Merge tag 'hyperv-fixes-signed-20240616' of...

Merge tag 'hyperv-fixes-signed-20240616' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull Hyper-V fixes from Wei Liu:

 - Some cosmetic changes for hv.c and balloon.c (Aditya Nagesh)

 - Two documentation updates (Michael Kelley)

 - Suppress the invalid warning for packed member alignment (Saurabh
   Sengar)

 - Two hv_balloon fixes (Michael Kelley)

* tag 'hyperv-fixes-signed-20240616' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
  Drivers: hv: Cosmetic changes for hv.c and balloon.c
  Documentation: hyperv: Improve synic and interrupt handling description
  Documentation: hyperv: Update spelling and fix typo
  tools: hv: suppress the invalid warning for packed member alignment
  hv_balloon: Enable hot-add for memblock sizes > 128 MiB
  hv_balloon: Use kernel macros to simplify open coded sequences

Documentation/virt/hyperv/clocks.rst

@@ -62,12 +62,21 @@ shared page with scale and offset values into user space.  User
 space code performs the same algorithm of reading the TSC and
 applying the scale and offset to get the constant 10 MHz clock.
 
-Linux clockevents are based on Hyper-V synthetic timer 0. While
-Hyper-V offers 4 synthetic timers for each CPU, Linux only uses
-timer 0. Interrupts from stimer0 are recorded on the "HVS" line in
-/proc/interrupts.  Clockevents based on the virtualized PIT and
-local APIC timer also work, but the Hyper-V synthetic timer is
-preferred.
+Linux clockevents are based on Hyper-V synthetic timer 0 (stimer0).
+While Hyper-V offers 4 synthetic timers for each CPU, Linux only uses
+timer 0. In older versions of Hyper-V, an interrupt from stimer0
+results in a VMBus control message that is demultiplexed by
+vmbus_isr() as described in the Documentation/virt/hyperv/vmbus.rst
+documentation. In newer versions of Hyper-V, stimer0 interrupts can
+be mapped to an architectural interrupt, which is referred to as
+"Direct Mode". Linux prefers to use Direct Mode when available. Since
+x86/x64 doesn't support per-CPU interrupts, Direct Mode statically
+allocates an x86 interrupt vector (HYPERV_STIMER0_VECTOR) across all CPUs
+and explicitly codes it to call the stimer0 interrupt handler. Hence
+interrupts from stimer0 are recorded on the "HVS" line in /proc/interrupts
+rather than being associated with a Linux IRQ. Clockevents based on the
+virtualized PIT and local APIC timer also work, but Hyper-V stimer0
+is preferred.
 
 The driver for the Hyper-V synthetic system clock and timers is
 drivers/clocksource/hyperv_timer.c.

Documentation/virt/hyperv/overview.rst

@@ -40,7 +40,7 @@ Linux guests communicate with Hyper-V in four different ways:
   arm64, these synthetic registers must be accessed using explicit
   hypercalls.
 
-* VMbus: VMbus is a higher-level software construct that is built on
+* VMBus: VMBus is a higher-level software construct that is built on
   the other 3 mechanisms.  It is a message passing interface between
   the Hyper-V host and the Linux guest.  It uses memory that is shared
   between Hyper-V and the guest, along with various signaling
@@ -54,8 +54,8 @@ x86/x64 architecture only.
 
 .. _Hyper-V Top Level Functional Spec (TLFS): https://docs.microsoft.com/en-us/virtualization/hyper-v-on-windows/tlfs/tlfs
 
-VMbus is not documented.  This documentation provides a high-level
-overview of VMbus and how it works, but the details can be discerned
+VMBus is not documented.  This documentation provides a high-level
+overview of VMBus and how it works, but the details can be discerned
 only from the code.
 
 Sharing Memory
@@ -74,7 +74,7 @@ follows:
   physical address space.  How Hyper-V is told about the GPA or list
   of GPAs varies.  In some cases, a single GPA is written to a
   synthetic register.  In other cases, a GPA or list of GPAs is sent
-  in a VMbus message.
+  in a VMBus message.
 
 * Hyper-V translates the GPAs into "real" physical memory addresses,
   and creates a virtual mapping that it can use to access the memory.
@@ -133,9 +133,9 @@ only the CPUs actually present in the VM, so Linux does not report
 any hot-add CPUs.
 
 A Linux guest CPU may be taken offline using the normal Linux
-mechanisms, provided no VMbus channel interrupts are assigned to
-the CPU.  See the section on VMbus Interrupts for more details
-on how VMbus channel interrupts can be re-assigned to permit
+mechanisms, provided no VMBus channel interrupts are assigned to
+the CPU.  See the section on VMBus Interrupts for more details
+on how VMBus channel interrupts can be re-assigned to permit
 taking a CPU offline.
 
 32-bit and 64-bit
@@ -169,14 +169,14 @@ and functionality. Hyper-V indicates feature/function availability
 via flags in synthetic MSRs that Hyper-V provides to the guest,
 and the guest code tests these flags.
 
-VMbus has its own protocol version that is negotiated during the
-initial VMbus connection from the guest to Hyper-V. This version
+VMBus has its own protocol version that is negotiated during the
+initial VMBus connection from the guest to Hyper-V. This version
 number is also output to dmesg during boot.  This version number
 is checked in a few places in the code to determine if specific
 functionality is present.
 
