[PATCH net-next,v4] net: mana: Add handler for hardware servicing events

[PATCH net-next,v4] net: mana: Add handler for hardware servicing events

[Haiyang Zhang]

To collaborate with hardware servicing events, upon receiving the special
EQE notification from the HW channel, remove the devices on this bus.
Then, after a waiting period based on the device specs, rescan the parent
bus to recover the devices.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: Shradha Gupta <shradhagupta@linux.microsoft.com>
Reviewed-by: Simon Horman <horms@kernel.org>
---
v4:
Renamed EQE type 135 to GDMA_EQE_HWC_RESET_REQUEST, since there can
be multiple cases of this reset request.

v3:
Updated for checkpatch warnings as suggested by Simon Horman.

v2:
Added dev_dbg for service type as suggested by Shradha Gupta.
Added driver cap bit.

---
 .../net/ethernet/microsoft/mana/gdma_main.c   | 64 +++++++++++++++++++
 include/net/mana/gdma.h                       | 11 +++-
 2 files changed, 73 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/microsoft/mana/gdma_main.c b/drivers/net/ethernet/microsoft/mana/gdma_main.c
index 4ffaf7588885..08b8297e1800 100644
--- a/drivers/net/ethernet/microsoft/mana/gdma_main.c
+++ b/drivers/net/ethernet/microsoft/mana/gdma_main.c
@@ -352,11 +352,55 @@ void mana_gd_ring_cq(struct gdma_queue *cq, u8 arm_bit)
 }
 EXPORT_SYMBOL_NS(mana_gd_ring_cq, "NET_MANA");
 
+#define MANA_SERVICE_PERIOD 10
+
+struct mana_serv_work {
+	struct work_struct serv_work;
+	struct pci_dev *pdev;
+};
+
+static void mana_serv_func(struct work_struct *w)
+{
+	struct mana_serv_work *mns_wk;
+	struct pci_bus *bus, *parent;
+	struct pci_dev *pdev;
+
+	mns_wk = container_of(w, struct mana_serv_work, serv_work);
+	pdev = mns_wk->pdev;
+
+	if (!pdev)
+		goto out;
+
+	bus = pdev->bus;
+	if (!bus) {
+		dev_err(&pdev->dev, "MANA service: no bus\n");
+		goto out;
+	}
+
+	parent = bus->parent;
+	if (!parent) {
+		dev_err(&pdev->dev, "MANA service: no parent bus\n");
+		goto out;
+	}
+
+	pci_stop_and_remove_bus_device_locked(bus->self);
+
+	msleep(MANA_SERVICE_PERIOD * 1000);
+
+	pci_lock_rescan_remove();
+	pci_rescan_bus(parent);
+	pci_unlock_rescan_remove();
+
+out:
+	kfree(mns_wk);
+}
+
 static void mana_gd_process_eqe(struct gdma_queue *eq)
 {
 	u32 head = eq->head % (eq->queue_size / GDMA_EQE_SIZE);
 	struct gdma_context *gc = eq->gdma_dev->gdma_context;
 	struct gdma_eqe *eq_eqe_ptr = eq->queue_mem_ptr;
+	struct mana_serv_work *mns_wk;
 	union gdma_eqe_info eqe_info;
 	enum gdma_eqe_type type;
 	struct gdma_event event;
@@ -400,6 +444,26 @@ static void mana_gd_process_eqe(struct gdma_queue *eq)
 		eq->eq.callback(eq->eq.context, eq, &event);
 		break;
 
+	case GDMA_EQE_HWC_FPGA_RECONFIG:
+	case GDMA_EQE_HWC_RESET_REQUEST:
+		dev_dbg(gc->dev, "Recv MANA service type:%d\n", type);
+
+		if (gc->in_service) {
+			dev_info(gc->dev, "Already in service\n");
+			break;
+		}
+
+		mns_wk = kzalloc(sizeof(*mns_wk), GFP_ATOMIC);
+		if (!mns_wk)
+			break;
+
+		dev_info(gc->dev, "Start MANA service type:%d\n", type);
+		gc->in_service = true;
+		mns_wk->pdev = to_pci_dev(gc->dev);
+		INIT_WORK(&mns_wk->serv_work, mana_serv_func);
+		schedule_work(&mns_wk->serv_work);
+		break;
+
 	default:
 		break;
 	}
diff --git a/include/net/mana/gdma.h b/include/net/mana/gdma.h
index 228603bf03f2..23ca45d207ba 100644
--- a/include/net/mana/gdma.h
+++ b/include/net/mana/gdma.h
@@ -58,8 +58,9 @@ enum gdma_eqe_type {
 	GDMA_EQE_HWC_INIT_EQ_ID_DB	= 129,
 	GDMA_EQE_HWC_INIT_DATA		= 130,
 	GDMA_EQE_HWC_INIT_DONE		= 131,
-	GDMA_EQE_HWC_SOC_RECONFIG	= 132,
+	GDMA_EQE_HWC_FPGA_RECONFIG	= 132,
 	GDMA_EQE_HWC_SOC_RECONFIG_DATA	= 133,
+	GDMA_EQE_HWC_RESET_REQUEST	= 135,
 	GDMA_EQE_RNIC_QP_FATAL		= 176,
 };
 
