KVM: VMX: Add a helper and macros to reduce boilerplate for sec exec ctls

Add a helper function and several wrapping macros to consolidate the
copy-paste code in vmx_compute_secondary_exec_control() for adjusting
controls that are dependent on guest CPUID bits.

No functional change intended.

Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Message-Id: <20200925003011.21016-1-sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f60c64b..b0ba1cc 100644 (file)
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -4081,6 +4081,61 @@ u32 vmx_exec_control(struct vcpu_vmx *vmx)
        return exec_control;
 }
 
+/*
+ * Adjust a single secondary execution control bit to intercept/allow an
+ * instruction in the guest.  This is usually done based on whether or not a
+ * feature has been exposed to the guest in order to correctly emulate faults.
+ */
+static inline void
+vmx_adjust_secondary_exec_control(struct vcpu_vmx *vmx, u32 *exec_control,
+                                 u32 control, bool enabled, bool exiting)
+{
+       /*
+        * If the control is for an opt-in feature, clear the control if the
+        * feature is not exposed to the guest, i.e. not enabled.  If the
+        * control is opt-out, i.e. an exiting control, clear the control if
+        * the feature _is_ exposed to the guest, i.e. exiting/interception is
+        * disabled for the associated instruction.  Note, the caller is
+        * responsible presetting exec_control to set all supported bits.
+        */
+       if (enabled == exiting)
+               *exec_control &= ~control;
+
+       /*
+        * Update the nested MSR settings so that a nested VMM can/can't set
+        * controls for features that are/aren't exposed to the guest.
+        */
+       if (nested) {
+               if (enabled)
+                       vmx->nested.msrs.secondary_ctls_high |= control;
+               else
+                       vmx->nested.msrs.secondary_ctls_high &= ~control;
+       }
+}
+
+/*
+ * Wrapper macro for the common case of adjusting a secondary execution control
+ * based on a single guest CPUID bit, with a dedicated feature bit.  This also
+ * verifies that the control is actually supported by KVM and hardware.
+ */
+#define vmx_adjust_sec_exec_control(vmx, exec_control, name, feat_name, ctrl_name, exiting) \
+({                                                                      \
+       bool __enabled;                                                  \
+                                                                        \
+       if (cpu_has_vmx_##name()) {                                      \
+               __enabled = guest_cpuid_has(&(vmx)->vcpu,                \
+                                           X86_FEATURE_##feat_name);    \
+               vmx_adjust_secondary_exec_control(vmx, exec_control,     \
+                       SECONDARY_EXEC_##ctrl_name, __enabled, exiting); \
+       }                                                                \
+})
+
+/* More macro magic for ENABLE_/opt-in versus _EXITING/opt-out controls. */
+#define vmx_adjust_sec_exec_feature(vmx, exec_control, lname, uname) \
+       vmx_adjust_sec_exec_control(vmx, exec_control, lname, uname, ENABLE_##uname, false)
+
+#define vmx_adjust_sec_exec_exiting(vmx, exec_control, lname, uname) \
+       vmx_adjust_sec_exec_control(vmx, exec_control, lname, uname, uname##_EXITING, true)
 
 static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 {
@@ -4130,33 +4185,12 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
 
                vcpu->arch.xsaves_enabled = xsaves_enabled;
 
-               if (!xsaves_enabled)
-                       exec_control &= ~SECONDARY_EXEC_XSAVES;
-
-               if (nested) {
-                       if (xsaves_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_XSAVES;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_XSAVES;
-               }
+               vmx_adjust_secondary_exec_control(vmx, &exec_control,
+                                                 SECONDARY_EXEC_XSAVES,
+                                                 xsaves_enabled, false);
        }
 
-       if (cpu_has_vmx_rdtscp()) {
-               bool rdtscp_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP);
-               if (!rdtscp_enabled)
-                       exec_control &= ~SECONDARY_EXEC_ENABLE_RDTSCP;
-
-               if (nested) {
-                       if (rdtscp_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_ENABLE_RDTSCP;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_ENABLE_RDTSCP;
-               }
-       }
+       vmx_adjust_sec_exec_feature(vmx, &exec_control, rdtscp, RDTSCP);
 
        /*
         * Expose INVPCID if and only if PCID is also exposed to the guest.
@@ -4166,71 +4200,14 @@ static void vmx_compute_secondary_exec_control(struct vcpu_vmx *vmx)
         */
        if (!guest_cpuid_has(vcpu, X86_FEATURE_PCID))
                guest_cpuid_clear(vcpu, X86_FEATURE_INVPCID);
+       vmx_adjust_sec_exec_feature(vmx, &exec_control, invpcid, INVPCID);
 
-       if (cpu_has_vmx_invpcid()) {
-               /* Exposing INVPCID only when PCID is exposed */
-               bool invpcid_enabled =
-                       guest_cpuid_has(vcpu, X86_FEATURE_INVPCID);
-
-               if (!invpcid_enabled)
-                       exec_control &= ~SECONDARY_EXEC_ENABLE_INVPCID;
-
-               if (nested) {
-                       if (invpcid_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_ENABLE_INVPCID;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_ENABLE_INVPCID;
-               }
-       }
-
-       if (cpu_has_vmx_rdrand()) {
-               bool rdrand_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDRAND);
-               if (rdrand_enabled)
-                       exec_control &= ~SECONDARY_EXEC_RDRAND_EXITING;
-
-               if (nested) {
-                       if (rdrand_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_RDRAND_EXITING;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_RDRAND_EXITING;
-               }
-       }
-
-       if (cpu_has_vmx_rdseed()) {
-               bool rdseed_enabled = guest_cpuid_has(vcpu, X86_FEATURE_RDSEED);
-               if (rdseed_enabled)
-                       exec_control &= ~SECONDARY_EXEC_RDSEED_EXITING;
-
-               if (nested) {
-                       if (rdseed_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_RDSEED_EXITING;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_RDSEED_EXITING;
-               }
-       }
-
-       if (cpu_has_vmx_waitpkg()) {
-               bool waitpkg_enabled =
-                       guest_cpuid_has(vcpu, X86_FEATURE_WAITPKG);
 
-               if (!waitpkg_enabled)
-                       exec_control &= ~SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE;
+       vmx_adjust_sec_exec_exiting(vmx, &exec_control, rdrand, RDRAND);
+       vmx_adjust_sec_exec_exiting(vmx, &exec_control, rdseed, RDSEED);
 
-               if (nested) {
-                       if (waitpkg_enabled)
-                               vmx->nested.msrs.secondary_ctls_high |=
-                                       SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE;
-                       else
-                               vmx->nested.msrs.secondary_ctls_high &=
-                                       ~SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE;
-               }
-       }
+       vmx_adjust_sec_exec_control(vmx, &exec_control, waitpkg, WAITPKG,
+                                   ENABLE_USR_WAIT_PAUSE, false);
 
        vmx->secondary_exec_control = exec_control;
 }