) { + kvm_queue_exception(vcpu, UD_VECTOR); + return 1; + } + + /* According to the Intel VMX instruction reference, the memory + * operand is read even if it isn't needed (e.g., for type==global) + */ + vmx_instruction_info = vmcs_read32(VMX_INSTRUCTION_INFO); + if (get_vmx_mem_address(vcpu, vmcs_readl(EXIT_QUALIFICATION), + vmx_instruction_info, &gva)) + return 1; + if (kvm_read_guest_virt(&vcpu->arch.emulate_ctxt, gva, &operand, + sizeof(operand), &e)) { + kvm_inject_page_fault(vcpu, &e); + return 1; + } + + type = kvm_register_read(vcpu, (vmx_instruction_info >> 28) & 0xf); + + switch (type) { + case VMX_EPT_EXTENT_GLOBAL: + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_GLOBAL_BIT)) + nested_vmx_failValid(vcpu, + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); + else { + /* + * Do nothing: when L1 changes EPT12, we already + * update EPT02 (the shadow EPT table) and call INVEPT. + * So when L1 calls INVEPT, there's nothing left to do. + */ + nested_vmx_succeed(vcpu); + } + break; + case VMX_EPT_EXTENT_CONTEXT: + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_CONTEXT_BIT)) + nested_vmx_failValid(vcpu, + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); + else { + /* Do nothing */ + nested_vmx_succeed(vcpu); + } + break; + case VMX_EPT_EXTENT_INDIVIDUAL_ADDR: + if (!(nested_vmx_ept_caps & VMX_EPT_EXTENT_INDIVIDUAL_BIT)) + nested_vmx_failValid(vcpu, + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); + else { + /* Do nothing */ + nested_vmx_succeed(vcpu); + } + break; + default: + nested_vmx_failValid(vcpu, + VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID); + } + + skip_emulated_instruction(vcpu); + return 1; +} + /* * The exit handlers return 1 if the exit was handled fully and guest execution * may resume. Otherwise they set the kvm_run parameter to indicate what needs @@ -6295,6 +6376,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = { [EXIT_REASON_PAUSE_INSTRUCTION] = handle_pause, [EXIT_REASON_MWAIT_INSTRUCTION] = handle_invalid_op, [EXIT_REASON_MONITOR_INSTRUCTION] = handle_invalid_op, + [EXIT_REASON_INVEPT] = handle_invept, }; static const int kvm_vmx_max_exit_handlers = @@ -6521,6 +6603,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu) case EXIT_REASON_VMPTRST: case EXIT_REASON_VMREAD: case EXIT_REASON_VMRESUME: case EXIT_REASON_VMWRITE: case EXIT_REASON_VMOFF: case EXIT_REASON_VMON: + case EXIT_REASON_INVEPT: /* * VMX instructions trap unconditionally. This allows L1 to * emulate them for its L2 guest, i.e., allows 3-level nesting! -- 1.8.1.2