Merge tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux

Pull hyperv updates from Wei Liu:

- Support for Virtual Trust Level (VTL) on arm64 (Roman Kisel)

- Fixes for Hyper-V UIO driver (Long Li)

- Fixes for Hyper-V PCI driver (Michael Kelley)

- Select CONFIG_SYSFB for Hyper-V guests (Michael Kelley)

- Documentation updates for Hyper-V VMBus (Michael Kelley)

- Enhance logging for hv_kvp_daemon (Shradha Gupta)

* tag 'hyperv-next-signed-20250602' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux: (23 commits)
Drivers: hv: Always select CONFIG_SYSFB for Hyper-V guests
Drivers: hv: vmbus: Add comments about races with "channels" sysfs dir
Documentation: hyperv: Update VMBus doc with new features and info
PCI: hv: Remove unnecessary flex array in struct pci_packet
Drivers: hv: Remove hv_alloc/free_* helpers
Drivers: hv: Use kzalloc for panic page allocation
uio_hv_generic: Align ring size to system page
uio_hv_generic: Use correct size for interrupt and monitor pages
Drivers: hv: Allocate interrupt and monitor pages aligned to system page boundary
arch/x86: Provide the CPU number in the wakeup AP callback
x86/hyperv: Fix APIC ID and VP index confusion in hv_snp_boot_ap()
PCI: hv: Get vPCI MSI IRQ domain from DeviceTree
ACPI: irq: Introduce acpi_get_gsi_dispatcher()
Drivers: hv: vmbus: Introduce hv_get_vmbus_root_device()
Drivers: hv: vmbus: Get the IRQ number from DeviceTree
dt-bindings: microsoft,vmbus: Add interrupt and DMA coherence properties
arm64, x86: hyperv: Report the VTL the system boots in
arm64: hyperv: Initialize the Virtual Trust Level field
Drivers: hv: Provide arch-neutral implementation of get_vtl()
Drivers: hv: Enable VTL mode for arm64
...

Documentation/devicetree/bindings/bus/microsoft,vmbus.yaml

···
   - Saurabh Sengar <[e-mail]>
 
 description:
-  VMBus is a software bus that implement the protocols for communication
-  between the root or host OS and guest OSs (virtual machines).
+  VMBus is a software bus that implements the protocols for communication
+  between the root or host OS and guest OS'es (virtual machines).
 
 properties:
   compatible:
···
   '#size-cells':
     const: 1
 
+  dma-coherent: true
+
+  interrupts:
+    maxItems: 1
+    description: Interrupt is used to report a message from the host.
+
 required:
   - compatible
   - ranges
+  - interrupts
   - '#address-cells'
   - '#size-cells'
 
···
 
 examples:
   - |
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/interrupt-controller/arm-gic.h>
     soc {
         #address-cells = <2>;
         #size-cells = <1>;
···
                 #address-cells = <2>;
                 #size-cells = <1>;
                 ranges = <0x0f 0xf0000000 0x0f 0xf0000000 0x10000000>;
+                dma-coherent;
+                interrupt-parent = <&gic>;
+                interrupts = <GIC_PPI 2 IRQ_TYPE_EDGE_RISING>;
             };
         };
     };

Documentation/virt/hyperv/vmbus.rst

···
 or /proc/irq corresponding to individual VMBus channel interrupts.
 
 An online CPU in a Linux guest may not be taken offline if it has
-VMBus channel interrupts assigned to it.  Any such channel
-interrupts must first be manually reassigned to another CPU as
-described above.  When no channel interrupts are assigned to the
-CPU, it can be taken offline.
+VMBus channel interrupts assigned to it. Starting in kernel v6.15,
+any such interrupts are automatically reassigned to some other CPU
+at the time of offlining. The "other" CPU is chosen by the
+implementation and is not load balanced or otherwise intelligently
+determined. If the CPU is onlined again, channel interrupts previously
+assigned to it are not moved back. As a result, after multiple CPUs
+have been offlined, and perhaps onlined again, the interrupt-to-CPU
+mapping may be scrambled and non-optimal. In such a case, optimal
+assignments must be re-established manually. For kernels v6.14 and
+earlier, any conflicting channel interrupts must first be manually
+reassigned to another CPU as described above. Then when no channel
+interrupts are assigned to the CPU, it can be taken offline.
 
 The VMBus channel interrupt handling code is designed to work
 correctly even if an interrupt is received on a CPU other than the
···
 its previous existence. Such a device might be re-added later,
 in which case it is treated as an entirely new device. See
 vmbus_onoffer_rescind().
+
+For some devices, such as the KVP device, Hyper-V automatically
+sends a rescind message when the primary channel is closed,
+likely as a result of unbinding the device from its driver.
+The rescind causes Linux to remove the device. But then Hyper-V
+immediately reoffers the device to the guest, causing a new
+instance of the device to be created in Linux. For other
+devices, such as the synthetic SCSI and NIC devices, closing the
+primary channel does *not* result in Hyper-V sending a rescind
+message. The device continues to exist in Linux on the VMBus,
+but with no driver bound to it. The same driver or a new driver
+can subsequently be bound to the existing instance of the device.

arch/arm64/hyperv/mshyperv.c

···
 }
 EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);
 
+#ifdef CONFIG_ACPI
+
+static bool __init hyperv_detect_via_acpi(void)
+{
+	if (acpi_disabled)
+		return false;
+	/*
+	 * Hypervisor ID is only available in ACPI v6+, and the
+	 * structure layout was extended in v6 to accommodate that
+	 * new field.
+	 *
+	 * At the very minimum, this check makes sure not to read
+	 * past the FADT structure.
+	 *
+	 * It is also needed to catch running in some unknown
+	 * non-Hyper-V environment that has ACPI 5.x or less.
+	 * In such a case, it can't be Hyper-V.
+	 */
+	if (acpi_gbl_FADT.header.revision < 6)
+		return false;
+	return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0;
+}
+
+#else
+
+static bool __init hyperv_detect_via_acpi(void)
+{
+	return false;
+}
+
+#endif
+
+static bool __init hyperv_detect_via_smccc(void)
+{
+	uuid_t hyperv_uuid = UUID_INIT(
+		0x58ba324d, 0x6447, 0x24cd,
+		0x75, 0x6c, 0xef, 0x8e,
+		0x24, 0x70, 0x59, 0x16);
+
+	return arm_smccc_hypervisor_has_uuid(&hyperv_uuid);
+}
+
 static int __init hyperv_init(void)
 {
 	struct hv_get_vp_registers_output	result;
···
 
 	/*
 	 * Allow for a kernel built with CONFIG_HYPERV to be running in
-	 * a non-Hyper-V environment, including on DT instead of ACPI.
+	 * a non-Hyper-V environment.
+	 *
 	 * In such cases, do nothing and return success.
 	 */
-	if (acpi_disabled)
-		return 0;
-
-	if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
+	if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc())
 		return 0;
 
