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![Jinank Jain](/assets/img/avatar_default.png)
Child partitions are free to allocate SynIC message and event page but in case of root partition it must use the pages allocated by Microsoft Hypervisor (MSHV). Base address for these pages can be found using synthetic MSRs exposed by MSHV. There is a slight difference in those MSRs for nested vs non-nested root partition. Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com> Reviewed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Link: https://lore.kernel.org/r/cb951fb1ad6814996fc54f4a255c5841a20a151f.1672639707.git.jinankjain@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org>
446 lines
12 KiB
C
446 lines
12 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (c) 2009, Microsoft Corporation.
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*
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* Authors:
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* Haiyang Zhang <haiyangz@microsoft.com>
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* Hank Janssen <hjanssen@microsoft.com>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/io.h>
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#include <linux/kernel.h>
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#include <linux/mm.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/hyperv.h>
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#include <linux/random.h>
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#include <linux/clockchips.h>
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#include <linux/delay.h>
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#include <linux/interrupt.h>
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#include <clocksource/hyperv_timer.h>
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#include <asm/mshyperv.h>
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#include "hyperv_vmbus.h"
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/* The one and only */
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struct hv_context hv_context;
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/*
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* hv_init - Main initialization routine.
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*
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* This routine must be called before any other routines in here are called
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*/
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int hv_init(void)
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{
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hv_context.cpu_context = alloc_percpu(struct hv_per_cpu_context);
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if (!hv_context.cpu_context)
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return -ENOMEM;
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return 0;
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}
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/*
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* Functions for allocating and freeing memory with size and
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* alignment HV_HYP_PAGE_SIZE. These functions are needed because
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* the guest page size may not be the same as the Hyper-V page
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* size. We depend upon kmalloc() aligning power-of-two size
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* allocations to the allocation size boundary, so that the
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* allocated memory appears to Hyper-V as a page of the size
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* it expects.
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*/
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void *hv_alloc_hyperv_page(void)
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{
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BUILD_BUG_ON(PAGE_SIZE < HV_HYP_PAGE_SIZE);
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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return (void *)__get_free_page(GFP_KERNEL);
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else
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return kmalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
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}
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void *hv_alloc_hyperv_zeroed_page(void)
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{
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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return (void *)__get_free_page(GFP_KERNEL | __GFP_ZERO);
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else
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return kzalloc(HV_HYP_PAGE_SIZE, GFP_KERNEL);
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}
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void hv_free_hyperv_page(unsigned long addr)
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{
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if (PAGE_SIZE == HV_HYP_PAGE_SIZE)
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free_page(addr);
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else
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kfree((void *)addr);
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}
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/*
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* hv_post_message - Post a message using the hypervisor message IPC.
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*
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* This involves a hypercall.
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*/
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int hv_post_message(union hv_connection_id connection_id,
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enum hv_message_type message_type,
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void *payload, size_t payload_size)
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{
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struct hv_input_post_message *aligned_msg;
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struct hv_per_cpu_context *hv_cpu;
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u64 status;
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if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT)
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return -EMSGSIZE;
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hv_cpu = get_cpu_ptr(hv_context.cpu_context);
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aligned_msg = hv_cpu->post_msg_page;
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aligned_msg->connectionid = connection_id;
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aligned_msg->reserved = 0;
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aligned_msg->message_type = message_type;
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aligned_msg->payload_size = payload_size;
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memcpy((void *)aligned_msg->payload, payload, payload_size);
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if (hv_isolation_type_snp())
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status = hv_ghcb_hypercall(HVCALL_POST_MESSAGE,
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(void *)aligned_msg, NULL,
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sizeof(*aligned_msg));
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else
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status = hv_do_hypercall(HVCALL_POST_MESSAGE,
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aligned_msg, NULL);
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/* Preemption must remain disabled until after the hypercall
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* so some other thread can't get scheduled onto this cpu and
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* corrupt the per-cpu post_msg_page
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*/
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put_cpu_ptr(hv_cpu);
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return hv_result(status);
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}
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int hv_synic_alloc(void)
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{
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int cpu;
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struct hv_per_cpu_context *hv_cpu;
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/*
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* First, zero all per-cpu memory areas so hv_synic_free() can
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* detect what memory has been allocated and cleanup properly
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* after any failures.
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*/
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for_each_present_cpu(cpu) {
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hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
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memset(hv_cpu, 0, sizeof(*hv_cpu));
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}
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hv_context.hv_numa_map = kcalloc(nr_node_ids, sizeof(struct cpumask),
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GFP_KERNEL);
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if (hv_context.hv_numa_map == NULL) {
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pr_err("Unable to allocate NUMA map\n");
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goto err;
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}
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for_each_present_cpu(cpu) {
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hv_cpu = per_cpu_ptr(hv_context.cpu_context, cpu);
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tasklet_init(&hv_cpu->msg_dpc,
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vmbus_on_msg_dpc, (unsigned long) hv_cpu);
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/*
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* Synic message and event pages are allocated by paravisor.
