+
+#ifdef CONFIG_IOMMU_SUPPORT
+void update_pasid(void)
+{
+ u64 pasid_state;
+ u32 pasid;
+
+ if (!cpu_feature_enabled(X86_FEATURE_ENQCMD))
+ return;
+
+ if (!current->mm)
+ return;
+
+ pasid = READ_ONCE(current->mm->pasid);
+ /* Set the valid bit in the PASID MSR/state only for valid pasid. */
+ pasid_state = pasid == PASID_DISABLED ?
+ pasid : pasid | MSR_IA32_PASID_VALID;
+
+ /*
+ * No need to hold fregs_lock() since the task's fpstate won't
+ * be changed by others (e.g. ptrace) while the task is being
+ * switched to or is in IPI.
+ */
+ if (!test_thread_flag(TIF_NEED_FPU_LOAD)) {
+ /* The MSR is active and can be directly updated. */
+ wrmsrl(MSR_IA32_PASID, pasid_state);
+ } else {
+ struct fpu *fpu = ¤t->thread.fpu;
+ struct ia32_pasid_state *ppasid_state;
+ struct xregs_state *xsave;
+
+ /*
+ * The CPU's xstate registers are not currently active. Just
+ * update the PASID state in the memory buffer here. The
+ * PASID MSR will be loaded when returning to user mode.
+ */
+ xsave = &fpu->state.xsave;
+ xsave->header.xfeatures |= XFEATURE_MASK_PASID;
+ ppasid_state = get_xsave_addr(xsave, XFEATURE_PASID);
+ /*
+ * Since XFEATURE_MASK_PASID is set in xfeatures, ppasid_state
+ * won't be NULL and no need to check its value.
+ *
+ * Only update the task's PASID state when it's different
+ * from the mm's pasid.
+ */
+ if (ppasid_state->pasid != pasid_state) {
+ /*
+ * Invalid fpregs so that state restoring will pick up
+ * the PASID state.
+ */
+ __fpu_invalidate_fpregs_state(fpu);
+ ppasid_state->pasid = pasid_state;
+ }
+ }
+}
+#endif /* CONFIG_IOMMU_SUPPORT */