 	/* Setup the guest ID */
···
 
 	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
 		hv_get_partition_id();
+	ms_hyperv.vtl = get_vtl();
+	if (ms_hyperv.vtl > 0) /* non default VTL */
+		pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);
 
 	ms_hyperv_late_init();
 

arch/arm64/kvm/hypercalls.c

···
 	u32 feature;
 	u8 action;
 	gpa_t gpa;
+	uuid_t uuid;
 
 	action = kvm_smccc_get_action(vcpu, func_id);
 	switch (action) {
···
 			val[0] = gpa;
 		break;
 	case ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID:
-		val[0] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0;
-		val[1] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1;
-		val[2] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2;
-		val[3] = ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3;
+		uuid = ARM_SMCCC_VENDOR_HYP_UID_KVM;
+		val[0] = smccc_uuid_to_reg(&uuid, 0);
+		val[1] = smccc_uuid_to_reg(&uuid, 1);
+		val[2] = smccc_uuid_to_reg(&uuid, 2);
+		val[3] = smccc_uuid_to_reg(&uuid, 3);
 		break;
 	case ARM_SMCCC_VENDOR_HYP_KVM_FEATURES_FUNC_ID:
 		val[0] = smccc_feat->vendor_hyp_bmap;

arch/x86/coco/sev/core.c

···
 	return page_address(p + 1);
 }
 
-static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip)
+static int wakeup_cpu_via_vmgexit(u32 apic_id, unsigned long start_ip, unsigned int cpu)
 {
 	struct sev_es_save_area *cur_vmsa, *vmsa;
 	struct svsm_ca *caa;
 	u8 sipi_vector;
-	int cpu, ret;
+	int ret;
 	u64 cr4;
 
 	/*
···
 
 	/* Override start_ip with known protected guest start IP */
 	start_ip = real_mode_header->sev_es_trampoline_start;
-
-	/* Find the logical CPU for the APIC ID */
-	for_each_present_cpu(cpu) {
-		if (arch_match_cpu_phys_id(cpu, apic_id))
-			break;
-	}
-	if (cpu >= nr_cpu_ids)
-		return -EINVAL;
-
 	cur_vmsa = per_cpu(sev_vmsa, cpu);
 
 	/*

arch/x86/hyperv/hv_init.c

···
 		old_setup_percpu_clockev();
 }
 
-#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
-static u8 __init get_vtl(void)
-{
-	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
-	struct hv_input_get_vp_registers *input;
-	struct hv_output_get_vp_registers *output;
-	unsigned long flags;
-	u64 ret;
-
-	local_irq_save(flags);
-	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
-	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
-
-	memset(input, 0, struct_size(input, names, 1));
-	input->partition_id = HV_PARTITION_ID_SELF;
-	input->vp_index = HV_VP_INDEX_SELF;
-	input->input_vtl.as_uint8 = 0;
-	input->names[0] = HV_REGISTER_VSM_VP_STATUS;
-
-	ret = hv_do_hypercall(control, input, output);
-	if (hv_result_success(ret)) {
-		ret = output->values[0].reg8 & HV_X64_VTL_MASK;
-	} else {
-		pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
-		BUG();
-	}
-
-	local_irq_restore(flags);
-	return ret;
-}
-#else
-static inline u8 get_vtl(void) { return 0; }
-#endif
-
 /*
  * This function is to be invoked early in the boot sequence after the
  * hypervisor has been detected.
···
 	return hypercall_msr.enable;
 }
 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
+
+int hv_apicid_to_vp_index(u32 apic_id)
+{
+	u64 control;
+	u64 status;
+	unsigned long irq_flags;
+	struct hv_get_vp_from_apic_id_in *input;
+	u32 *output, ret;
+
+	local_irq_save(irq_flags);
+
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	memset(input, 0, sizeof(*input));
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->apic_ids[0] = apic_id;
+
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_INDEX_FROM_APIC_ID;
+	status = hv_do_hypercall(control, input, output);
+	ret = output[0];
+
+	local_irq_restore(irq_flags);
+
+	if (!hv_result_success(status)) {
+		pr_err("failed to get vp index from apic id %d, status %#llx\n",
+		       apic_id, status);
+		return -EINVAL;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(hv_apicid_to_vp_index);

arch/x86/hyperv/hv_vtl.c

···
 
 void __init hv_vtl_init_platform(void)
 {
-	pr_info("Linux runs in Hyper-V Virtual Trust Level\n");
+	/*
+	 * This function is a no-op if the VTL mode is not enabled.
+	 * If it is, this function runs if and only the kernel boots in
+	 * VTL2 which the x86 hv initialization path makes sure of.
+	 */
+	pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);
 
 	x86_platform.realmode_reserve = x86_init_noop;
 	x86_platform.realmode_init = x86_init_noop;
···
 	return ret;
 }
 
-static int hv_vtl_apicid_to_vp_id(u32 apic_id)
+static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip, unsigned int cpu)
 {
-	u64 control;
-	u64 status;
-	unsigned long irq_flags;
-	struct hv_get_vp_from_apic_id_in *input;
-	u32 *output, ret;
-
-	local_irq_save(irq_flags);
-
-	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
-	memset(input, 0, sizeof(*input));
-	input->partition_id = HV_PARTITION_ID_SELF;
-	input->apic_ids[0] = apic_id;
-
-	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
-
-	control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_ID_FROM_APIC_ID;
-	status = hv_do_hypercall(control, input, output);
-	ret = output[0];
-
-	local_irq_restore(irq_flags);
-
-	if (!hv_result_success(status)) {
-		pr_err("failed to get vp id from apic id %d, status %#llx\n",
-		       apic_id, status);
-		return -EINVAL;
-	}
-
-	return ret;
-}
-
-static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip)
-{
-	int vp_id, cpu;
-
-	/* Find the logical CPU for the APIC ID */
-	for_each_present_cpu(cpu) {
-		if (arch_match_cpu_phys_id(cpu, apicid))
-			break;
-	}
-	if (cpu >= nr_cpu_ids)
-		return -EINVAL;
+	int vp_index;
 
 	pr_debug("Bringing up CPU with APIC ID %d in VTL2...\n", apicid);
-	vp_id = hv_vtl_apicid_to_vp_id(apicid);
+	vp_index = hv_apicid_to_vp_index(apicid);
 
-	if (vp_id < 0) {
+	if (vp_index < 0) {
 		pr_err("Couldn't find CPU with APIC ID %d\n", apicid);
 		return -EINVAL;
 	}
-	if (vp_id > ms_hyperv.max_vp_index) {
-		pr_err("Invalid CPU id %d for APIC ID %d\n", vp_id, apicid);
+	if (vp_index > ms_hyperv.max_vp_index) {
+		pr_err("Invalid CPU id %d for APIC ID %d\n", vp_index, apicid);
 		return -EINVAL;
 	}
 
-	return hv_vtl_bringup_vcpu(vp_id, cpu, start_eip);
+	return hv_vtl_bringup_vcpu(vp_index, cpu, start_eip);
 }
 
 int __init hv_vtl_early_init(void)

arch/x86/hyperv/ivm.c

···
 #include <linux/bitfield.h>
 #include <linux/types.h>
 #include <linux/slab.h>
+#include <linux/cpu.h>
 #include <asm/svm.h>
 #include <asm/sev.h>
 #include <asm/io.h>
···
 		free_page((unsigned long)vmsa);
 }
 
-int hv_snp_boot_ap(u32 cpu, unsigned long start_ip)
+int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu)
 {
 	struct sev_es_save_area *vmsa = (struct sev_es_save_area *)
 		__get_free_page(GFP_KERNEL | __GFP_ZERO);
···
 	u64 ret, retry = 5;
 	struct hv_enable_vp_vtl *start_vp_input;
 	unsigned long flags;
+	int vp_index;
 
 	if (!vmsa)
 		return -ENOMEM;
+
+	/* Find the Hyper-V VP index which might be not the same as APIC ID */
+	vp_index = hv_apicid_to_vp_index(apic_id);
+	if (vp_index < 0 || vp_index > ms_hyperv.max_vp_index)
+		return -EINVAL;
 
 	native_store_gdt(&gdtr);
 
