From 2996fca0690f03a5220203588f4a0d8c5acba2b0 Mon Sep 17 00:00:00 2001 From: Jan Kiszka Date: Mon, 16 Jun 2014 13:59:43 +0200 Subject: [PATCH] KVM: nVMX: Allow to disable VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS Allow L1 to "leak" its debug controls into L2, i.e. permit cleared VM_{ENTRY_LOAD,EXIT_SAVE}_DEBUG_CONTROLS. This requires to manually transfer the state of DR7 and IA32_DEBUGCTLMSR from L1 into L2 as both run on different VMCS. Signed-off-by: Jan Kiszka Signed-off-by: Paolo Bonzini --- arch/x86/kvm/vmx.c | 44 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 38 insertions(+), 6 deletions(-) diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c index 66365a009cff..b93e2ae2bb62 100644 --- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -383,6 +383,9 @@ struct nested_vmx { struct hrtimer preemption_timer; bool preemption_timer_expired; + + /* to migrate it to L2 if VM_ENTRY_LOAD_DEBUG_CONTROLS is off */ + u64 vmcs01_debugctl; }; #define POSTED_INTR_ON 0 @@ -2243,7 +2246,9 @@ static u32 nested_vmx_true_procbased_ctls_low; static u32 nested_vmx_secondary_ctls_low, nested_vmx_secondary_ctls_high; static u32 nested_vmx_pinbased_ctls_low, nested_vmx_pinbased_ctls_high; static u32 nested_vmx_exit_ctls_low, nested_vmx_exit_ctls_high; +static u32 nested_vmx_true_exit_ctls_low; static u32 nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high; +static u32 nested_vmx_true_entry_ctls_low; static u32 nested_vmx_misc_low, nested_vmx_misc_high; static u32 nested_vmx_ept_caps; static __init void nested_vmx_setup_ctls_msrs(void) @@ -2289,6 +2294,10 @@ static __init void nested_vmx_setup_ctls_msrs(void) if (vmx_mpx_supported()) nested_vmx_exit_ctls_high |= VM_EXIT_CLEAR_BNDCFGS; + /* We support free control of debug control saving. */ + nested_vmx_true_exit_ctls_low = nested_vmx_exit_ctls_low & + ~VM_EXIT_SAVE_DEBUG_CONTROLS; + /* entry controls */ rdmsr(MSR_IA32_VMX_ENTRY_CTLS, nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high); @@ -2303,6 +2312,10 @@ static __init void nested_vmx_setup_ctls_msrs(void) if (vmx_mpx_supported()) nested_vmx_entry_ctls_high |= VM_ENTRY_LOAD_BNDCFGS; + /* We support free control of debug control loading. */ + nested_vmx_true_entry_ctls_low = nested_vmx_entry_ctls_low & + ~VM_ENTRY_LOAD_DEBUG_CONTROLS; + /* cpu-based controls */ rdmsr(MSR_IA32_VMX_PROCBASED_CTLS, nested_vmx_procbased_ctls_low, nested_vmx_procbased_ctls_high); @@ -2409,11 +2422,17 @@ static int vmx_get_vmx_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata) nested_vmx_procbased_ctls_high); break; case MSR_IA32_VMX_TRUE_EXIT_CTLS: + *pdata = vmx_control_msr(nested_vmx_true_exit_ctls_low, + nested_vmx_exit_ctls_high); + break; case MSR_IA32_VMX_EXIT_CTLS: *pdata = vmx_control_msr(nested_vmx_exit_ctls_low, nested_vmx_exit_ctls_high); break; case MSR_IA32_VMX_TRUE_ENTRY_CTLS: + *pdata = vmx_control_msr(nested_vmx_true_entry_ctls_low, + nested_vmx_entry_ctls_high); + break; case MSR_IA32_VMX_ENTRY_CTLS: *pdata = vmx_control_msr(nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high); @@ -7836,7 +7855,13 