// SPDX-License-Identifier: GPL-2.0-only /* * Copyright (c) 2009, Microsoft Corporation. * * Authors: * Haiyang Zhang <haiyangz@microsoft.com> * Hank Janssen <hjanssen@microsoft.com> */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/io.h> #include <linux/kernel.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/vmalloc.h> #include <linux/hyperv.h> #include <linux/random.h> #include <linux/clockchips.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <clocksource/hyperv_timer.h> #include <asm/mshyperv.h> #include "hyperv_vmbus.h" /* The one and only */ struct hv_context hv_context; /* * hv_init - Main initialization routine. * * This routine must be called before any other routines in here are called */ int hv_init(void) { hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context); if (!hv_context.cpu_context) return -ENOMEM; return 0; } /* * 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); } 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); } void hv_free_hyperv_page(unsigned long addr) { if (PAGE_SIZE == HV_HYP_PAGE_SIZE) free_page(addr); else kfree((void *)addr); } /* * hv_post_message - Post a message using the hypervisor message IPC. * * 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) { struct hv_input_post_message *aligned_msg; struct hv_per_cpu_context *hv_cpu; u64 status; if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) return -EMSGSIZE; hv_cpu = get_cpu_ptr(hv_context.cpu_context); aligned_msg = hv_cpu->post_msg_page; aligned_msg->connectionid = connection_id; aligned_msg->reserved = 0; aligned_msg->message_type = message_type; aligned_msg->payload_size = payload_size; memcpy((void *)aligned_msg->payload, payload, payload_size); if (hv_isolation_type_snp()) status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE, (void *)aligned_msg, NULL, sizeof(*aligned_msg)); else status = hv_do_hypercall(HVCALL_POST_MESSAGE, aligned_msg, NULL); /* Preemption must remain disabled until after the hypercall * so some other thread can't get scheduled onto this cpu and * corrupt the per-cpu post_msg_page */ put_cpu_ptr(hv_cpu); return hv_result(status); } int hv_synic_alloc(void) { int cpu; struct hv_per_cpu_context *hv_cpu; /* * First, zero all per-cpu memory areas so hv_synic_free() can * detect what memory has been allocated and cleanup properly * after any failures. */ for_each_present_cpu(cpu) { hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); memset(hv_cpu, 0, sizeof(*hv_cpu)); } hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask), GFP_KERNEL); if (hv_context.hv_numa_map == NULL) { pr_err("Unable to allocate NUMA map\n"); goto err; } for_each_present_cpu(cpu) { hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); tasklet_init(&hv_cpu->msg_dpc, vmbus_on_msg_dpc, (unsigned long) hv_cpu); /* * Synic message and event pages are allocated by paravisor. * Skip these pages allocation here. */ 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) { 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) { pr_err("Unable to allocate SYNIC event page\n"); goto err; } } hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC); if (hv_cpu->post_msg_page == NULL) { pr_err("Unable to allocate post msg page\n"); goto err; } } return 0; err: /* * Any memory allocations that succeeded will be freed when * the caller cleans up by calling hv_synic_free() */ return -ENOMEM; } void hv_synic_free(void) { int cpu; for_each_present_cpu(cpu) { struct hv_per_cpu_context *hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu); free_page((unsigned long)hv_cpu->synic_event_page); free_page((unsigned long)hv_cpu->synic_message_page); free_page((unsigned long)hv_cpu->post_msg_page); } kfree(hv_context.hv_numa_map); } /* * hv_synic_init - Initialize the Synthetic Interrupt Controller. * * If it is already initialized by another entity (ie x2v shim), we need to * retrieve the initialized message and event pages. Otherwise, we create and * initialize the message and event pages. */ void hv_synic_enable_regs(unsigned int 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; union hv_synic_scontrol sctrl; /* Setup the Synic's message page */ simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP); simp.simp_enabled = 1; 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); if (!hv_cpu->synic_message_page) pr_err("Fail to map syinc message page.\n"); } else { simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page) >> HV_HYP_PAGE_SHIFT; } hv_set_register(HV_REGISTER_SIMP, simp.as_uint64); /* Setup the Synic's event page */ siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP); siefp.siefp_enabled = 1; 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); if (!hv_cpu->synic_event_page) pr_err("Fail to map syinc event page.