···
 	start_vp_input = (struct hv_enable_vp_vtl *)ap_start_input_arg;
 	memset(start_vp_input, 0, sizeof(*start_vp_input));
 	start_vp_input->partition_id = -1;
-	start_vp_input->vp_index = cpu;
+	start_vp_input->vp_index = vp_index;
 	start_vp_input->target_vtl.target_vtl = ms_hyperv.vtl;
 	*(u64 *)&start_vp_input->vp_context = __pa(vmsa) | 1;
 

arch/x86/include/asm/apic.h

···
 	u32	(*get_apic_id)(u32 id);
 
 	/* wakeup_secondary_cpu */
-	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 	/* wakeup secondary CPU using 64-bit wakeup point */
-	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 
 	char	*name;
 };
···
 	void	(*send_IPI_self)(int vector);
 	u64	(*icr_read)(void);
 	void	(*icr_write)(u32 low, u32 high);
-	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip);
-	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip);
+	int	(*wakeup_secondary_cpu)(u32 apicid, unsigned long start_eip, unsigned int cpu);
+	int	(*wakeup_secondary_cpu_64)(u32 apicid, unsigned long start_eip, unsigned int cpu);
 };
 
 /*

arch/x86/include/asm/mshyperv.h

···
 #ifdef CONFIG_AMD_MEM_ENCRYPT
 bool hv_ghcb_negotiate_protocol(void);
 void __noreturn hv_ghcb_terminate(unsigned int set, unsigned int reason);
-int hv_snp_boot_ap(u32 cpu, unsigned long start_ip);
+int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip, unsigned int cpu);
 #else
 static inline bool hv_ghcb_negotiate_protocol(void) { return false; }
 static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
-static inline int hv_snp_boot_ap(u32 cpu, unsigned long start_ip) { return 0; }
+static inline int hv_snp_boot_ap(u32 apic_id, unsigned long start_ip,
+		unsigned int cpu) { return 0; }
 #endif
 
 #if defined(CONFIG_AMD_MEM_ENCRYPT) || defined(CONFIG_INTEL_TDX_GUEST)
···
 {
 	return native_rdmsrq(reg);
 }
+int hv_apicid_to_vp_index(u32 apic_id);
 
 #else /* CONFIG_HYPERV */
 static inline void hyperv_init(void) {}
···
 static inline u64 hv_get_msr(unsigned int reg) { return 0; }
 static inline void hv_set_non_nested_msr(unsigned int reg, u64 value) { }
 static inline u64 hv_get_non_nested_msr(unsigned int reg) { return 0; }
+static inline int hv_apicid_to_vp_index(u32 apic_id) { return -EINVAL; }
 #endif /* CONFIG_HYPERV */
 
 

arch/x86/kernel/acpi/madt_wakeup.c

···
 	return 0;
 }
 
-static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip)
+static int acpi_wakeup_cpu(u32 apicid, unsigned long start_ip, unsigned int cpu)
 {
 	if (!acpi_mp_wake_mailbox_paddr) {
 		pr_warn_once("No MADT mailbox: cannot bringup secondary CPUs. Booting with kexec?\n");

arch/x86/kernel/apic/apic_noop.c

···
 static void noop_send_IPI_all(int vector) { }
 static void noop_send_IPI_self(int vector) { }
 static void noop_apic_icr_write(u32 low, u32 id) { }
-static int noop_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip) { return -1; }
+
+static int noop_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip,
+	unsigned int cpu)
+{
+	return -1;
+}
+
 static u64 noop_apic_icr_read(void) { return 0; }
 static u32 noop_get_apic_id(u32 apicid) { return 0; }
 static void noop_apic_eoi(void) { }

arch/x86/kernel/apic/apic_numachip.c

···
 	numachip2_write32_lcsr(NUMACHIP2_APIC_ICR, (apicid << 12) | val);
 }
 
-static int numachip_wakeup_secondary(u32 phys_apicid, unsigned long start_rip)
+static int numachip_wakeup_secondary(u32 phys_apicid, unsigned long start_rip, unsigned int cpu)
 {
 	numachip_apic_icr_write(phys_apicid, APIC_DM_INIT);
 	numachip_apic_icr_write(phys_apicid, APIC_DM_STARTUP |

arch/x86/kernel/apic/x2apic_uv_x.c

···
 	}
 }
 
-static int uv_wakeup_secondary(u32 phys_apicid, unsigned long start_rip)
+static int uv_wakeup_secondary(u32 phys_apicid, unsigned long start_rip, unsigned int cpu)
 {
 	unsigned long val;
 	int pnode;

arch/x86/kernel/smpboot.c

···
 /*
  * Wake up AP by INIT, INIT, STARTUP sequence.
  */
-static int wakeup_secondary_cpu_via_init(u32 phys_apicid, unsigned long start_eip)
+static int wakeup_secondary_cpu_via_init(u32 phys_apicid, unsigned long start_eip, unsigned int cpu)
 {
 	unsigned long send_status = 0, accept_status = 0;
 	int num_starts, j, maxlvt;
···
  * Returns zero if startup was successfully sent, else error code from
  * ->wakeup_secondary_cpu.
  */
-static int do_boot_cpu(u32 apicid, int cpu, struct task_struct *idle)
+static int do_boot_cpu(u32 apicid, unsigned int cpu, struct task_struct *idle)
 {
 	unsigned long start_ip = real_mode_header->trampoline_start;
 	int ret;
···
 	 * - Use an INIT boot APIC message
 	 */
 	if (apic->wakeup_secondary_cpu_64)
-		ret = apic->wakeup_secondary_cpu_64(apicid, start_ip);
+		ret = apic->wakeup_secondary_cpu_64(apicid, start_ip, cpu);
 	else if (apic->wakeup_secondary_cpu)
-		ret = apic->wakeup_secondary_cpu(apicid, start_ip);
+		ret = apic->wakeup_secondary_cpu(apicid, start_ip, cpu);
 	else
-		ret = wakeup_secondary_cpu_via_init(apicid, start_ip);
+		ret = wakeup_secondary_cpu_via_init(apicid, start_ip, cpu);
 
 	/* If the wakeup mechanism failed, cleanup the warm reset vector */
 	if (ret)

drivers/acpi/irq.c

···
 
 enum acpi_irq_model_id acpi_irq_model;
 
-static struct fwnode_handle *(*acpi_get_gsi_domain_id)(u32 gsi);
+static acpi_gsi_domain_disp_fn acpi_get_gsi_domain_id;
 static u32 (*acpi_gsi_to_irq_fallback)(u32 gsi);
 
 /**
···
  *	for a given GSI
  */
 void __init acpi_set_irq_model(enum acpi_irq_model_id model,
-			       struct fwnode_handle *(*fn)(u32))
+			       acpi_gsi_domain_disp_fn fn)
 {
 	acpi_irq_model = model;
 	acpi_get_gsi_domain_id = fn;
 }
+
+/*
+ * acpi_get_gsi_dispatcher() - Get the GSI dispatcher function
+ *
+ * Return the dispatcher function that computes the domain fwnode for
+ * a given GSI.
+ */
+acpi_gsi_domain_disp_fn acpi_get_gsi_dispatcher(void)
+{
+	return acpi_get_gsi_domain_id;
+}
+EXPORT_SYMBOL_GPL(acpi_get_gsi_dispatcher);
 
