From: Jim Mattson <jmattson@google.com>
Date: Wed, 23 Aug 2017 16:32:04 -0700
Subject: kvm: vmx: Raise #UD on unsupported RDRAND
Patch-mainline: v4.14-rc1
Git-commit: 45ec368c9addbbf3fb25fc33d3f22f838ec91714
References: bsc#1077761
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@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
arch/x86/kvm/vmx.c | 31 ++++++++++++++++++++++++++++++-
1 file changed, 30 insertions(+), 1 deletion(-)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2808,7 +2808,7 @@
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 |
@@ -3661,6 +3661,7 @@
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;
@@ -5256,6 +5257,12 @@
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;
@@ -5325,6 +5332,21 @@
}
}
+ 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;
}
@@ -6830,6 +6852,12 @@
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;
@@ -8073,6 +8101,7 @@
[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,