path: root/drivers/hv/mshv_root_hv_call.c

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2023, Microsoft Corporation.
 *
 * Hypercall helper functions used by the mshv_root module.
 *
 * Authors: Microsoft Linux virtualization team
 */

#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/export.h>
#include <asm/mshyperv.h>

#include "mshv_root.h"

/* Determined empirically */
#define HV_INIT_PARTITION_DEPOSIT_PAGES 208
#define HV_MAP_GPA_DEPOSIT_PAGES	256
#define HV_UMAP_GPA_PAGES		512

#define HV_PAGE_COUNT_2M_ALIGNED(pg_count) (!((pg_count) & (0x200 - 1)))

#define HV_WITHDRAW_BATCH_SIZE	(HV_HYP_PAGE_SIZE / sizeof(u64))
#define HV_MAP_GPA_BATCH_SIZE	\
	((HV_HYP_PAGE_SIZE - sizeof(struct hv_input_map_gpa_pages)) \
		/ sizeof(u64))
#define HV_GET_VP_STATE_BATCH_SIZE	\
	((HV_HYP_PAGE_SIZE - sizeof(struct hv_input_get_vp_state)) \
		/ sizeof(u64))
#define HV_SET_VP_STATE_BATCH_SIZE	\
	((HV_HYP_PAGE_SIZE - sizeof(struct hv_input_set_vp_state)) \
		/ sizeof(u64))
#define HV_GET_GPA_ACCESS_STATES_BATCH_SIZE	\
	((HV_HYP_PAGE_SIZE - sizeof(union hv_gpa_page_access_state)) \
		/ sizeof(union hv_gpa_page_access_state))
#define HV_MODIFY_SPARSE_SPA_PAGE_HOST_ACCESS_MAX_PAGE_COUNT		       \
	((HV_HYP_PAGE_SIZE -						       \
	  sizeof(struct hv_input_modify_sparse_spa_page_host_access)) /        \
	 sizeof(u64))

int hv_call_withdraw_memory(u64 count, int node, u64 partition_id)
{
	struct hv_input_withdraw_memory *input_page;
	struct hv_output_withdraw_memory *output_page;
	struct page *page;
	u16 completed;
	unsigned long remaining = count;
	u64 status;
	int i;
	unsigned long flags;

	page = alloc_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;
	output_page = page_address(page);

	while (remaining) {
		local_irq_save(flags);

		input_page = *this_cpu_ptr(hyperv_pcpu_input_arg);

		memset(input_page, 0, sizeof(*input_page));
		input_page->partition_id = partition_id;
		status = hv_do_rep_hypercall(HVCALL_WITHDRAW_MEMORY,
					     min(remaining, HV_WITHDRAW_BATCH_SIZE),
					     0, input_page, output_page);

		local_irq_restore(flags);

		completed = hv_repcomp(status);

		for (i = 0; i < completed; i++)
			__free_page(pfn_to_page(output_page->gpa_page_list[i]));

		if (!hv_result_success(status)) {
			if (hv_result(status) == HV_STATUS_NO_RESOURCES)
				status = HV_STATUS_SUCCESS;
			break;
		}

		remaining -= completed;
	}
	free_page((unsigned long)output_page);

	return hv_result_to_errno(status);
}

int hv_call_create_partition(u64 flags,
			     struct hv_partition_creation_properties creation_properties,
			     union hv_partition_isolation_properties isolation_properties,
			     u64 *partition_id)
{
	struct hv_input_create_partition *input;
	struct hv_output_create_partition *output;
	u64 status;
	int ret;
	unsigned long irq_flags;

	do {
		local_irq_save(irq_flags);
		input = *this_cpu_ptr(hyperv_pcpu_input_arg);
		output = *this_cpu_ptr(hyperv_pcpu_output_arg);

		memset(input, 0, sizeof(*input));
		input->flags = flags;
		input->compatibility_version = HV_COMPATIBILITY_21_H2;

		memcpy(&input->partition_creation_properties, &creation_properties,
		       sizeof(creation_properties));

		memcpy(&input->isolation_properties, &isolation_properties,
		       sizeof(isolation_properties));

		status = hv_do_hypercall(HVCALL_CREATE_PARTITION,
					 input, output);

		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
			if (hv_result_success(status))
				*partition_id = output->partition_id;
			local_irq_restore(irq_flags);
			ret = hv_result_to_errno(status);
			break;
		}
		local_irq_restore(irq_flags);
		ret = hv_call_deposit_pages(NUMA_NO_NODE,
					    hv_current_partition_id, 1);
	} while (!ret);

	return ret;
}

int hv_call_initialize_partition(u64 partition_id)
{
	struct hv_input_initialize_partition input;
	u64 status;
	int ret;

	input.partition_id = partition_id;

	ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id,
				    HV_INIT_PARTITION_DEPOSIT_PAGES);
	if (ret)
		return ret;

	do {
		status = hv_do_fast_hypercall8(HVCALL_INITIALIZE_PARTITION,
					       *(u64 *)&input);

		if (hv_result(status) != HV_STATUS_INSUFFICIENT_MEMORY) {
			ret = hv_result_to_errno(status);
			break;
		}
		ret = hv_call_deposit_pages(NUMA_NO_NODE, partition_id, 1);
	} while (!ret);

	return ret;
}

int hv_call_finalize_partition(u64