Subject: Re: [PATCH 0/8] KVM: PPC: Implement passthrough of emulated devices for nested guests

From: Suraj Jitindar Singh <[email-masked]>
Date: Fri, 07 Dec 2018 14:45:50 +1100

On Fri, 2018-12-07 at 14:43 +1100, Suraj Jitindar Singh wrote:
> This patch series allows for emulated devices to be passed through to
> nested
> guests, irrespective of at which level the device is being emulated.
> 
> Note that the emulated device must be using dma, not virtio.
> 
> For example, passing through an emulated e1000:
> 
> 1. Emulate the device at L(n) for L(n+1)
> 
> qemu-system-ppc64 -netdev type=user,id=net0 -device e1000,netdev=net0
> 
> 2. Assign the VFIO-PCI driver at L(n+1)
> 
> echo 0000:00:00.0 > /sys/bus/pci/drivers/e1000/unbind
> echo 0000:00:00.0 > /sys/bus/pci/drivers/vfio-pci/bind
> chmod 666 /dev/vfio/0
> 
> 3. Pass the device through from L(n+1) to L(n+2)
> 
> qemu-system-ppc64 -device vfio-pci,host=0000:00:00.0
> 
> 4. L(n+2) can now access the device which will be emulated at L(n)

Note,
[PATCH] KVM: PPC: Book3S PR: Set hflag to indicate that POWER9 supports
1T segments
is not supposed to be part of this series

> 
> Suraj Jitindar Singh (8):
>   KVM: PPC: Only report KVM_CAP_SPAPR_TCE_VFIO on powernv machines
>   KVM: PPC: Book3S HV: Add function kvmhv_vcpu_is_radix()
>   KVM: PPC: Book3S HV: Implement functions to access quadrants 1 & 2
>   KVM: PPC: Add load_from_eaddr and store_to_eaddr to the kvmppc_ops
>     struct
>   KVM: PPC: Update kvmppc_st and kvmppc_ld to use quadrants
>   KVM: PPC: Book3S HV: Allow passthrough of an emulated device to an
> L2
>     guest
>   KVM: PPC: Introduce new hcall H_COPY_TOFROM_GUEST to access
> quadrants
>     1 & 2
>   KVM: PPC: Book3S HV: Allow passthrough of an emulated device to an
> L3
>     guest
> 
>  arch/powerpc/include/asm/hvcall.h        |   1 +
>  arch/powerpc/include/asm/kvm_book3s.h    |  10 ++-
>  arch/powerpc/include/asm/kvm_book3s_64.h |  13 ++++
>  arch/powerpc/include/asm/kvm_host.h      |   3 +
>  arch/powerpc/include/asm/kvm_ppc.h       |   4 ++
>  arch/powerpc/kernel/exceptions-64s.S     |   9 +++
>  arch/powerpc/kvm/book3s_64_mmu_radix.c   |  97
> ++++++++++++++++++++++++++
>  arch/powerpc/kvm/book3s_hv.c             |  58 ++++++++++++++--
>  arch/powerpc/kvm/book3s_hv_nested.c      | 114
> +++++++++++++++++++++++++++++--
>  arch/powerpc/kvm/powerpc.c               |  28 +++++++-
>  arch/powerpc/mm/fault.c                  |   1 +
>  11 files changed, 323 insertions(+), 15 deletions(-)
>