spapr: initial implementation for H_TPM_COMM/spapr-tpm-proxy

This implements the H_TPM_COMM hypercall, which is used by an
Ultravisor to pass TPM commands directly to the host's TPM device, or
a TPM Resource Manager associated with the device.

This also introduces a new virtual device, spapr-tpm-proxy, which
is used to configure the host TPM path to be used to service
requests sent by H_TPM_COMM hcalls, for example:

  -device spapr-tpm-proxy,id=tpmp0,host-path=/dev/tpmrm0

By default, no spapr-tpm-proxy will be created, and hcalls will return
H_FUNCTION.

The full specification for this hypercall can be found in
docs/specs/ppc-spapr-uv-hcalls.txt

Since SVM-related hcalls like H_TPM_COMM use a reserved range of
0xEF00-0xEF80, we introduce a separate hcall table here to handle
them.

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com
Message-Id: <20190717205842.17827-3-mdroth@linux.vnet.ibm.com>
[dwg: Corrected #include for upstream change]
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 178 insertions, 0 deletions

diff --git a/hw/ppc/spapr_tpm_proxy.c b/hw/ppc/spapr_tpm_proxy.c
new file mode 100644
index 0000000..b835d25
--- /dev/null
+++ b/hw/ppc/spapr_tpm_proxy.c
@@ -0,0 +1,178 @@
+/*
+ * SPAPR TPM Proxy/Hypercall
+ *
+ * Copyright IBM Corp. 2019
+ *
+ * Authors:
+ *  Michael Roth      <mdroth@linux.vnet.ibm.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "sysemu/reset.h"
+#include "cpu.h"
+#include "hw/ppc/spapr.h"
+#include "hw/qdev-properties.h"
+#include "trace.h"
+
+#define TPM_SPAPR_BUFSIZE 4096
+
+enum {
+    TPM_COMM_OP_EXECUTE = 1,
+    TPM_COMM_OP_CLOSE_SESSION = 2,
+};
+
+static void spapr_tpm_proxy_reset(void *opaque)
+{
+    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(opaque);
+
+    if (tpm_proxy->host_fd != -1) {
+        close(tpm_proxy->host_fd);
+        tpm_proxy->host_fd = -1;
+    }
+}
+
+static ssize_t tpm_execute(SpaprTpmProxy *tpm_proxy, target_ulong *args)
+{
+    uint64_t data_in = ppc64_phys_to_real(args[1]);
+    target_ulong data_in_size = args[2];
+    uint64_t data_out = ppc64_phys_to_real(args[3]);
+    target_ulong data_out_size = args[4];
+    uint8_t buf_in[TPM_SPAPR_BUFSIZE];
+    uint8_t buf_out[TPM_SPAPR_BUFSIZE];
+    ssize_t ret;
+
+    trace_spapr_tpm_execute(data_in, data_in_size, data_out, data_out_size);
+
+    if (data_in_size > TPM_SPAPR_BUFSIZE) {
+        error_report("invalid TPM input buffer size: " TARGET_FMT_lu,
+                     data_in_size);
+        return H_P3;
+    }
+
+    if (data_out_size < TPM_SPAPR_BUFSIZE) {
+        error_report("invalid TPM output buffer size: " TARGET_FMT_lu,
+                     data_out_size);
+        return H_P5;
+    }
+
+    if (tpm_proxy->host_fd == -1) {
+        tpm_proxy->host_fd = open(tpm_proxy->host_path, O_RDWR);
+        if (tpm_proxy->host_fd == -1) {
+            error_report("failed to open TPM device %s: %d",
+                         tpm_proxy->host_path, errno);
+            return H_RESOURCE;
+        }
+    }
+
+    cpu_physical_memory_read(data_in, buf_in, data_in_size);
+
+    do {
+        ret = write(tpm_proxy->host_fd, buf_in, data_in_size);
+        if (ret > 0) {
+            data_in_size -= ret;
+        }
+    } while ((ret >= 0 && data_in_size > 0) || (ret == -1 && errno == EINTR));
+
+    if (ret == -1) {
+        error_report("failed to write to TPM device %s: %d",
+                     tpm_proxy->host_path, errno);
+        return H_RESOURCE;
+    }
+
+    do {
+        ret = read(tpm_proxy->host_fd, buf_out, data_out_size);
+    } while (ret == 0 || (ret == -1 && errno == EINTR));
+
+    if (ret == -1) {
+        error_report("failed to read from TPM device %s: %d",
+                     tpm_proxy->host_path, errno);
+        return H_RESOURCE;
+    }
+
+    cpu_physical_memory_write(data_out, buf_out, ret);
+    args[0] = ret;
+
+    return H_SUCCESS;
+}
+
+static target_ulong h_tpm_comm(PowerPCCPU *cpu,
+                               SpaprMachineState *spapr,
+                               target_ulong opcode,
+                               target_ulong *args)
+{
+    target_ulong op = args[0];
+    SpaprTpmProxy *tpm_proxy = spapr->tpm_proxy;
+
+    if (!tpm_proxy) {
+        error_report("TPM proxy not available");
+        return H_FUNCTION;
+    }
+
+    trace_spapr_h_tpm_comm(tpm_proxy->host_path ?: "null", op);
+
+    switch (op) {
+    case TPM_COMM_OP_EXECUTE:
+        return tpm_execute(tpm_proxy, args);
+    case TPM_COMM_OP_CLOSE_SESSION:
+        spapr_tpm_proxy_reset(tpm_proxy);
+        return H_SUCCESS;
+    default:
+        return H_PARAMETER;
+    }
+}
+
+static void spapr_tpm_proxy_realize(DeviceState *d, Error **errp)
+{
+    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
+
+    if (tpm_proxy->host_path == NULL) {
+        error_setg(errp, "must specify 'host-path' option for device");
+        return;
+    }
+
+    tpm_proxy->host_fd = -1;
+    qemu_register_reset(spapr_tpm_proxy_reset, tpm_proxy);
+}
+
+static void spapr_tpm_proxy_unrealize(DeviceState *d, Error **errp)
+{
+    SpaprTpmProxy *tpm_proxy = SPAPR_TPM_PROXY(d);
+
+    qemu_unregister_reset(spapr_tpm_proxy_reset, tpm_proxy);
+}
+
+static Property spapr_tpm_proxy_properties[] = {
+    DEFINE_PROP_STRING("host-path", SpaprTpmProxy, host_path),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void spapr_tpm_proxy_class_init(ObjectClass *k, void *data)
+{
+    DeviceClass *dk = DEVICE_CLASS(k);
+
+    dk->realize = spapr_tpm_proxy_realize;
+    dk->unrealize = spapr_tpm_proxy_unrealize;
+    dk->user_creatable = true;
+    dk->props = spapr_tpm_proxy_properties;
+}
+
+static const TypeInfo spapr_tpm_proxy_info = {
+    .name          = TYPE_SPAPR_TPM_PROXY,
+    .parent        = TYPE_DEVICE,
+    .instance_size = sizeof(SpaprTpmProxy),
+    .class_init    = spapr_tpm_proxy_class_init,
+};
+
+static void spapr_tpm_proxy_register_types(void)
+{
+    type_register_static(&spapr_tpm_proxy_info);
+    spapr_register_hypercall(SVM_H_TPM_COMM, h_tpm_comm);
+}
+
+type_init(spapr_tpm_proxy_register_types)