mirror of https://gitee.com/openkylin/linux.git
cfb65c15d7
It was reported that older GCCs compile smm_test in a way that breaks it completely: kvm_exit: reason EXIT_CPUID rip 0x4014db info 0 0 func 7ffffffd idx 830 rax 0 rbx 0 rcx 0 rdx 0, cpuid entry not found ... kvm_exit: reason EXIT_MSR rip 0x40abd9 info 0 0 kvm_msr: msr_read 487 = 0x0 (#GP) ... Note, '7ffffffd' was supposed to be '80000001' as we're checking for SVM. Dropping '-O2' from compiler flags help. Turns out, asm block in sync_with_host() is wrong. We us 'in 0xe, %%al' instruction to sync with the host and in 'AL' register we actually pass the parameter (stage) but after sync 'AL' gets written to but GCC thinks the value is still there and uses it to compute 'EAX' for 'cpuid'. smm_test can't fully use standard ucall() framework as we need to write a very simple SMI handler there. Fix the immediate issue by making RAX input/output operand. While on it, make sync_with_host() static inline. Reported-by: Marcelo Bandeira Condotta <mcondotta@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Message-Id: <20200610164116.770811-1-vkuznets@redhat.com> Reviewed-by: Jim Mattson <jmattson@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> |
||
|---|---|---|
| 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.