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Linux kernel source tree
0e02219f9c
Marc reported that enabling protected mode on a device with GICv2
doesn't fail gracefully as one would expect, and leads to a host
kernel crash.
As it turns out, the first half of pKVM init happens before the vgic
probe, and so by the time we find out we have a GICv2 we're already
committed to keeping the pKVM vectors installed at EL2 -- pKVM rejects
stub HVCs for obvious security reasons. However, the error path on KVM
init leads to teardown_hyp_mode() which unconditionally frees hypervisor
allocations (including the EL2 stacks and per-cpu pages) under the
assumption that a previous cpu_hyp_uninit() execution has reset the
vectors back to the stubs, which is false with pKVM.
Interestingly, host stage-2 protection is not enabled yet at this point,
so this use-after-free may go unnoticed for a while. The issue becomes
more obvious after the finalize_pkvm() call.
Fix this by keeping track of the CPUs on which pKVM is initialized in
the kvm_hyp_initialized per-cpu variable, and use it from
teardown_hyp_mode() to skip freeing pages that are in fact used.
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 | ||
| .pylintrc | ||
| .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.