cxl: Add guest-specific code

The new of.c file contains code to parse the device tree to find out
about cxl adapters and AFUs.

guest.c implements the guest-specific callbacks for the backend API.

The process element ID is not known until the context is attached, so
we have to separate the context ID assigned by the cxl driver from the
process element ID visible to the user applications. In bare-metal,
the 2 IDs match.

Co-authored-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Frederic Barrat <fbarrat@linux.vnet.ibm.com>
Signed-off-by: Christophe Lombard <clombard@linux.vnet.ibm.com>
Reviewed-by: Manoj Kumar <manoj@linux.vnet.ibm.com>
Acked-by: Ian Munsie <imunsie@au1.ibm.com>
[mpe: Fix SMP=n build, fix PSERIES=n build, minor whitespace fixes]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

1 files changed, 950 insertions, 0 deletions

diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
new file mode 100644
index 000000000000..d7d53d869283
--- /dev/null
+++ b/drivers/misc/cxl/guest.c
@@ -0,0 +1,950 @@
+/*
+ * Copyright 2015 IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/delay.h>
+
+#include "cxl.h"
+#include "hcalls.h"
+#include "trace.h"
+
+
+static irqreturn_t guest_handle_psl_slice_error(struct cxl_context *ctx, u64 dsisr,
+					u64 errstat)
+{
+	pr_devel("in %s\n", __func__);
+	dev_crit(&ctx->afu->dev, "PSL ERROR STATUS: 0x%.16llx\n", errstat);
+
+	return cxl_ops->ack_irq(ctx, 0, errstat);
+}
+
+static ssize_t guest_collect_vpd(struct cxl *adapter, struct cxl_afu *afu,
+			void *buf, size_t len)
+{
+	unsigned int entries, mod;
+	unsigned long **vpd_buf = NULL;
+	struct sg_list *le;
+	int rc = 0, i, tocopy;
+	u64 out = 0;
+
+	if (buf == NULL)
+		return -EINVAL;
+
+	/* number of entries in the list */
+	entries = len / SG_BUFFER_SIZE;
+	mod = len % SG_BUFFER_SIZE;
+	if (mod)
+		entries++;
+
+	if (entries > SG_MAX_ENTRIES) {
+		entries = SG_MAX_ENTRIES;
+		len = SG_MAX_ENTRIES * SG_BUFFER_SIZE;
+		mod = 0;
+	}
+
+	vpd_buf = kzalloc(entries * sizeof(unsigned long *), GFP_KERNEL);
+	if (!vpd_buf)
+		return -ENOMEM;
+
+	le = (struct sg_list *)get_zeroed_page(GFP_KERNEL);
+	if (!le) {
+		rc = -ENOMEM;
+		goto err1;
+	}
+
+	for (i = 0; i < entries; i++) {
+		vpd_buf[i] = (unsigned long *)get_zeroed_page(GFP_KERNEL);
+		if (!vpd_buf[i]) {
+			rc = -ENOMEM;
+			goto err2;
+		}
+		le[i].phys_addr = cpu_to_be64(virt_to_phys(vpd_buf[i]));
+		le[i].len = cpu_to_be64(SG_BUFFER_SIZE);
+		if ((i == (entries - 1)) && mod)
+			le[i].len = cpu_to_be64(mod);
+	}
+
+	if (adapter)
+		rc = cxl_h_collect_vpd_adapter(adapter->guest->handle,
+					virt_to_phys(le), entries, &out);
+	else
+		rc = cxl_h_collect_vpd(afu->guest->handle, 0,
+				virt_to_phys(le), entries, &out);
+	pr_devel("length of available (entries: %i), vpd: %#llx\n",
+		entries, out);
+
+	if (!rc) {
+		/*
+		 * hcall returns in 'out' the size of available VPDs.
+		 * It fills the buffer with as much data as possible.
