On Thu, Sep 14 2017 at 10:57:28 am 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, collection lists are not emptied. > > 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 introduces a new attribute, KVM_DEV_ARM_ITS_CTRL_RESET in > the KVM_DEV_ARM_VGIC_GRP_CTRL group. > > Upon this action, we can invalidate the various memory structures > pointed by GITS_BASERn and GITS_CBASER, free the ITS internal caches > and reset the relevant registers. > > Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx> > > --- > > An alternative would consist in having the userspace writing > individual registers with default values: GITS_BASERn, GITS_CBASER > and GITS_CTLR. On kernel side we would reset related lists when > detecting the valid bit is set to false. I'm not sure this is necessarily a "either/or" situation. It looks to me that we're not completely doing the right thing when writing to the GITS_BASER registers, and that writing a new value (with the valid bit set or not) should have an action of some sort on the fate of the existing mappings. Thoughts? M. -- Jazz is not dead. It just smells funny.
