Merge tag 'hyperv-next-signed-20230220' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

 - allow Linux to run as the nested root partition for Microsoft
   Hypervisor (Jinank Jain and Nuno Das Neves)

 - clean up the return type of callback functions (Dawei Li)

* tag 'hyperv-next-signed-20230220' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  x86/hyperv: Fix hv_get/set_register for nested bringup
  Drivers: hv: Make remove callback of hyperv driver void returned
  Drivers: hv: Enable vmbus driver for nested root partition
  x86/hyperv: Add an interface to do nested hypercalls
  Drivers: hv: Setup synic registers in case of nested root partition
  x86/hyperv: Add support for detecting nested hypervisor

5 files changed, 20 insertions, 17 deletions

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 4d6480d57546..8b0dd8e5244d 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -147,7 +147,7 @@ int hv_synic_alloc(void)
 		 * Synic message and event pages are allocated by paravisor.
 		 * Skip these pages allocation here.
 		 */
-		if (!hv_isolation_type_snp()) {
+		if (!hv_isolation_type_snp() && !hv_root_partition) {
 			hv_cpu->synic_message_page =
 				(void *)get_zeroed_page(GFP_ATOMIC);
 			if (hv_cpu->synic_message_page == NULL) {
@@ -216,7 +216,7 @@ void hv_synic_enable_regs(unsigned int cpu)
 	simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
 	simp.simp_enabled = 1;
 
-	if (hv_isolation_type_snp()) {
+	if (hv_isolation_type_snp() || hv_root_partition) {
 		hv_cpu->synic_message_page
 			= memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
 				   HV_HYP_PAGE_SIZE, MEMREMAP_WB);
@@ -233,7 +233,7 @@ void hv_synic_enable_regs(unsigned int cpu)
 	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
 	siefp.siefp_enabled = 1;
 
-	if (hv_isolation_type_snp()) {
+	if (hv_isolation_type_snp() || hv_root_partition) {
 		hv_cpu->synic_event_page =
 			memremap(siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT,
 				 HV_HYP_PAGE_SIZE, MEMREMAP_WB);
@@ -315,20 +315,24 @@ void hv_synic_disable_regs(unsigned int cpu)
 	 * addresses.
 	 */
 	simp.simp_enabled = 0;
-	if (hv_isolation_type_snp())
+	if (hv_isolation_type_snp() || hv_root_partition) {
 		memunmap(hv_cpu->synic_message_page);
-	else
+		hv_cpu->synic_message_page = NULL;
+	} else {
 		simp.base_simp_gpa = 0;
+	}
 
 	hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
 
 	siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
 	siefp.siefp_enabled = 0;
 
-	if (hv_isolation_type_snp())
+	if (hv_isolation_type_snp() || hv_root_partition) {
 		memunmap(hv_cpu->synic_event_page);
-	else
+		hv_cpu->synic_event_page = NULL;
+	} else {
 		siefp.base_siefp_gpa = 0;
+	}
 
 	hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
 
diff --git a/drivers/hv/hv_balloon.c b/drivers/hv/hv_balloon.c
index 64ac5bdee3a6..dffcc894f117 100644
--- a/drivers/hv/hv_balloon.c
+++ b/drivers/hv/hv_balloon.c
@@ -2042,7 +2042,7 @@ connect_error:
 	return ret;
 }
 
-static int balloon_remove(struct hv_device *dev)
+static void balloon_remove(struct hv_device *dev)
 {
 	struct hv_dynmem_device *dm = hv_get_drvdata(dev);
 	struct hv_hotadd_state *has, *tmp;
@@ -2083,8 +2083,6 @@ static int balloon_remove(struct hv_device *dev)
 		kfree(has);
 	}
 	spin_unlock_irqrestore(&dm_device.ha_lock, flags);
-
-	return 0;
 }
 
 static int balloon_suspend(struct hv_device *hv_dev)
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index ae68298c0dca..52a6f89ccdbd 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -25,17 +25,20 @@
 #include <asm/mshyperv.h>
 
 /*
- * hv_root_partition and ms_hyperv are defined here with other Hyper-V
- * specific globals so they are shared across all architectures and are
+ * hv_root_partition, ms_hyperv and hv_nested are defined here with other
+ * Hyper-V specific globals so they are shared across all architectures and are
  * built only when CONFIG_HYPERV is defined.  But on x86,
  * ms_hyperv_init_platform() is built even when CONFIG_HYPERV is not
- * defined, and it uses these two variables.  So mark them as __weak
+ * defined, and it uses these three variables.  So mark them as __weak
  * here, allowing for an overriding definition in the module containing
  * ms_hyperv_init_platform().
  */
 bool __weak hv_root_partition;
 EXPORT_SYMBOL_GPL(hv_root_partition);
 
+bool __weak hv_nested;
+EXPORT_SYMBOL_GPL(hv_nested);
+
 struct ms_hyperv_info __weak ms_hyperv;
 EXPORT_SYMBOL_GPL(ms_hyperv);
 
diff --git a/drivers/hv/hv_util.c b/drivers/hv/hv_util.c
index d776074b49cb..42aec2c5606a 100644
--- a/drivers/hv/hv_util.c
+++ b/drivers/hv/hv_util.c
@@ -602,7 +602,7 @@ error1:
 	return ret;
 }
 
-static int util_remove(struct hv_device *dev)
+static void util_remove(struct hv_device *dev)
 {
 	struct hv_util_service *srv = hv_get_drvdata(dev);
 
@@ -610,8 +610,6 @@ static int util_remove(struct hv_device *dev)
 		srv->util_deinit();
 	vmbus_close(dev->channel);
 	kfree(srv->recv_buffer);
-
-	return 0;
 }
 
 /*
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 3146710d4ac6..1901556efe79 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -2744,7 +2744,7 @@ static int __init hv_acpi_init(void)
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
-	if (hv_root_partition)
+	if (hv_root_partition && !hv_nested)
 		return 0;
 
 	/*