+		 */
+		if (out < len)
+			len = out;
+		rc = len;
+		if (out) {
+			for (i = 0; i < entries; i++) {
+				if (len < SG_BUFFER_SIZE)
+					tocopy = len;
+				else
+					tocopy = SG_BUFFER_SIZE;
+				memcpy(buf, vpd_buf[i], tocopy);
+				buf += tocopy;
+				len -= tocopy;
+			}
+		}
+	}
+err2:
+	for (i = 0; i < entries; i++) {
+		if (vpd_buf[i])
+			free_page((unsigned long) vpd_buf[i]);
+	}
+	free_page((unsigned long) le);
+err1:
+	kfree(vpd_buf);
+	return rc;
+}
+
+static int guest_get_irq_info(struct cxl_context *ctx, struct cxl_irq_info *info)
+{
+	return cxl_h_collect_int_info(ctx->afu->guest->handle, ctx->process_token, info);
+}
+
+static irqreturn_t guest_psl_irq(int irq, void *data)
+{
+	struct cxl_context *ctx = data;
+	struct cxl_irq_info irq_info;
+	int rc;
+
+	pr_devel("%d: received PSL interrupt %i\n", ctx->pe, irq);
+	rc = guest_get_irq_info(ctx, &irq_info);
+	if (rc) {
+		WARN(1, "Unable to get IRQ info: %i\n", rc);
+		return IRQ_HANDLED;
+	}
+
+	rc = cxl_irq(irq, ctx, &irq_info);
+	return rc;
+}
+
+static irqreturn_t guest_slice_irq_err(int irq, void *data)
+{
+	struct cxl_afu *afu = data;
+	int rc;
+	u64 serr;
+
+	WARN(irq, "CXL SLICE ERROR interrupt %i\n", irq);
+	rc = cxl_h_get_fn_error_interrupt(afu->guest->handle, &serr);
+	if (rc) {
+		dev_crit(&afu->dev, "Couldn't read PSL_SERR_An: %d\n", rc);
+		return IRQ_HANDLED;
+	}
+	dev_crit(&afu->dev, "PSL_SERR_An: 0x%.16llx\n", serr);
+
+	rc = cxl_h_ack_fn_error_interrupt(afu->guest->handle, serr);
+	if (rc)
+		dev_crit(&afu->dev, "Couldn't ack slice error interrupt: %d\n",
+			rc);
+
+	return IRQ_HANDLED;
+}
+
+
+static int irq_alloc_range(struct cxl *adapter, int len, int *irq)
+{
+	int i, n;
+	struct irq_avail *cur;
+
+	for (i = 0; i < adapter->guest->irq_nranges; i++) {
+		cur = &adapter->guest->irq_avail[i];
+		n = bitmap_find_next_zero_area(cur->bitmap, cur->range,
+					0, len, 0);
+		if (n < cur->range) {
+			bitmap_set(cur->bitmap, n, len);
+			*irq = cur->offset + n;
+			pr_devel("guest: allocate IRQs %#x->%#x\n",
+				*irq, *irq + len - 1);
+
+			return 0;
+		}
+	}
+	return -ENOSPC;
+}
+
+static int irq_free_range(struct cxl *adapter, int irq, int len)
+{
+	int i, n;
+	struct irq_avail *cur;
+
+	if (len == 0)
+		return -ENOENT;
+
+	for (i = 0; i < adapter->guest->irq_nranges; i++) {
+		cur = &adapter->guest->irq_avail[i];
+		if (irq >= cur->offset &&
+			(irq + len) <= (cur->offset + cur->range)) {
+			n = irq - cur->offset;
+			bitmap_clear(cur->bitmap, n, len);
+			pr_devel("guest: release IRQs %#x->%#x\n",
+				irq, irq + len - 1);
+			return 0;
+		}
+	}
+	return -ENOENT;
+}
+
+static int guest_reset(struct cxl *adapter)
+{
+	int rc;
+
+	pr_devel("Adapter reset request\n");
+	rc = cxl_h_reset_adapter(adapter->guest->handle);
+	return rc;
+}
+
+static int guest_alloc_one_irq(struct cxl *adapter)
+{
+	int irq;
+
+	spin_lock(&adapter->guest->irq_alloc_lock);
+	if (irq_alloc_range(adapter, 1, &irq))
