8347b99473
Copy the incoming @data comman to an internal buffer so that callers can put SEV command buffers on the stack without running afoul of CONFIG_VMAP_STACK=y, i.e. without bombing on vmalloc'd pointers. As of today, the largest supported command takes a 68 byte buffer, i.e. pretty much every command can be put on the stack. Because sev_cmd_mutex is held for the entirety of a transaction, only a single bounce buffer is required. Use the internal buffer unconditionally, as the majority of in-kernel users will soon switch to using the stack. At that point, checking virt_addr_valid() becomes (negligible) overhead in most cases, and supporting both paths slightly increases complexity. Since the commands are all quite small, the cost of the copies is insignificant compared to the latency of communicating with the PSP. Allocate a full page for the buffer as opportunistic preparation for SEV-SNP, which requires the command buffer to be in firmware state for commands that trigger memory writes from the PSP firmware. Using a full page now will allow SEV-SNP support to simply transition the page as needed. Cc: Brijesh Singh <brijesh.singh@amd.com> Cc: Borislav Petkov <bp@suse.de> Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Christophe Leroy <christophe.leroy@csgroup.eu> Signed-off-by: Sean Christopherson <seanjc@google.com> Message-Id: <20210406224952.4177376-5-seanjc@google.com> Reviewed-by: Brijesh Singh <brijesh.singh@amd.com> Acked-by: Tom Lendacky <thomas.lendacky@amd.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
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| Documentation | ||
| LICENSES | ||
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| 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.