From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH 01/12] Subject: [PATCH 01/10] nEPT: Support LOAD_IA32_EFER entry/exit controls for L1 Date: Thu, 25 Apr 2013 11:10:26 +0300 Message-ID: <20130425081026.GX12401@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "kvm@vger.kernel.org" To: "Nakajima, Jun" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:4396 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755744Ab3DYIKb (ORCPT ); Thu, 25 Apr 2013 04:10:31 -0400 Content-Disposition: inline In-Reply-To: Sender: kvm-owner@vger.kernel.org List-ID: All the patches are mangled by your email client. Please use "git send-email --thread" to send them. On Thu, Apr 25, 2013 at 12:50:19AM -0700, Nakajima, Jun wrote: > 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 > > modified: arch/x86/kvm/vmx.c > --- > arch/x86/kvm/vmx.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c > index 6667042..9e0ec9d 100644 > --- a/arch/x86/kvm/vmx.c > +++ b/arch/x86/kvm/vmx.c > @@ -2057,6 +2057,7 @@ static __init void nested_vmx_setup_ctls_msrs(void) > #else > nested_vmx_exit_ctls_high = 0; > #endif > + nested_vmx_exit_ctls_high |= VM_EXIT_LOAD_IA32_EFER; > > /* entry controls */ > rdmsr(MSR_IA32_VMX_ENTRY_CTLS, > @@ -2064,6 +2065,7 @@ static __init void nested_vmx_setup_ctls_msrs(void) > nested_vmx_entry_ctls_low = 0; > nested_vmx_entry_ctls_high &= > VM_ENTRY_LOAD_IA32_PAT | VM_ENTRY_IA32E_MODE; > + nested_vmx_entry_ctls_high |= VM_ENTRY_LOAD_IA32_EFER; > > /* cpu-based controls */ > rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, > @@ -7050,10 +7052,18 @@ 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 IA32_MODE, 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) > -- > 1.8.2.1.610.g562af5b > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb.