Commit 0d400f77 authored by Christophe Lombard's avatar Christophe Lombard Committed by Michael Ellerman
Browse files

cxl: Adapter failure handling 



Check the AFU state whenever an API is called. The hypervisor may
issue a reset of the adapter when it detects a fault. When it happens,
it launches an error recovery which will either move the AFU to a
permanent failure state, or in the disabled state.
If the AFU is found to be disabled, detach all existing contexts from
it before issuing a AFU reset to re-enable it.

Before detaching contexts, notify any kernel driver through the EEH
callbacks of the AFU pci device.

Co-authored-by: default avatarFrederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: default avatarFrederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: default avatarChristophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: default avatarManoj Kumar <manoj@linux.vnet.ibm.com>
Acked-by: default avatarIan Munsie <imunsie@au1.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent d601ea91

drivers/misc/cxl/context.c

+1 −1
Original line number Diff line number Diff line
@@ -220,7 +220,7 @@ int __detach_context(struct cxl_context *ctx) 
	 * If detach fails when hw is down, we don't care.

	 */

	WARN_ON(cxl_ops->detach_process(ctx) &&

		cxl_ops->link_ok(ctx->afu->adapter));

		cxl_ops->link_ok(ctx->afu->adapter, ctx->afu));

	flush_work(&ctx->fault_work); /* Only needed for dedicated process */



	/* release the reference to the group leader and mm handling pid */

drivers/misc/cxl/cxl.h

+10 −8
Original line number Diff line number Diff line
@@ -379,6 +379,8 @@ struct cxl_afu_guest { 
	phys_addr_t p2n_phys;

	u64 p2n_size;

	int max_ints;

	struct mutex recovery_lock;

	int previous_state;

};



struct cxl_afu {
@@ -617,7 +619,7 @@ struct cxl_process_element { 
	__be32 software_state;

} __packed;



static inline bool cxl_adapter_link_ok(struct cxl *cxl)

static inline bool cxl_adapter_link_ok(struct cxl *cxl, struct cxl_afu *afu)

{

	struct pci_dev *pdev;
@@ -636,13 +638,13 @@ static inline void __iomem *_cxl_p1_addr(struct cxl *cxl, cxl_p1_reg_t reg) 


static inline void cxl_p1_write(struct cxl *cxl, cxl_p1_reg_t reg, u64 val)

{

	if (likely(cxl_adapter_link_ok(cxl)))

	if (likely(cxl_adapter_link_ok(cxl, NULL)))

		out_be64(_cxl_p1_addr(cxl, reg), val);

}



static inline u64 cxl_p1_read(struct cxl *cxl, cxl_p1_reg_t reg)

{

	if (likely(cxl_adapter_link_ok(cxl)))

	if (likely(cxl_adapter_link_ok(cxl, NULL)))

		return in_be64(_cxl_p1_addr(cxl, reg));

	else

		return ~0ULL;
@@ -656,13 +658,13 @@ static inline void __iomem *_cxl_p1n_addr(struct cxl_afu *afu, cxl_p1n_reg_t reg 


static inline void cxl_p1n_write(struct cxl_afu *afu, cxl_p1n_reg_t reg, u64 val)

{

	if (likely(cxl_adapter_link_ok(afu->adapter)))

	if (likely(cxl_adapter_link_ok(afu->adapter, afu)))

		out_be64(_cxl_p1n_addr(afu, reg), val);

}



static inline u64 cxl_p1n_read(struct cxl_afu *afu, cxl_p1n_reg_t reg)

{

	if (likely(cxl_adapter_link_ok(afu->adapter)))

	if (likely(cxl_adapter_link_ok(afu->adapter, afu)))

		return in_be64(_cxl_p1n_addr(afu, reg));

	else

		return ~0ULL;
@@ -675,13 +677,13 @@ static inline void __iomem *_cxl_p2n_addr(struct cxl_afu *afu, cxl_p2n_reg_t reg 


static inline void cxl_p2n_write(struct cxl_afu *afu, cxl_p2n_reg_t reg, u64 val)

{

	if (likely(cxl_adapter_link_ok(afu->adapter)))

	if (likely(cxl_adapter_link_ok(afu->adapter, afu)))

		out_be64(_cxl_p2n_addr(afu, reg), val);

}



static inline u64 cxl_p2n_read(struct cxl_afu *afu, cxl_p2n_reg_t reg)