 /**
  * acpi_set_gsi_to_irq_fallback - Register a GSI transfer

drivers/firmware/smccc/kvm_guest.c

···
 
 void __init kvm_init_hyp_services(void)
 {
+	uuid_t kvm_uuid = ARM_SMCCC_VENDOR_HYP_UID_KVM;
 	struct arm_smccc_res res;
 	u32 val[4];
 
-	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC)
-		return;
-
-	arm_smccc_1_1_invoke(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
-	if (res.a0 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0 ||
-	    res.a1 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1 ||
-	    res.a2 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2 ||
-	    res.a3 != ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3)
+	if (!arm_smccc_hypervisor_has_uuid(&kvm_uuid))
 		return;
 
 	memset(&res, 0, sizeof(res));

drivers/firmware/smccc/smccc.c

···
 }
 EXPORT_SYMBOL_GPL(arm_smccc_get_soc_id_revision);
 
+bool arm_smccc_hypervisor_has_uuid(const uuid_t *hyp_uuid)
+{
+	struct arm_smccc_res res = {};
+	uuid_t uuid;
+
+	if (arm_smccc_1_1_get_conduit() != SMCCC_CONDUIT_HVC)
+		return false;
+
+	arm_smccc_1_1_hvc(ARM_SMCCC_VENDOR_HYP_CALL_UID_FUNC_ID, &res);
+	if (res.a0 == SMCCC_RET_NOT_SUPPORTED)
+		return false;
+
+	uuid = smccc_res_to_uuid(res.a0, res.a1, res.a2, res.a3);
+	return uuid_equal(&uuid, hyp_uuid);
+}
+EXPORT_SYMBOL_GPL(arm_smccc_hypervisor_has_uuid);
+
 static int __init smccc_devices_init(void)
 {
 	struct platform_device *pdev;

drivers/hv/Kconfig

···
 config HYPERV
 	tristate "Microsoft Hyper-V client drivers"
 	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
-		|| (ACPI && ARM64 && !CPU_BIG_ENDIAN)
+		|| (ARM64 && !CPU_BIG_ENDIAN)
 	select PARAVIRT
 	select X86_HV_CALLBACK_VECTOR if X86
 	select OF_EARLY_FLATTREE if OF
+	select SYSFB if !HYPERV_VTL_MODE
 	help
 	  Select this option to run Linux as a Hyper-V client operating
 	  system.
 
 config HYPERV_VTL_MODE
 	bool "Enable Linux to boot in VTL context"
-	depends on X86_64 && HYPERV
+	depends on (X86_64 || ARM64) && HYPERV
 	depends on SMP
 	default n
 	help
···
 
 	  Select this option to build a Linux kernel to run at a VTL other than
 	  the normal VTL0, which currently is only VTL2.  This option
-	  initializes the x86 platform for VTL2, and adds the ability to boot
+	  initializes the kernel to run in VTL2, and adds the ability to boot
 	  secondary CPUs directly into 64-bit context as required for VTLs other
 	  than 0.  A kernel built with this option must run at VTL2, and will
 	  not run as a normal guest.

drivers/hv/connection.c

···
 	mutex_init(&vmbus_connection.channel_mutex);
 
 	/*
+	 * The following Hyper-V interrupt and monitor pages can be used by
+	 * UIO for mapping to user-space, so they should always be allocated on
+	 * system page boundaries. The system page size must be >= the Hyper-V
+	 * page size.
+	 */
+	BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
+
+	/*
 	 * Setup the vmbus event connection for channel interrupt
 	 * abstraction stuff
 	 */
-	vmbus_connection.int_page = hv_alloc_hyperv_zeroed_page();
+	vmbus_connection.int_page =
+		(void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
 	if (vmbus_connection.int_page == NULL) {
 		ret = -ENOMEM;
 		goto cleanup;
···
 	 * Setup the monitor notification facility. The 1st page for
 	 * parent->child and the 2nd page for child->parent
 	 */
-	vmbus_connection.monitor_pages[0] = hv_alloc_hyperv_page();
-	vmbus_connection.monitor_pages[1] = hv_alloc_hyperv_page();
+	vmbus_connection.monitor_pages[0] = (void *)__get_free_page(GFP_KERNEL);
+	vmbus_connection.monitor_pages[1] = (void *)__get_free_page(GFP_KERNEL);
 	if ((vmbus_connection.monitor_pages[0] == NULL) ||
 	    (vmbus_connection.monitor_pages[1] == NULL)) {
 		ret = -ENOMEM;
···
 		destroy_workqueue(vmbus_connection.work_queue);
 
 	if (vmbus_connection.int_page) {
-		hv_free_hyperv_page(vmbus_connection.int_page);
+		free_page((unsigned long)vmbus_connection.int_page);
 		vmbus_connection.int_page = NULL;
 	}
 
 	if (vmbus_connection.monitor_pages[0]) {
 		if (!set_memory_encrypted(
 			(unsigned long)vmbus_connection.monitor_pages[0], 1))
-			hv_free_hyperv_page(vmbus_connection.monitor_pages[0]);
+			free_page((unsigned long)
+				vmbus_connection.monitor_pages[0]);
 		vmbus_connection.monitor_pages[0] = NULL;
 	}
 
 	if (vmbus_connection.monitor_pages[1]) {
 		if (!set_memory_encrypted(
 			(unsigned long)vmbus_connection.monitor_pages[1], 1))
-			hv_free_hyperv_page(vmbus_connection.monitor_pages[1]);
+			free_page((unsigned long)
+				vmbus_connection.monitor_pages[1]);
 		vmbus_connection.monitor_pages[1] = NULL;
 	}
 }

drivers/hv/hv_common.c

···
 	hv_synic_eventring_tail = NULL;
 }
 
-/*
- * Functions for allocating and freeing memory with size and
- * alignment HV_HYP_PAGE_SIZE. These functions are needed because
- * the guest page size may not be the same as the Hyper-V page
- * size. We depend upon kmalloc() aligning power-of-two size
- * allocations to the allocation size boundary, so that the
- * allocated memory appears to Hyper-V as a page of the size
- * it expects.
- */
-
-void *hv_alloc_hyperv_page(void)
-{
-	BUILD_BUG_ON(PAGE_SIZE <  HV_HYP_PAGE_SIZE);
-
-	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
-		return (void *)__get_free_page(GFP_KERNEL);
-	else
-		return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
-
-void *hv_alloc_hyperv_zeroed_page(void)
-{
-	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
-		return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
-	else
-		return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
-}
-EXPORT_SYMBOL_GPL(hv_alloc_hyperv_zeroed_page);
-
-void hv_free_hyperv_page(void *addr)
-{
-	if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
-		free_page((unsigned long)addr);
-	else
-		kfree(addr);
-}
-EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
-
 static void *hv_panic_page;
 
 /*
···
 	atomic_notifier_chain_unregister(&panic_notifier_list,
 					 &hyperv_panic_report_block);
 
-	hv_free_hyperv_page(hv_panic_page);
+	kfree(hv_panic_page);
 	hv_panic_page = NULL;
 }
 
···
 {
 	int ret;
 
