From 3df5c37e55c8f9e20d0e9bf01a4e875f72a738f3 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 26 Sep 2018 09:23:44 -0700 Subject: [PATCH] KVM: nVMX: try to set EFER bits correctly when initializing controls VM_ENTRY_IA32E_MODE and VM_{ENTRY,EXIT}_LOAD_IA32_EFER will be explicitly set/cleared as needed by vmx_set_efer(), but attempt to get the bits set correctly when intializing the control fields. Setting the value correctly can avoid multiple VMWrites. Signed-off-by: Sean Christopherson Reviewed-by: Jim Mattson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 51 +++++++++++++++++++++++++++++++--------------- 1 file changed, 35 insertions(+), 16 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 7a245f1dca87..38c0db14e996 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -11972,6 +11972,17 @@ static bool nested_has_guest_tlb_tag(struct kvm_vcpu *vcpu) (nested_cpu_has_vpid(vmcs12) && to_vmx(vcpu)->nested.vpid02); } +static u64 nested_vmx_calc_efer(struct vcpu_vmx *vmx, struct vmcs12 *vmcs12) +{ + if (vmx->nested.nested_run_pending && + (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)) + return vmcs12->guest_ia32_efer; + else if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) + return vmx->vcpu.arch.efer | (EFER_LMA | EFER_LME); + else + return vmx->vcpu.arch.efer & ~(EFER_LMA | EFER_LME); +} + static void prepare_vmcs02_full(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) { struct vcpu_vmx *vmx = to_vmx(vcpu); @@ -12116,6 +12127,7 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, { struct vcpu_vmx *vmx = to_vmx(vcpu); u32 exec_control, vmcs12_exec_ctrl; + u64 guest_efer; if (vmx->nested.dirty_vmcs12) { prepare_vmcs02_full(vcpu, vmcs12); @@ -12264,19 +12276,32 @@ static int 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); + /* + * vmcs12's VM_{ENTRY,EXIT}_LOAD_IA32_EFER and VM_ENTRY_IA32E_MODE + * are emulated by vmx_set_efer(), below, but speculate on the + * related bits (if supported by the CPU) in the hope that we can + * avoid VMWrites during vmx_set_efer(). + */ + guest_efer = nested_vmx_calc_efer(vmx, vmcs12); + /* 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. */ - vm_exit_controls_init(vmx, vmcs_config.vmexit_ctrl); + exec_control = vmcs_config.vmexit_ctrl; + if (cpu_has_load_ia32_efer && guest_efer != host_efer) + exec_control |= VM_EXIT_LOAD_IA32_EFER; + vm_exit_controls_init(vmx, exec_control); - /* vmcs12's VM_ENTRY_LOAD_IA32_EFER and VM_ENTRY_IA32E_MODE are - * emulated by vmx_set_efer(), below. - */ - vm_entry_controls_init(vmx, - (vmcs12->vm_entry_controls & ~VM_ENTRY_LOAD_IA32_EFER & - ~VM_ENTRY_IA32E_MODE) | - (vmcs_config.vmentry_ctrl & ~VM_ENTRY_IA32E_MODE)); + exec_control = (vmcs12->vm_entry_controls | vmcs_config.vmentry_ctrl) & + ~VM_ENTRY_IA32E_MODE & ~VM_ENTRY_LOAD_IA32_EFER; + if (cpu_has_load_ia32_efer) { + if (guest_efer & EFER_LMA) + exec_control |= VM_ENTRY_IA32E_MODE; + if (guest_efer != host_efer) + exec_control |= VM_ENTRY_LOAD_IA32_EFER; + } + vm_entry_controls_init(vmx, exec_control); if (vmx->nested.nested_run_pending && (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_PAT)) { @@ -12350,14 +12375,8 @@ static int prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, vmx_set_cr4(vcpu, vmcs12->guest_cr4); vmcs_writel(CR4_READ_SHADOW, nested_read_cr4(vmcs12)); - if (vmx->nested.nested_run_pending && - (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_IA32_EFER)) - vcpu->arch.efer = vmcs12->guest_ia32_efer; - else if (vmcs12->vm_entry_controls & VM_ENTRY_IA32E_MODE) - vcpu->arch.efer |= (EFER_LMA | EFER_LME); - else - vcpu->arch.efer &= ~(EFER_LMA | EFER_LME); - /* Note: modifies VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */ + vcpu->arch.efer = guest_efer; + /* Note: may modify VM_ENTRY/EXIT_CONTROLS and GUEST/HOST_IA32_EFER */ vmx_set_efer(vcpu, vcpu->arch.efer); /* -- 2.30.2