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At the moment, the in-kernel emulated ITS is not properly reset. On guest restart/reset some registers keep their old values and internal structures like device, ITE, and collection lists are not freed. This may lead to various bugs. Among them, we can have incorrect state backup or failure when saving the ITS state at early guest boot stage. This patch documents a new attribute, KVM_DEV_ARM_ITS_CTRL_RESET in the KVM_DEV_ARM_VGIC_GRP_CTRL group. Upon this action, we can reset registers and especially those pointing to tables previously allocated by the guest and free the internal data structures storing the list of devices, collections and lpis. The usual approach for device reset of having userspace write the reset values of the registers to the kernel via the register read/write APIs doesn't work for the ITS because it has some internal state (caches) which is not exposed as registers, and there is no register interface for "drop cached data without writing it back to RAM". So we need a KVM API which mimics the hardware's reset line, to provide the equivalent behaviour to a "pull the power cord out of the back of the machine" reset. Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org> Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Eric Auger <eric.auger@redhat.com> Reported-by: wanghaibin <wanghaibin.wang@huawei.com> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.