Subject: Re: [PATCH v5 16/18] cxl: Support the cxl kernel API from a guest

From: Manoj Kumar <[email-masked]>
Date: Wed, 24 Feb 2016 15:09:25 -0600

Reviewed-by: Manoj Kumar <[email-masked]>

---
Manoj Kumar

On 2/23/2016 10:21 AM, Frederic Barrat wrote:
> Like on bare-metal, the cxl driver creates a virtual PHB and a pci
> device for the AFU. The configuration space of the device is mapped to
> the configuration record of the AFU.
>
> Reuse the code defined in afu_cr_read8|16|32() when reading the
> configuration space of the AFU device.
>
> Even though the (virtual) AFU device is a pci device, the adapter is
> not. So a driver using the cxl kernel API cannot read the VPD of the
> adapter through the usual PCI interface. Therefore, we add a call to
> the cxl kernel API:
> ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
>
> Co-authored-by: Christophe Lombard <[email-masked]>
> Signed-off-by: Frederic Barrat <[email-masked]>
> Signed-off-by: Christophe Lombard <[email-masked]>
> ---
>   drivers/misc/cxl/api.c    |  63 ++++++++++++++-----
>   drivers/misc/cxl/cxl.h    |   6 +-
>   drivers/misc/cxl/guest.c  |  26 ++++++++
>   drivers/misc/cxl/native.c |  50 +++++++++++++++
>   drivers/misc/cxl/pci.c    |   9 ++-
>   drivers/misc/cxl/vphb.c   | 154 +++++++++++++++++++---------------------------
>   include/misc/cxl.h        |   5 ++
>   7 files changed, 203 insertions(+), 110 deletions(-)
>
> diff --git a/drivers/misc/cxl/api.c b/drivers/misc/cxl/api.c
> index 325f957..75ec2f9 100644
> --- a/drivers/misc/cxl/api.c
> +++ b/drivers/misc/cxl/api.c
> @@ -89,28 +89,11 @@ int cxl_release_context(struct cxl_context *ctx)
>   }
>   EXPORT_SYMBOL_GPL(cxl_release_context);
>
> -int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
> -{
> -	if (num == 0)
> -		num = ctx->afu->pp_irqs;
> -	return afu_allocate_irqs(ctx, num);
> -}
> -EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
> -
> -void cxl_free_afu_irqs(struct cxl_context *ctx)
> -{
> -	afu_irq_name_free(ctx);
> -	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
> -}
> -EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
> -
>   static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
>   {
>   	__u16 range;
>   	int r;
>
> -	WARN_ON(num == 0);
> -
>   	for (r = 0; r < CXL_IRQ_RANGES; r++) {
>   		range = ctx->irqs.range[r];
>   		if (num < range) {
> @@ -121,6 +104,44 @@ static irq_hw_number_t cxl_find_afu_irq(struct cxl_context *ctx, int num)
>   	return 0;
>   }
>
> +int cxl_allocate_afu_irqs(struct cxl_context *ctx, int num)
> +{
> +	int res;
> +	irq_hw_number_t hwirq;
> +
> +	if (num == 0)
> +		num = ctx->afu->pp_irqs;
> +	res = afu_allocate_irqs(ctx, num);
> +	if (!res && !cpu_has_feature(CPU_FTR_HVMODE)) {
> +		/* In a guest, the PSL interrupt is not multiplexed. It was
> +		 * allocated above, and we need to set its handler
> +		 */
> +		hwirq = cxl_find_afu_irq(ctx, 0);
> +		if (hwirq)
