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We currently have a global VTCR_EL2 value for each guest, even if the guest uses NV. This implies that the guest's own S2 must fit in the host's. This is odd, for multiple reasons: - the PARange values and the number of IPA bits don't necessarily match: you can have 33 bits of IPA space, and yet you can only describe 32 or 36 bits of PARange - When userspace set the IPA space, it creates a contract with the kernel saying "this is the IPA space I'm prepared to handle". At no point does it constraint the guest's own IPA space as long as the guest doesn't try to use a [I]PA outside of the IPA space set by userspace - We don't even try to hide the value of ID_AA64MMFR0_EL1.PARange. And then there is the consequence of the above: if a guest tries to create a S2 that has for input address something that is larger than the IPA space defined by the host, we inject a fatal exception. This is no good. For all intent and purposes, a guest should be able to have the S2 it really wants, as long as the *output* address of that S2 isn't outside of the IPA space. For that, we need to have a per-s2_mmu VTCR_EL2 setting, which allows us to represent the full PARange. Move the vctr field into the s2_mmu structure, which has no impact whatsoever, except for NV. Note that once we are able to override ID_AA64MMFR0_EL1.PARange from userspace, we'll also be able to restrict the size of the shadow S2 that NV uses. Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20231012205108.3937270-1-maz@kernel.org Signed-off-by: Oliver Upton <oliver.upton@linux.dev> |
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| 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 | ||
| .cocciconfig | ||
| .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 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.