From 45ec368c9addbbf3fb25fc33d3f22f838ec91714 Mon Sep 17 00:00:00 2001 From: Jim Mattson Date: Wed, 23 Aug 2017 16:32:04 -0700 Subject: [PATCH] kvm: vmx: Raise #UD on unsupported RDRAND 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 Signed-off-by: Paolo Bonzini --- 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, -- 2.20.1