- An SGX use after free fix.

- A fix for the fix to disable CET instrumentation generation for kernel code.
 We forgot 32-bit, which we seem to do very often nowadays.
 
 - A Xen PV fix to irqdomain init ordering.
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Merge tag 'x86_urgent_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 fixes from Borislav Petkov:
 "I kinda knew while typing 'I hope this is the last batch of x86/urgent
  updates' last week, Murphy was reading too and uttered 'Hold my
  beer!'.

  So here's more fixes... Thanks Murphy.

  Anyway, three more x86/urgent fixes for 5.11 final. We should be
  finally ready (famous last words). :-)

   - An SGX use after free fix

   - A fix for the fix to disable CET instrumentation generation for
     kernel code. We forgot 32-bit, which we seem to do very often
     nowadays

   - A Xen PV fix to irqdomain init ordering"

* tag 'x86_urgent_for_v5.11' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/pci: Create PCI/MSI irqdomain after x86_init.pci.arch_init()
  x86/build: Disable CET instrumentation in the kernel for 32-bit too
  x86/sgx: Maintain encl->refcount for each encl->mm_list entry

arch/x86/Makefile

@@ -50,6 +50,9 @@ export BITS
 KBUILD_CFLAGS += -mno-sse -mno-mmx -mno-sse2 -mno-3dnow
 KBUILD_CFLAGS += $(call cc-option,-mno-avx,)
 
+# Intel CET isn't enabled in the kernel
+KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
+
 ifeq ($(CONFIG_X86_32),y)
         BITS := 32
         UTS_MACHINE := i386
@@ -120,9 +123,6 @@ else
 
         KBUILD_CFLAGS += -mno-red-zone
         KBUILD_CFLAGS += -mcmodel=kernel
-
-	# Intel CET isn't enabled in the kernel
-	KBUILD_CFLAGS += $(call cc-option,-fcf-protection=none)
 endif
 
 ifdef CONFIG_X86_X32

arch/x86/kernel/cpu/sgx/driver.c

@@ -72,6 +72,9 @@ static int sgx_release(struct inode *inode, struct file *file)
 		synchronize_srcu(&encl->srcu);
 		mmu_notifier_unregister(&encl_mm->mmu_notifier, encl_mm->mm);
 		kfree(encl_mm);
+
+		/* 'encl_mm' is gone, put encl_mm->encl reference: */
+		kref_put(&encl->refcount, sgx_encl_release);
 	}
 
 	kref_put(&encl->refcount, sgx_encl_release);

arch/x86/kernel/cpu/sgx/encl.c

@@ -481,6 +481,9 @@ static void sgx_mmu_notifier_free(struct mmu_notifier *mn)
 {
 	struct sgx_encl_mm *encl_mm = container_of(mn, struct sgx_encl_mm, mmu_notifier);
 
+	/* 'encl_mm' is going away, put encl_mm->encl reference: */
+	kref_put(&encl_mm->encl->refcount, sgx_encl_release);
+
 	kfree(encl_mm);
 }
 
@@ -534,6 +537,8 @@ int sgx_encl_mm_add(struct sgx_encl *encl, struct mm_struct *mm)
 	if (!encl_mm)
 		return -ENOMEM;
 
+	/* Grab a refcount for the encl_mm->encl reference: */
+	kref_get(&encl->refcount);
 	encl_mm->encl = encl;
 	encl_mm->mm = mm;
 	encl_mm->mmu_notifier.ops = &sgx_mmu_notifier_ops;

arch/x86/pci/init.c

@@ -9,16 +9,23 @@
    in the right sequence from here. */
 static __init int pci_arch_init(void)
 {
-	int type;
-
-	x86_create_pci_msi_domain();
+	int type, pcbios = 1;
 
 	type = pci_direct_probe();
 
 	if (!(pci_probe & PCI_PROBE_NOEARLY))
 		pci_mmcfg_early_init();
 
-	if (x86_init.pci.arch_init && !x86_init.pci.arch_init())
+	if (x86_init.pci.arch_init)
+		pcbios = x86_init.pci.arch_init();
+
+	/*
+	 * Must happen after x86_init.pci.arch_init(). Xen sets up the
+	 * x86_init.irqs.create_pci_msi_domain there.
+	 */
+	x86_create_pci_msi_domain();
+
+	if (!pcbios)
 		return 0;
 
 	pci_pcbios_init();