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75253db41a
Implement a workaround for an SNP erratum where the CPU will incorrectly signal an RMP violation #PF if a hugepage (2MB or 1GB) collides with the RMP entry of a VMCB, VMSA or AVIC backing page. When SEV-SNP is globally enabled, the CPU marks the VMCB, VMSA, and AVIC backing pages as "in-use" via a reserved bit in the corresponding RMP entry after a successful VMRUN. This is done for _all_ VMs, not just SNP-Active VMs. If the hypervisor accesses an in-use page through a writable translation, the CPU will throw an RMP violation #PF. On early SNP hardware, if an in-use page is 2MB-aligned and software accesses any part of the associated 2MB region with a hugepage, the CPU will incorrectly treat the entire 2MB region as in-use and signal a an RMP violation #PF. To avoid this, the recommendation is to not use a 2MB-aligned page for the VMCB, VMSA or AVIC pages. Add a generic allocator that will ensure that the page returned is not 2MB-aligned and is safe to be used when SEV-SNP is enabled. Also implement similar handling for the VMCB/VMSA pages of nested guests. [ mdr: Squash in nested guest handling from Ashish, commit msg fixups. ] Reported-by: Alper Gun <alpergun@google.com> # for nested VMSA case Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Co-developed-by: Marc Orr <marcorr@google.com> Signed-off-by: Marc Orr <marcorr@google.com> Co-developed-by: Ashish Kalra <ashish.kalra@amd.com> Signed-off-by: Ashish Kalra <ashish.kalra@amd.com> Signed-off-by: Michael Roth <michael.roth@amd.com> Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: Paolo Bonzini <pbonzini@redhat.com> Link: https://lore.kernel.org/r/20240126041126.1927228-22-michael.roth@amd.com |
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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 | ||
| .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 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.