+		irq = -ENOSPC;
+	spin_unlock(&adapter->guest->irq_alloc_lock);
+	return irq;
+}
+
+static void guest_release_one_irq(struct cxl *adapter, int irq)
+{
+	spin_lock(&adapter->guest->irq_alloc_lock);
+	irq_free_range(adapter, irq, 1);
+	spin_unlock(&adapter->guest->irq_alloc_lock);
+}
+
+static int guest_alloc_irq_ranges(struct cxl_irq_ranges *irqs,
+				struct cxl *adapter, unsigned int num)
+{
+	int i, try, irq;
+
+	memset(irqs, 0, sizeof(struct cxl_irq_ranges));
+
+	spin_lock(&adapter->guest->irq_alloc_lock);
+	for (i = 0; i < CXL_IRQ_RANGES && num; i++) {
+		try = num;
+		while (try) {
+			if (irq_alloc_range(adapter, try, &irq) == 0)
+				break;
+			try /= 2;
+		}
+		if (!try)
+			goto error;
+		irqs->offset[i] = irq;
+		irqs->range[i] = try;
+		num -= try;
+	}
+	if (num)
+		goto error;
+	spin_unlock(&adapter->guest->irq_alloc_lock);
+	return 0;
+
+error:
+	for (i = 0; i < CXL_IRQ_RANGES; i++)
+		irq_free_range(adapter, irqs->offset[i], irqs->range[i]);
+	spin_unlock(&adapter->guest->irq_alloc_lock);
+	return -ENOSPC;
+}
+
+static void guest_release_irq_ranges(struct cxl_irq_ranges *irqs,
+				struct cxl *adapter)
+{
+	int i;
+
+	spin_lock(&adapter->guest->irq_alloc_lock);
+	for (i = 0; i < CXL_IRQ_RANGES; i++)
+		irq_free_range(adapter, irqs->offset[i], irqs->range[i]);
+	spin_unlock(&adapter->guest->irq_alloc_lock);
+}
+
+static int guest_register_serr_irq(struct cxl_afu *afu)
+{
+	afu->err_irq_name = kasprintf(GFP_KERNEL, "cxl-%s-err",
+				      dev_name(&afu->dev));
+	if (!afu->err_irq_name)
+		return -ENOMEM;
+
+	if (!(afu->serr_virq = cxl_map_irq(afu->adapter, afu->serr_hwirq,
+				 guest_slice_irq_err, afu, afu->err_irq_name))) {
+		kfree(afu->err_irq_name);
+		afu->err_irq_name = NULL;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+static void guest_release_serr_irq(struct cxl_afu *afu)
+{
+	cxl_unmap_irq(afu->serr_virq, afu);
+	cxl_ops->release_one_irq(afu->adapter, afu->serr_hwirq);
+	kfree(afu->err_irq_name);
+}
+
+static int guest_ack_irq(struct cxl_context *ctx, u64 tfc, u64 psl_reset_mask)
+{
+	return cxl_h_control_faults(ctx->afu->guest->handle, ctx->process_token,
+				tfc >> 32, (psl_reset_mask != 0));
+}
+
+static void disable_afu_irqs(struct cxl_context *ctx)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+	int r, i;
+
+	pr_devel("Disabling AFU(%d) interrupts\n", ctx->afu->slice);
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		hwirq = ctx->irqs.offset[r];
+		for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
+			virq = irq_find_mapping(NULL, hwirq);
+			disable_irq(virq);
+		}
+	}
+}
+
+static void enable_afu_irqs(struct cxl_context *ctx)
+{
+	irq_hw_number_t hwirq;
+	unsigned int virq;
+	int r, i;
+
+	pr_devel("Enabling AFU(%d) interrupts\n", ctx->afu->slice);
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		hwirq = ctx->irqs.offset[r];
+		for (i = 0; i < ctx->irqs.range[r]; hwirq++, i++) {
