The hypervisor is aware of all system properties. For the guest bios it's hard and complex to detect all system properties. For that reason, it would be better if the hypervisor creates acpi tables instead of the guest. Therefore, the hypervisor has to send the acpi tables to the guest. At the moment, bhyve just copies the acpi tables into the guest memory. This approach has some restrictions. You have to keep sure that the guest doesn't overwrite them accidentally. Additionally, the size of acpi tables is limited. Providing a plain copy of all acpi tables by fwcfg isn't possible. Acpi tables have to point to each other. So, if the guest copies the acpi tables into memory by it's own, it has to patch the tables. Due to different layouts for different acpi tables, there's no generic way to do that. For that reason, qemu created a table loader interface. It contains commands for the guest for loading specific blobs into guest memory and patching those blobs. This commit adds a qemu_loader class which handles the creation of qemu loader commands. At the moment, the WRITE_POINTER command isn't implement. It won't be required by bhyve's acpi table generation yet. Reviewed by: markj MFC after: 1 week Sponsored by: Beckhoff Automation GmbH & Co. KG Differential Revision: https://reviews.freebsd.org/D38438
78 lines
2.8 KiB
C
78 lines
2.8 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause
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*
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* Copyright (c) 2022 Beckhoff Automation GmbH & Co. KG
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* Author: Corvin Köhne <c.koehne@beckhoff.com>
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*/
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#pragma once
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#include "qemu_fwcfg.h"
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struct qemu_loader;
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/*
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* Some guest bios like seabios assume the RSDP to be located in the FSEG. Bhyve
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* only supports OVMF which has no such requirement.
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*/
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enum qemu_loader_zone {
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QEMU_LOADER_ALLOC_HIGH = 1,
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QEMU_LOADER_ALLOC_FSEG, /* 0x0F000000 - 0x100000 */
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};
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/**
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* Loads a fwcfg item into guest memory. This command has to be issued before
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* any subsequent command can be used.
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*
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* @param loader Qemu loader instance the command should be added to.
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* @param name Name of the fwcfg item which should be allocated.
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* @param alignment Alignment required by the data.
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* @param zone Memory zone in which it should be loaded.
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*/
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int qemu_loader_alloc(struct qemu_loader *loader, const uint8_t *name,
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uint32_t alignment, enum qemu_loader_zone zone);
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/**
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* Calculates a checksum for @p name and writes it to @p name + @p off . The
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* checksum calculation ranges from @p start to @p start + @p len. The checksum
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* field is always one byte large and all bytes in the specified range,
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* including the checksum, have to sum up to 0.
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*
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* @param loader Qemu loader instance the command should be added to.
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* @param name Name of the fwcfg item which should be patched.
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* @param off Offset into @p name .
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* @param start Start offset of checksum calculation.
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* @param len Length of the checksum calculation.
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*/
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int qemu_loader_add_checksum(struct qemu_loader *loader, const uint8_t *name,
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uint32_t off, uint32_t start, uint32_t len);
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/**
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* Adds the address of @p src_name to the value at @p dest_name + @p off . The
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* size of the pointer is determined by @p dest_size and should be 1, 2, 4 or 8.
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*
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* @param loader Qemu loader instance the command should be added to.
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* @param dest_name Name of the fwcfg item which should be patched.
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* @param src_name Name of the fwcfg item which address should be written to
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* @p dest_name + @p off.
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* @param off Offset into @p dest_name .
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* @param size Size of the pointer (1, 2, 4 or 8).
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*/
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int qemu_loader_add_pointer(struct qemu_loader *loader,
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const uint8_t *dest_name, const uint8_t *src_name, uint32_t off,
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uint8_t size);
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/**
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* Creates a qemu loader instance.
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*
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* @param new_loader Returns the newly created qemu loader instance.
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* @param fwcfg_name Name of the FwCfg item which represents the qemu loader
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*/
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int qemu_loader_create(struct qemu_loader **new_loader,
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const uint8_t *fwcfg_name);
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/**
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* Signals that all commands are written to the qemu loader. This function
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* creates a proper FwCfg item and registers it.
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*
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* @param loader Qemu loader instance which should be finished.
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*/
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int qemu_loader_finish(struct qemu_loader *loader);
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