KVM/ARM Fixes for Linux v4.6-rc2.

Fixes a bug that corrupts stage-2 translationson 16-bit VMID equipped systems
 and fixes CPU PM and Hotplug after the EL2 init code has been moved to C.
 -----BEGIN PGP SIGNATURE-----
 Version: GnuPG v1
 
 iQEcBAABAgAGBQJW/jk7AAoJEEtpOizt6ddyL1EH/RcWeOllk64dLpFouig8F+Oe
 Lm7b6okB8qJjZdpyStqWYGEWjd2kwZ5buUqmCf8kNPrQ143c3xwKAeb3hBly+6vK
 RDbef6nZqqPihbYTohFzquQKOY8haselciYwmW6+Lkq8uaZ6jNSTbDKwjtDI8rry
 +1FuSZKrUVz5xaj5qn4gDJjTmnZbX5rcdtwN3S9/AikPDtNZFZHcj8Qn/ps9jjLP
 jB2XCIRXFZdxxYOAlYbRx+sTVEnsTBYAwCrvFErJAfBH8m0QR94mn1epU7QzdrKN
 dnKbG4IYy19aPmOpfhGuQrUZ1G09QNSWQQ+BhG0pvq0/GBD0exkMdRssp11AXoI=
 =XE1Y
 -----END PGP SIGNATURE-----

Merge tag 'kvm-arm-for-4.6-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/ARM Fixes for Linux v4.6-rc2.

Fixes a bug that corrupts stage-2 translationson 16-bit VMID equipped systems
and fixes CPU PM and Hotplug after the EL2 init code has been moved to C.

arch/arm/kvm/arm.c

@@ -1061,15 +1061,27 @@ static void cpu_init_hyp_mode(void *dummy)
 	kvm_arm_init_debug();
 }
 
+static void cpu_hyp_reinit(void)
+{
+	if (is_kernel_in_hyp_mode()) {
+		/*
+		 * cpu_init_stage2() is safe to call even if the PM
+		 * event was cancelled before the CPU was reset.
+		 */
+		cpu_init_stage2(NULL);
+	} else {
+		if (__hyp_get_vectors() == hyp_default_vectors)
+			cpu_init_hyp_mode(NULL);
+	}
+}
+
 static int hyp_init_cpu_notify(struct notifier_block *self,
 			       unsigned long action, void *cpu)
 {
 	switch (action) {
 	case CPU_STARTING:
 	case CPU_STARTING_FROZEN:
-		if (__hyp_get_vectors() == hyp_default_vectors)
+		cpu_hyp_reinit();
-			cpu_init_hyp_mode(NULL);
-		break;
 	}
 
 	return NOTIFY_OK;
@@ -1084,9 +1096,8 @@ static int hyp_init_cpu_pm_notifier(struct notifier_block *self,
 				    unsigned long cmd,
 				    void *v)
 {
-	if (cmd == CPU_PM_EXIT &&
+	if (cmd == CPU_PM_EXIT) {
-	    __hyp_get_vectors() == hyp_default_vectors) {
+		cpu_hyp_reinit();
-		cpu_init_hyp_mode(NULL);
 		return NOTIFY_OK;
 	}
 
@@ -1127,6 +1138,22 @@ static int init_subsystems(void)
 {
 	int err;
 
+	/*
+	 * Register CPU Hotplug notifier
+	 */
+	cpu_notifier_register_begin();
+	err = __register_cpu_notifier(&hyp_init_cpu_nb);
+	cpu_notifier_register_done();
+	if (err) {
+		kvm_err("Cannot register KVM init CPU notifier (%d)\n", err);
+		return err;
+	}
+
+	/*
+	 * Register CPU lower-power notifier
+	 */
+	hyp_cpu_pm_init();
+
 	/*
 	 * Init HYP view of VGIC
 	 */
@@ -1270,19 +1297,6 @@ static int init_hyp_mode(void)
 	free_boot_hyp_pgd();
 #endif
 
-	cpu_notifier_register_begin();
-
-	err = __register_cpu_notifier(&hyp_init_cpu_nb);
-
-	cpu_notifier_register_done();
-
-	if (err) {
-		kvm_err("Cannot register HYP init CPU notifier (%d)\n", err);
-		goto out_err;
-	}
-
-	hyp_cpu_pm_init();
-
 	/* set size of VMID supported by CPU */
 	kvm_vmid_bits = kvm_get_vmid_bits();
 	kvm_info("%d-bit VMID\n", kvm_vmid_bits);

arch/arm64/include/asm/kvm_arm.h

@@ -124,7 +124,9 @@
 #define VTCR_EL2_SL0_LVL1	(1 << 6)
 #define VTCR_EL2_T0SZ_MASK	0x3f
 #define VTCR_EL2_T0SZ_40B	24
-#define VTCR_EL2_VS		19
+#define VTCR_EL2_VS_SHIFT	19
+#define VTCR_EL2_VS_8BIT	(0 << VTCR_EL2_VS_SHIFT)
+#define VTCR_EL2_VS_16BIT	(1 << VTCR_EL2_VS_SHIFT)
 
 /*
  * We configure the Stage-2 page tables to always restrict the IPA space to be

arch/arm64/include/asm/sysreg.h

@@ -141,6 +141,9 @@
 #define ID_AA64MMFR1_VMIDBITS_SHIFT	4
 #define ID_AA64MMFR1_HADBS_SHIFT	0
 
+#define ID_AA64MMFR1_VMIDBITS_8		0
+#define ID_AA64MMFR1_VMIDBITS_16	2
+
 /* id_aa64mmfr2 */
 #define ID_AA64MMFR2_UAO_SHIFT		4
 

arch/arm64/kvm/hyp/s2-setup.c

@@ -36,8 +36,10 @@ void __hyp_text __init_stage2_translation(void)
 	 * Read the VMIDBits bits from ID_AA64MMFR1_EL1 and set the VS
 	 * bit in VTCR_EL2.
 	 */
-	tmp = (read_sysreg(id_aa64mmfr1_el1) >> 4) & 0xf;
+	tmp = (read_sysreg(id_aa64mmfr1_el1) >> ID_AA64MMFR1_VMIDBITS_SHIFT) & 0xf;
-	val |= (tmp == 2) ? VTCR_EL2_VS : 0;
+	val |= (tmp == ID_AA64MMFR1_VMIDBITS_16) ?
+			VTCR_EL2_VS_16BIT :
+			VTCR_EL2_VS_8BIT;
 
 	write_sysreg(val, vtcr_el2);
 }