{

	if (likely(cxl_adapter_link_ok(afu->adapter)))

	if (likely(cxl_adapter_link_ok(afu->adapter, afu)))

		return in_be64(_cxl_p2n_addr(afu, reg));

	else

		return ~0ULL;
@@ -857,7 +859,7 @@ struct cxl_backend_ops { 
			u64 wed, u64 amr);

	int (*detach_process)(struct cxl_context *ctx);

	bool (*support_attributes)(const char *attr_name, enum cxl_attrs type);

	bool (*link_ok)(struct cxl *cxl);

	bool (*link_ok)(struct cxl *cxl, struct cxl_afu *afu);

	void (*release_afu)(struct device *dev);

	ssize_t (*afu_read_err_buffer)(struct cxl_afu *afu, char *buf,

				loff_t off, size_t count);

drivers/misc/cxl/file.c

+5 −5
Original line number Diff line number Diff line
@@ -76,7 +76,7 @@ static int __afu_open(struct inode *inode, struct file *file, bool master) 
	if (!afu->current_mode)

		goto err_put_afu;



	if (!cxl_ops->link_ok(adapter)) {

	if (!cxl_ops->link_ok(adapter, afu)) {

		rc = -EIO;

		goto err_put_afu;

	}
@@ -257,7 +257,7 @@ long afu_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 
	if (ctx->status == CLOSED)

		return -EIO;



	if (!cxl_ops->link_ok(ctx->afu->adapter))

	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))

		return -EIO;



	pr_devel("afu_ioctl\n");
@@ -287,7 +287,7 @@ int afu_mmap(struct file *file, struct vm_area_struct *vm) 
	if (ctx->status != STARTED)

		return -EIO;



	if (!cxl_ops->link_ok(ctx->afu->adapter))

	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))

		return -EIO;



	return cxl_context_iomap(ctx, vm);
@@ -334,7 +334,7 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count, 
	int rc;

	DEFINE_WAIT(wait);



	if (!cxl_ops->link_ok(ctx->afu->adapter))

	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))

		return -EIO;



	if (count < CXL_READ_MIN_SIZE)
@@ -347,7 +347,7 @@ ssize_t afu_read(struct file *file, char __user *buf, size_t count, 
		if (ctx_event_pending(ctx))

			break;



		if (!cxl_ops->link_ok(ctx->afu->adapter)) {

		if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu)) {

			rc = -EIO;

			goto out;

		}

drivers/misc/cxl/guest.c

+164 −3
Original line number Diff line number Diff line
@@ -15,6 +15,46 @@ 
#include "hcalls.h"

#include "trace.h"



#define CXL_ERROR_DETECTED_EVENT	1

#define CXL_SLOT_RESET_EVENT		2

#define CXL_RESUME_EVENT		3



static void pci_error_handlers(struct cxl_afu *afu,

				int bus_error_event,

				pci_channel_state_t state)

{

	struct pci_dev *afu_dev;



	if (afu->phb == NULL)

		return;



	list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {

		if (!afu_dev->driver)

			continue;



		switch (bus_error_event) {

		case CXL_ERROR_DETECTED_EVENT:

			afu_dev->error_state = state;



			if (afu_dev->driver->err_handler &&

			    afu_dev->driver->err_handler->error_detected)

				afu_dev->driver->err_handler->error_detected(afu_dev, state);

		break;

		case CXL_SLOT_RESET_EVENT:

			afu_dev->error_state = state;



			if (afu_dev->driver->err_handler &&

			    afu_dev->driver->err_handler->slot_reset)

				afu_dev->driver->err_handler->slot_reset(afu_dev);

		break;

		case CXL_RESUME_EVENT:

			if (afu_dev->driver->err_handler &&

			    afu_dev->driver->err_handler->resume)

				afu_dev->driver->err_handler->resume(afu_dev);

		break;

		}

	}

}



static irqreturn_t guest_handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr,

					u64 errstat)
@@ -133,6 +173,22 @@ static irqreturn_t guest_psl_irq(int irq, void *data) 
	return rc;

}



static int afu_read_error_state(struct cxl_afu *afu, int *state_out)

{

	u64 state;

	int rc = 0;



	rc = cxl_h_read_error_state(afu->guest->handle, &state);

	if (!rc) {

		WARN_ON(state != H_STATE_NORMAL &&

			state != H_STATE_DISABLE &&

			state != H_STATE_TEMP_UNAVAILABLE &&

			state != H_STATE_PERM_UNAVAILABLE);

		*state_out = state & 0xffffffff;

	}

	return rc;

}



static irqreturn_t guest_slice_irq_err(int irq, void *data)

{

	struct cxl_afu *afu = data;
@@ -201,10 +257,26 @@ static int irq_free_range(struct cxl *adapter, int irq, int len) 


static int guest_reset(struct cxl *adapter)