@@ -388,6 +389,8 @@ struct gdma_context {
 	u32			test_event_eq_id;
 
 	bool			is_pf;
+	bool			in_service;
+
 	phys_addr_t		bar0_pa;
 	void __iomem		*bar0_va;
 	void __iomem		*shm_base;
@@ -558,12 +561,16 @@ enum {
 /* Driver can handle holes (zeros) in the device list */
 #define GDMA_DRV_CAP_FLAG_1_DEV_LIST_HOLES_SUP BIT(11)
 
+/* Driver can self reset on EQE notification */
+#define GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE BIT(14)
+
 #define GDMA_DRV_CAP_FLAGS1 \
 	(GDMA_DRV_CAP_FLAG_1_EQ_SHARING_MULTI_VPORT | \
 	 GDMA_DRV_CAP_FLAG_1_NAPI_WKDONE_FIX | \
 	 GDMA_DRV_CAP_FLAG_1_HWC_TIMEOUT_RECONFIG | \
 	 GDMA_DRV_CAP_FLAG_1_VARIABLE_INDIRECTION_TABLE_SUPPORT | \
-	 GDMA_DRV_CAP_FLAG_1_DEV_LIST_HOLES_SUP)
+	 GDMA_DRV_CAP_FLAG_1_DEV_LIST_HOLES_SUP | \
+	 GDMA_DRV_CAP_FLAG_1_SELF_RESET_ON_EQE)
 
 #define GDMA_DRV_CAP_FLAGS2 0
 
-- 
2.34.1

Re: [PATCH net-next,v4] net: mana: Add handler for hardware servicing events

[Jakub Kicinski]

On Wed, 14 May 2025 13:30:37 -0700 Haiyang Zhang wrote:
> +		dev_info(gc->dev, "Start MANA service type:%d\n", type);
> +		gc->in_service = true;
> +		mns_wk->pdev = to_pci_dev(gc->dev);
> +		INIT_WORK(&mns_wk->serv_work, mana_serv_func);
> +		schedule_work(&mns_wk->serv_work);

I don't see any refcounting in this patch, and the work is not
canceled. What if the device is removed between work being scheduled
and running?

RE: [EXTERNAL] Re: [PATCH net-next,v4] net: mana: Add handler for hardware servicing events

[Haiyang Zhang]

> -----Original Message-----
> From: Jakub Kicinski <kuba@kernel.org>
> Sent: Friday, May 16, 2025 9:05 PM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: linux-hyperv@vger.kernel.org; netdev@vger.kernel.org; Dexuan Cui
> <decui@microsoft.com>; stephen@networkplumber.org; KY Srinivasan
> <kys@microsoft.com>; Paul Rosswurm <paulros@microsoft.com>;
> olaf@aepfle.de; vkuznets@redhat.com; davem@davemloft.net;
> wei.liu@kernel.org; edumazet@google.com; pabeni@redhat.com;
> leon@kernel.org; Long Li <longli@microsoft.com>;
> ssengar@linux.microsoft.com; linux-rdma@vger.kernel.org;
> daniel@iogearbox.net; john.fastabend@gmail.com; bpf@vger.kernel.org;
> ast@kernel.org; hawk@kernel.org; tglx@linutronix.de;
> shradhagupta@linux.microsoft.com; andrew+netdev@lunn.ch; Konstantin
> Taranov <kotaranov@microsoft.com>; horms@kernel.org; linux-
> kernel@vger.kernel.org
> Subject: [EXTERNAL] Re: [PATCH net-next,v4] net: mana: Add handler for
> hardware servicing events
> 
> On Wed, 14 May 2025 13:30:37 -0700 Haiyang Zhang wrote:
> > +		dev_info(gc->dev, "Start MANA service type:%d\n", type);
> > +		gc->in_service = true;
> > +		mns_wk->pdev = to_pci_dev(gc->dev);
> > +		INIT_WORK(&mns_wk->serv_work, mana_serv_func);
> > +		schedule_work(&mns_wk->serv_work);
> 
> I don't see any refcounting in this patch, and the work is not
> canceled. What if the device is removed between work being scheduled
> and running?

Thanks for the review. I added refcnt handling, and submitted a new
patch.

- Haiyang