-	hv_panic_page = hv_alloc_hyperv_zeroed_page();
+	hv_panic_page = kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
 	if (!hv_panic_page) {
 		pr_err("Hyper-V: panic message page memory allocation failed\n");
 		return;
···
 	ret = kmsg_dump_register(&hv_kmsg_dumper);
 	if (ret) {
 		pr_err("Hyper-V: kmsg dump register error 0x%x\n", ret);
-		hv_free_hyperv_page(hv_panic_page);
+		kfree(hv_panic_page);
 		hv_panic_page = NULL;
 	}
 }
···
 		pr_err("Hyper-V: failed to get partition ID: %#x\n",
 		       hv_result(status));
 }
+#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
+u8 __init get_vtl(void)
+{
+	u64 control = HV_HYPERCALL_REP_COMP_1 | HVCALL_GET_VP_REGISTERS;
+	struct hv_input_get_vp_registers *input;
+	struct hv_output_get_vp_registers *output;
+	unsigned long flags;
+	u64 ret;
+
+	local_irq_save(flags);
+	input = *this_cpu_ptr(hyperv_pcpu_input_arg);
+	output = *this_cpu_ptr(hyperv_pcpu_output_arg);
+
+	memset(input, 0, struct_size(input, names, 1));
+	input->partition_id = HV_PARTITION_ID_SELF;
+	input->vp_index = HV_VP_INDEX_SELF;
+	input->input_vtl.as_uint8 = 0;
+	input->names[0] = HV_REGISTER_VSM_VP_STATUS;
+
+	ret = hv_do_hypercall(control, input, output);
+	if (hv_result_success(ret)) {
+		ret = output->values[0].reg8 & HV_VTL_MASK;
+	} else {
+		pr_err("Failed to get VTL(error: %lld) exiting...\n", ret);
+		BUG();
+	}
+
+	local_irq_restore(flags);
+	return ret;
+}
+#endif
 
 int __init hv_common_init(void)
 {

drivers/hv/vmbus_drv.c

···
 	struct hv_vmbus_device_id id;
 };
 
-static struct device  *hv_dev;
+/* VMBus Root Device */
+static struct device  *vmbus_root_device;
 
 static int hyperv_cpuhp_online;
 
···
 static struct resource *hyperv_mmio;
 static DEFINE_MUTEX(hyperv_mmio_lock);
 
+struct device *hv_get_vmbus_root_device(void)
+{
+	return vmbus_root_device;
+}
+EXPORT_SYMBOL_GPL(hv_get_vmbus_root_device);
+
 static int vmbus_exists(void)
 {
-	if (hv_dev == NULL)
+	if (vmbus_root_device == NULL)
 		return -ENODEV;
 
 	return 0;
···
 	return id;
 }
 
-/* vmbus_add_dynid - add a new device ID to this driver and re-probe devices */
+/* vmbus_add_dynid - add a new device ID to this driver and re-probe devices
+ *
+ * This function can race with vmbus_device_register(). This function is
+ * typically running on a user thread in response to writing to the "new_id"
+ * sysfs entry for a driver. vmbus_device_register() is running on a
+ * workqueue thread in response to the Hyper-V host offering a device to the
+ * guest. This function calls driver_attach(), which looks for an existing
+ * device matching the new id, and attaches the driver to which the new id
+ * has been assigned. vmbus_device_register() calls device_register(), which
+ * looks for a driver that matches the device being registered. If both
+ * operations are running simultaneously, the device driver probe function runs
+ * on whichever thread establishes the linkage between the driver and device.
+ *
+ * In most cases, it doesn't matter which thread runs the driver probe
+ * function. But if vmbus_device_register() does not find a matching driver,
+ * it proceeds to create the "channels" subdirectory and numbered per-channel
+ * subdirectory in sysfs. While that multi-step creation is in progress, this
+ * function could run the driver probe function. If the probe function checks
+ * for, or operates on, entries in the "channels" subdirectory, including by
+ * calling hv_create_ring_sysfs(), the operation may or may not succeed
+ * depending on the race. The race can't create a kernel failure in VMBus
+ * or device subsystem code, but probe functions in VMBus drivers doing such
+ * operations must be prepared for the failure case.
+ */
 static int vmbus_add_dynid(struct hv_driver *drv, guid_t *guid)
 {
 	struct vmbus_dynid *dynid;
···
 	 * On x86/x64 coherence is assumed and these calls have no effect.
 	 */
 	hv_setup_dma_ops(child_device,
-		device_get_dma_attr(hv_dev) == DEV_DMA_COHERENT);
+		device_get_dma_attr(vmbus_root_device) == DEV_DMA_COHERENT);
 	return 0;
 }
 
···
  * ring for userspace to use.
  * Note: Race conditions can happen with userspace and it is not encouraged to create new
  * use-cases for this. This was added to maintain backward compatibility, while solving
- * one of the race conditions in uio_hv_generic while creating sysfs.
+ * one of the race conditions in uio_hv_generic while creating sysfs. See comments with
+ * vmbus_add_dynid() and vmbus_device_register().
  *
  * Returns 0 on success or error code on failure.
  */
···
 		     &child_device_obj->channel->offermsg.offer.if_instance);
 
 	child_device_obj->device.bus = &hv_bus;
-	child_device_obj->device.parent = hv_dev;
+	child_device_obj->device.parent = vmbus_root_device;
 	child_device_obj->device.release = vmbus_device_release;
 
 	child_device_obj->device.dma_parms = &child_device_obj->dma_parms;
···
 		return ret;
 	}
 
+	/*
+	 * If device_register() found a driver to assign to the device, the
+	 * driver's probe function has already run at this point. If that
+	 * probe function accesses or operates on the "channels" subdirectory
+	 * in sysfs, those operations will have failed because the "channels"
+	 * subdirectory doesn't exist until the code below runs. Or if the
+	 * probe function creates a /dev entry, a user space program could
+	 * find and open the /dev entry, and then create a race by accessing
+	 * the "channels" subdirectory while the creation steps are in progress
+	 * here. The race can't result in a kernel failure, but the user space
+	 * program may get an error in accessing "channels" or its
+	 * subdirectories. See also comments with vmbus_add_dynid() about a
+	 * related race condition.
+	 */
 	child_device_obj->channels_kset = kset_create_and_add("channels",
 							      NULL, kobj);
 	if (!child_device_obj->channels_kset) {
···
 	struct acpi_device *ancestor;
 	struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
 
-	hv_dev = &device->dev;
+	vmbus_root_device = &device->dev;
 
 	/*
 	 * Older versions of Hyper-V for ARM64 fail to include the _CCA
···
 }
 #endif
 
+static int vmbus_set_irq(struct platform_device *pdev)
+{
+	struct irq_data *data;
+	int irq;
+	irq_hw_number_t hwirq;
+
+	irq = platform_get_irq(pdev, 0);
+	/* platform_get_irq() may not return 0. */
+	if (irq < 0)
+		return irq;
+
+	data = irq_get_irq_data(irq);
+	if (!data) {
+		pr_err("No interrupt data for VMBus virq %d\n", irq);
+		return -ENODEV;
+	}
+	hwirq = irqd_to_hwirq(data);
+
+	vmbus_irq = irq;
+	vmbus_interrupt = hwirq;
+	pr_debug("VMBus virq %d, hwirq %d\n", vmbus_irq, vmbus_interrupt);
+
+	return 0;
+}
+
 static int vmbus_device_add(struct platform_device *pdev)
 {
 	struct resource **cur_res = &hyperv_mmio;
···
 	struct device_node *np = pdev->dev.of_node;
 	int ret;
 
-	hv_dev = &pdev->dev;
+	vmbus_root_device = &pdev->dev;
 
 	ret = of_range_parser_init(&parser, np);
+	if (ret)
+		return ret;
+
+	if (!__is_defined(HYPERVISOR_CALLBACK_VECTOR))
+		ret = vmbus_set_irq(pdev);
 	if (ret)
 		return ret;
 