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* Skip these pages allocation here.
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*/
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if (!hv_isolation_type_snp() && !hv_root_partition) {
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hv_cpu->synic_message_page =
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(void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->synic_message_page == NULL) {
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pr_err("Unable to allocate SYNIC message page\n");
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goto err;
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}
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hv_cpu->synic_event_page =
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(void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->synic_event_page == NULL) {
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pr_err("Unable to allocate SYNIC event page\n");
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goto err;
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}
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}
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hv_cpu->post_msg_page = (void *)get_zeroed_page(GFP_ATOMIC);
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if (hv_cpu->post_msg_page == NULL) {
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pr_err("Unable to allocate post msg page\n");
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goto err;
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}
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}
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return 0;
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err:
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/*
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* Any memory allocations that succeeded will be freed when
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* the caller cleans up by calling hv_synic_free()
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*/
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return -ENOMEM;
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}
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void hv_synic_free(void)
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{
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int cpu;
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for_each_present_cpu(cpu) {
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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free_page((unsigned long)hv_cpu->synic_event_page);
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free_page((unsigned long)hv_cpu->synic_message_page);
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free_page((unsigned long)hv_cpu->post_msg_page);
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}
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kfree(hv_context.hv_numa_map);
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}
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/*
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* hv_synic_init - Initialize the Synthetic Interrupt Controller.
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*
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* If it is already initialized by another entity (ie x2v shim), we need to
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* retrieve the initialized message and event pages. Otherwise, we create and
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* initialize the message and event pages.
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*/
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void hv_synic_enable_regs(unsigned int cpu)
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{
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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union hv_synic_simp simp;
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union hv_synic_siefp siefp;
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union hv_synic_sint shared_sint;
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union hv_synic_scontrol sctrl;
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/* Setup the Synic's message page */
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simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
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simp.simp_enabled = 1;
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if (hv_isolation_type_snp() || hv_root_partition) {
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hv_cpu->synic_message_page
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= memremap(simp.base_simp_gpa << HV_HYP_PAGE_SHIFT,
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HV_HYP_PAGE_SIZE, MEMREMAP_WB);
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if (!hv_cpu->synic_message_page)
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pr_err("Fail to map syinc message page.\n");
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} else {
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simp.base_simp_gpa = virt_to_phys(hv_cpu->synic_message_page)
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>> HV_HYP_PAGE_SHIFT;
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}
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hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
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/* Setup the Synic's event page */
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siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
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siefp.siefp_enabled = 1;
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if (hv_isolation_type_snp() || hv_root_partition) {
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hv_cpu->synic_event_page =
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memremap(siefp.base_siefp_gpa << HV_HYP_PAGE_SHIFT,
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HV_HYP_PAGE_SIZE, MEMREMAP_WB);
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if (!hv_cpu->synic_event_page)
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pr_err("Fail to map syinc event page.\n");
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} else {
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siefp.base_siefp_gpa = virt_to_phys(hv_cpu->synic_event_page)
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>> HV_HYP_PAGE_SHIFT;
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}
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hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
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/* Setup the shared SINT. */
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if (vmbus_irq != -1)
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enable_percpu_irq(vmbus_irq, 0);
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shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
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VMBUS_MESSAGE_SINT);
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shared_sint.vector = vmbus_interrupt;
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shared_sint.masked = false;
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/*
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* On architectures where Hyper-V doesn't support AEOI (e.g., ARM64),
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* it doesn't provide a recommendation flag and AEOI must be disabled.
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*/
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#ifdef HV_DEPRECATING_AEOI_RECOMMENDED
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shared_sint.auto_eoi =
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!(ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED);
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#else
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shared_sint.auto_eoi = 0;
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#endif
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hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
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shared_sint.as_uint64);
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/* Enable the global synic bit */
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sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
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sctrl.enable = 1;
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hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
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}
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int hv_synic_init(unsigned int cpu)
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{
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hv_synic_enable_regs(cpu);
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hv_stimer_legacy_init(cpu, VMBUS_MESSAGE_SINT);
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return 0;
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}
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/*
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* hv_synic_cleanup - Cleanup routine for hv_synic_init().
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*/
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void hv_synic_disable_regs(unsigned int cpu)
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{
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struct hv_per_cpu_context *hv_cpu
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= per_cpu_ptr(hv_context.cpu_context, cpu);
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union hv_synic_sint shared_sint;
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union hv_synic_simp simp;
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union hv_synic_siefp siefp;
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union hv_synic_scontrol sctrl;
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shared_sint.as_uint64 = hv_get_register(HV_REGISTER_SINT0 +
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VMBUS_MESSAGE_SINT);
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shared_sint.masked = 1;
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/* Need to correctly cleanup in the case of SMP!!! */
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/* Disable the interrupt */
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hv_set_register(HV_REGISTER_SINT0 + VMBUS_MESSAGE_SINT,
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shared_sint.as_uint64);
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simp.as_uint64 = hv_get_register(HV_REGISTER_SIMP);
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/*
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* In Isolation VM, sim and sief pages are allocated by
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* paravisor. These pages also will be used by kdump
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* kernel. So just reset enable bit here and keep page
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* addresses.