-Furthermore, each synthetic device on VMbus also has a protocol
-version that is separate from the VMbus protocol version. Device
+Furthermore, each synthetic device on VMBus also has a protocol
+version that is separate from the VMBus protocol version. Device
 drivers for these synthetic devices typically negotiate the device
 protocol version, and may test that protocol version to determine
 if specific device functionality is present.

drivers/hv/hv.c

@@ -45,8 +45,8 @@ int hv_init(void)
  * This involves a hypercall.
  */
 int hv_post_message(union hv_connection_id connection_id,
-		  enum hv_message_type message_type,
-		  void *payload, size_t payload_size)
+			enum hv_message_type message_type,
+			void *payload, size_t payload_size)
 {
 	struct hv_input_post_message *aligned_msg;
 	unsigned long flags;
@@ -86,7 +86,7 @@ int hv_post_message(union hv_connection_id connection_id,
 			status = HV_STATUS_INVALID_PARAMETER;
 	} else {
 		status = hv_do_hypercall(HVCALL_POST_MESSAGE,
-				aligned_msg, NULL);
+					 aligned_msg, NULL);
 	}
 
 	local_irq_restore(flags);
@@ -111,7 +111,7 @@ int hv_synic_alloc(void)
 
 	hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
 					 GFP_KERNEL);
-	if (hv_context.hv_numa_map == NULL) {
+	if (!hv_context.hv_numa_map) {
 		pr_err("Unable to allocate NUMA map\n");
 		goto err;
 	}
@@ -120,11 +120,11 @@ int hv_synic_alloc(void)
 		hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
 
 		tasklet_init(&hv_cpu->msg_dpc,
-			     vmbus_on_msg_dpc, (unsigned long) hv_cpu);
+			     vmbus_on_msg_dpc, (unsigned long)hv_cpu);
 
 		if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
 			hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
-			if (hv_cpu->post_msg_page == NULL) {
+			if (!hv_cpu->post_msg_page) {
 				pr_err("Unable to allocate post msg page\n");
 				goto err;
 			}
@@ -147,14 +147,14 @@ int hv_synic_alloc(void)
 		if (!ms_hyperv.paravisor_present && !hv_root_partition) {
 			hv_cpu->synic_message_page =
 				(void *)get_zeroed_page(GFP_ATOMIC);
-			if (hv_cpu->synic_message_page == NULL) {
+			if (!hv_cpu->synic_message_page) {
 				pr_err("Unable to allocate SYNIC message page\n");
 				goto err;
 			}
 
 			hv_cpu->synic_event_page =
 				(void *)get_zeroed_page(GFP_ATOMIC);
-			if (hv_cpu->synic_event_page == NULL) {
+			if (!hv_cpu->synic_event_page) {
 				pr_err("Unable to allocate SYNIC event page\n");
 
 				free_page((unsigned long)hv_cpu->synic_message_page);
@@ -203,14 +203,13 @@ int hv_synic_alloc(void)
 	return ret;
 }
 
-
 void hv_synic_free(void)
 {
 	int cpu, ret;
 
 	for_each_present_cpu(cpu) {
-		struct hv_per_cpu_context *hv_cpu
-			= per_cpu_ptr(hv_context.cpu_context, cpu);
+		struct hv_per_cpu_context *hv_cpu =
+			per_cpu_ptr(hv_context.cpu_context, cpu);
 
 		/* It's better to leak the page if the encryption fails. */
 		if (ms_hyperv.paravisor_present && hv_isolation_type_tdx()) {
@@ -262,8 +261,8 @@ void hv_synic_free(void)
  */
 void hv_synic_enable_regs(unsigned int cpu)
 {
-	struct hv_per_cpu_context *hv_cpu
-		= per_cpu_ptr(hv_context.cpu_context, cpu);
+	struct hv_per_cpu_context *hv_cpu =
+		per_cpu_ptr(hv_context.cpu_context, cpu);
 	union hv_synic_simp simp;
 	union hv_synic_siefp siefp;
 	union hv_synic_sint shared_sint;
@@ -277,8 +276,8 @@ void hv_synic_enable_regs(unsigned int cpu)
 		/* Mask out vTOM bit. ioremap_cache() maps decrypted */
 		u64 base = (simp.base_simp_gpa << HV_HYP_PAGE_SHIFT) &
 				~ms_hyperv.shared_gpa_boundary;
-		hv_cpu->synic_message_page
-			= (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
+		hv_cpu->synic_message_page =
+			(void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
 		if (!hv_cpu->synic_message_page)
 			pr_err("Fail to map synic message page.\n");
 	} else {
@@ -296,8 +295,8 @@ void hv_synic_enable_regs(unsigned int cpu)
 		/* Mask out vTOM bit. ioremap_cache() maps decrypted */
 		u64 base = (siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT) &
 				~ms_hyperv.shared_gpa_boundary;
-		hv_cpu->synic_event_page
-			= (void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
+		hv_cpu->synic_event_page =
+			(void *)ioremap_cache(base, HV_HYP_PAGE_SIZE);
 		if (!hv_cpu->synic_event_page)
 			pr_err("Fail to map synic event page.\n");
 	} else {
@@ -348,8 +347,8 @@ int hv_synic_init(unsigned int cpu)
  */
 void hv_synic_disable_regs(unsigned int cpu)
 {
-	struct hv_per_cpu_context *hv_cpu
-		= per_cpu_ptr(hv_context.cpu_context, cpu);
+	struct hv_per_cpu_context *hv_cpu =
+		per_cpu_ptr(hv_context.cpu_context, cpu);
 	union hv_synic_sint shared_sint;
 	union hv_synic_simp simp;
 	union hv_synic_siefp siefp;

tools/hv/Makefile

@@ -17,6 +17,7 @@ endif
 MAKEFLAGS += -r
 
 override CFLAGS += -O2 -Wall -g -D_GNU_SOURCE -I$(OUTPUT)include
+override CFLAGS += -Wno-address-of-packed-member
 
 ALL_TARGETS := hv_kvp_daemon hv_vss_daemon
 ifneq ($(ARCH), aarch64)