> +			cxl_map_irq(ctx->afu->adapter, hwirq, cxl_ops->psl_interrupt, ctx, "psl");
> +	}
> +	return res;
> +}
> +EXPORT_SYMBOL_GPL(cxl_allocate_afu_irqs);
> +
> +void cxl_free_afu_irqs(struct cxl_context *ctx)
> +{
> +	irq_hw_number_t hwirq;
> +	unsigned int virq;
> +
> +	if (!cpu_has_feature(CPU_FTR_HVMODE)) {
> +		hwirq = cxl_find_afu_irq(ctx, 0);
> +		if (hwirq) {
> +			virq = irq_find_mapping(NULL, hwirq);
> +			if (virq)
> +				cxl_unmap_irq(virq, ctx);
> +		}
> +	}
> +	afu_irq_name_free(ctx);
> +	cxl_ops->release_irq_ranges(&ctx->irqs, ctx->afu->adapter);
> +}
> +EXPORT_SYMBOL_GPL(cxl_free_afu_irqs);
> +
>   int cxl_map_afu_irq(struct cxl_context *ctx, int num,
>   		    irq_handler_t handler, void *cookie, char *name)
>   {
> @@ -356,3 +377,11 @@ void cxl_perst_reloads_same_image(struct cxl_afu *afu,
>   	afu->adapter->perst_same_image = perst_reloads_same_image;
>   }
>   EXPORT_SYMBOL_GPL(cxl_perst_reloads_same_image);
> +
> +ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count)
> +{
> +	struct cxl_afu *afu = cxl_pci_to_afu(dev);
> +
> +	return cxl_ops->read_adapter_vpd(afu->adapter, buf, count);
> +}
> +EXPORT_SYMBOL_GPL(cxl_read_adapter_vpd);
> diff --git a/drivers/misc/cxl/cxl.h b/drivers/misc/cxl/cxl.h
> index 0bf536c..6c2521c 100644
> --- a/drivers/misc/cxl/cxl.h
> +++ b/drivers/misc/cxl/cxl.h
> @@ -581,6 +581,7 @@ int cxl_pci_setup_irq(struct cxl *adapter, unsigned int hwirq, unsigned int virq
>   int cxl_update_image_control(struct cxl *adapter);
>   int cxl_pci_reset(struct cxl *adapter);
>   void cxl_pci_release_afu(struct device *dev);
> +ssize_t cxl_pci_read_adapter_vpd(struct cxl *adapter, void *buf, size_t len);
>
>   /* common == phyp + powernv */
>   struct cxl_process_element_common {
> @@ -802,7 +803,6 @@ int cxl_psl_purge(struct cxl_afu *afu);
>
>   void cxl_stop_trace(struct cxl *cxl);
>   int cxl_pci_vphb_add(struct cxl_afu *afu);
> -void cxl_pci_vphb_reconfigure(struct cxl_afu *afu);
>   void cxl_pci_vphb_remove(struct cxl_afu *afu);
>
>   extern struct pci_driver cxl_pci_driver;
> @@ -863,6 +863,10 @@ struct cxl_backend_ops {
>   	int (*afu_cr_read16)(struct cxl_afu *afu, int cr_idx, u64 offset, u16 *val);
>   	int (*afu_cr_read32)(struct cxl_afu *afu, int cr_idx, u64 offset, u32 *val);
>   	int (*afu_cr_read64)(struct cxl_afu *afu, int cr_idx, u64 offset, u64 *val);
> +	int (*afu_cr_write8)(struct cxl_afu *afu, int cr_idx, u64 offset, u8 val);
> +	int (*afu_cr_write16)(struct cxl_afu *afu, int cr_idx, u64 offset, u16 val);
> +	int (*afu_cr_write32)(struct cxl_afu *afu, int cr_idx, u64 offset, u32 val);
> +	ssize_t (*read_adapter_vpd)(struct cxl *adapter, void *buf, size_t count);
>   };
>   extern const struct cxl_backend_ops cxl_native_ops;
>   extern const struct cxl_backend_ops cxl_guest_ops;
> diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
> index 8340f2a..2563896 100644
> --- a/drivers/misc/cxl/guest.c
> +++ b/drivers/misc/cxl/guest.c
