163e9fc695
When VM runs in kvm mode, system will not exit to host mode when executing a general software breakpoint instruction such as INSN_BREAK, trap exception happens in guest mode rather than host mode. In order to debug guest kernel on host side, one mechanism should be used to let VM exit to host mode. Here a hypercall instruction with a special code is used for software breakpoint usage. VM exits to host mode and kvm hypervisor identifies the special hypercall code and sets exit_reason with KVM_EXIT_DEBUG. And then let qemu handle it. Idea comes from ppc kvm, one api KVM_REG_LOONGARCH_DEBUG_INST is added to get the hypercall code. VMM needs get sw breakpoint instruction with this api and set the corresponding sw break point for guest kernel. Signed-off-by: Bibo Mao <maobibo@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
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.