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*/
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simp.simp_enabled = 0;
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if (hv_isolation_type_snp() || hv_root_partition) {
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memunmap(hv_cpu->synic_message_page);
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hv_cpu->synic_message_page = NULL;
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} else {
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simp.base_simp_gpa = 0;
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}
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hv_set_register(HV_REGISTER_SIMP, simp.as_uint64);
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siefp.as_uint64 = hv_get_register(HV_REGISTER_SIEFP);
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siefp.siefp_enabled = 0;
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if (hv_isolation_type_snp() || hv_root_partition) {
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memunmap(hv_cpu->synic_event_page);
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hv_cpu->synic_event_page = NULL;
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} else {
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siefp.base_siefp_gpa = 0;
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}
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hv_set_register(HV_REGISTER_SIEFP, siefp.as_uint64);
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/* Disable the global synic bit */
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sctrl.as_uint64 = hv_get_register(HV_REGISTER_SCONTROL);
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sctrl.enable = 0;
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hv_set_register(HV_REGISTER_SCONTROL, sctrl.as_uint64);
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if (vmbus_irq != -1)
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disable_percpu_irq(vmbus_irq);
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}
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#define HV_MAX_TRIES 3
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/*
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* Scan the event flags page of 'this' CPU looking for any bit that is set. If we find one
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* bit set, then wait for a few milliseconds. Repeat these steps for a maximum of 3 times.
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* Return 'true', if there is still any set bit after this operation; 'false', otherwise.
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*
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* If a bit is set, that means there is a pending channel interrupt. The expectation is
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* that the normal interrupt handling mechanism will find and process the channel interrupt
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* "very soon", and in the process clear the bit.
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*/
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static bool hv_synic_event_pending(void)
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{
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struct hv_per_cpu_context *hv_cpu = this_cpu_ptr(hv_context.cpu_context);
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union hv_synic_event_flags *event =
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(union hv_synic_event_flags *)hv_cpu->synic_event_page + VMBUS_MESSAGE_SINT;
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unsigned long *recv_int_page = event->flags; /* assumes VMBus version >= VERSION_WIN8 */
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bool pending;
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u32 relid;
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int tries = 0;
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retry:
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pending = false;
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for_each_set_bit(relid, recv_int_page, HV_EVENT_FLAGS_COUNT) {
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/* Special case - VMBus channel protocol messages */
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if (relid == 0)
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continue;
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pending = true;
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break;
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}
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if (pending && tries++ < HV_MAX_TRIES) {
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usleep_range(10000, 20000);
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goto retry;
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}
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return pending;
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}
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int hv_synic_cleanup(unsigned int cpu)
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{
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struct vmbus_channel *channel, *sc;
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bool channel_found = false;
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if (vmbus_connection.conn_state != CONNECTED)
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goto always_cleanup;
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/*
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* Hyper-V does not provide a way to change the connect CPU once
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* it is set; we must prevent the connect CPU from going offline
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* while the VM is running normally. But in the panic or kexec()
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* path where the vmbus is already disconnected, the CPU must be
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* allowed to shut down.
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*/
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if (cpu == VMBUS_CONNECT_CPU)
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return -EBUSY;
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/*
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* Search for channels which are bound to the CPU we're about to
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* cleanup. In case we find one and vmbus is still connected, we
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* fail; this will effectively prevent CPU offlining.
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*
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* TODO: Re-bind the channels to different CPUs.
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*/
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mutex_lock(&vmbus_connection.channel_mutex);
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list_for_each_entry(channel, &vmbus_connection.chn_list, listentry) {
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if (channel->target_cpu == cpu) {
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channel_found = true;
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break;
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}
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list_for_each_entry(sc, &channel->sc_list, sc_list) {
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if (sc->target_cpu == cpu) {
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channel_found = true;
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break;
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}
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}
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if (channel_found)
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break;
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}
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mutex_unlock(&vmbus_connection.channel_mutex);
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if (channel_found)
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return -EBUSY;
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/*
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* channel_found == false means that any channels that were previously
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* assigned to the CPU have been reassigned elsewhere with a call of
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* vmbus_send_modifychannel(). Scan the event flags page looking for
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* bits that are set and waiting with a timeout for vmbus_chan_sched()
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* to process such bits. If bits are still set after this operation
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* and VMBus is connected, fail the CPU offlining operation.
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*/
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if (vmbus_proto_version >= VERSION_WIN10_V4_1 && hv_synic_event_pending())
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return -EBUSY;
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always_cleanup:
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hv_stimer_legacy_cleanup(cpu);
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hv_synic_disable_regs(cpu);
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return 0;
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}
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