> @@ -418,6 +418,24 @@ static int guest_afu_cr_read64(struct cxl_afu *afu, int cr_idx,	u64 offset,
>   	return _guest_afu_cr_readXX(8, afu, cr_idx, offset, out);
>   }
>
> +static int guest_afu_cr_write32(struct cxl_afu *afu, int cr, u64 off, u32 in)
> +{
> +	/* config record is not writable from guest */
> +	return -EPERM;
> +}
> +
> +static int guest_afu_cr_write16(struct cxl_afu *afu, int cr, u64 off, u16 in)
> +{
> +	/* config record is not writable from guest */
> +	return -EPERM;
> +}
> +
> +static int guest_afu_cr_write8(struct cxl_afu *afu, int cr, u64 off, u8 in)
> +{
> +	/* config record is not writable from guest */
> +	return -EPERM;
> +}
> +
>   static int attach_afu_directed(struct cxl_context *ctx, u64 wed, u64 amr)
>   {
>   	struct cxl_process_element_hcall *elem;
> @@ -794,6 +812,9 @@ int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_n
>
>   	afu->enabled = true;
>
> +	if ((rc = cxl_pci_vphb_add(afu)))
> +		dev_info(&afu->dev, "Can't register vPHB\n");
> +
>   	return 0;
>
>   err_put2:
> @@ -819,6 +840,7 @@ void cxl_guest_remove_afu(struct cxl_afu *afu)
>   	if (!afu)
>   		return;
>
> +	cxl_pci_vphb_remove(afu);
>   	cxl_sysfs_afu_remove(afu);
>
>   	spin_lock(&afu->adapter->afu_list_lock);
> @@ -974,4 +996,8 @@ const struct cxl_backend_ops cxl_guest_ops = {
>   	.afu_cr_read16 = guest_afu_cr_read16,
>   	.afu_cr_read32 = guest_afu_cr_read32,
>   	.afu_cr_read64 = guest_afu_cr_read64,
> +	.afu_cr_write8 = guest_afu_cr_write8,
> +	.afu_cr_write16 = guest_afu_cr_write16,
> +	.afu_cr_write32 = guest_afu_cr_write32,
> +	.read_adapter_vpd = cxl_guest_read_adapter_vpd,
>   };
> diff --git a/drivers/misc/cxl/native.c b/drivers/misc/cxl/native.c
> index acb9486..1ca1011 100644
> --- a/drivers/misc/cxl/native.c
> +++ b/drivers/misc/cxl/native.c
> @@ -1018,6 +1018,52 @@ static int native_afu_cr_read8(struct cxl_afu *afu, int cr, u64 off, u8 *out)
>   	return rc;
>   }
>
> +static int native_afu_cr_write32(struct cxl_afu *afu, int cr, u64 off, u32 in)
> +{
> +	if (unlikely(!cxl_ops->link_ok(afu->adapter)))
> +		return -EIO;
> +	if (unlikely(off >= afu->crs_len))
> +		return -ERANGE;
> +	out_le32(afu->native->afu_desc_mmio + afu->crs_offset +
> +		(cr * afu->crs_len) + off, in);
> +	return 0;
> +}
> +
> +static int native_afu_cr_write16(struct cxl_afu *afu, int cr, u64 off, u16 in)
> +{
> +	u64 aligned_off = off & ~0x3L;
> +	u32 val32, mask, shift;
> +	int rc;
> +
> +	rc = native_afu_cr_read32(afu, cr, aligned_off, &val32);
> +	if (rc)
> +		return rc;
> +	shift = (off & 0x3) * 8;
> +	WARN_ON(shift == 24);
> +	mask = 0xffff << shift;
> +	val32 = (val32 & ~mask) | (in << shift);
> +
> +	rc = native_afu_cr_write32(afu, cr, aligned_off, val32);
> +	return rc;
> +}
> +
> +static int native_afu_cr_write8(struct cxl_afu *afu, int cr, u64 off, u8 in)
> +{
> +	u64 aligned_off = off & ~0x3L;
> +	u32 val32, mask, shift;
> +	int rc;
> +
