Enable the passing of a file descriptor via fd=<..> to access the host's
TPM device using the TPM passthrough driver.
Signed-off-by: Stefan Berger<address@hidden>
---
v13:
- Only accepting a character device's file descriptor
v12:
- added documentation part
---
hw/tpm_passthrough.c | 73 +++++++++++++++++++++++++++++++++++++-------------
qemu-config.c | 5 +++
qemu-options.hx | 6 +++-
3 files changed, 64 insertions(+), 20 deletions(-)
diff --git a/hw/tpm_passthrough.c b/hw/tpm_passthrough.c
index f9cfe3d..57bb77a 100644
--- a/hw/tpm_passthrough.c
+++ b/hw/tpm_passthrough.c
@@ -361,33 +361,68 @@ static int tpm_passthrough_handle_device_opts(QemuOpts
*opts, TPMBackend *tb)
const char *value;
char buf[64];
int n;
+ struct stat statbuf;
- value = qemu_opt_get(opts, "path");
- if (!value) {
- value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
- }
+ value = qemu_opt_get(opts, "fd");
+ if (value) {
+ if (qemu_opt_get(opts, "path")) {
+ error_report("fd= is invalid with path=");
+ return -1;
+ }
+
+ tb->s.tpm_pt->tpm_fd = qemu_parse_fd(value);
+ if (tb->s.tpm_pt->tpm_fd< 0) {
+ error_report("Illegal file descriptor for TPM device.\n");
+ return -1;
+ }
- n = snprintf(tb->s.tpm_pt->tpm_dev, sizeof(tb->s.tpm_pt->tpm_dev),
- "%s", value);
+ snprintf(buf, sizeof(buf), "fd=%d", tb->s.tpm_pt->tpm_fd);
- if (n>= sizeof(tb->s.tpm_pt->tpm_dev)) {
- error_report("TPM device path is too long.\n");
- goto err_exit;
- }
+ tb->parameters = g_strdup(buf);
- snprintf(buf, sizeof(buf), "path=%s", tb->s.tpm_pt->tpm_dev);
+ if (tb->parameters == NULL) {
+ goto err_close_tpmdev;
+ }
+ } else {
+ value = qemu_opt_get(opts, "path");
+ if (!value) {
+ value = TPM_PASSTHROUGH_DEFAULT_DEVICE;
+ }
+
+ n = snprintf(tb->s.tpm_pt->tpm_dev, sizeof(tb->s.tpm_pt->tpm_dev),
+ "%s", value);
+
+ if (n>= sizeof(tb->s.tpm_pt->tpm_dev)) {
+ error_report("TPM device path is too long.\n");
+ goto err_exit;
+ }
- tb->parameters = g_strdup(buf);
+ snprintf(buf, sizeof(buf), "path=%s", tb->s.tpm_pt->tpm_dev);
- if (tb->parameters == NULL) {
- return 1;
+ tb->parameters = g_strdup(buf);
+
+ if (tb->parameters == NULL) {
+ return 1;
+ }
+
+ tb->s.tpm_pt->tpm_fd = open(tb->s.tpm_pt->tpm_dev, O_RDWR);
+ if (tb->s.tpm_pt->tpm_fd< 0) {
+ error_report("Cannot access TPM device using '%s'.\n",
+ tb->s.tpm_pt->tpm_dev);
+ goto err_exit;
+ }
}
- tb->s.tpm_pt->tpm_fd = open(tb->s.tpm_pt->tpm_dev, O_RDWR);
- if (tb->s.tpm_pt->tpm_fd< 0) {
- error_report("Cannot access TPM device using '%s'.\n",
- tb->s.tpm_pt->tpm_dev);
- goto err_exit;
+ if (fstat(tb->s.tpm_pt->tpm_fd,&statbuf) != 0) {
+ error_report("Cannot determine file descriptor type for TPM "
+ "device: %s", strerror(errno));
+ goto err_close_tpmdev;
+ }
+
+ /* only allow character devices for now */
+ if (!S_ISCHR(statbuf.st_mode)) {
+ error_report("TPM file descriptor is not a character device");
+ goto err_close_tpmdev;
}