[PATCH kernel v7 01/20] powerpc/ioda/npu: Call skiboot's hot reset hook when disabling NPU2

Alexey Kardashevskiy
2018-12-20T08:23:31Z

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>
---
Changes:
v2:
* updated the commit log
---
arch/powerpc/platforms/powernv/pci-ioda.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index 9ee7a30..29c6837 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3676,6 +3676,15 @@ 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;
@@ -3720,6 +3729,7 @@ 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 = {
--
2.17.1