> +	rc = native_afu_cr_read32(afu, cr, aligned_off, &val32);
> +	if (rc)
> +		return rc;
> +	shift = (off & 0x3) * 8;
> +	mask = 0xff << shift;
> +	val32 = (val32 & ~mask) | (in << shift);
> +
> +	rc = native_afu_cr_write32(afu, cr, aligned_off, val32);
> +	return rc;
> +}
> +
>   const struct cxl_backend_ops cxl_native_ops = {
>   	.module = THIS_MODULE,
>   	.adapter_reset = cxl_pci_reset,
> @@ -1043,4 +1089,8 @@ const struct cxl_backend_ops cxl_native_ops = {
>   	.afu_cr_read16 = native_afu_cr_read16,
>   	.afu_cr_read32 = native_afu_cr_read32,
>   	.afu_cr_read64 = native_afu_cr_read64,
> +	.afu_cr_write8 = native_afu_cr_write8,
> +	.afu_cr_write16 = native_afu_cr_write16,
> +	.afu_cr_write32 = native_afu_cr_write32,
> +	.read_adapter_vpd = cxl_pci_read_adapter_vpd,
>   };
> diff --git a/drivers/misc/cxl/pci.c b/drivers/misc/cxl/pci.c
> index fb4fd45..6cae044 100644
> --- a/drivers/misc/cxl/pci.c
> +++ b/drivers/misc/cxl/pci.c
> @@ -881,6 +881,7 @@ static void cxl_pci_remove_afu(struct cxl_afu *afu)
>   	if (!afu)
>   		return;
>
> +	cxl_pci_vphb_remove(afu);
>   	cxl_sysfs_afu_remove(afu);
>   	cxl_debugfs_afu_remove(afu);
>
> @@ -1067,6 +1068,11 @@ static int cxl_vsec_looks_ok(struct cxl *adapter, struct pci_dev *dev)
>   	return 0;
>   }
>
> +ssize_t cxl_pci_read_adapter_vpd(struct cxl *adapter, void *buf, size_t len)
> +{
> +	return pci_read_vpd(to_pci_dev(adapter->dev.parent), 0, len, buf);
> +}
> +
>   static void cxl_release_adapter(struct device *dev)
>   {
>   	struct cxl *adapter = to_cxl_adapter(dev);
> @@ -1272,7 +1278,6 @@ static void cxl_remove(struct pci_dev *dev)
>   	 */
>   	for (i = 0; i < adapter->slices; i++) {
>   		afu = adapter->afu[i];
> -		cxl_pci_vphb_remove(afu);
>   		cxl_pci_remove_afu(afu);
>   	}
>   	cxl_pci_remove_adapter(adapter);
> @@ -1451,8 +1456,6 @@ static pci_ers_result_t cxl_pci_slot_reset(struct pci_dev *pdev)
>   		if (cxl_afu_select_best_mode(afu))
>   			goto err;
>
> -		cxl_pci_vphb_reconfigure(afu);
> -
>   		list_for_each_entry(afu_dev, &afu->phb->bus->devices, bus_list) {
>   			/* Reset the device context.
>   			 * TODO: make this less disruptive
> diff --git a/drivers/misc/cxl/vphb.c b/drivers/misc/cxl/vphb.c
> index baa4087..c960a09 100644
> --- a/drivers/misc/cxl/vphb.c
> +++ b/drivers/misc/cxl/vphb.c
> @@ -99,113 +99,90 @@ static int cxl_pcie_cfg_record(u8 bus, u8 devfn)
>   	return (bus << 8) + devfn;
>   }
>
> -static unsigned long cxl_pcie_cfg_addr(struct pci_controller* phb,
> -				       u8 bus, u8 devfn, int offset)
> -{
> -	int record = cxl_pcie_cfg_record(bus, devfn);
> -
> -	return (unsigned long)phb->cfg_addr + ((unsigned long)phb->cfg_data * record) + offset;
> -}
> -
> -
>   static int cxl_pcie_config_info(struct pci_bus *bus, unsigned int devfn,
> -				int offset, int len,
> -				volatile void __iomem **ioaddr,
> -				u32 *mask, int *shift)
> +				struct cxl_afu **_afu, int *_record)
>   {
