From mboxrd@z Thu Jan 1 00:00:00 1970 From: Orit Wasserman Subject: Re: [PATCH v5 01/14] nEPT: Support LOAD_IA32_EFER entry/exit controls for L1 Date: Thu, 01 Aug 2013 14:22:25 +0300 Message-ID: <51FA44F1.3010507@redhat.com> References: <1375282131-9713-1-git-send-email-gleb@redhat.com> <1375282131-9713-2-git-send-email-gleb@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Xiao Guangrong , Jun Nakajima , Yang Zhang , pbonzini@redhat.com To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38814 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754152Ab3HALVZ (ORCPT ); Thu, 1 Aug 2013 07:21:25 -0400 In-Reply-To: <1375282131-9713-2-git-send-email-gleb@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 07/31/2013 05:48 PM, Gleb Natapov wrote: > From: Nadav Har'El > > Recent KVM, since http://kerneltrap.org/mailarchive/linux-kvm/2010/5/2/6261577 > switch the EFER MSR when EPT is used and the host and guest have different > NX bits. So if we add support for nested EPT (L1 guest using EPT to run L2) > and want to be able to run recent KVM as L1, we need to allow L1 to use this > EFER switching feature. > > To do this EFER switching, KVM uses VM_ENTRY/EXIT_LOAD_IA32_EFER if available, > and if it isn't, it uses the generic VM_ENTRY/EXIT_MSR_LOAD. This patch adds > support for the former (the latter is still unsupported). > > Nested entry and exit emulation (prepare_vmcs_02 and load_vmcs12_host_state, > respectively) already handled VM_ENTRY/EXIT_LOAD_IA32_EFER correctly. So all > that's left to do in this patch is to properly advertise this feature to L1. > > Note that vmcs12's VM_ENTRY/EXIT_LOAD_IA32_EFER are emulated by L0, by using > vmx_set_efer (which itself sets one of several vmcs02 fields), so we always > support this feature, regardless of whether the host supports it. > > Signed-off-by: Nadav Har'El > Signed-off-by: Jun Nakajima > Signed-off-by: Xinhao Xu > Signed-off-by: Yang Zhang > Signed-off-by: Gleb Natapov > --- > arch/x86/kvm/vmx.c | 23 ++++++++++++++++------- > 1 file changed, 16 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index e999dc7..27efa6a 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2198,7 +2198,8 @@ static __init void nested_vmx_setup_ctls_msrs(void) > #else > nested_vmx_exit_ctls_high = 0; > #endif > - nested_vmx_exit_ctls_high |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR; > + nested_vmx_exit_ctls_high |= (VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR | > + VM_EXIT_LOAD_IA32_EFER); > > /* entry controls */ > rdmsr(MSR_IA32_VMX_ENTRY_CTLS, > @@ -2207,8 +2208,8 @@ static __init void nested_vmx_setup_ctls_msrs(void) > nested_vmx_entry_ctls_low = VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR; > nested_vmx_entry_ctls_high &= > VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_IA32E_MODE; > - nested_vmx_entry_ctls_high |= VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR; > - > + nested_vmx_entry_ctls_high |= (VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR | > + VM_ENTRY_LOAD_IA32_EFER); > /* cpu-based controls */ > rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, > nested_vmx_procbased_ctls_low, nested_vmx_procbased_ctls_high); > @@ -7529,10 +7530,18 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) > vcpu->arch.cr0_guest_owned_bits &= ~vmcs12->cr0_guest_host_mask; > vmcs_writel(CR0_GUEST_HOST_MASK, ~vcpu->arch.cr0_guest_owned_bits); > > - /* Note: IA32_MODE, LOAD_IA32_EFER are modified by vmx_set_efer below */ > - vmcs_write32(VM_EXIT_CONTROLS, > - vmcs12->vm_exit_controls | vmcs_config.vmexit_ctrl); > - vmcs_write32(VM_ENTRY_CONTROLS, vmcs12->vm_entry_controls | > + /* L2->L1 exit controls are emulated - the hardware exit is to L0 so > + * we should use its exit controls. Note that VM_EXIT_LOAD_IA32_EFER > + * bits are further modified by vmx_set_efer() below. > + */ > + vmcs_write32(VM_EXIT_CONTROLS, vmcs_config.vmexit_ctrl); > + > + /* vmcs12's VM_ENTRY_LOAD_IA32_EFER and VM_ENTRY_IA32E_MODE are > + * emulated by vmx_set_efer(), below. > + */ > + vmcs_write32(VM_ENTRY_CONTROLS, > + (vmcs12->vm_entry_controls & ~VM_ENTRY_LOAD_IA32_EFER & > + ~VM_ENTRY_IA32E_MODE) | > (vmcs_config.vmentry_ctrl & ~VM_ENTRY_IA32E_MODE)); > > if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT) > Reviewed-by: Orit Wasserman