On Thu, Oct 26 2017 at 6:23:10 pm BST, Eric Auger <eric.auger@xxxxxxxxxx> wrote: > 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. > > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > Reported-by: wanghaibin <wanghaibin.wang@xxxxxxxxxx> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx> M. -- Jazz is not dead. It just smells funny.
