38620fc4e8
When running as PVH or HVM Linux will use holes in the memory map as scratch space to map grants, foreign domain pages and possibly miscellaneous other stuff. However the usage of such memory map holes for Xen purposes can be problematic. The request of holesby Xen happen quite early in the kernel boot process (grant table setup already uses scratch map space), and it's possible that by then not all devices have reclaimed their MMIO space. It's not unlikely for chunks of Xen scratch map space to end up using PCI bridge MMIO window memory, which (as expected) causes quite a lot of issues in the system. At least for PVH dom0 we have the possibility of using regions marked as UNUSABLE in the e820 memory map. Either if the region is UNUSABLE in the native memory map, or it has been converted into UNUSABLE in order to hide RAM regions from dom0, the second stage translation page-tables can populate those areas without issues. PV already has this kind of logic, where the balloon driver is inflated at boot. Re-use the current logic in order to also inflate it when running as PVH. onvert UNUSABLE regions up to the ratio specified in EXTRA_MEM_RATIO to RAM, while reserving them using xen_add_extra_mem() (which is also moved so it's no longer tied to CONFIG_PV). [jgross: fixed build for CONFIG_PVH without CONFIG_XEN_PVH] Signed-off-by: Roger Pau Monné <roger.pau@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com> Link: https://lore.kernel.org/r/20240220174341.56131-1-roger.pau@citrix.com Signed-off-by: Juergen Gross <jgross@suse.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
README
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.