+			virq = irq_find_mapping(NULL, hwirq);
+			enable_irq(virq);
+		}
+	}
+}
+
+static int _guest_afu_cr_readXX(int sz, struct cxl_afu *afu, int cr_idx,
+			u64 offset, u64 *val)
+{
+	unsigned long cr;
+	char c;
+	int rc = 0;
+
+	if (afu->crs_len < sz)
+		return -ENOENT;
+
+	if (unlikely(offset >= afu->crs_len))
+		return -ERANGE;
+
+	cr = get_zeroed_page(GFP_KERNEL);
+	if (!cr)
+		return -ENOMEM;
+
+	rc = cxl_h_get_config(afu->guest->handle, cr_idx, offset,
+			virt_to_phys((void *)cr), sz);
+	if (rc)
+		goto err;
+
+	switch (sz) {
+	case 1:
+		c = *((char *) cr);
+		*val = c;
+		break;
+	case 2:
+		*val = in_le16((u16 *)cr);
+		break;
+	case 4:
+		*val = in_le32((unsigned *)cr);
+		break;
+	case 8:
+		*val = in_le64((u64 *)cr);
+		break;
+	default:
+		WARN_ON(1);
+	}
+err:
+	free_page(cr);
+	return rc;
+}
+
+static int guest_afu_cr_read32(struct cxl_afu *afu, int cr_idx, u64 offset,
+			u32 *out)
+{
+	int rc;
+	u64 val;
+
+	rc = _guest_afu_cr_readXX(4, afu, cr_idx, offset, &val);
+	if (!rc)
+		*out = (u32) val;
+	return rc;
+}
+
+static int guest_afu_cr_read16(struct cxl_afu *afu, int cr_idx, u64 offset,
+			u16 *out)
+{
+	int rc;
+	u64 val;
+
+	rc = _guest_afu_cr_readXX(2, afu, cr_idx, offset, &val);
+	if (!rc)
+		*out = (u16) val;
+	return rc;
+}
+
+static int guest_afu_cr_read8(struct cxl_afu *afu, int cr_idx, u64 offset,
+			u8 *out)
+{
+	int rc;
+	u64 val;
+
+	rc = _guest_afu_cr_readXX(1, afu, cr_idx, offset, &val);
+	if (!rc)
+		*out = (u8) val;
+	return rc;
+}
+
+static int guest_afu_cr_read64(struct cxl_afu *afu, int cr_idx, u64 offset,
+			u64 *out)
+{
+	return _guest_afu_cr_readXX(8, afu, cr_idx, offset, out);
+}
+
+static int attach_afu_directed(struct cxl_context *ctx, u64 wed, u64 amr)
+{
+	struct cxl_process_element_hcall *elem;
+	struct cxl *adapter = ctx->afu->adapter;
+	const struct cred *cred;
+	u32 pid, idx;
+	int rc, r, i;
+	u64 mmio_addr, mmio_size;
+	__be64 flags = 0;
+
+	/* Must be 8 byte aligned and cannot cross a 4096 byte boundary */
+	if (!(elem = (struct cxl_process_element_hcall *)
+			get_zeroed_page(GFP_KERNEL)))
+		return -ENOMEM;
+
+	elem->version = cpu_to_be64(CXL_PROCESS_ELEMENT_VERSION);
+	if (ctx->kernel) {
+		pid = 0;
+		flags |= CXL_PE_TRANSLATION_ENABLED;
+		flags |= CXL_PE_PRIVILEGED_PROCESS;
+		if (mfmsr() & MSR_SF)
+			flags |= CXL_PE_64_BIT;
+	} else {
+		pid = current->pid;
+		flags |= CXL_PE_PROBLEM_STATE;
+		flags |= CXL_PE_TRANSLATION_ENABLED;
+		if (!test_tsk_thread_flag(current, TIF_32BIT))
+			flags |= CXL_PE_64_BIT;
+		cred = get_current_cred();
+		if (uid_eq(cred->euid, GLOBAL_ROOT_UID))
+			flags |= CXL_PE_PRIVILEGED_PROCESS;
+		put_cred(cred);
+	}
+	elem->flags         = cpu_to_be64(flags);
+	elem->common.tid    = cpu_to_be32(0); /* Unused */
+	elem->common.pid    = cpu_to_be32(pid);
+	elem->common.csrp   = cpu_to_be64(0); /* disable */
+	elem->common.aurp0  = cpu_to_be64(0); /* disable */
