KVM: x86: Add nested virtualization support for MPX
This is simple to do, the "host" BNDCFGS is either 0 or the guest value.
However, both controls have to be present. We cannot provide MPX if
we only have one of the "load BNDCFGS" or "clear BNDCFGS" controls.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index f4e5aed..c95bea1 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -206,6 +206,7 @@
u64 guest_pdptr1;
u64 guest_pdptr2;
u64 guest_pdptr3;
+ u64 guest_bndcfgs;
u64 host_ia32_pat;
u64 host_ia32_efer;
u64 host_ia32_perf_global_ctrl;
@@ -541,6 +542,7 @@
GUEST_CS_LIMIT,
GUEST_CS_BASE,
GUEST_ES_BASE,
+ GUEST_BNDCFGS,
CR0_GUEST_HOST_MASK,
CR0_READ_SHADOW,
CR4_READ_SHADOW,
@@ -596,6 +598,7 @@
FIELD64(GUEST_PDPTR1, guest_pdptr1),
FIELD64(GUEST_PDPTR2, guest_pdptr2),
FIELD64(GUEST_PDPTR3, guest_pdptr3),
+ FIELD64(GUEST_BNDCFGS, guest_bndcfgs),
FIELD64(HOST_IA32_PAT, host_ia32_pat),
FIELD64(HOST_IA32_EFER, host_ia32_efer),
FIELD64(HOST_IA32_PERF_GLOBAL_CTRL, host_ia32_perf_global_ctrl),
@@ -736,6 +739,7 @@
static void vmx_sync_pir_to_irr_dummy(struct kvm_vcpu *vcpu);
static void copy_vmcs12_to_shadow(struct vcpu_vmx *vmx);
static void copy_shadow_to_vmcs12(struct vcpu_vmx *vmx);
+static bool vmx_mpx_supported(void);
static DEFINE_PER_CPU(struct vmcs *, vmxarea);
static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -2287,6 +2291,8 @@
nested_vmx_exit_ctls_high |= VM_EXIT_ALWAYSON_WITHOUT_TRUE_MSR |
VM_EXIT_LOAD_IA32_EFER | VM_EXIT_SAVE_IA32_EFER |
VM_EXIT_SAVE_VMX_PREEMPTION_TIMER;
+ if (vmx_mpx_supported())
+ nested_vmx_exit_ctls_high |= VM_EXIT_CLEAR_BNDCFGS;
/* entry controls */
rdmsr(MSR_IA32_VMX_ENTRY_CTLS,
@@ -2300,6 +2306,8 @@
VM_ENTRY_LOAD_IA32_PAT;
nested_vmx_entry_ctls_high |= (VM_ENTRY_ALWAYSON_WITHOUT_TRUE_MSR |
VM_ENTRY_LOAD_IA32_EFER);
+ if (vmx_mpx_supported())
+ nested_vmx_entry_ctls_high |= VM_ENTRY_LOAD_BNDCFGS;
/* cpu-based controls */
rdmsr(MSR_IA32_VMX_PROCBASED_CTLS,
@@ -7866,6 +7874,9 @@
set_cr4_guest_host_mask(vmx);
+ if (vmcs12->vm_entry_controls & VM_ENTRY_LOAD_BNDCFGS)
+ vmcs_write64(GUEST_BNDCFGS, vmcs12->guest_bndcfgs);
+
if (vmcs12->cpu_based_vm_exec_control & CPU_BASED_USE_TSC_OFFSETING)
vmcs_write64(TSC_OFFSET,
vmx->nested.vmcs01_tsc_offset + vmcs12->tsc_offset);
@@ -8351,6 +8362,8 @@
vmcs12->guest_sysenter_cs = vmcs_read32(GUEST_SYSENTER_CS);
vmcs12->guest_sysenter_esp = vmcs_readl(GUEST_SYSENTER_ESP);
vmcs12->guest_sysenter_eip = vmcs_readl(GUEST_SYSENTER_EIP);
+ if (vmx_mpx_supported())
+ vmcs12->guest_bndcfgs = vmcs_read64(GUEST_BNDCFGS);
/* update exit information fields: */
@@ -8460,6 +8473,10 @@
vmcs_writel(GUEST_IDTR_BASE, vmcs12->host_idtr_base);
vmcs_writel(GUEST_GDTR_BASE, vmcs12->host_gdtr_base);
+ /* If not VM_EXIT_CLEAR_BNDCFGS, the L2 value propagates to L1. */
+ if (vmcs12->vm_exit_controls & VM_EXIT_CLEAR_BNDCFGS)
+ vmcs_write64(GUEST_BNDCFGS, 0);
+
if (vmcs12->vm_exit_controls & VM_EXIT_LOAD_IA32_PAT) {
vmcs_write64(GUEST_IA32_PAT, vmcs12->host_ia32_pat);
vcpu->arch.pat = vmcs12->host_ia32_pat;