Linux kernel source tree
e93ec87286
Today a PV guest (including dom0) can create 2MB contiguous memory
regions for DMA buffers at max. This has led to problems at least
with the megaraid_sas driver, which wants to allocate a 2.3MB DMA
buffer.
The limiting factor is the frame array used to do the hypercall for
making the memory contiguous, which has 512 entries and is just a
static array in mmu_pv.c.
In order to not waste memory for non-PV guests, put the initial
frame array into .init.data section and dynamically allocate an array
from the .init_after_bootmem hook of PV guests.
In case a contiguous memory area larger than the initially supported
2MB is requested, allocate a larger buffer for the frame list. Note
that such an allocation is tried only after memory management has been
initialized properly, which is tested via a flag being set in the
.init_after_bootmem hook.
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 reStructuredText 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.