+	elem->common.aurp1  = cpu_to_be64(0); /* disable */
+
+	cxl_prefault(ctx, wed);
+
+	elem->common.sstp0  = cpu_to_be64(ctx->sstp0);
+	elem->common.sstp1  = cpu_to_be64(ctx->sstp1);
+	for (r = 0; r < CXL_IRQ_RANGES; r++) {
+		for (i = 0; i < ctx->irqs.range[r]; i++) {
+			if (r == 0 && i == 0) {
+				elem->pslVirtualIsn = cpu_to_be32(ctx->irqs.offset[0]);
+			} else {
+				idx = ctx->irqs.offset[r] + i - adapter->guest->irq_base_offset;
+				elem->applicationVirtualIsnBitmap[idx / 8] |= 0x80 >> (idx % 8);
+			}
+		}
+	}
+	elem->common.amr = cpu_to_be64(amr);
+	elem->common.wed = cpu_to_be64(wed);
+
+	disable_afu_irqs(ctx);
+
+	rc = cxl_h_attach_process(ctx->afu->guest->handle, elem,
+				&ctx->process_token, &mmio_addr, &mmio_size);
+	if (rc == H_SUCCESS) {
+		if (ctx->master || !ctx->afu->pp_psa) {
+			ctx->psn_phys = ctx->afu->psn_phys;
+			ctx->psn_size = ctx->afu->adapter->ps_size;
+		} else {
+			ctx->psn_phys = mmio_addr;
+			ctx->psn_size = mmio_size;
+		}
+		if (ctx->afu->pp_psa && mmio_size &&
+			ctx->afu->pp_size == 0) {
+			/*
+			 * There's no property in the device tree to read the
+			 * pp_size. We only find out at the 1st attach.
+			 * Compared to bare-metal, it is too late and we
+			 * should really lock here. However, on powerVM,
+			 * pp_size is really only used to display in /sys.
+			 * Being discussed with pHyp for their next release.
+			 */
+			ctx->afu->pp_size = mmio_size;
+		}
+		/* from PAPR: process element is bytes 4-7 of process token */
+		ctx->external_pe = ctx->process_token & 0xFFFFFFFF;
+		pr_devel("CXL pe=%i is known as %i for pHyp, mmio_size=%#llx",
+			ctx->pe, ctx->external_pe, ctx->psn_size);
+		ctx->pe_inserted = true;
+		enable_afu_irqs(ctx);
+	}
+
+	free_page((u64)elem);
+	return rc;
+}
+
+static int guest_attach_process(struct cxl_context *ctx, bool kernel, u64 wed, u64 amr)
+{
+	pr_devel("in %s\n", __func__);
+
+	ctx->kernel = kernel;
+	if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
+		return attach_afu_directed(ctx, wed, amr);
+
+	/* dedicated mode not supported on FW840 */
+
+	return -EINVAL;
+}
+
+static int detach_afu_directed(struct cxl_context *ctx)
+{
+	if (!ctx->pe_inserted)
+		return 0;
+	if (cxl_h_detach_process(ctx->afu->guest->handle, ctx->process_token))
+		return -1;
+	return 0;
+}
+
+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))
+		return -EIO;
+
+	if (ctx->afu->current_mode == CXL_MODE_DIRECTED)
+		return detach_afu_directed(ctx);
+
+	return -EINVAL;
+}
+
+static void guest_release_afu(struct device *dev)
+{
+	struct cxl_afu *afu = to_cxl_afu(dev);
+
+	pr_devel("%s\n", __func__);
+
+	idr_destroy(&afu->contexts_idr);
+
+	kfree(afu->guest);
+	kfree(afu);
+}
+
+ssize_t cxl_guest_read_afu_vpd(struct cxl_afu *afu, void *buf, size_t len)
+{
+	return guest_collect_vpd(NULL, afu, buf, len);
+}
+
+#define ERR_BUFF_MAX_COPY_SIZE PAGE_SIZE
+static ssize_t guest_afu_read_err_buffer(struct cxl_afu *afu, char *buf,
