/* * PCI Backend - Functions for creating a virtual configuration space for * exported PCI Devices. * It's dangerous to allow PCI Driver Domains to change their * device's resources (memory, i/o ports, interrupts). We need to * restrict changes to certain PCI Configuration registers: * BARs, INTERRUPT_PIN, most registers in the header... * * Author: Ryan Wilson <hap9@epoch.ncsc.mil> */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/pci.h> #include "pciback.h" #include "conf_space.h" #include "conf_space_quirks.h" bool permissive; module_param(permissive, bool, 0644); /* This is where xen_pcibk_read_config_byte, xen_pcibk_read_config_word, * xen_pcibk_write_config_word, and xen_pcibk_write_config_byte are created. */ #define DEFINE_PCI_CONFIG(op, size, type) \ int xen_pcibk_##op##_config_##size \ (struct pci_dev *dev, int offset, type value, void *data) \ { \ return pci_##op##_config_##size(dev, offset, value); \ } DEFINE_PCI_CONFIG(read, byte, u8 *) DEFINE_PCI_CONFIG(read, word, u16 *) DEFINE_PCI_CONFIG(read, dword, u32 *) DEFINE_PCI_CONFIG(write, byte, u8) DEFINE_PCI_CONFIG(write, word, u16) DEFINE_PCI_CONFIG(write, dword, u32) static int conf_space_read(struct pci_dev *dev, const struct config_field_entry *entry, int offset, u32 *value) { int ret = 0; const struct config_field *field = entry->field; *value = 0; switch (field->size) { case 1: if (field->u.b.read) ret = field->u.b.read(dev, offset, (u8 *) value, entry->data); break; case 2: if (field->u.w.read) ret = field->u.w.read(dev, offset, (u16 *) value, entry->data); break; case 4: if (field->u.dw.read) ret = field->u.dw.read(dev, offset, value, entry->data); break; } return ret; } static int conf_space_write(struct pci_dev *dev, const struct config_field_entry *entry, int offset, u32 value) { int ret = 0; const struct config_field *field = entry->field; switch (field->size) { case 1: if (field->u.b.write) ret = field->u.b.write(dev, offset, (u8) value, entry->data); break; case 2: if (field->u.w.write) ret = field->u.w.write(dev, offset, (u16) value, entry->data); break; case 4: if (field->u.dw.write) ret = field->u.dw.write(dev, offset, value, entry->data); break; } return ret; } static inline u32 get_mask(int size) { if (size == 1) return 0xff; else if (size == 2) return 0xffff; else return 0xffffffff; } static inline int valid_request(int offset, int size) { /* Validate request (no un-aligned requests) */ if ((size == 1 || size == 2 || size == 4) && (offset % size) == 0) return 1; return 0; } static inline u32 merge_value(u32 val, u32 new_val, u32 new_val_mask, int offset) { if (offset >= 0) { new_val_mask <<= (offset * 8); new_val <<= (offset * 8); } else { new_val_mask >>= (offset * -8); new_val >>= (offset * -8); } val = (val & ~new_val_mask) | (new_val & new_val_mask); return val; } static int xen_pcibios_err_to_errno(int err) { switch (err) { case PCIBIOS_SUCCESSFUL: return XEN_PCI_ERR_success; case PCIBIOS_DEVICE_NOT_FOUND: return XEN_PCI_ERR_dev_not_found; case PCIBIOS_BAD_REGISTER_NUMBER: return XEN_PCI_ERR_invalid_offset; case PCIBIOS_FUNC_NOT_SUPPORTED: return XEN_PCI_ERR_not_implemented; case PCIBIOS_SET_FAILED: return XEN_PCI_ERR_access_denied; } return err; } int xen_pcibk_config_read(struct pci_dev *dev, int offset, int size, u32 *ret_val) { int err = 0; struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); const struct config_field_entry *cfg_entry; const struct config_field *field; int req_start, req_end, field_start, field_end; /* if read fails for any reason, return 0 * (as if device didn't respond) */ u32 value = 0, tmp_val; if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x\n", pci_name(dev), size, offset); if (!valid_request(offset, size)) { err = XEN_PCI_ERR_invalid_offset; goto out; } /* Get the real value first, then modify as appropriate */ switch (size) { case 1: err = pci_read_config_byte(dev, offset, (u8 *) &value); break; case 2: err = pci_read_config_word(dev, offset, (u16 *) &value); break; case 4: err = pci_read_config_dword(dev, offset, &value); break; } list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { field = cfg_entry->field; req_start = offset; req_end = offset + size; field_start = OFFSET(cfg_entry); field_end = OFFSET(cfg_entry) + field->size; if ((req_start >= field_start && req_start < field_end) || (req_end > field_start && req_end <= field_end)) { err = conf_space_read(dev, cfg_entry, field_start, &tmp_val); if (err) goto out; value = merge_value(value, tmp_val, get_mask(field->size), field_start - req_start); } } out: if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: read %d bytes at 0x%x = %x\n", pci_name(dev), size, offset, value); *ret_val = value; return xen_pcibios_err_to_errno(err); } int xen_pcibk_config_write(struct pci_dev *dev, int offset, int size, u32 value) { int err = 0, handled = 0; struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); const struct config_field_entry *cfg_entry; const struct config_field *field; u32 tmp_val; int req_start, req_end, field_start, field_end; if (unlikely(verbose_request)) printk(KERN_DEBUG DRV_NAME ": %s: write request %d bytes at 0x%x = %x\n", pci_name(dev), size, offset, value); if (!valid_request(offset, size)) return XEN_PCI_ERR_invalid_offset; list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { field = cfg_entry->field; req_start = offset; req_end = offset + size; field_start = OFFSET(cfg_entry); field_end = OFFSET(cfg_entry) + field->size; if ((req_start >= field_start && req_start < field_end) || (req_end > field_start && req_end <= field_end)) { tmp_val = 0; err = xen_pcibk_config_read(dev, field_start, field->size, &tmp_val); if (err) break; tmp_val = merge_value(tmp_val, value, get_mask(size), req_start - field_start); err = conf_space_write(dev, cfg_entry, field_start, tmp_val); /* handled is set true here, but not every byte * may have been written! Properly detecting if * every byte is handled is unnecessary as the * flag is used to detect devices that need * special helpers to work correctly. */ handled = 1; } } if (!handled && !err) { /* By default, anything not specificially handled above is * read-only. The permissive flag changes this behavior so * that anything not specifically handled above is writable. * This means that some fields may still be read-only because * they have entries in the config_field list that intercept * the write and do nothing. */ if (dev_data->permissive || permissive) { switch (size) { case 1: err = pci_write_config_byte(dev, offset, (u8) value); break; case 2: err = pci_write_config_word(dev, offset, (u16) value); break; case 4: err = pci_write_config_dword(dev, offset, (u32) value); break; } } else if (!dev_data->warned_on_write) { dev_data->warned_on_write = 1; dev_warn(&dev->dev, "Driver tried to write to a " "read-only configuration space field at offset" " 0x%x, size %d. This may be harmless, but if " "you have problems with your device:\n" "1) see permissive attribute in sysfs\n" "2) report problems to the xen-devel " "mailing list along with details of your " "device obtained from lspci.\n", offset, size); } } return xen_pcibios_err_to_errno(err); } void xen_pcibk_config_free_dyn_fields(struct pci_dev *dev) { struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); struct config_field_entry *cfg_entry, *t; const struct config_field *field; dev_dbg(&dev->dev, "free-ing dynamically allocated virtual " "configuration space fields\n"); if (!dev_data) return; list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) { field = cfg_entry->field; if (field->clean) { field->clean((struct config_field *)field); kfree(cfg_entry->data); list_del(&cfg_entry->list); kfree(cfg_entry); } } } void xen_pcibk_config_reset_dev(struct pci_dev *dev) { struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); const struct config_field_entry *cfg_entry; const struct config_field *field; dev_dbg(&dev->dev, "resetting virtual configuration space\n"); if (!dev_data) return; list_for_each_entry(cfg_entry, &dev_data->config_fields, list) { field = cfg_entry->field; if (field->reset) field->reset(dev, OFFSET(cfg_entry), cfg_entry->data); } } void xen_pcibk_config_free_dev(struct pci_dev *dev) { struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); struct config_field_entry *cfg_entry, *t; const struct config_field *field; dev_dbg(&dev->dev, "free-ing virtual configuration space fields\n"); if (!dev_data) return; list_for_each_entry_safe(cfg_entry, t, &dev_data->config_fields, list) { list_del(&cfg_entry->list); field = cfg_entry->field; if (field->release) field->release(dev, OFFSET(cfg_entry), cfg_entry->data); kfree(cfg_entry); } } int xen_pcibk_config_add_field_offset(struct pci_dev *dev, const struct config_field *field, unsigned int base_offset) { int err = 0; struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); struct config_field_entry *cfg_entry; void *tmp; cfg_entry = kmalloc(sizeof(*cfg_entry), GFP_KERNEL); if (!cfg_entry) { err = -ENOMEM; goto out; } cfg_entry->data = NULL; cfg_entry->field = field; cfg_entry->base_offset = base_offset; /* silently ignore duplicate fields */ err = xen_pcibk_field_is_dup(dev, OFFSET(cfg_entry)); if (err) goto out; if (field->init) { tmp = field->init(dev, OFFSET(cfg_entry)); if (IS_ERR(tmp)) { err = PTR_ERR(tmp); goto out; } cfg_entry->data = tmp; } dev_dbg(&dev->dev, "added config field at offset 0x%02x\n", OFFSET(cfg_entry)); list_add_tail(&cfg_entry->list, &dev_data->config_fields); out: if (err) kfree(cfg_entry); return err; } /* This sets up the device's virtual configuration space to keep track of * certain registers (like the base address registers (BARs) so that we can * keep the client from manipulating them directly. */ int xen_pcibk_config_init_dev(struct pci_dev *dev) { int err = 0; struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(dev); dev_dbg(&dev->dev, "initializing virtual configuration space\n"); INIT_LIST_HEAD(&dev_data->config_fields); err = xen_pcibk_config_header_add_fields(dev); if (err) goto out; err = xen_pcibk_config_capability_add_fields(dev); if (err) goto out; err = xen_pcibk_config_quirks_init(dev); out: return err; } int xen_pcibk_config_init(void) { return xen_pcibk_config_capability_init(); }