nested.c

  1// SPDX-License-Identifier: GPL-2.0
  2
  3/*
  4 * Hyper-V nested virtualization code.
  5 *
  6 * Copyright (C) 2018, Microsoft, Inc.
  7 *
  8 * Author : Lan Tianyu <Tianyu.Lan@microsoft.com>
  9 */
 10#define pr_fmt(fmt)  "Hyper-V: " fmt
 11
 12
 13#include <linux/types.h>
 14#include <linux/export.h>
 15#include <hyperv/hvhdk.h>
 16#include <asm/mshyperv.h>
 17#include <asm/tlbflush.h>
 18
 19#include <asm/trace/hyperv.h>
 20
 21int hyperv_flush_guest_mapping(u64 as)
 22{
 23	struct hv_guest_mapping_flush *flush;
 24	u64 status;
 25	unsigned long flags;
 26	int ret = -ENOTSUPP;
 27
 28	if (!hv_hypercall_pg)
 29		goto fault;
 30
 31	local_irq_save(flags);
 32
 33	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
 34
 35	if (unlikely(!flush)) {
 36		local_irq_restore(flags);
 37		goto fault;
 38	}
 39
 40	flush->address_space = as;
 41	flush->flags = 0;
 42
 43	status = hv_do_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_SPACE,
 44				 flush, NULL);
 45	local_irq_restore(flags);
 46
 47	if (hv_result_success(status))
 48		ret = 0;
 49
 50fault:
 51	trace_hyperv_nested_flush_guest_mapping(as, ret);
 52	return ret;
 53}
 54EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping);
 55
 56int hyperv_fill_flush_guest_mapping_list(
 57		struct hv_guest_mapping_flush_list *flush,
 58		u64 start_gfn, u64 pages)
 59{
 60	u64 cur = start_gfn;
 61	u64 additional_pages;
 62	int gpa_n = 0;
 63
 64	do {
 65		/*
 66		 * If flush requests exceed max flush count, go back to
 67		 * flush tlbs without range.
 68		 */
 69		if (gpa_n >= HV_MAX_FLUSH_REP_COUNT)
 70			return -ENOSPC;
 71
 72		additional_pages = min_t(u64, pages, HV_MAX_FLUSH_PAGES) - 1;
 73
 74		flush->gpa_list[gpa_n].page.additional_pages = additional_pages;
 75		flush->gpa_list[gpa_n].page.largepage = false;
 76		flush->gpa_list[gpa_n].page.basepfn = cur;
 77
 78		pages -= additional_pages + 1;
 79		cur += additional_pages + 1;
 80		gpa_n++;
 81	} while (pages > 0);
 82
 83	return gpa_n;
 84}
 85EXPORT_SYMBOL_GPL(hyperv_fill_flush_guest_mapping_list);
 86
 87int hyperv_flush_guest_mapping_range(u64 as,
 88		hyperv_fill_flush_list_func fill_flush_list_func, void *data)
 89{
 90	struct hv_guest_mapping_flush_list *flush;
 91	u64 status;
 92	unsigned long flags;
 93	int ret = -ENOTSUPP;
 94	int gpa_n = 0;
 95
 96	if (!hv_hypercall_pg || !fill_flush_list_func)
 97		goto fault;
 98
 99	local_irq_save(flags);
100
101	flush = *this_cpu_ptr(hyperv_pcpu_input_arg);
102
103	if (unlikely(!flush)) {
104		local_irq_restore(flags);
105		goto fault;
106	}
107
108	flush->address_space = as;
109	flush->flags = 0;
110
111	gpa_n = fill_flush_list_func(flush, data);
112	if (gpa_n < 0) {
113		local_irq_restore(flags);
114		goto fault;
115	}
116
117	status = hv_do_rep_hypercall(HVCALL_FLUSH_GUEST_PHYSICAL_ADDRESS_LIST,
118				     gpa_n, 0, flush, NULL);
119
120	local_irq_restore(flags);
121
122	if (hv_result_success(status))
123		ret = 0;
124	else
125		ret = hv_result(status);
126fault:
127	trace_hyperv_nested_flush_guest_mapping_range(as, ret);
128	return ret;
129}
130EXPORT_SYMBOL_GPL(hyperv_flush_guest_mapping_range);