+					loff_t off, size_t count)
+{
+	void *tbuf = NULL;
+	int rc = 0;
+
+	tbuf = (void *) get_zeroed_page(GFP_KERNEL);
+	if (!tbuf)
+		return -ENOMEM;
+
+	rc = cxl_h_get_afu_err(afu->guest->handle,
+			       off & 0x7,
+			       virt_to_phys(tbuf),
+			       count);
+	if (rc)
+		goto err;
+
+	if (count > ERR_BUFF_MAX_COPY_SIZE)
+		count = ERR_BUFF_MAX_COPY_SIZE - (off & 0x7);
+	memcpy(buf, tbuf, count);
+err:
+	free_page((u64)tbuf);
+
+	return rc;
+}
+
+static int guest_afu_check_and_enable(struct cxl_afu *afu)
+{
+	return 0;
+}
+
+static int activate_afu_directed(struct cxl_afu *afu)
+{
+	int rc;
+
+	dev_info(&afu->dev, "Activating AFU(%d) directed mode\n", afu->slice);
+
+	afu->current_mode = CXL_MODE_DIRECTED;
+
+	afu->num_procs = afu->max_procs_virtualised;
+
+	if ((rc = cxl_chardev_m_afu_add(afu)))
+		return rc;
+
+	if ((rc = cxl_sysfs_afu_m_add(afu)))
+		goto err;
+
+	if ((rc = cxl_chardev_s_afu_add(afu)))
+		goto err1;
+
+	return 0;
+err1:
+	cxl_sysfs_afu_m_remove(afu);
+err:
+	cxl_chardev_afu_remove(afu);
+	return rc;
+}
+
+static int guest_afu_activate_mode(struct cxl_afu *afu, int mode)
+{
+	if (!mode)
+		return 0;
+	if (!(mode & afu->modes_supported))
+		return -EINVAL;
+
+	if (mode == CXL_MODE_DIRECTED)
+		return activate_afu_directed(afu);
+
+	if (mode == CXL_MODE_DEDICATED)
+		dev_err(&afu->dev, "Dedicated mode not supported\n");
+
+	return -EINVAL;
+}
+
+static int deactivate_afu_directed(struct cxl_afu *afu)
+{
+	dev_info(&afu->dev, "Deactivating AFU(%d) directed mode\n", afu->slice);
+
+	afu->current_mode = 0;
+	afu->num_procs = 0;
+
+	cxl_sysfs_afu_m_remove(afu);
+	cxl_chardev_afu_remove(afu);
+
+	cxl_ops->afu_reset(afu);
+
+	return 0;
+}
+
+static int guest_afu_deactivate_mode(struct cxl_afu *afu, int mode)
+{
+	if (!mode)
+		return 0;
+	if (!(mode & afu->modes_supported))
+		return -EINVAL;
+
+	if (mode == CXL_MODE_DIRECTED)
+		return deactivate_afu_directed(afu);
+	return 0;
+}
+
+static int guest_afu_reset(struct cxl_afu *afu)
+{
+	pr_devel("AFU(%d) reset request\n", afu->slice);
+	return cxl_h_reset_afu(afu->guest->handle);
+}
+
+static int guest_map_slice_regs(struct cxl_afu *afu)
+{
+	if (!(afu->p2n_mmio = ioremap(afu->guest->p2n_phys, afu->guest->p2n_size))) {
+		dev_err(&afu->dev, "Error mapping AFU(%d) MMIO regions\n",
+			afu->slice);
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+static void guest_unmap_slice_regs(struct cxl_afu *afu)
+{
+	if (afu->p2n_mmio)
+		iounmap(afu->p2n_mmio);
+}
+
+static bool guest_link_ok(struct cxl *cxl)
+{
+	return true;
+}
+
+static int afu_properties_look_ok(struct cxl_afu *afu)
+{
+	if (afu->pp_irqs < 0) {
+		dev_err(&afu->dev, "Unexpected per-process minimum interrupt value\n");
+		return -EINVAL;
+	}
+
+	if (afu->max_procs_virtualised < 1) {
+		dev_err(&afu->dev, "Unexpected max number of processes virtualised value\n");
+		return -EINVAL;
+	}
+
+	if (afu->crs_len < 0) {
