From: Jim Mattson <jmattson@xxxxxxxxxx>
A guest may not be configured to support RDRAND, even when the host
does. If the guest does not support RDRAND, intercept the instruction
and synthesize #UD. Also clear the "allowed-1" bit for RDRAND exiting
in the IA32_VMX_PROCBASED_CTLS2 MSR.
Signed-off-by: Jim Mattson <jmattson@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 08381a5d8879..1f2c69de7872 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2818,7 +2818,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
vmx->nested.nested_vmx_secondary_ctls_high);
vmx->nested.nested_vmx_secondary_ctls_low = 0;
vmx->nested.nested_vmx_secondary_ctls_high &=
- SECONDARY_EXEC_RDRAND | SECONDARY_EXEC_RDSEED |
+ SECONDARY_EXEC_RDSEED |
SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
SECONDARY_EXEC_DESC |
SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
@@ -3671,6 +3671,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
SECONDARY_EXEC_VIRTUAL_INTR_DELIVERY |
SECONDARY_EXEC_SHADOW_VMCS |
SECONDARY_EXEC_XSAVES |
+ SECONDARY_EXEC_RDRAND |
SECONDARY_EXEC_ENABLE_PML |
SECONDARY_EXEC_TSC_SCALING |
SECONDARY_EXEC_ENABLE_VMFUNC;
@@ -5273,6 +5274,12 @@ static u32 vmx_exec_control(struct vcpu_vmx *vmx)
return exec_control;
}
+static bool vmx_rdrand_supported(void)
+{
+ return vmcs_config.cpu_based_2nd_exec_ctrl &
+ SECONDARY_EXEC_RDRAND;
+}
+
static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
{
struct kvm_vcpu *vcpu = &vmx->vcpu;
@@ -5342,6 +5349,21 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
}
}
+ if (vmx_rdrand_supported()) {
+ bool rdrand_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDRAND);
+ if (rdrand_enabled)
+ exec_control &= ~SECONDARY_EXEC_RDRAND;
+
+ if (nested) {
+ if (rdrand_enabled)
+ vmx->nested.nested_vmx_secondary_ctls_high |=
+ SECONDARY_EXEC_RDRAND;
+ else
+ vmx->nested.nested_vmx_secondary_ctls_high &=
+ ~SECONDARY_EXEC_RDRAND;
+ }
+ }
+
vmx->secondary_exec_control = exec_control;
}
@@ -6847,6 +6869,12 @@ static int handle_mwait(struct kvm_vcpu *vcpu)
return handle_nop(vcpu);
}
+static int handle_invalid_op(struct kvm_vcpu *vcpu)
+{
+ kvm_queue_exception(vcpu, UD_VECTOR);
+ return 1;
+}
+
static int handle_monitor_trap(struct kvm_vcpu *vcpu)
{
return 1;
@@ -8090,6 +8118,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
[EXIT_REASON_MONITOR_INSTRUCTION] = handle_monitor,
[EXIT_REASON_INVEPT] = handle_invept,
[EXIT_REASON_INVVPID] = handle_invvpid,
+ [EXIT_REASON_RDRAND] = handle_invalid_op,
[EXIT_REASON_XSAVES] = handle_xsaves,
[EXIT_REASON_XRSTORS] = handle_xrstors,
[EXIT_REASON_PML_FULL] = handle_pml_full,
--
1.8.3.1
