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 "cpu.h"
  19#include "hw/ppc/spapr.h"
  20#include "hw/qdev-properties.h"
  21#include "trace.h"
  22
  23#define TPM_SPAPR_BUFSIZE 4096
  24
  25enum {
  26    TPM_COMM_OP_EXECUTE = 1,
  27    TPM_COMM_OP_CLOSE_SESSION = 2,
  28};
  29
  30static void spapr_tpm_proxy_reset(void *opaque)
  31{
  32    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(opaque);
  33
  34    if (tpm_proxy->host_fd != -1) {
  35        close(tpm_proxy->host_fd);
  36        tpm_proxy->host_fd = -1;
  37    }
  38}
  39
  40static ssize_t tpm_execute(SpaprTpmProxy *tpm_proxy, target_ulong *args)
  41{
  42    uint64_t data_in = ppc64_phys_to_real(args[1]);
  43    target_ulong data_in_size = args[2];
  44    uint64_t data_out = ppc64_phys_to_real(args[3]);
  45    target_ulong data_out_size = args[4];
  46    uint8_t buf_in[TPM_SPAPR_BUFSIZE];
  47    uint8_t buf_out[TPM_SPAPR_BUFSIZE];
  48    ssize_t ret;
  49
  50    trace_spapr_tpm_execute(data_in, data_in_size, data_out, data_out_size);
  51
  52    if (data_in_size > TPM_SPAPR_BUFSIZE) {
  53        error_report("invalid TPM input buffer size: " TARGET_FMT_lu,
  54                     data_in_size);
  55        return H_P3;
  56    }
  57
  58    if (data_out_size < TPM_SPAPR_BUFSIZE) {
  59        error_report("invalid TPM output buffer size: " TARGET_FMT_lu,
  60                     data_out_size);
  61        return H_P5;
  62    }
  63
  64    if (tpm_proxy->host_fd == -1) {
  65        tpm_proxy->host_fd = open(tpm_proxy->host_path, O_RDWR);
  66        if (tpm_proxy->host_fd == -1) {
  67            error_report("failed to open TPM device %s: %d",
  68                         tpm_proxy->host_path, errno);
  69            return H_RESOURCE;
  70        }
  71    }
  72
  73    cpu_physical_memory_read(data_in, buf_in, data_in_size);
  74
  75    do {
  76        ret = write(tpm_proxy->host_fd, buf_in, data_in_size);
  77        if (ret > 0) {
  78            data_in_size -= ret;
  79        }
  80    } while ((ret >= 0 && data_in_size > 0) || (ret == -1 && errno == EINTR));
  81
  82    if (ret == -1) {
  83        error_report("failed to write to TPM device %s: %d",
  84                     tpm_proxy->host_path, errno);
  85        return H_RESOURCE;
  86    }
  87
  88    do {
  89        ret = read(tpm_proxy->host_fd, buf_out, data_out_size);
  90    } while (ret == 0 || (ret == -1 && errno == EINTR));
  91
  92    if (ret == -1) {
  93        error_report("failed to read from TPM device %s: %d",
  94                     tpm_proxy->host_path, errno);
  95        return H_RESOURCE;
  96    }
  97
  98    cpu_physical_memory_write(data_out, buf_out, ret);
  99    args[0] = ret;
 100
 101    return H_SUCCESS;
 102}
 103
 104static target_ulong h_tpm_comm(PowerPCCPU *cpu,
 105                               SpaprMachineState *spapr,
 106                               target_ulong opcode,
 107                               target_ulong *args)
 108{
 109    target_ulong op = args[0];
 110    SpaprTpmProxy *tpm_proxy = spapr->tpm_proxy;
 111
 112    if (!tpm_proxy) {
 113        error_report("TPM proxy not available");
 114        return H_FUNCTION;
 115    }
 116
 117    trace_spapr_h_tpm_comm(tpm_proxy->host_path, op);
 118
 119    switch (op) {
 120    case TPM_COMM_OP_EXECUTE:
 121        return tpm_execute(tpm_proxy, args);
 122    case TPM_COMM_OP_CLOSE_SESSION:
 123        spapr_tpm_proxy_reset(tpm_proxy);
 124        return H_SUCCESS;
 125    default:
 126        return H_PARAMETER;
 127    }
 128}
 129
 130static void spapr_tpm_proxy_realize(DeviceState *d, Error **errp)
 131{
 132    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
 133
 134    if (tpm_proxy->host_path == NULL) {
 135        error_setg(errp, "must specify 'host-path' option for device");
 136        return;
 137    }
 138
 139    tpm_proxy->host_fd = -1;
 140    qemu_register_reset(spapr_tpm_proxy_reset, tpm_proxy);
 141}
 142
 143static void spapr_tpm_proxy_unrealize(DeviceState *d, Error **errp)
 144{
 145    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
 146
 147    qemu_unregister_reset(spapr_tpm_proxy_reset, tpm_proxy);
 148}
 149
 150static Property spapr_tpm_proxy_properties[] = {
 151    DEFINE_PROP_STRING("host-path", SpaprTpmProxy, host_path),
 152    DEFINE_PROP_END_OF_LIST(),
 153};
 154
 155static void spapr_tpm_proxy_class_init(ObjectClass *k, void *data)
 156{
 157    DeviceClass *dk = DEVICE_CLASS(k);
 158
 159    dk->realize = spapr_tpm_proxy_realize;
 160    dk->unrealize = spapr_tpm_proxy_unrealize;
 161    dk->user_creatable = true;
 162    dk->props = spapr_tpm_proxy_properties;
 163}
 164
 165static const TypeInfo spapr_tpm_proxy_info = {
 166    .name          = TYPE_SPAPR_TPM_PROXY,
 167    .parent        = TYPE_DEVICE,
 168    .instance_size = sizeof(SpaprTpmProxy),
 169    .class_init    = spapr_tpm_proxy_class_init,
 170};
 171
 172static void spapr_tpm_proxy_register_types(void)
 173{
 174    type_register_static(&spapr_tpm_proxy_info);
 175    spapr_register_hypercall(SVM_H_TPM_COMM, h_tpm_comm);
 176}
 177
 178type_init(spapr_tpm_proxy_register_types)
 179