···
 	if (ret)
 		return ret;
 
-	if (!hv_dev) {
+	if (!vmbus_root_device) {
 		ret = -ENODEV;
 		goto cleanup;
 	}
···
 
 cleanup:
 	platform_driver_unregister(&vmbus_platform_driver);
-	hv_dev = NULL;
+	vmbus_root_device = NULL;
 	return ret;
 }
 

drivers/pci/controller/pci-hyperv.c

···
 #include <linux/irqdomain.h>
 #include <linux/acpi.h>
 #include <linux/sizes.h>
+#include <linux/of_irq.h>
 #include <asm/mshyperv.h>
 
 /*
···
 	void (*completion_func)(void *context, struct pci_response *resp,
 				int resp_packet_size);
 	void *compl_ctxt;
-
-	struct pci_message message[];
 };
 
 /*
···
 	int ret;
 
 	fwspec.fwnode = domain->parent->fwnode;
-	fwspec.param_count = 2;
-	fwspec.param[0] = hwirq;
-	fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+	if (is_of_node(fwspec.fwnode)) {
+		/* SPI lines for OF translations start at offset 32 */
+		fwspec.param_count = 3;
+		fwspec.param[0] = 0;
+		fwspec.param[1] = hwirq - 32;
+		fwspec.param[2] = IRQ_TYPE_EDGE_RISING;
+	} else {
+		fwspec.param_count = 2;
+		fwspec.param[0] = hwirq;
+		fwspec.param[1] = IRQ_TYPE_EDGE_RISING;
+	}
 
 	ret = irq_domain_alloc_irqs_parent(domain, virq, 1, &fwspec);
 	if (ret)
···
 	.activate = hv_pci_vec_irq_domain_activate,
 };
 
+#ifdef CONFIG_OF
+
+static struct irq_domain *hv_pci_of_irq_domain_parent(void)
+{
+	struct device_node *parent;
+	struct irq_domain *domain;
+
+	parent = of_irq_find_parent(hv_get_vmbus_root_device()->of_node);
+	if (!parent)
+		return NULL;
+	domain = irq_find_host(parent);
+	of_node_put(parent);
+
+	return domain;
+}
+
+#endif
+
+#ifdef CONFIG_ACPI
+
+static struct irq_domain *hv_pci_acpi_irq_domain_parent(void)
+{
+	acpi_gsi_domain_disp_fn gsi_domain_disp_fn;
+
+	gsi_domain_disp_fn = acpi_get_gsi_dispatcher();
+	if (!gsi_domain_disp_fn)
+		return NULL;
+	return irq_find_matching_fwnode(gsi_domain_disp_fn(0),
+				     DOMAIN_BUS_ANY);
+}
+
+#endif
+
 static int hv_pci_irqchip_init(void)
 {
 	static struct hv_pci_chip_data *chip_data;
 	struct fwnode_handle *fn = NULL;
+	struct irq_domain *irq_domain_parent = NULL;
 	int ret = -ENOMEM;
 
 	chip_data = kzalloc(sizeof(*chip_data), GFP_KERNEL);
···
 	 * way to ensure that all the corresponding devices are also gone and
 	 * no interrupts will be generated.
 	 */
-	hv_msi_gic_irq_domain = acpi_irq_create_hierarchy(0, HV_PCI_MSI_SPI_NR,
-							  fn, &hv_pci_domain_ops,
-							  chip_data);
+#ifdef CONFIG_ACPI
+	if (!acpi_disabled)
+		irq_domain_parent = hv_pci_acpi_irq_domain_parent();
+#endif
+#ifdef CONFIG_OF
+	if (!irq_domain_parent)
+		irq_domain_parent = hv_pci_of_irq_domain_parent();
+#endif
+	if (!irq_domain_parent) {
+		WARN_ONCE(1, "Invalid firmware configuration for VMBus interrupts\n");
+		ret = -EINVAL;
+		goto free_chip;
+	}
+
+	hv_msi_gic_irq_domain = irq_domain_create_hierarchy(irq_domain_parent, 0,
+		HV_PCI_MSI_SPI_NR,
+		fn, &hv_pci_domain_ops,
+		chip_data);
 
 	if (!hv_msi_gic_irq_domain) {
 		pr_err("Failed to create Hyper-V arm64 vPCI MSI IRQ domain\n");
···
 	memset(&pkt, 0, sizeof(pkt));
 	pkt.pkt.completion_func = hv_pci_read_config_compl;
 	pkt.pkt.compl_ctxt = &comp_pkt;
-	read_blk = (struct pci_read_block *)&pkt.pkt.message;
+	read_blk = (struct pci_read_block *)pkt.buf;
 	read_blk->message_type.type = PCI_READ_BLOCK;
 	read_blk->wslot.slot = devfn_to_wslot(pdev->devfn);
 	read_blk->block_id = block_id;
···
 	memset(&pkt, 0, sizeof(pkt));
 	pkt.pkt.completion_func = hv_pci_write_config_compl;
 	pkt.pkt.compl_ctxt = &comp_pkt;
-	write_blk = (struct pci_write_block *)&pkt.pkt.message;
+	write_blk = (struct pci_write_block *)pkt.buf;
 	write_blk->message_type.type = PCI_WRITE_BLOCK;
 	write_blk->wslot.slot = devfn_to_wslot(pdev->devfn);
 	write_blk->block_id = block_id;
···
 		return;
 	}
 	memset(&ctxt, 0, sizeof(ctxt));
-	int_pkt = (struct pci_delete_interrupt *)&ctxt.pkt.message;
+	int_pkt = (struct pci_delete_interrupt *)ctxt.buffer;
 	int_pkt->message_type.type =
 		PCI_DELETE_INTERRUPT_MESSAGE;
 	int_pkt->wslot.slot = hpdev->desc.win_slot.slot;
···
 	comp_pkt.hpdev = hpdev;
 	pkt.init_packet.compl_ctxt = &comp_pkt;
 	pkt.init_packet.completion_func = q_resource_requirements;
-	res_req = (struct pci_child_message *)&pkt.init_packet.message;
+	res_req = (struct pci_child_message *)pkt.buffer;
 	res_req->message_type.type = PCI_QUERY_RESOURCE_REQUIREMENTS;
 	res_req->wslot.slot = desc->win_slot.slot;
 
···
 		pci_destroy_slot(hpdev->pci_slot);
 
 	memset(&ctxt, 0, sizeof(ctxt));
-	ejct_pkt = (struct pci_eject_response *)&ctxt.pkt.message;
+	ejct_pkt = (struct pci_eject_response *)ctxt.buffer;
 	ejct_pkt->message_type.type = PCI_EJECTION_COMPLETE;
 	ejct_pkt->wslot.slot = hpdev->desc.win_slot.slot;
 	vmbus_sendpacket(hbus->hdev->channel, ejct_pkt,
···
 	init_completion(&comp_pkt.host_event);
 	pkt->completion_func = hv_pci_generic_compl;
 	pkt->compl_ctxt = &comp_pkt;
-	version_req = (struct pci_version_request *)&pkt->message;
+	version_req = (struct pci_version_request *)(pkt + 1);
 	version_req->message_type.type = PCI_QUERY_PROTOCOL_VERSION;
 
 	for (i = 0; i < num_version; i++) {
···
 	init_completion(&comp_pkt.host_event);
 	pkt->completion_func = hv_pci_generic_compl;
 	pkt->compl_ctxt = &comp_pkt;
-	d0_entry = (struct pci_bus_d0_entry *)&pkt->message;
+	d0_entry = (struct pci_bus_d0_entry *)(pkt + 1);
 	d0_entry->message_type.type = PCI_BUS_D0ENTRY;
 	d0_entry->mmio_base = hbus->mem_config->start;
 
