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
--- 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;
+ vmx_adjust_sec_exec_exiting(vmx, &exec_control, rdrand, RDRAND);
+ vmx_adjust_sec_exec_exiting(vmx, &exec_control, rdseed, RDSEED);
- 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;
-
- 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;
}