Merge tag 'hyperv-fixes-signed-20220407' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv fixes from Wei Liu:

 - Correctly propagate coherence information for VMbus devices (Michael
   Kelley)

 - Disable balloon and memory hot-add on ARM64 temporarily (Boqun Feng)

 - Use barrier to prevent reording when reading ring buffer (Michael
   Kelley)

 - Use virt_store_mb in favour of smp_store_mb (Andrea Parri)

 - Fix VMbus device object initialization (Andrea Parri)

 - Deactivate sysctl_record_panic_msg on isolated guest (Andrea Parri)

 - Fix a crash when unloading VMbus module (Guilherme G. Piccoli)

* tag 'hyperv-fixes-signed-20220407' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  Drivers: hv: vmbus: Replace smp_store_mb() with virt_store_mb()
  Drivers: hv: balloon: Disable balloon and hot-add accordingly
  Drivers: hv: balloon: Support status report for larger page sizes
  Drivers: hv: vmbus: Prevent load re-ordering when reading ring buffer
  PCI: hv: Propagate coherence from VMbus device to PCI device
  Drivers: hv: vmbus: Propagate VMbus coherence to each VMbus device
  Drivers: hv: vmbus: Fix potential crash on module unload
  Drivers: hv: vmbus: Fix initialization of device object in vmbus_device_register()
  Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests

1 files changed, 54 insertions, 11 deletions

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 60ee8b329f9e..14de17087864 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -77,8 +77,8 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
 
 	/*
 	 * Hyper-V should be notified only once about a panic.  If we will be
-	 * doing hyperv_report_panic_msg() later with kmsg data, don't do
-	 * the notification here.
+	 * doing hv_kmsg_dump() with kmsg data later, don't do the notification
+	 * here.
 	 */
 	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE
 	    && hyperv_report_reg()) {
@@ -100,8 +100,8 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
 
 	/*
 	 * Hyper-V should be notified only once about a panic.  If we will be
-	 * doing hyperv_report_panic_msg() later with kmsg data, don't do
-	 * the notification here.
+	 * doing hv_kmsg_dump() with kmsg data later, don't do the notification
+	 * here.
 	 */
 	if (hyperv_report_reg())
 		hyperv_report_panic(regs, val, true);
@@ -921,6 +921,21 @@ static int vmbus_probe(struct device *child_device)
 }
 
 /*
+ * vmbus_dma_configure -- Configure DMA coherence for VMbus device
+ */
+static int vmbus_dma_configure(struct device *child_device)
+{
+	/*
+	 * On ARM64, propagate the DMA coherence setting from the top level
+	 * VMbus ACPI device to the child VMbus device being added here.
+	 * On x86/x64 coherence is assumed and these calls have no effect.
+	 */
+	hv_setup_dma_ops(child_device,
+		device_get_dma_attr(&hv_acpi_dev->dev) == DEV_DMA_COHERENT);
+	return 0;
+}
+
+/*
  * vmbus_remove - Remove a vmbus device
  */
 static void vmbus_remove(struct device *child_device)
@@ -1040,6 +1055,7 @@ static struct bus_type  hv_bus = {
 	.remove =		vmbus_remove,
 	.probe =		vmbus_probe,
 	.uevent =		vmbus_uevent,
+	.dma_configure =	vmbus_dma_configure,
 	.dev_groups =		vmbus_dev_groups,
 	.drv_groups =		vmbus_drv_groups,
 	.bus_groups =		vmbus_bus_groups,
@@ -1546,14 +1562,20 @@ static int vmbus_bus_init(void)
 	if (ret)
 		goto err_connect;
 
+	if (hv_is_isolation_supported())
+		sysctl_record_panic_msg = 0;
+
 	/*
 	 * Only register if the crash MSRs are available
 	 */
 	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
 		u64 hyperv_crash_ctl;
 		/*
-		 * Sysctl registration is not fatal, since by default
-		 * reporting is enabled.
+		 * Panic message recording (sysctl_record_panic_msg)
+		 * is enabled by default in non-isolated guests and
+		 * disabled by default in isolated guests; the panic
+		 * message recording won't be available in isolated
+		 * guests should the following registration fail.
 		 */
 		hv_ctl_table_hdr = register_sysctl_table(hv_root_table);
 		if (!hv_ctl_table_hdr)
@@ -2097,6 +2119,10 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	child_device_obj->device.parent = &hv_acpi_dev->dev;
 	child_device_obj->device.release = vmbus_device_release;
 
+	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
+	child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
+	dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
+
 	/*
 	 * Register with the LDM. This will kick off the driver/device
 	 * binding...which will eventually call vmbus_match() and vmbus_probe()
@@ -2122,9 +2148,6 @@ int vmbus_device_register(struct hv_device *child_device_obj)
 	}
 	hv_debug_add_dev_dir(child_device_obj);
 
-	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
-	child_device_obj->device.dma_mask = &child_device_obj->dma_mask;
-	dma_set_mask(&child_device_obj->device, DMA_BIT_MASK(64));
 	return 0;
 
 err_kset_unregister:
@@ -2428,6 +2451,21 @@ static int vmbus_acpi_add(struct acpi_device *device)
 
 	hv_acpi_dev = device;
 
+	/*
+	 * Older versions of Hyper-V for ARM64 fail to include the _CCA
+	 * method on the top level VMbus device in the DSDT. But devices
+	 * are hardware coherent in all current Hyper-V use cases, so fix
+	 * up the ACPI device to behave as if _CCA is present and indicates
+	 * hardware coherence.
+	 */
+	ACPI_COMPANION_SET(&device->dev, device);
+	if (IS_ENABLED(CONFIG_ACPI_CCA_REQUIRED) &&
+	    device_get_dma_attr(&device->dev) == DEV_DMA_NOT_SUPPORTED) {
+		pr_info("No ACPI _CCA found; assuming coherent device I/O\n");
+		device->flags.cca_seen = true;
+		device->flags.coherent_dma = true;
+	}
+
 	result = acpi_walk_resources(device->handle, METHOD_NAME__CRS,
 					vmbus_walk_resources, NULL);
 
@@ -2780,10 +2818,15 @@ static void __exit vmbus_exit(void)
 	if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) {
 		kmsg_dump_unregister(&hv_kmsg_dumper);
 		unregister_die_notifier(&hyperv_die_block);
-		atomic_notifier_chain_unregister(&panic_notifier_list,
-						 &hyperv_panic_block);
 	}
 
+	/*
+	 * The panic notifier is always registered, hence we should
+	 * also unconditionally unregister it here as well.
+	 */
+	atomic_notifier_chain_unregister(&panic_notifier_list,
+					 &hyperv_panic_block);
+
 	free_page((unsigned long)hv_panic_page);
 	unregister_sysctl_table(hv_ctl_table_hdr);
 	hv_ctl_table_hdr = NULL;