Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753518AbaBYSOA (ORCPT ); Tue, 25 Feb 2014 13:14:00 -0500 Received: from mx1.redhat.com ([209.132.183.28]:32408 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753193AbaBYSN7 (ORCPT ); Tue, 25 Feb 2014 13:13:59 -0500 Message-ID: <530CDD59.4040006@redhat.com> Date: Tue, 25 Feb 2014 19:13:45 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Jan Kiszka , linux-kernel@vger.kernel.org CC: gleb@kernel.org, mtosatti@redhat.com, Liu Jinsong Subject: Re: [PATCH 2/2] KVM: x86: Add nested virtualization support for MPX References: <1393350577-11532-1-git-send-email-pbonzini@redhat.com> <1393350577-11532-3-git-send-email-pbonzini@redhat.com> <530CDB5D.6020304@siemens.com> In-Reply-To: <530CDB5D.6020304@siemens.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 25/02/2014 19:05, Jan Kiszka ha scritto: > On 2014-02-25 18:49, Paolo Bonzini wrote: >> This is simple to do, the "host" BNDCFGS is either 0 or the guest value. >> However, both controls have to be present. We cannot provide MPX if >> we only have one of the "load BNDCFGS" or "clear BNDCFGS" controls. >> >> Signed-off-by: Paolo Bonzini >> --- >> arch/x86/kvm/vmx.c | 16 ++++++++++++++++ >> 1 file changed, 16 insertions(+) >> >> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c >> index 729b1e42aded..da28ac46ca88 100644 >> --- a/arch/x86/kvm/vmx.c >> +++ b/arch/x86/kvm/vmx.c >> @@ -202,6 +202,7 @@ struct __packed vmcs12 { >> u64 guest_pdptr1; >> u64 guest_pdptr2; >> u64 guest_pdptr3; >> + u64 guest_bndcfgs; >> u64 host_ia32_pat; >> u64 host_ia32_efer; >> u64 host_ia32_perf_global_ctrl; >> @@ -534,6 +535,7 @@ static const unsigned long shadow_read_write_fields[] = { >> GUEST_CS_LIMIT, >> GUEST_CS_BASE, >> GUEST_ES_BASE, >> + GUEST_BNDCFGS, >> CR0_GUEST_HOST_MASK, >> CR0_READ_SHADOW, >> CR4_READ_SHADOW, >> @@ -589,6 +591,7 @@ static const unsigned short vmcs_field_to_offset_table[] = { >> FIELD64(GUEST_PDPTR1, guest_pdptr1), >> FIELD64(GUEST_PDPTR2, guest_pdptr2), >> FIELD64(GUEST_PDPTR3, guest_pdptr3), >> + FIELD64(GUEST_BNDCFGS, guest_bndcfgs), >> FIELD64(HOST_IA32_PAT, host_ia32_pat), >> FIELD64(HOST_IA32_EFER, host_ia32_efer), >> FIELD64(HOST_IA32_PERF_GLOBAL_CTRL, host_ia32_perf_global_ctrl), >> @@ -719,6 +722,7 @@ static unsigned long nested_ept_get_cr3(struct kvm_vcpu *vcpu); >> static u64 construct_eptp(unsigned long root_hpa); >> static void kvm_cpu_vmxon(u64 addr); >> static void kvm_cpu_vmxoff(void); >> +static bool vmx_mpx_supported(void); >> static int vmx_set_tss_addr(struct kvm *kvm, unsigned int addr); >> static void vmx_set_segment(struct kvm_vcpu *vcpu, >> struct kvm_segment *var, int seg); >> @@ -2279,6 +2283,8 @@ static __init void nested_vmx_setup_ctls_msrs(void) >> } >> nested_vmx_exit_ctls_high |= (VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR | >> VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER); >> + if (vmx_mpx_supported()) >> + nested_vmx_exit_ctls_high |= VM_EXIT_CLEAR_BNDCFGS; >> >> /* entry controls */ >> rdmsr(MSR_IA32_VMX_ENTRY_CTLS, >> @@ -2292,6 +2298,8 @@ static __init void nested_vmx_setup_ctls_msrs(void) >> VM_ENTRY_LOAD_IA32_PAT; >> nested_vmx_entry_ctls_high |= (VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR | >> VM_ENTRY_LOAD_IA32_EFER); >> + if (vmx_mpx_supported()) >> + nested_vmx_entry_ctls_high |= VM_ENTRY_LOAD_BNDCFGS; >> >> /* cpu-based controls */ >> rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, >> @@ -7847,6 +7855,9 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) >> >> set_cr4_guest_host_mask(vmx); >> >> + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS) >> + vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs); >> + >> if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING) >> vmcs_write64(TSC_OFFSET, >> vmx->nested.vmcs01_tsc_offset + vmcs12->tsc_offset); >> @@ -8277,6 +8288,7 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, >> vmcs12->guest_sysenter_cs = vmcs_read32(GUEST_SYSENTER_CS); >> vmcs12->guest_sysenter_esp = vmcs_readl(GUEST_SYSENTER_ESP); >> vmcs12->guest_sysenter_eip = vmcs_readl(GUEST_SYSENTER_EIP); >> + vmcs12->guest_bndcfgs = vmcs_readl(GUEST_BNDCFGS); > > Can we read this value unconditionally, even when the host does not > support the feature? return -EWRONGPATCH; >> >> /* update exit information fields: */ >> >> @@ -8386,6 +8398,10 @@ static void load_vmcs12_host_state(struct kvm_vcpu *vcpu, >> vmcs_writel(GUEST_IDTR_BASE, vmcs12->host_idtr_base); >> vmcs_writel(GUEST_GDTR_BASE, vmcs12->host_gdtr_base); >> >> + /* If not VM_EXIT_CLEAR_BNDCFGS, the L2 value propagates to L1. */ >> + if (vmcs12->vm_exit_controls & VM_EXIT_CLEAR_BNDCFGS) >> + vmcs_write64(GUEST_BNDCFGS, 0); >> + >> if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_PAT) { >> vmcs_write64(GUEST_IA32_PAT, vmcs12->host_ia32_pat); >> vcpu->arch.pat = vmcs12->host_ia32_pat; >> > > Do we also have a unit test to stress this? Or are we lacking silicon > with MPX and corresponding VMX features? No silicon yet. There is an emulator, but it is already slow enough without nested virtualization... it would be three-level virtualization :) Paolo -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/