On Mon, Aug 5, 2013 at 4:07 PM, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > From: Nadav Har'El <nyh@xxxxxxxxxx> > > 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. > > Reviewed-by: Orit Wasserman <owasserm@xxxxxxxxxx> > Signed-off-by: Nadav Har'El <nyh@xxxxxxxxxx> > Signed-off-by: Jun Nakajima <jun.nakajima@xxxxxxxxx> > Signed-off-by: Xinhao Xu <xinhao.xu@xxxxxxxxx> > Signed-off-by: Yang Zhang <yang.z.zhang@xxxxxxxxx> > Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx> > --- > 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); Gleb, why we don't need to check whether host supports VM_EXIT_LOAD_IA32_EFER here, as what you noted in my VM_EXIT_LOAD_IA32_PAT patch? Arthur > > /* 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) > -- > 1.7.10.4 > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