+		dev_err(&afu->dev, "Unexpected configuration record size value\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+int cxl_guest_init_afu(struct cxl *adapter, int slice, struct device_node *afu_np)
+{
+	struct cxl_afu *afu;
+	bool free = true;
+	int rc;
+
+	pr_devel("in %s - AFU(%d)\n", __func__, slice);
+	if (!(afu = cxl_alloc_afu(adapter, slice)))
+		return -ENOMEM;
+
+	if (!(afu->guest = kzalloc(sizeof(struct cxl_afu_guest), GFP_KERNEL))) {
+		kfree(afu);
+		return -ENOMEM;
+	}
+
+	if ((rc = dev_set_name(&afu->dev, "afu%i.%i",
+					  adapter->adapter_num,
+					  slice)))
+		goto err1;
+
+	adapter->slices++;
+
+	if ((rc = cxl_of_read_afu_handle(afu, afu_np)))
+		goto err1;
+
+	if ((rc = cxl_ops->afu_reset(afu)))
+		goto err1;
+
+	if ((rc = cxl_of_read_afu_properties(afu, afu_np)))
+		goto err1;
+
+	if ((rc = afu_properties_look_ok(afu)))
+		goto err1;
+
+	if ((rc = guest_map_slice_regs(afu)))
+		goto err1;
+
+	if ((rc = guest_register_serr_irq(afu)))
+		goto err2;
+
+	/*
+	 * After we call this function we must not free the afu directly, even
+	 * if it returns an error!
+	 */
+	if ((rc = cxl_register_afu(afu)))
+		goto err_put1;
+
+	if ((rc = cxl_sysfs_afu_add(afu)))
+		goto err_put1;
+
+	/*
+	 * pHyp doesn't expose the programming models supported by the
+	 * AFU. pHyp currently only supports directed mode. If it adds
+	 * dedicated mode later, this version of cxl has no way to
+	 * detect it. So we'll initialize the driver, but the first
+	 * attach will fail.
+	 * Being discussed with pHyp to do better (likely new property)
+	 */
+	if (afu->max_procs_virtualised == 1)
+		afu->modes_supported = CXL_MODE_DEDICATED;
+	else
+		afu->modes_supported = CXL_MODE_DIRECTED;
+
+	if ((rc = cxl_afu_select_best_mode(afu)))
+		goto err_put2;
+
+	adapter->afu[afu->slice] = afu;
+
+	afu->enabled = true;
+
+	return 0;
+
+err_put2:
+	cxl_sysfs_afu_remove(afu);
+err_put1:
+	device_unregister(&afu->dev);
+	free = false;
+	guest_release_serr_irq(afu);
+err2:
+	guest_unmap_slice_regs(afu);
+err1:
+	if (free) {
+		kfree(afu->guest);
+		kfree(afu);
+	}
+	return rc;
+}
+
+void cxl_guest_remove_afu(struct cxl_afu *afu)
+{
+	pr_devel("in %s - AFU(%d)\n", __func__, afu->slice);
+
+	if (!afu)
+		return;
+
+	cxl_sysfs_afu_remove(afu);
+
+	spin_lock(&afu->adapter->afu_list_lock);
+	afu->adapter->afu[afu->slice] = NULL;
+	spin_unlock(&afu->adapter->afu_list_lock);
+
+	cxl_context_detach_all(afu);
+	cxl_ops->afu_deactivate_mode(afu, afu->current_mode);
+	guest_release_serr_irq(afu);
+	guest_unmap_slice_regs(afu);
+
+	device_unregister(&afu->dev);
+}
+
+static void free_adapter(struct cxl *adapter)
+{
+	struct irq_avail *cur;
+	int i;
+
+	if (adapter->guest->irq_avail) {
+		for (i = 0; i < adapter->guest->irq_nranges; i++) {
+			cur = &adapter->guest->irq_avail[i];
+			kfree(cur->bitmap);
+		}
+		kfree(adapter->guest->irq_avail);
+	}
+	kfree(adapter->guest->status);
+	cxl_remove_adapter_nr(adapter);