{

	int rc;

	struct cxl_afu *afu = NULL;

	int i, rc;



	pr_devel("Adapter reset request\n");

	for (i = 0; i < adapter->slices; i++) {

		if ((afu = adapter->afu[i])) {

			pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,

					pci_channel_io_frozen);

			cxl_context_detach_all(afu);

		}

	}



	rc = cxl_h_reset_adapter(adapter->guest->handle);

	for (i = 0; i < adapter->slices; i++) {

		if (!rc && (afu = adapter->afu[i])) {

			pci_error_handlers(afu, CXL_SLOT_RESET_EVENT,

					pci_channel_io_normal);

			pci_error_handlers(afu, CXL_RESUME_EVENT, 0);

		}

	}

	return rc;

}
@@ -556,7 +628,7 @@ static int guest_detach_process(struct cxl_context *ctx) 
	pr_devel("in %s\n", __func__);

	trace_cxl_detach(ctx);



	if (!cxl_ops->link_ok(ctx->afu->adapter))

	if (!cxl_ops->link_ok(ctx->afu->adapter, ctx->afu))

		return -EIO;



	if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
@@ -730,8 +802,95 @@ static void guest_unmap_slice_regs(struct cxl_afu *afu) 
		iounmap(afu->p2n_mmio);

}



static bool guest_link_ok(struct cxl *cxl)

static int afu_update_state(struct cxl_afu *afu)

{

	int rc, cur_state;



	rc = afu_read_error_state(afu, &cur_state);

	if (rc)

		return rc;



	if (afu->guest->previous_state == cur_state)

		return 0;



	pr_devel("AFU(%d) update state to %#x\n", afu->slice, cur_state);



	switch (cur_state) {

	case H_STATE_NORMAL:

		afu->guest->previous_state = cur_state;

		rc = 1;

		break;



	case H_STATE_DISABLE:

		pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,

				pci_channel_io_frozen);



		cxl_context_detach_all(afu);

		if ((rc = cxl_ops->afu_reset(afu)))

			pr_devel("reset hcall failed %d\n", rc);



		rc = afu_read_error_state(afu, &cur_state);

		if (!rc && cur_state == H_STATE_NORMAL) {

			pci_error_handlers(afu, CXL_SLOT_RESET_EVENT,

					pci_channel_io_normal);

			pci_error_handlers(afu, CXL_RESUME_EVENT, 0);

			rc = 1;

		}

		afu->guest->previous_state = 0;

		break;



	case H_STATE_TEMP_UNAVAILABLE:

		afu->guest->previous_state = cur_state;

		break;



	case H_STATE_PERM_UNAVAILABLE:

		dev_err(&afu->dev, "AFU is in permanent error state\n");

		pci_error_handlers(afu, CXL_ERROR_DETECTED_EVENT,

				pci_channel_io_perm_failure);

		afu->guest->previous_state = cur_state;

		break;



	default:

		pr_err("Unexpected AFU(%d) error state: %#x\n",

		       afu->slice, cur_state);

		return -EINVAL;

	}



	return rc;

}



static int afu_do_recovery(struct cxl_afu *afu)

{

	int rc;



	/* many threads can arrive here, in case of detach_all for example.

	 * Only one needs to drive the recovery

	 */

	if (mutex_trylock(&afu->guest->recovery_lock)) {

		rc = afu_update_state(afu);

		mutex_unlock(&afu->guest->recovery_lock);

		return rc;

	}

	return 0;

}



static bool guest_link_ok(struct cxl *cxl, struct cxl_afu *afu)

{

	int state;



	if (afu) {

		if (afu_read_error_state(afu, &state) ||

			state != H_STATE_NORMAL) {

			if (afu_do_recovery(afu) > 0) {

				/* check again in case we've just fixed it */

				if (!afu_read_error_state(afu, &state) &&

					state == H_STATE_NORMAL)

					return true;

			}

			return false;

		}

	}



	return true;

}
@@ -770,6 +929,8 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n 
		return -ENOMEM;

	}



	mutex_init(&afu->guest->recovery_lock);



	if ((rc = dev_set_name(&afu->dev, "afu%i.%i",

					  adapter->adapter_num,

					  slice)))

drivers/misc/cxl/main.c

+1 −1
Original line number Diff line number Diff line
@@ -48,7 +48,7 @@ int cxl_afu_slbia(struct cxl_afu *afu) 
		/* If the adapter has gone down, we can assume that we

		 * will PERST it and that will invalidate everything.

		 */

		if (!cxl_ops->link_ok(afu->adapter))

		if (!cxl_ops->link_ok(afu->adapter, afu))

			return -EIO;

		cpu_relax();

	}

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