On 24.08.2017 15:37, Paolo Bonzini wrote:
> From: Jim Mattson <jmattson@xxxxxxxxxx>
>
> A guest may not be configured to support RDSEED, even when the host
> does. If the guest does not support RDSEED, intercept the instruction
> and synthesize #UD. Also clear the "allowed-1" bit for RDSEED 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 | 24 +++++++++++++++++++++++-
> 1 file changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index 1f2c69de7872..954e26079cd6 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -2818,7 +2818,6 @@ 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_RDSEED |
> SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES |
> SECONDARY_EXEC_DESC |
> SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE |
> @@ -3671,6 +3670,7 @@ 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_RDSEED |
> SECONDARY_EXEC_RDRAND |
> SECONDARY_EXEC_ENABLE_PML |
> SECONDARY_EXEC_TSC_SCALING |
> @@ -5280,6 +5280,12 @@ static bool vmx_rdrand_supported(void)
> SECONDARY_EXEC_RDRAND;
> }
>
> +static bool vmx_rdseed_supported(void)
> +{
> + return vmcs_config.cpu_based_2nd_exec_ctrl &
> + SECONDARY_EXEC_RDSEED;
> +}
> +
> static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
> {
> struct kvm_vcpu *vcpu = &vmx->vcpu;
> @@ -5364,6 +5370,21 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
> }
> }
>
> + if (vmx_rdseed_supported()) {
> + bool rdseed_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDSEED);
> + if (rdseed_enabled)
> + exec_control &= ~SECONDARY_EXEC_RDSEED;
> +
> + if (nested) {
> + if (rdseed_enabled)
> + vmx->nested.nested_vmx_secondary_ctls_high |=
> + SECONDARY_EXEC_RDSEED;
> + else
> + vmx->nested.nested_vmx_secondary_ctls_high &=
> + ~SECONDARY_EXEC_RDSEED;
> + }
> + }
> +
> vmx->secondary_exec_control = exec_control;
> }
>
> @@ -8119,6 +8140,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
> [EXIT_REASON_INVEPT] = handle_invept,
> [EXIT_REASON_INVVPID] = handle_invvpid,
> [EXIT_REASON_RDRAND] = handle_invalid_op,
> + [EXIT_REASON_RDSEED] = handle_invalid_op,
> [EXIT_REASON_XSAVES] = handle_xsaves,
> [EXIT_REASON_XRSTORS] = handle_xrstors,
> [EXIT_REASON_PML_FULL] = handle_pml_full,
>
Reviewed-by: David Hildenbrand <david@xxxxxxxxxx>
--
Thanks,
David
