hw/pci-host/xen_igd_pt.c

   1 /*
   2  * QEMU Intel IGD Passthrough Host Bridge Emulation
   3  *
   4  * Copyright (c) 2006 Fabrice Bellard
   5  *
   6  * SPDX-License-Identifier: MIT
   7  *
   8  * Permission is hereby granted, free of charge, to any person obtaining a copy
   9  * of this software and associated documentation files (the "Software"), to deal
  10  * in the Software without restriction, including without limitation the rights
  11  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  12  * copies of the Software, and to permit persons to whom the Software is
  13  * furnished to do so, subject to the following conditions:
  14  *
  15  * The above copyright notice and this permission notice shall be included in
  16  * all copies or substantial portions of the Software.
  17  *
  18  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  19  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  20  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
  21  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  22  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  23  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  24  * THE SOFTWARE.
  25  */
  26
  27 #include "qemu/osdep.h"
  28 #include "hw/pci/pci.h"
  29 #include "hw/pci/pci_host.h"
  30 #include "hw/pci-host/i440fx.h"
  31 #include "qapi/error.h"
  32
  33 typedef struct {
  34     uint8_t offset;
  35     uint8_t len;
  36 } IGDHostInfo;
  37
  38 /* Here we just expose minimal host bridge offset subset. */
  39 static const IGDHostInfo igd_host_bridge_infos[] = {
  40     {PCI_REVISION_ID,         2},
  41     {PCI_SUBSYSTEM_VENDOR_ID, 2},
  42     {PCI_SUBSYSTEM_ID,        2},
  43     {0x50,                    2}, /* SNB: processor graphics control register */
  44     {0x52,                    2}, /* processor graphics control register */
  45     {0xa4,                    4}, /* SNB: graphics base of stolen memory */
  46     {0xa8,                    4}, /* SNB: base of GTT stolen memory */
  47 };
  48
  49 static void host_pci_config_read(int pos, int len, uint32_t *val, Error **errp)
  50 {
  51     int rc, config_fd;
  52     /* Access real host bridge. */
  53     char *path = g_strdup_printf("/sys/bus/pci/devices/%04x:%02x:%02x.%d/%s",
  54                                  0, 0, 0, 0, "config");
  55
  56     config_fd = open(path, O_RDWR);
  57     if (config_fd < 0) {
  58         error_setg_errno(errp, errno, "Failed to open: %s", path);
  59         goto out;
  60     }
  61
  62     if (lseek(config_fd, pos, SEEK_SET) != pos) {
  63         error_setg_errno(errp, errno, "Failed to seek: %s", path);
  64         goto out_close_fd;
  65     }
  66
  67     do {
  68         rc = read(config_fd, (uint8_t *)val, len);
  69     } while (rc < 0 && (errno == EINTR || errno == EAGAIN));
  70     if (rc != len) {
  71         error_setg_errno(errp, errno, "Failed to read: %s", path);
  72     }
  73
  74  out_close_fd:
  75     close(config_fd);
  76  out:
  77     g_free(path);
  78 }
  79
  80 static void igd_pt_i440fx_realize(PCIDevice *pci_dev, Error **errp)
  81 {
  82     ERRP_GUARD();
  83     uint32_t val = 0;
  84     size_t i;
  85     int pos, len;
  86
  87     for (i = 0; i < ARRAY_SIZE(igd_host_bridge_infos); i++) {
  88         pos = igd_host_bridge_infos[i].offset;
  89         len = igd_host_bridge_infos[i].len;
  90         host_pci_config_read(pos, len, &val, errp);
  91         if (*errp) {
  92             return;
  93         }
  94         pci_default_write_config(pci_dev, pos, val, len);
  95     }
  96 }
  97
  98 static void igd_passthrough_i440fx_class_init(ObjectClass *klass, void *data)
  99 {
 100     DeviceClass *dc = DEVICE_CLASS(klass);
 101     PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
 102
 103     k->realize = igd_pt_i440fx_realize;
 104     dc->desc = "IGD Passthrough Host bridge";
 105 }
 106
 107 static const TypeInfo igd_passthrough_i440fx_info = {
 108     .name          = TYPE_IGD_PASSTHROUGH_I440FX_PCI_DEVICE,
 109     .parent        = TYPE_I440FX_PCI_DEVICE,
 110     .instance_size = sizeof(PCII440FXState),
 111     .class_init    = igd_passthrough_i440fx_class_init,
 112 };
 113
 114 static void igd_pt_i440fx_register_types(void)
 115 {
 116     type_register_static(&igd_passthrough_i440fx_info);
 117 }
 118
 119 type_init(igd_pt_i440fx_register_types)