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zephyr/drivers/xen/Kconfig

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xenvm: drivers: xen: add Xen grant table driver This commit introduces driver for granting access for own grant table and for mapping/unmapping foreign gref. Grant tables are used for data exchange between Xen domains via shared memory page(s) (e.g. for sharing ring buffer with driver data) This functionality is widely used and needed for implementing PV backend/frontend drivers. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2021-12-07 12:52:45 +02:00
# SPDX-License-Identifier: Apache-2.0
drivers: xen: gnttab: limit number of grant frames via config 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>
2024-05-14 20:53:41 +03:00
# Copyright (c) 2022-2024 EPAM Systems
xenvm: drivers: xen: add Xen grant table driver This commit introduces driver for granting access for own grant table and for mapping/unmapping foreign gref. Grant tables are used for data exchange between Xen domains via shared memory page(s) (e.g. for sharing ring buffer with driver data) This functionality is widely used and needed for implementing PV backend/frontend drivers. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2021-12-07 12:52:45 +02:00
xen: refactor Xen hypervisor Kconfig options Xen-related Kconfig options were highly dependand on BOARD/SOC xenvm. It is not correct because Xen support may be used on any board and SoC. So, Kconfig structure was refactored, now CONFIG_XEN is located in arch/ directory (same as in Linux kernel) and can be selected for any Cortex-A arm64 setup (no other platforms are currently supported). Also remove confusion in Domain 0 naming: Domain-0, initial domain, Dom0, privileged domain etc. Now all options related to Xen Domain 0 will be controlled by CONFIG_XEN_DOM0. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2023-06-13 13:19:18 +03:00
if XEN
xenvm: drivers: xen: add Xen grant table driver This commit introduces driver for granting access for own grant table and for mapping/unmapping foreign gref. Grant tables are used for data exchange between Xen domains via shared memory page(s) (e.g. for sharing ring buffer with driver data) This functionality is widely used and needed for implementing PV backend/frontend drivers. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2021-12-07 12:52:45 +02:00
menu "Xen drivers"
config XEN_GRANT_TABLE
bool "Xen grant table driver"
depends on HEAP_MEM_POOL_SIZE > 0
default y
help
Xen grant table driver. Please note that driver uses dynamic memory
allocation with k_malloc(), so CONFIG_HEAP_MEM_POOL_SIZE should be
>= number of pages, that you want to alloc and grant or foreign frames
that you want to map.
config XEN_GRANT_TABLE_INIT_PRIORITY
int "Grant table driver init priority"
depends on XEN_GRANT_TABLE
default 50
drivers: xen: gnttab: limit number of grant frames via config 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>
2024-05-14 20:53:41 +03:00
config NR_GRANT_FRAMES
int "Number of grant frames mapped to Zephyr"
depends on XEN_GRANT_TABLE
default 1
help
This value configures how much grant frames will be supported by Zephyr
grant table driver in runtime. This value should be <= max_grant_frames
configured for domain in Xen hypervisor.
xenvm: drivers: xen: add Xen grant table driver This commit introduces driver for granting access for own grant table and for mapping/unmapping foreign gref. Grant tables are used for data exchange between Xen domains via shared memory page(s) (e.g. for sharing ring buffer with driver data) This functionality is widely used and needed for implementing PV backend/frontend drivers. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2021-12-07 12:52:45 +02:00
endmenu
xen: refactor Xen hypervisor Kconfig options Xen-related Kconfig options were highly dependand on BOARD/SOC xenvm. It is not correct because Xen support may be used on any board and SoC. So, Kconfig structure was refactored, now CONFIG_XEN is located in arch/ directory (same as in Linux kernel) and can be selected for any Cortex-A arm64 setup (no other platforms are currently supported). Also remove confusion in Domain 0 naming: Domain-0, initial domain, Dom0, privileged domain etc. Now all options related to Xen Domain 0 will be controlled by CONFIG_XEN_DOM0. Signed-off-by: Dmytro Firsov <dmytro_firsov@epam.com>
2023-06-13 13:19:18 +03:00
endif # XEN
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