From 164793379ad3b7ef5fc5a28260c111358892dff3 Mon Sep 17 00:00:00 2001 From: Andrew Donnellan Date: Thu, 28 Jul 2016 15:39:41 +1000 Subject: [PATCH] cxl: Fix NULL dereference in cxl_context_init() on PowerVM guests Commit f67a6722d650 ("cxl: Workaround PE=0 hardware limitation in Mellanox CX4") added a "min_pe" field to struct cxl_service_layer_ops, to allow us to work around a Mellanox CX-4 hardware limitation. When allocating the PE number in cxl_context_init(), we read from ctx->afu->adapter->native->sl_ops->min_pe to get the minimum PE number. Unsurprisingly, in a PowerVM guest ctx->afu->adapter->native is NULL, and guests don't have a cxl_service_layer_ops struct anywhere. Move min_pe from struct cxl_service_layer_ops to struct cxl so it's accessible in both native and PowerVM environments. For the Mellanox CX-4, set the min_pe value in set_sl_ops(). Fixes: f67a6722d650 ("cxl: Workaround PE=0 hardware limitation in Mellanox CX4") Reported-by: Frederic Barrat Signed-off-by: Andrew Donnellan Acked-by: Ian Munsie Reviewed-by: Frederic Barrat Signed-off-by: Michael Ellerman --- drivers/misc/cxl/context.c | 3 +-- drivers/misc/cxl/cxl.h | 2 +- drivers/misc/cxl/pci.c | 3 ++- 3 files changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/misc/cxl/context.c b/drivers/misc/cxl/context.c index bdee9a01ef35..c466ee2b0c97 100644 --- a/drivers/misc/cxl/context.c +++ b/drivers/misc/cxl/context.c @@ -90,8 +90,7 @@ int cxl_context_init(struct cxl_context *ctx, struct cxl_afu *afu, bool master, */ mutex_lock(&afu->contexts_lock); idr_preload(GFP_KERNEL); - i = idr_alloc(&ctx->afu->contexts_idr, ctx, - ctx->afu->adapter->native->sl_ops->min_pe, + i = idr_alloc(&ctx->afu->contexts_idr, ctx, ctx->afu->adapter->min_pe, ctx->afu->num_procs, GFP_NOWAIT); idr_preload_end(); mutex_unlock(&afu->contexts_lock); diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h index de090533f18c..344a0ff8f8c7 100644 --- a/drivers/misc/cxl/cxl.h +++ b/drivers/misc/cxl/cxl.h @@ -561,7 +561,6 @@ struct cxl_service_layer_ops { u64 (*timebase_read)(struct cxl *adapter); int capi_mode; bool needs_reset_before_disable; - int min_pe; }; struct cxl_native { @@ -603,6 +602,7 @@ struct cxl { struct bin_attribute cxl_attr; int adapter_num; int user_irqs; + int min_pe; u64 ps_size; u16 psl_rev; u16 base_image; diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c index d152e2de8c93..1d0347c36e6d 100644 --- a/drivers/misc/cxl/pci.c +++ b/drivers/misc/cxl/pci.c @@ -1521,14 +1521,15 @@ static const struct cxl_service_layer_ops xsl_ops = { .write_timebase_ctrl = write_timebase_ctrl_xsl, .timebase_read = timebase_read_xsl, .capi_mode = OPAL_PHB_CAPI_MODE_DMA, - .min_pe = 1, /* Workaround for Mellanox CX4 HW bug */ }; static void set_sl_ops(struct cxl *adapter, struct pci_dev *dev) { if (dev->vendor == PCI_VENDOR_ID_MELLANOX && dev->device == 0x1013) { + /* Mellanox CX-4 */ dev_info(&adapter->dev, "Device uses an XSL\n"); adapter->native->sl_ops = &xsl_ops; + adapter->min_pe = 1; /* Workaround for CX-4 hardware bug */ } else { dev_info(&adapter->dev, "Device uses a PSL\n"); adapter->native->sl_ops = &psl_ops; -- 2.20.1