···
 
 		if (hbus->protocol_version < PCI_PROTOCOL_VERSION_1_2) {
 			res_assigned =
-				(struct pci_resources_assigned *)&pkt->message;
+				(struct pci_resources_assigned *)(pkt + 1);
 			res_assigned->message_type.type =
 				PCI_RESOURCES_ASSIGNED;
 			res_assigned->wslot.slot = hpdev->desc.win_slot.slot;
 		} else {
 			res_assigned2 =
-				(struct pci_resources_assigned2 *)&pkt->message;
+				(struct pci_resources_assigned2 *)(pkt + 1);
 			res_assigned2->message_type.type =
 				PCI_RESOURCES_ASSIGNED2;
 			res_assigned2->wslot.slot = hpdev->desc.win_slot.slot;
 		}
 		put_pcichild(hpdev);
 
-		ret = vmbus_sendpacket(hdev->channel, &pkt->message,
+		ret = vmbus_sendpacket(hdev->channel, pkt + 1,
 				size_res, (unsigned long)pkt,
 				VM_PKT_DATA_INBAND,
 				VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);
···
 		struct pci_packet teardown_packet;
 		u8 buffer[sizeof(struct pci_message)];
 	} pkt;
+	struct pci_message *msg;
 	struct hv_pci_compl comp_pkt;
 	struct hv_pci_dev *hpdev, *tmp;
 	unsigned long flags;
···
 	init_completion(&comp_pkt.host_event);
 	pkt.teardown_packet.completion_func = hv_pci_generic_compl;
 	pkt.teardown_packet.compl_ctxt = &comp_pkt;
-	pkt.teardown_packet.message[0].type = PCI_BUS_D0EXIT;
+	msg = (struct pci_message *)pkt.buffer;
+	msg->type = PCI_BUS_D0EXIT;
 
-	ret = vmbus_sendpacket_getid(chan, &pkt.teardown_packet.message,
-				     sizeof(struct pci_message),
+	ret = vmbus_sendpacket_getid(chan, msg, sizeof(*msg),
 				     (unsigned long)&pkt.teardown_packet,
 				     &trans_id, VM_PKT_DATA_INBAND,
 				     VMBUS_DATA_PACKET_FLAG_COMPLETION_REQUESTED);

drivers/uio/uio_hv_generic.c

···
 	if (!ring_size)
 		ring_size = SZ_2M;
 
+	/* Adjust ring size if necessary to have it page aligned */
+	ring_size = VMBUS_RING_SIZE(ring_size);
+
 	pdata = devm_kzalloc(&dev->device, sizeof(*pdata), GFP_KERNEL);
 	if (!pdata)
 		return -ENOMEM;
···
 	pdata->info.mem[INT_PAGE_MAP].name = "int_page";
 	pdata->info.mem[INT_PAGE_MAP].addr
 		= (uintptr_t)vmbus_connection.int_page;
-	pdata->info.mem[INT_PAGE_MAP].size = PAGE_SIZE;
+	pdata->info.mem[INT_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
 	pdata->info.mem[INT_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 
 	pdata->info.mem[MON_PAGE_MAP].name = "monitor_page";
 	pdata->info.mem[MON_PAGE_MAP].addr
 		= (uintptr_t)vmbus_connection.monitor_pages[1];
-	pdata->info.mem[MON_PAGE_MAP].size = PAGE_SIZE;
+	pdata->info.mem[MON_PAGE_MAP].size = HV_HYP_PAGE_SIZE;
 	pdata->info.mem[MON_PAGE_MAP].memtype = UIO_MEM_LOGICAL;
 
 	if (channel->device_id == HV_NIC) {

include/asm-generic/mshyperv.h

···
 int hv_common_cpu_die(unsigned int cpu);
 void hv_identify_partition_type(void);
 
-void *hv_alloc_hyperv_page(void);
-void *hv_alloc_hyperv_zeroed_page(void);
-void hv_free_hyperv_page(void *addr);
-
 /**
  * hv_cpu_number_to_vp_number() - Map CPU to VP.
  * @cpu_number: CPU number in Linux terms
···
 	return -EOPNOTSUPP;
 }
 #endif /* CONFIG_MSHV_ROOT */
+
+#if IS_ENABLED(CONFIG_HYPERV_VTL_MODE)
+u8 __init get_vtl(void);
+#else
+static inline u8 get_vtl(void) { return 0; }
+#endif
 
 #endif

include/hyperv/hvgdk_mini.h

···
 #define HVCALL_CREATE_PORT				0x0095
 #define HVCALL_CONNECT_PORT				0x0096
 #define HVCALL_START_VP					0x0099
-#define HVCALL_GET_VP_ID_FROM_APIC_ID			0x009a
+#define HVCALL_GET_VP_INDEX_FROM_APIC_ID			0x009a
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE	0x00af
 #define HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST	0x00b0
 #define HVCALL_SIGNAL_EVENT_DIRECT			0x00c0
···
 	u64 cpu_mask;
 } __packed;
 
-#define	HV_X64_VTL_MASK			GENMASK(3, 0)
+#define	HV_VTL_MASK			GENMASK(3, 0)
 
 /* Hyper-V memory host visibility */
 enum hv_mem_host_visibility {

include/linux/acpi.h

···
 int acpi_gsi_to_irq (u32 gsi, unsigned int *irq);
 int acpi_isa_irq_to_gsi (unsigned isa_irq, u32 *gsi);
 
+typedef struct fwnode_handle *(*acpi_gsi_domain_disp_fn)(u32);
+
 void acpi_set_irq_model(enum acpi_irq_model_id model,
-			struct fwnode_handle *(*)(u32));
+			acpi_gsi_domain_disp_fn fn);
+acpi_gsi_domain_disp_fn acpi_get_gsi_dispatcher(void);
 void acpi_set_gsi_to_irq_fallback(u32 (*)(u32));
 
 struct irq_domain *acpi_irq_create_hierarchy(unsigned int flags,

include/linux/arm-smccc.h

···
 
 #include <linux/args.h>
 #include <linux/init.h>
+
+#ifndef __ASSEMBLY__
+#include <linux/uuid.h>
+#endif
+
 #include <uapi/linux/const.h>
 
 /*
···
 			   ARM_SMCCC_FUNC_QUERY_CALL_UID)
 
 /* KVM UID value: 28b46fb6-2ec5-11e9-a9ca-4b564d003a74 */
-#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_0	0xb66fb428U
-#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_1	0xe911c52eU
-#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_2	0x564bcaa9U
-#define ARM_SMCCC_VENDOR_HYP_UID_KVM_REG_3	0x743a004dU
+#define ARM_SMCCC_VENDOR_HYP_UID_KVM UUID_INIT(\
+	0xb66fb428, 0xc52e, 0xe911, \
+	0xa9, 0xca, 0x4b, 0x56, \
+	0x4d, 0x00, 0x3a, 0x74)
 
