qemu/hw/ppc/spapr_tpm_proxy.c
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   1/*
   2 * SPAPR TPM Proxy/Hypercall
   3 *
   4 * Copyright IBM Corp. 2019
   5 *
   6 * Authors:
   7 *  Michael Roth      <mdroth@linux.vnet.ibm.com>
   8 *
   9 * This work is licensed under the terms of the GNU GPL, version 2 or later.
  10 * See the COPYING file in the top-level directory.
  11 */
  12
  13#include "qemu/osdep.h"
  14#include "qemu-common.h"
  15#include "qapi/error.h"
  16#include "qemu/error-report.h"
  17#include "sysemu/reset.h"
  18#include "hw/ppc/spapr.h"
  19#include "hw/qdev-properties.h"
  20#include "trace.h"
  21
  22#define TPM_SPAPR_BUFSIZE 4096
  23
  24enum {
  25    TPM_COMM_OP_EXECUTE = 1,
  26    TPM_COMM_OP_CLOSE_SESSION = 2,
  27};
  28
  29static void spapr_tpm_proxy_reset(void *opaque)
  30{
  31    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(opaque);
  32
  33    if (tpm_proxy->host_fd != -1) {
  34        close(tpm_proxy->host_fd);
  35        tpm_proxy->host_fd = -1;
  36    }
  37}
  38
  39static ssize_t tpm_execute(SpaprTpmProxy *tpm_proxy, target_ulong *args)
  40{
  41    uint64_t data_in = ppc64_phys_to_real(args[1]);
  42    target_ulong data_in_size = args[2];
  43    uint64_t data_out = ppc64_phys_to_real(args[3]);
  44    target_ulong data_out_size = args[4];
  45    uint8_t buf_in[TPM_SPAPR_BUFSIZE];
  46    uint8_t buf_out[TPM_SPAPR_BUFSIZE];
  47    ssize_t ret;
  48
  49    trace_spapr_tpm_execute(data_in, data_in_size, data_out, data_out_size);
  50
  51    if (data_in_size > TPM_SPAPR_BUFSIZE) {
  52        error_report("invalid TPM input buffer size: " TARGET_FMT_lu,
  53                     data_in_size);
  54        return H_P3;
  55    }
  56
  57    if (data_out_size < TPM_SPAPR_BUFSIZE) {
  58        error_report("invalid TPM output buffer size: " TARGET_FMT_lu,
  59                     data_out_size);
  60        return H_P5;
  61    }
  62
  63    if (tpm_proxy->host_fd == -1) {
  64        tpm_proxy->host_fd = open(tpm_proxy->host_path, O_RDWR);
  65        if (tpm_proxy->host_fd == -1) {
  66            error_report("failed to open TPM device %s: %d",
  67                         tpm_proxy->host_path, errno);
  68            return H_RESOURCE;
  69        }
  70    }
  71
  72    cpu_physical_memory_read(data_in, buf_in, data_in_size);
  73
  74    do {
  75        ret = write(tpm_proxy->host_fd, buf_in, data_in_size);
  76        if (ret > 0) {
  77            data_in_size -= ret;
  78        }
  79    } while ((ret >= 0 && data_in_size > 0) || (ret == -1 && errno == EINTR));
  80
  81    if (ret == -1) {
  82        error_report("failed to write to TPM device %s: %d",
  83                     tpm_proxy->host_path, errno);
  84        return H_RESOURCE;
  85    }
  86
  87    do {
  88        ret = read(tpm_proxy->host_fd, buf_out, data_out_size);
  89    } while (ret == 0 || (ret == -1 && errno == EINTR));
  90
  91    if (ret == -1) {
  92        error_report("failed to read from TPM device %s: %d",
  93                     tpm_proxy->host_path, errno);
  94        return H_RESOURCE;
  95    }
  96
  97    cpu_physical_memory_write(data_out, buf_out, ret);
  98    args[0] = ret;
  99
 100    return H_SUCCESS;
 101}
 102
 103static target_ulong h_tpm_comm(PowerPCCPU *cpu,
 104                               SpaprMachineState *spapr,
 105                               target_ulong opcode,
 106                               target_ulong *args)
 107{
 108    target_ulong op = args[0];
 109    SpaprTpmProxy *tpm_proxy = spapr->tpm_proxy;
 110
 111    if (!tpm_proxy) {
 112        error_report("TPM proxy not available");
 113        return H_FUNCTION;
 114    }
 115
 116    trace_spapr_h_tpm_comm(tpm_proxy->host_path, op);
 117
 118    switch (op) {
 119    case TPM_COMM_OP_EXECUTE:
 120        return tpm_execute(tpm_proxy, args);
 121    case TPM_COMM_OP_CLOSE_SESSION:
 122        spapr_tpm_proxy_reset(tpm_proxy);
 123        return H_SUCCESS;
 124    default:
 125        return H_PARAMETER;
 126    }
 127}
 128
 129static void spapr_tpm_proxy_realize(DeviceState *d, Error **errp)
 130{
 131    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
 132
 133    if (tpm_proxy->host_path == NULL) {
 134        error_setg(errp, "must specify 'host-path' option for device");
 135        return;
 136    }
 137
 138    tpm_proxy->host_fd = -1;
 139    qemu_register_reset(spapr_tpm_proxy_reset, tpm_proxy);
 140}
 141
 142static void spapr_tpm_proxy_unrealize(DeviceState *d)
 143{
 144    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
 145
 146    qemu_unregister_reset(spapr_tpm_proxy_reset, tpm_proxy);
 147}
 148
 149static Property spapr_tpm_proxy_properties[] = {
 150    DEFINE_PROP_STRING("host-path", SpaprTpmProxy, host_path),
 151    DEFINE_PROP_END_OF_LIST(),
 152};
 153
 154static void spapr_tpm_proxy_class_init(ObjectClass *k, void *data)
 155{
 156    DeviceClass *dk = DEVICE_CLASS(k);
 157
 158    dk->realize = spapr_tpm_proxy_realize;
 159    dk->unrealize = spapr_tpm_proxy_unrealize;
 160    dk->user_creatable = true;
 161    device_class_set_props(dk, spapr_tpm_proxy_properties);
 162}
 163
 164static const TypeInfo spapr_tpm_proxy_info = {
 165    .name          = TYPE_SPAPR_TPM_PROXY,
 166    .parent        = TYPE_DEVICE,
 167    .instance_size = sizeof(SpaprTpmProxy),
 168    .class_init    = spapr_tpm_proxy_class_init,
 169};
 170
 171static void spapr_tpm_proxy_register_types(void)
 172{
 173    type_register_static(&spapr_tpm_proxy_info);
 174    spapr_register_hypercall(SVM_H_TPM_COMM, h_tpm_comm);
 175}
 176
 177type_init(spapr_tpm_proxy_register_types)
 178