>   	struct pci_controller *phb;
>   	struct cxl_afu *afu;
> -	unsigned long addr;
> +	int record;
>
>   	phb = pci_bus_to_host(bus);
>   	if (phb == NULL)
>   		return PCIBIOS_DEVICE_NOT_FOUND;
> -	afu = (struct cxl_afu *)phb->private_data;
>
> -	if (cxl_pcie_cfg_record(bus->number, devfn) > afu->crs_num)
> +	afu = (struct cxl_afu *)phb->private_data;
> +	record = cxl_pcie_cfg_record(bus->number, devfn);
> +	if (record > afu->crs_num)
>   		return PCIBIOS_DEVICE_NOT_FOUND;
> -	if (offset >= (unsigned long)phb->cfg_data)
> -		return PCIBIOS_BAD_REGISTER_NUMBER;
> -	addr = cxl_pcie_cfg_addr(phb, bus->number, devfn, offset);
>
> -	*ioaddr = (void *)(addr & ~0x3ULL);
> -	*shift = ((addr & 0x3) * 8);
> -	switch (len) {
> -	case 1:
> -		*mask = 0xff;
> -		break;
> -	case 2:
> -		*mask = 0xffff;
> -		break;
> -	default:
> -		*mask = 0xffffffff;
> -		break;
> -	}
> +	*_afu = afu;
> +	*_record = record;
>   	return 0;
>   }
>
> -
> -static inline bool cxl_config_link_ok(struct pci_bus *bus)
> -{
> -	struct pci_controller *phb;
> -	struct cxl_afu *afu;
> -
> -	/* Config space IO is based on phb->cfg_addr, which is based on
> -	 * afu_desc_mmio. This isn't safe to read/write when the link
> -	 * goes down, as EEH tears down MMIO space.
> -	 *
> -	 * Check if the link is OK before proceeding.
> -	 */
> -
> -	phb = pci_bus_to_host(bus);
> -	if (phb == NULL)
> -		return false;
> -	afu = (struct cxl_afu *)phb->private_data;
> -	return cxl_ops->link_ok(afu->adapter);
> -}
> -
>   static int cxl_pcie_read_config(struct pci_bus *bus, unsigned int devfn,
>   				int offset, int len, u32 *val)
>   {
> -	volatile void __iomem *ioaddr;
> -	int shift, rc;
> -	u32 mask;
> +	int rc, record;
> +	struct cxl_afu *afu;
> +	u8 val8;
> +	u16 val16;
> +	u32 val32;
>
> -	rc = cxl_pcie_config_info(bus, devfn, offset, len, &ioaddr,
> -				  &mask, &shift);
> +	rc = cxl_pcie_config_info(bus, devfn, &afu, &record);
>   	if (rc)
>   		return rc;
>
> -	if (!cxl_config_link_ok(bus))
> +	switch (len) {
> +	case 1:
> +		rc = cxl_ops->afu_cr_read8(afu, record, offset,	&val8);
> +		*val = val8;
> +		break;
> +	case 2:
> +		rc = cxl_ops->afu_cr_read16(afu, record, offset, &val16);
> +		*val = val16;
> +		break;
> +	case 4:
> +		rc = cxl_ops->afu_cr_read32(afu, record, offset, &val32);
> +		*val = val32;
> +		break;
> +	default:
> +		WARN_ON(1);
> +	}
> +
> +	if (rc)
>   		return PCIBIOS_DEVICE_NOT_FOUND;
>
> -	/* Can only read 32 bits */
> -	*val = (in_le32(ioaddr) >> shift) & mask;
>   	return PCIBIOS_SUCCESSFUL;
>   }
>
>   static int cxl_pcie_write_config(struct pci_bus *bus, unsigned int devfn,
>   				 int offset, int len, u32 val)
>   {
> -	volatile void __iomem *ioaddr;
> -	u32 v, mask;
> -	int shift, rc;
> +	int rc, record;
> +	struct cxl_afu *afu;
>
> -	rc = cxl_pcie_config_info(bus, devfn, offset, len, &ioaddr,
> -				  &mask, &shift);
> +	rc = cxl_pcie_config_info(bus, devfn, &afu, &record);
>   	if (rc)
