cd31a41328
Xen allocates a region that should be used as a place for grant table mapping and passes it via the device tree. By design, this region may be quite large (up to 4096+ frames/pages), but the number of frames is usually limited by the max_grant_frames domain parameter (usually 32 or 64). Linux maps these frames on demand and when reaches mentioned limit it just stops expanding. At the same time, previous implementation of Zephyr gnttab driver calculated the number of grant frames by dividing whole region by page size and tried to map it during init. If the region specified in the device tree was larger than the max_grant_frames set by Xen, it would fail on ASSERT, since Xen would return an error. To address these issues CONFIG_NR_GRANT_FRAMES was introduced. It allows to limit size of grant table and map only required number of pages. Additionally, a check for max_grant_frames Xen limit was introduced to initialization - if this value will be less than CONFIG_NR_GRANT_FRAMES, k_panic() will be called. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
34 lines
902 B
Text
34 lines
902 B
Text
# SPDX-License-Identifier: Apache-2.0
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# Copyright (c) 2022-2024 EPAM Systems
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if XEN
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menu "Xen drivers"
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config XEN_GRANT_TABLE
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bool "Xen grant table driver"
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depends on HEAP_MEM_POOL_SIZE > 0
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default y
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help
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Xen grant table driver. Please note that driver uses dynamic memory
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allocation with k_malloc(), so CONFIG_HEAP_MEM_POOL_SIZE should be
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>= number of pages, that you want to alloc and grant or foreign frames
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that you want to map.
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config XEN_GRANT_TABLE_INIT_PRIORITY
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int "Grant table driver init priority"
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depends on XEN_GRANT_TABLE
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default 50
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config NR_GRANT_FRAMES
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int "Number of grant frames mapped to Zephyr"
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depends on XEN_GRANT_TABLE
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default 1
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help
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This value configures how much grant frames will be supported by Zephyr
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grant table driver in runtime. This value should be <= max_grant_frames
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configured for domain in Xen hypervisor.
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endmenu
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endif # XEN
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