\n"); } else { siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page) >> HV_HYP_PAGE_SHIFT; } hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64); /* Setup the shared SINT. */ if (vmbus_irq != -1) enable_percpu_irq(vmbus_irq, 0); shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT); shared_sint.vector = vmbus_interrupt; shared_sint.masked = false; /* * On architectures where Hyper-V doesn't support AEOI (e.g., ARM64), * it doesn't provide a recommendation flag and AEOI must be disabled. */ #ifdef HV_DEPRECATING_AEOI_RECOMMENDED shared_sint.auto_eoi = !(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED); #else shared_sint.auto_eoi = 0; #endif hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64); /* Enable the global synic bit */ sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL); sctrl.enable = 1; hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64); } int hv_synic_init(unsigned int cpu) { hv_synic_enable_regs(cpu); hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT); return 0; } /* * hv_synic_cleanup - Cleanup routine for hv_synic_init(). */ void hv_synic_disable_regs(unsigned int 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; union hv_synic_scontrol sctrl; shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT); shared_sint.masked = 1; /* Need to correctly cleanup in the case of SMP!!! */ /* Disable the interrupt */ hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64); simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP); /* * In Isolation VM, sim and sief pages are allocated by * paravisor. These pages also will be used by kdump * kernel. So just reset enable bit here and keep page * addresses. */ simp.simp_enabled = 0; if (hv_isolation_type_snp() || hv_root_partition) { memunmap(hv_cpu->synic_message_page); 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() || hv_root_partition) { memunmap(hv_cpu->synic_event_page); hv_cpu->synic_event_page = NULL; } else { siefp.base_siefp_gpa = 0; } hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64); /* Disable the global synic bit */ sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL); sctrl.enable = 0; hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64); if (vmbus_irq != -1) disable_percpu_irq(vmbus_irq); } #define HV_MAX_TRIES 3 /* * Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one * bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times. * Return 'true', if there is still any set bit after this operation; 'false', otherwise. * * If a bit is set, that means there is a pending channel interrupt. The expectation is * that the normal interrupt handling mechanism will find and process the channel interrupt * "very soon", and in the process clear the bit. */ static bool hv_synic_event_pending(void) { struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context); union hv_synic_event_flags *event = (union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT; unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */ bool pending; u32 relid; int tries = 0; retry: pending = false; for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) { /* Special case - VMBus channel protocol messages */ if (relid == 0) continue; pending = true; break; } if (pending && tries++ < HV_MAX_TRIES) { usleep_range(10000, 20000); goto retry; } return pending; } int hv_synic_cleanup(unsigned int cpu) { struct vmbus_channel *channel, *sc; bool channel_found = false; if (vmbus_connection.conn_state != CONNECTED) goto always_cleanup; /* * Hyper-V does not provide a way to change the connect CPU once * it is set; we must prevent the connect CPU from going offline * while the VM is running normally. But in the panic or kexec() * path where the vmbus is already disconnected, the CPU must be * allowed to shut down. */ if (cpu == VMBUS_CONNECT_CPU) return -EBUSY; /* * Search for channels which are bound to the CPU we're about to * cleanup. In case we find one and vmbus is still connected, we * fail; this will effectively prevent CPU offlining. * * TODO: Re-bind the channels to different CPUs. */ mutex_lock(&vmbus_connection.channel_mutex); list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) { if (channel->target_cpu == cpu) { channel_found = true; break; } list_for_each_entry(sc, &channel->sc_list, sc_list) { if (sc->target_cpu == cpu) { channel_found = true; break; } } if (channel_found) break; } mutex_unlock(&vmbus_connection.channel_mutex); if (channel_found) return -EBUSY; /* * channel_found == false means that any channels that were previously * assigned to the CPU have been reassigned elsewhere with a call of * vmbus_send_modifychannel(). Scan the event flags page looking for * bits that are set and waiting with a timeout for vmbus_chan_sched() * to process such bits. If bits are still set after this operation * and VMBus is connected, fail the CPU offlining operation. */ if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending()) return -EBUSY; always_cleanup: hv_stimer_legacy_cleanup(cpu); hv_synic_disable_regs(cpu); return 0; }