Hi Ganapatro, On Fri, 26 Nov 2021 05:45:26 +0000, Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx> wrote: > > Hi Marc, > > > On 25-11-2021 07:19 pm, Marc Zyngier wrote: > > [+ Quentin] > > > > Hi Ganapatro, > > > > On Mon, 22 Nov 2021 09:58:02 +0000, > > Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx> wrote: > >> > >> The kvm_pgtable_stage2_init/kvm_pgtable_stage2_init_flags function > >> assume arch->mmu is same across all stage 2 mmu and initializes > >> the pgt(page table) using arch->mmu. > >> Using armc->mmu is not appropriate when nested virtualization is enabled > >> since there are multiple stage 2 mmu tables are initialized to manage > >> Guest-Hypervisor as well as Nested VM for the same vCPU. > >> > >> Add a mmu argument to kvm_pgtable_stage2_init that can be used during > >> initialization. This patch is a preparatory patch for the > >> nested virtualization series and no functional changes. > > > > Thanks for having had a look, and for the analysis. This is obviously > > a result of a hasty conversion to the 'new' page table code, and a > > total oversight on my part. > > > > I'm however not particularly thrilled with the approach you have taken > > though, as carrying both the kvm->arch pointer *and* the mmu pointer > > seems totally redundant (the mmu structure already has a backpointer > > to kvm->arch or its pkvm equivalent). All we need is to rework the > > initialisation for this pointer to be correct at the point of where we > > follow it first. > > > > I've pushed out my own version of this[1]. Please have a look. > > > > Thanks, > > > > M. > > > > [1] https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=kvm-arm64/nv-5.16-WIP&id=21790a24d88c3ed37989533709dad3d40905f5c3 > > > > Thanks for the rework and rebasing to 5.16. > > I went through the patch, the gist of the patch seems to me same. > Please free feel to add, > Reviewed-by: Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx> Thanks! > Looks like kvm-arm64/nv-5.16-WIP branch is broken for NV. > I tried booting Guest hypervisor using lkvm and the vcpu init from > lkvm is failing(Fatal: Unable to initialise vcpu). Did not dig/debug > more in to the issue yet. I'm still trying to iron a few issues, but you should be able to boot a NV guest. However, the way it is enabled has changed: you need to pass 'kvm-arm.mode=nested' to the command line instead of the previous 'kvm-arm.nested=1' which I have got rid of. That could well be the issue. With the current state of the tree (I just pushed another fix), you should be able to boot a L1 guest hypervisor and a L2 guest. I'm getting a crash at the point where the L2 guest reaches userspace though, so something is broken in the PSTATE or ERET tracking, I'd expect. M. -- Without deviation from the norm, progress is not possible.