+	kfree(adapter->guest);
+	kfree(adapter);
+}
+
+static int properties_look_ok(struct cxl *adapter)
+{
+	/* The absence of this property means that the operational
+	 * status is unknown or okay
+	 */
+	if (strlen(adapter->guest->status) &&
+	    strcmp(adapter->guest->status, "okay")) {
+		pr_err("ABORTING:Bad operational status of the device\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+ssize_t cxl_guest_read_adapter_vpd(struct cxl *adapter, void *buf, size_t len)
+{
+	return guest_collect_vpd(adapter, NULL, buf, len);
+}
+
+void cxl_guest_remove_adapter(struct cxl *adapter)
+{
+	pr_devel("in %s\n", __func__);
+
+	cxl_sysfs_adapter_remove(adapter);
+
+	device_unregister(&adapter->dev);
+}
+
+static void release_adapter(struct device *dev)
+{
+	free_adapter(to_cxl_adapter(dev));
+}
+
+struct cxl *cxl_guest_init_adapter(struct device_node *np, struct platform_device *pdev)
+{
+	struct cxl *adapter;
+	bool free = true;
+	int rc;
+
+	if (!(adapter = cxl_alloc_adapter()))
+		return ERR_PTR(-ENOMEM);
+
+	if (!(adapter->guest = kzalloc(sizeof(struct cxl_guest), GFP_KERNEL))) {
+		free_adapter(adapter);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	adapter->slices = 0;
+	adapter->guest->pdev = pdev;
+	adapter->dev.parent = &pdev->dev;
+	adapter->dev.release = release_adapter;
+	dev_set_drvdata(&pdev->dev, adapter);
+
+	if ((rc = cxl_of_read_adapter_handle(adapter, np)))
+		goto err1;
+
+	if ((rc = cxl_of_read_adapter_properties(adapter, np)))
+		goto err1;
+
+	if ((rc = properties_look_ok(adapter)))
+		goto err1;
+
+	/*
+	 * After we call this function we must not free the adapter directly,
+	 * even if it returns an error!
+	 */
+	if ((rc = cxl_register_adapter(adapter)))
+		goto err_put1;
+
+	if ((rc = cxl_sysfs_adapter_add(adapter)))
+		goto err_put1;
+
+	return adapter;
+
+err_put1:
+	device_unregister(&adapter->dev);
+	free = false;
+err1:
+	if (free)
+		free_adapter(adapter);
+	return ERR_PTR(rc);
+}
+
+const struct cxl_backend_ops cxl_guest_ops = {
+	.module = THIS_MODULE,
+	.adapter_reset = guest_reset,
+	.alloc_one_irq = guest_alloc_one_irq,
+	.release_one_irq = guest_release_one_irq,
+	.alloc_irq_ranges = guest_alloc_irq_ranges,
+	.release_irq_ranges = guest_release_irq_ranges,
+	.setup_irq = NULL,
+	.handle_psl_slice_error = guest_handle_psl_slice_error,
+	.psl_interrupt = guest_psl_irq,
+	.ack_irq = guest_ack_irq,
+	.attach_process = guest_attach_process,
+	.detach_process = guest_detach_process,
+	.link_ok = guest_link_ok,
+	.release_afu = guest_release_afu,
+	.afu_read_err_buffer = guest_afu_read_err_buffer,
+	.afu_check_and_enable = guest_afu_check_and_enable,
+	.afu_activate_mode = guest_afu_activate_mode,
+	.afu_deactivate_mode = guest_afu_deactivate_mode,
+	.afu_reset = guest_afu_reset,
+	.afu_cr_read8 = guest_afu_cr_read8,
+	.afu_cr_read16 = guest_afu_cr_read16,
+	.afu_cr_read32 = guest_afu_cr_read32,
+	.afu_cr_read64 = guest_afu_cr_read64,
+};