KVM: vmx: Enable VMFUNCs

Enable VMFUNC in the secondary execution controls.  This simplifies the
changes necessary to expose it to nested hypervisors.  VMFUNCs still
cause #UD when invoked.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Bandan Das <bsd@redhat.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index 35cd06f..da5375e 100644 (file)
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -72,6 +72,7 @@
 #define SECONDARY_EXEC_PAUSE_LOOP_EXITING      0x00000400
 #define SECONDARY_EXEC_RDRAND                  0x00000800
 #define SECONDARY_EXEC_ENABLE_INVPCID          0x00001000
+#define SECONDARY_EXEC_ENABLE_VMFUNC            0x00002000
 #define SECONDARY_EXEC_SHADOW_VMCS              0x00004000
 #define SECONDARY_EXEC_RDSEED                  0x00010000
 #define SECONDARY_EXEC_ENABLE_PML               0x00020000
@@ -187,6 +188,8 @@ enum vmcs_field {
        APIC_ACCESS_ADDR_HIGH           = 0x00002015,
        POSTED_INTR_DESC_ADDR           = 0x00002016,
        POSTED_INTR_DESC_ADDR_HIGH      = 0x00002017,
+       VM_FUNCTION_CONTROL             = 0x00002018,
+       VM_FUNCTION_CONTROL_HIGH        = 0x00002019,
        EPT_POINTER                     = 0x0000201a,
        EPT_POINTER_HIGH                = 0x0000201b,
        EOI_EXIT_BITMAP0                = 0x0000201c,

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index a653005..f2063c9 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1300,6 +1300,12 @@ static inline bool cpu_has_vmx_tsc_scaling(void)
                SECONDARY_EXEC_TSC_SCALING;
 }
 
+static inline bool cpu_has_vmx_vmfunc(void)
+{
+       return vmcs_config.cpu_based_2nd_exec_ctrl &
+               SECONDARY_EXEC_ENABLE_VMFUNC;
+}
+
 static inline bool report_flexpriority(void)
 {
        return flexpriority_enabled;
@@ -3628,7 +3634,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
                        SECONDARY_EXEC_SHADOW_VMCS |
                        SECONDARY_EXEC_XSAVES |
                        SECONDARY_EXEC_ENABLE_PML |
-                       SECONDARY_EXEC_TSC_SCALING;
+                       SECONDARY_EXEC_TSC_SCALING |
+                       SECONDARY_EXEC_ENABLE_VMFUNC;
                if (adjust_vmx_controls(min2, opt2,
                                        MSR_IA32_VMX_PROCBASED_CTLS2,
                                        &_cpu_based_2nd_exec_control) < 0)
@@ -5345,6 +5352,9 @@ static int vmx_vcpu_setup(struct vcpu_vmx *vmx)
        vmcs_writel(HOST_GS_BASE, 0); /* 22.2.4 */
 #endif
 
+       if (cpu_has_vmx_vmfunc())
+               vmcs_write64(VM_FUNCTION_CONTROL, 0);
+
        vmcs_write32(VM_EXIT_MSR_STORE_COUNT, 0);
        vmcs_write32(VM_EXIT_MSR_LOAD_COUNT, 0);
        vmcs_write64(VM_EXIT_MSR_LOAD_ADDR, __pa(vmx->msr_autoload.host));
@@ -7835,6 +7845,12 @@ static int handle_preemption_timer(struct kvm_vcpu *vcpu)
        return 1;
 }
 
+static int handle_vmfunc(struct kvm_vcpu *vcpu)
+{
+       kvm_queue_exception(vcpu, UD_VECTOR);
+       return 1;
+}
+
 /*
  * The exit handlers return 1 if the exit was handled fully and guest execution
  * may resume.  Otherwise they set the kvm_run parameter to indicate what needs
@@ -7885,6 +7901,7 @@ static int (*const kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu) = {
        [EXIT_REASON_XSAVES]                  = handle_xsaves,
        [EXIT_REASON_XRSTORS]                 = handle_xrstors,
        [EXIT_REASON_PML_FULL]                = handle_pml_full,
+       [EXIT_REASON_VMFUNC]                  = handle_vmfunc,
        [EXIT_REASON_PREEMPTION_TIMER]        = handle_preemption_timer,
 };
 
@@ -8221,6 +8238,9 @@ static bool nested_vmx_exit_reflected(struct kvm_vcpu *vcpu, u32 exit_reason)
        case EXIT_REASON_PML_FULL:
                /* We emulate PML support to L1. */
                return false;
+       case EXIT_REASON_VMFUNC:
+               /* VM functions are emulated through L2->L0 vmexits. */
+               return false;
        default:
                return true;
        }