powerpc/ioda/npu: Call skiboot's hot reset hook when disabling NPU2

The skiboot firmware has a hot reset handler which fences the NVIDIA V100
GPU RAM on Witherspoons and makes accesses no-op instead of throwing HMIs:
https://github.com/open-power/skiboot/commit/fca2b2b839a67

Now we are going to pass V100 via VFIO which most certainly involves
KVM guests which are often terminated without getting a chance to offline
GPU RAM so we end up with a running machine with misconfigured memory.
Accessing this memory produces hardware management interrupts (HMI)
which bring the host down.

To suppress HMIs, this wires up this hot reset hook to vfio_pci_disable()
via pci_disable_device() which switches NPU2 to a safe mode and prevents
HMIs.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Acked-by: Alistair Popple <alistair@popple.id.au>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 036a8b0..c39def4 100644 (file)
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3667,6 +3667,15 @@ static void pnv_pci_release_device(struct pci_dev *pdev)
                pnv_ioda_release_pe(pe);
 }
 
+static void pnv_npu_disable_device(struct pci_dev *pdev)
+{
+       struct eeh_dev *edev = pci_dev_to_eeh_dev(pdev);
+       struct eeh_pe *eehpe = edev ? edev->pe : NULL;
+
+       if (eehpe && eeh_ops && eeh_ops->reset)
+               eeh_ops->reset(eehpe, EEH_RESET_HOT);
+}
+
 static void pnv_pci_ioda_shutdown(struct pci_controller *hose)
 {
        struct pnv_phb *phb = hose->private_data;
@@ -3707,6 +3716,7 @@ static const struct pci_controller_ops pnv_npu_ioda_controller_ops = {
        .reset_secondary_bus    = pnv_pci_reset_secondary_bus,
        .dma_set_mask           = pnv_npu_dma_set_mask,
        .shutdown               = pnv_pci_ioda_shutdown,
+       .disable_device         = pnv_npu_disable_device,
 };
 
 static const struct pci_controller_ops pnv_npu_ocapi_ioda_controller_ops = {