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 <jan.kiszka@xxxxxxxxxxx>
---
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 475f2dc..f20a5ee 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)
--
1.8.1.1.298.ge7eed54
--
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