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| _2025-03-07_11：05：33_ | 2025-03-07 11：05：33 | | Troubleshooting KVM Virtualization Problem With Log Files in Linux - nixCraft | | 原文链接失效了?试试备份 | | TAGs:虚拟化&容器 kvm | | Summary: This article by Vivek Gite discusses troubleshooting KVM virtualization issues using log files on a Linux system. The author covers the locations of various log files related to KVM, including those for virt-install, virt-manager, and running virtual machines. The article also explains how to use Linux tools like grep and tail to view these logs. Additionally, it mentions the use of the virsh command to connect to guest serial consoles for troubleshooting. The article concludes by mentioning the existence of KVM configuration files in the /etc/libvirt/qemu/ directory and the installation of kvm-tools package for diagnostic and debugging tools.Vivek Gite 的这篇文章讨论了在 Linux 系统上使用日志文件对 KVM 虚拟化问题进行故障排除。作者介绍了与 KVM 相关的各种日志文件的位置，包括 virt-install、virt-manager 和正在运行的虚拟机的日志文件。本文还介绍了如何使用 grep 和 tail 等 Linux 工具查看这些日志。此外，它还提到了使用 virsh 命令连接到客户机串行控制台以进行故障排除。文章最后提到了 /etc/libvirt/qemu/ 目录下存在 KVM 配置文件，并安装了用于诊断和调试工具的 kvm-tools 软件包。 | |
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| _2025-03-31_14：35：51_ | 2025-03-31 14：35：51 | | 虚拟机中的 HLT 优化_ kvm-poll-control - 知乎 | | 原文链接失效了?试试备份 | | TAGs:虚拟化&容器 kvm cpu idle | | Summary: This text is about the implementation and functionality of KVM's halt poll control feature, which is a paravirtualization (PV) technique used in the Linux kernel to optimize virtualization by transferring the polling (round-robin checking) phase of HLT (halt processor) instructions from the host to the guest. This can help reduce some HLT-induced VM-exits. The text also discusses the background and working mechanism of this feature by referring to the Linux kernel code. | |
| _2025-03-31_21：55：14_ | 2025-03-31 21：55：14 | | 虚拟机中的 HLT 优化_ kvm-poll-control - 知乎 | | 原文链接失效了?试试备份 | | TAGs:虚拟化&容器 kvm cpu idle | | Summary: The Linux kernel function `wait_for_random_bytes` is used to ensure that the random number generator (RNG) in the Linux kernel is ready and has sufficient entropy before continuing execution in situations where secure random numbers are required, such as encryption operations or key generation. The function blocks the current thread until the RNG has completed initialization and has an adequate amount of entropy. It is particularly important during system startup or when the entropy pool has not yet accumulated sufficient random data. By using `wait_for_random_bytes`, developers can prevent the generation of weak random numbers, which could lead to security vulnerabilities. The function works by checking if the RNG is ready using the `crng_ready()` function. If the RNG is not yet initialized, the function blocks the current thread and adds it to the `crng_init_wait` queue, waiting until the RNG is ready to continue execution. The function can be used in various contexts, such as in driver initialization or in generating secure tokens. It is essential to note that the function should only be used in contexts where sleeping is allowed, as it may call functions that cause the system to sleep, such as `wait_event`. Additionally, the function can have performance implications, especially during system startup when the entropy pool may take a long time to initialize. Alternative solutions include using non-blocking functions or actively adding entropy sources to the pool. Related functions include `get_random_bytes`, `add_hwgenerator_randomness`, and `urandom_read`.Linux 内核函数 'wait_for_random_bytes' 用于确保 Linux 内核中的随机数生成器 （RNG） 已准备就绪并具有足够的熵，然后才能在需要安全随机数的情况下继续执行，例如加密作或密钥生成。该函数会阻止当前线程，直到 RNG 完成初始化并具有足够的熵量。在系统启动期间或熵池尚未积累足够的随机数据时，这一点尤为重要。通过使用 'wait_for_random_bytes'，开发人员可以防止产生弱随机数，这可能会导致安全漏洞。该函数通过使用 'crng_ready（）' 函数检查 RNG 是否准备就绪来工作。如果 RNG 尚未初始化，该函数会阻止当前线程并将其添加到 'crng_init_wait' 队列中，等待 RNG 准备好继续执行。该函数可用于各种上下文，例如驱动程序初始化或生成安全令牌。需要注意的是，该函数只应在允许休眠的上下文中使用，因为它可能会调用导致系统休眠的函数，例如 'wait_event'。此外，该函数可能会对性能产生影响，尤其是在系统启动期间，此时熵池可能需要很长时间才能初始化。替代解决方案包括使用非阻塞函数或主动向池中添加熵源。相关函数包括 'get_random_bytes'、'add_hwgenerator_randomness' 和 'urandom_read'。 | |
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| _2025-03-18_16：48：13_ | 2025-03-18 16：48：13 | | Using Kernel Samepage Merging with KVM – The Linux Cluster | | 原文链接失效了?试试备份 | | TAGs:虚拟化&容器 kvm 内存 ksm | | Summary: The Linux Cluster Blog post discusses using Kernel Samepage Merging (KSM) with KVM for more efficient use of memory in Linux Cluster and Enterprise Linux systems. KSM is a Linux kernel feature that combines identical memory pages from multiple processes into one copy-on-write memory region. To verify KSM support, users can check the kernel configuration file and the number of kernel pages. Additionally, KVM guests need to request identical pages merging using the new madvise interface for KSM to take effect.Linux 集群博客文章讨论了将内核同页合并 （KSM） 与 KVM 结合使用，以便在 Linux 集群和企业 Linux 系统中更高效地使用内存。KSM 是一项 Linux 内核功能，它将来自多个进程的相同内存页合并到一个写入时复制内存区域。要验证 KSM 是否支持，用户可以检查内核配置文件和内核页数。此外，KVM 客户机需要使用新的 madvise 接口请求合并相同的页面，KSM 才能生效。 | |
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| _2025-03-24_10：03：30_ | 2025-03-24 10：03：30 | | 虚拟化支持 — Linux 内核文档 - Linux 内核 | | 原文链接失效了?试试备份 | | TAGs:虚拟化&容器 kvm | | Summary: This page discusses various virtualization technologies and related documentation. Topics include KVM with its API and support for different systems like ARM, x86, and LoongArch. There's also a section on UML (Unikernel Microhypervisor) and how to create and run instances, as well as advanced themes and contributing. Other topics include Paravirt_ops, Nitro Enclaves, and the SEV (Secure Enclaves) and TDX (TensorFlow Datacenter) customer API documents. The page also covers Hyper-V enhancements, including VMBus, clock and timer support, PCI passthrough devices, and confidential computing virtual machines.本页讨论各种虚拟化技术和相关文档。主题包括 KVM 及其 API 以及对 ARM、x86 和 LoongArch 等不同系统的支持。还有一个部分介绍了 UML （Unikernel Microhypervisor） 以及如何创建和运行实例，以及高级主题和贡献。其他主题包括 Paravirt_ops、Nitro Enclaves 以及 SEV （Secure Enclaves） 和 TDX （TensorFlow Datacenter） 客户 API 文档。该页面还介绍了 Hyper-V 增强功能，包括 VMBus、时钟和计时器支持、PCI 直通设备和机密计算虚拟机。 | |