>   		return rc;
>
> -	if (!cxl_config_link_ok(bus))
> -		return PCIBIOS_DEVICE_NOT_FOUND;
> -
> -	/* Can only write 32 bits so do read-modify-write */
> -	mask <<= shift;
> -	val <<= shift;
> +	switch (len) {
> +	case 1:
> +		rc = cxl_ops->afu_cr_write8(afu, record, offset, val & 0xff);
> +		break;
> +	case 2:
> +		rc = cxl_ops->afu_cr_write16(afu, record, offset, val & 0xffff);
> +		break;
> +	case 4:
> +		rc = cxl_ops->afu_cr_write32(afu, record, offset, val);
> +		break;
> +	default:
> +		WARN_ON(1);
> +	}
>
> -	v = (in_le32(ioaddr) & ~mask) | (val & mask);
> +	if (rc)
> +		return PCIBIOS_SET_FAILED;
>
> -	out_le32(ioaddr, v);
>   	return PCIBIOS_SUCCESSFUL;
>   }
>
> @@ -233,23 +210,31 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
>   {
>   	struct pci_dev *phys_dev;
>   	struct pci_controller *phb, *phys_phb;
> -
> -	phys_dev = to_pci_dev(afu->adapter->dev.parent);
> -	phys_phb = pci_bus_to_host(phys_dev->bus);
> +	struct device_node *vphb_dn;
> +	struct device *parent;
> +
> +	if (cpu_has_feature(CPU_FTR_HVMODE)) {
> +		phys_dev = to_pci_dev(afu->adapter->dev.parent);
> +		phys_phb = pci_bus_to_host(phys_dev->bus);
> +		vphb_dn = phys_phb->dn;
> +		parent = &phys_dev->dev;
> +	} else {
> +		vphb_dn = afu->adapter->dev.parent->of_node;
> +		parent = afu->adapter->dev.parent;
> +	}
>
>   	/* Alloc and setup PHB data structure */
> -	phb = pcibios_alloc_controller(phys_phb->dn);
> -
> +	phb = pcibios_alloc_controller(vphb_dn);
>   	if (!phb)
>   		return -ENODEV;
>
>   	/* Setup parent in sysfs */
> -	phb->parent = &phys_dev->dev;
> +	phb->parent = parent;
>
>   	/* Setup the PHB using arch provided callback */
>   	phb->ops = &cxl_pcie_pci_ops;
> -	phb->cfg_addr = afu->native->afu_desc_mmio + afu->crs_offset;
> -	phb->cfg_data = (void *)(u64)afu->crs_len;
> +	phb->cfg_addr = NULL;
> +	phb->cfg_data = 0;
>   	phb->private_data = afu;
>   	phb->controller_ops = cxl_pci_controller_ops;
>
> @@ -272,15 +257,6 @@ int cxl_pci_vphb_add(struct cxl_afu *afu)
>   	return 0;
>   }
>
> -void cxl_pci_vphb_reconfigure(struct cxl_afu *afu)
> -{
> -	/* When we are reconfigured, the AFU's MMIO space is unmapped
> -	 * and remapped. We need to reflect this in the PHB's view of
> -	 * the world.
> -	 */
> -	afu->phb->cfg_addr = afu->native->afu_desc_mmio + afu->crs_offset;
> -}
> -
>   void cxl_pci_vphb_remove(struct cxl_afu *afu)
>   {
>   	struct pci_controller *phb;
> diff --git a/include/misc/cxl.h b/include/misc/cxl.h
> index f2ffe5b..5bcf11a 100644
> --- a/include/misc/cxl.h
> +++ b/include/misc/cxl.h
> @@ -210,4 +210,9 @@ ssize_t cxl_fd_read(struct file *file, char __user *buf, size_t count,
>   void cxl_perst_reloads_same_image(struct cxl_afu *afu,
>   				  bool perst_reloads_same_image);
>
> +/*
> + * Read the VPD for the card where the AFU resides
> + */
> +ssize_t cxl_read_adapter_vpd(struct pci_dev *dev, void *buf, size_t count);
> +
>   #endif /* _MISC_CXL_H */
>