Thread (35 messages) 35 messages, 4 authors, 2018-12-13

Re: [PATCH kernel v4 01/19] powerpc/ioda/npu: Call skiboot's hot reset hook when disabling NPU2

From: David Gibson <hidden>
Date: 2018-12-05 04:48:42

On Fri, Nov 23, 2018 at 04:52:46PM +1100, Alexey Kardashevskiy wrote:
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 <redacted>
Acked-by: Alistair Popple <redacted>
Reviewed-by: David Gibson <redacted>
quoted hunk ↗ jump to hunk
---
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 = {
-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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