 /* KVM "vendor specific" services */
 #define ARM_SMCCC_KVM_FUNC_FEATURES		0
···
  * When ARM_SMCCC_ARCH_SOC_ID is not present, returns SMCCC_RET_NOT_SUPPORTED.
  */
 s32 arm_smccc_get_soc_id_revision(void);
+
+#ifndef __ASSEMBLY__
+
+/*
+ * Returns whether a specific hypervisor UUID is advertised for the
+ * Vendor Specific Hypervisor Service range.
+ */
+bool arm_smccc_hypervisor_has_uuid(const uuid_t *uuid);
+
+static inline uuid_t smccc_res_to_uuid(u32 r0, u32 r1, u32 r2, u32 r3)
+{
+	uuid_t uuid = {
+		.b = {
+			[0]  = (r0 >> 0)  & 0xff,
+			[1]  = (r0 >> 8)  & 0xff,
+			[2]  = (r0 >> 16) & 0xff,
+			[3]  = (r0 >> 24) & 0xff,
+
+			[4]  = (r1 >> 0)  & 0xff,
+			[5]  = (r1 >> 8)  & 0xff,
+			[6]  = (r1 >> 16) & 0xff,
+			[7]  = (r1 >> 24) & 0xff,
+
+			[8]  = (r2 >> 0)  & 0xff,
+			[9]  = (r2 >> 8)  & 0xff,
+			[10] = (r2 >> 16) & 0xff,
+			[11] = (r2 >> 24) & 0xff,
+
+			[12] = (r3 >> 0)  & 0xff,
+			[13] = (r3 >> 8)  & 0xff,
+			[14] = (r3 >> 16) & 0xff,
+			[15] = (r3 >> 24) & 0xff,
+		},
+	};
+
+	return uuid;
+}
+
+static inline u32 smccc_uuid_to_reg(const uuid_t *uuid, int reg)
+{
+	u32 val = 0;
+
+	val |= (u32)(uuid->b[4 * reg + 0] << 0);
+	val |= (u32)(uuid->b[4 * reg + 1] << 8);
+	val |= (u32)(uuid->b[4 * reg + 2] << 16);
+	val |= (u32)(uuid->b[4 * reg + 3] << 24);
+
+	return val;
+}
+
+#endif /* !__ASSEMBLY__ */
 
 /**
  * struct arm_smccc_res - Result from SMC/HVC call

include/linux/hyperv.h

···
 	return dev_get_drvdata(&dev->device);
 }
 
+struct device *hv_get_vmbus_root_device(void);
+
 struct hv_ring_buffer_debug_info {
 	u32 current_interrupt_mask;
 	u32 current_read_index;

tools/hv/hv_kvp_daemon.c

···
 };
 
 static int in_hand_shake;
+static int debug;
 
 static char *os_name = "";
 static char *os_major = "";
···
 	kvp_release_lock(pool);
 }
 
+static void kvp_dump_initial_pools(int pool)
+{
+	int i;
+
+	syslog(LOG_DEBUG, "===Start dumping the contents of pool %d ===\n",
+	       pool);
+
+	for (i = 0; i < kvp_file_info[pool].num_records; i++)
+		syslog(LOG_DEBUG, "pool: %d, %d/%d key=%s val=%s\n",
+		       pool, i + 1, kvp_file_info[pool].num_records,
+		       kvp_file_info[pool].records[i].key,
+		       kvp_file_info[pool].records[i].value);
+}
+
 static void kvp_update_mem_state(int pool)
 {
 	FILE *filep;
···
 			return 1;
 		kvp_file_info[i].num_records = 0;
 		kvp_update_mem_state(i);
+		if (debug)
+			kvp_dump_initial_pools(i);
 	}
 
 	return 0;
···
 		 * Found a match; just move the remaining
 		 * entries up.
 		 */
+		if (debug)
+			syslog(LOG_DEBUG, "%s: deleting the KVP: pool=%d key=%s val=%s",
+			       __func__, pool, record[i].key, record[i].value);
 		if (i == (num_records - 1)) {
 			kvp_file_info[pool].num_records--;
 			kvp_update_file(pool);
···
 		kvp_update_file(pool);
 		return 0;
 	}
+
+	if (debug)
+		syslog(LOG_DEBUG, "%s: could not delete KVP: pool=%d key=%s. Record not found",
+		       __func__, pool, key);
+
 	return 1;
 }
 
 static int kvp_key_add_or_modify(int pool, const __u8 *key, int key_size,
 				 const __u8 *value, int value_size)
 {
-	int i;
-	int num_records;
 	struct kvp_record *record;
+	int num_records;
 	int num_blocks;
+	int i;
+
+	if (debug)
+		syslog(LOG_DEBUG, "%s: got a KVP: pool=%d key=%s val=%s",
+		       __func__, pool, key, value);
 
 	if ((key_size > HV_KVP_EXCHANGE_MAX_KEY_SIZE) ||
-		(value_size > HV_KVP_EXCHANGE_MAX_VALUE_SIZE))
+		(value_size > HV_KVP_EXCHANGE_MAX_VALUE_SIZE)) {
+		syslog(LOG_ERR, "%s: Too long key or value: key=%s, val=%s",
+		       __func__, key, value);
+
+		if (debug)
+			syslog(LOG_DEBUG, "%s: Too long key or value: pool=%d, key=%s, val=%s",
+			       __func__, pool, key, value);
 		return 1;
+	}
 
 	/*
 	 * First update the in-memory state.
···
 		 */
 		memcpy(record[i].value, value, value_size);
 		kvp_update_file(pool);
+		if (debug)
+			syslog(LOG_DEBUG, "%s: updated: pool=%d key=%s val=%s",
+			       __func__, pool, key, value);
 		return 0;
 	}
 
···
 		record = realloc(record, sizeof(struct kvp_record) *
 			 ENTRIES_PER_BLOCK * (num_blocks + 1));
 
-		if (record == NULL)
+		if (!record) {
+			syslog(LOG_ERR, "%s: Memory alloc failure", __func__);
 			return 1;
+		}
 		kvp_file_info[pool].num_blocks++;
 
 	}
···
 	memcpy(record[i].key, key, key_size);
 	kvp_file_info[pool].records = record;
 	kvp_file_info[pool].num_records++;
+
+	if (debug)
+		syslog(LOG_DEBUG, "%s: added: pool=%d key=%s val=%s",
+		       __func__, pool, key, value);
+
 	kvp_update_file(pool);
 	return 0;
 }
···
 	fprintf(stderr, "Usage: %s [options]\n"
 		"Options are:\n"
 		"  -n, --no-daemon        stay in foreground, don't daemonize\n"
+		"  -d, --debug            Enable debug logs(syslog debug by default)\n"
 		"  -h, --help             print this help\n", argv[0]);
 }
 
···
 	static struct option long_options[] = {
 		{"help",	no_argument,	   0,  'h' },
 		{"no-daemon",	no_argument,	   0,  'n' },
+		{"debug",	no_argument,	   0,  'd' },
 		{0,		0,		   0,  0   }
 	};
 
-	while ((opt = getopt_long(argc, argv, "hn", long_options,
+	while ((opt = getopt_long(argc, argv, "hnd", long_options,
 				  &long_index)) != -1) {
 		switch (opt) {
 		case 'n':
···
 		case 'h':
 			print_usage(argv);
 			exit(0);
+		case 'd':
+			debug = 1;
+			break;
 		default:
 			print_usage(argv);
 			exit(EXIT_FAILURE);
···
 	 * unpredictable amount of time to finish.
 	 */
 	kvp_get_domain_name(full_domain_name, sizeof(full_domain_name));
+
+	if (debug)
+		syslog(LOG_INFO, "Logging debug info in syslog(debug)");
 
 	if (kvp_file_init()) {
 		syslog(LOG_ERR, "Failed to initialize the pools");