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs_writel(GUEST_GDTR_BASE, vmcs12->guest_gdtr_base); vmcs_writel(GUEST_IDTR_BASE, vmcs12->guest_idtr_base); - vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl); + if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS) { + kvm_set_dr(vcpu, 7, vmcs12->guest_dr7); + vmcs_write64(GUEST_IA32_DEBUGCTL, vmcs12->guest_ia32_debugctl); + } else { + kvm_set_dr(vcpu, 7, vcpu->arch.dr7); + vmcs_write64(GUEST_IA32_DEBUGCTL, vmx->nested.vmcs01_debugctl); + } vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, vmcs12->vm_entry_intr_info_field); vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE, @@ -7846,7 +7871,6 @@ static void prepare_vmcs02(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12) vmcs_write32(GUEST_INTERRUPTIBILITY_INFO, vmcs12->guest_interruptibility_info); vmcs_write32(GUEST_SYSENTER_CS, vmcs12->guest_sysenter_cs); - kvm_set_dr(vcpu, 7, vmcs12->guest_dr7); vmx_set_rflags(vcpu, vmcs12->guest_rflags); vmcs_writel(GUEST_PENDING_DBG_EXCEPTIONS, vmcs12->guest_pending_dbg_exceptions); @@ -8143,9 +8167,11 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) !vmx_control_verify(vmcs12->pin_based_vm_exec_control, nested_vmx_pinbased_ctls_low, nested_vmx_pinbased_ctls_high) || !vmx_control_verify(vmcs12->vm_exit_controls, - nested_vmx_exit_ctls_low, nested_vmx_exit_ctls_high) || + nested_vmx_true_exit_ctls_low, + nested_vmx_exit_ctls_high) || !vmx_control_verify(vmcs12->vm_entry_controls, - nested_vmx_entry_ctls_low, nested_vmx_entry_ctls_high)) + nested_vmx_true_entry_ctls_low, + nested_vmx_entry_ctls_high)) { nested_vmx_failValid(vcpu, VMXERR_ENTRY_INVALID_CONTROL_FIELD); return 1; @@ -8222,6 +8248,9 @@ static int nested_vmx_run(struct kvm_vcpu *vcpu, bool launch) vmx->nested.vmcs01_tsc_offset = vmcs_read64(TSC_OFFSET); + if (!(vmcs12->vm_entry_controls & VM_ENTRY_LOAD_DEBUG_CONTROLS)) + vmx->nested.vmcs01_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); + cpu = get_cpu(); vmx->loaded_vmcs = vmcs02; vmx_vcpu_put(vcpu); @@ -8399,7 +8428,6 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, vmcs12->guest_cr0 = vmcs12_guest_cr0(vcpu, vmcs12); vmcs12->guest_cr4 = vmcs12_guest_cr4(vcpu, vmcs12); - kvm_get_dr(vcpu, 7, (unsigned long *)&vmcs12->guest_dr7); vmcs12->guest_rsp = kvm_register_read(vcpu, VCPU_REGS_RSP); vmcs12->guest_rip = kvm_register_read(vcpu, VCPU_REGS_RIP); vmcs12->guest_rflags = vmcs_readl(GUEST_RFLAGS); @@ -8478,9 +8506,13 @@ static void prepare_vmcs12(struct kvm_vcpu *vcpu, struct vmcs12 *vmcs12, (vmcs12->vm_entry_controls & ~VM_ENTRY_IA32E_MODE) | (vm_entry_controls_get(to_vmx(vcpu)) & VM_ENTRY_IA32E_MODE); + if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_DEBUG_CONTROLS) { + kvm_get_dr(vcpu, 7, (unsigned long *)&vmcs12->guest_dr7); + vmcs12->guest_ia32_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); + } + /* TODO: These cannot have changed unless we have MSR bitmaps and * the relevant bit asks not to trap the change */ - vmcs12->guest_ia32_debugctl = vmcs_read64(GUEST_IA32_DEBUGCTL); if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_IA32_PAT) vmcs12->guest_ia32_pat = vmcs_read64(GUEST_IA32_PAT); if (vmcs12->vm_exit_controls & VM_EXIT_SAVE_IA32_EFER) -- 2.20.1