tpm: Probe for connected TPM 1.2 or TPM 2

In the TPM passthrough backend driver, modify the probing code so
that we can check whether a TPM 1.2 or TPM 2 is being used
and adapt the behavior of the TPM TIS accordingly.

Move the code that tested for a TPM 1.2 into tpm_utils.c
and extend it with test for probing for TPM 2. Have the
function return the version of TPM found.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 6 insertions, 53 deletions

diff --git a/hw/tpm/tpm_passthrough.c b/hw/tpm/tpm_passthrough.c
index f1361d2..8d8523a 100644
--- a/hw/tpm/tpm_passthrough.c
+++ b/hw/tpm/tpm_passthrough.c
@@ -33,6 +33,7 @@
 #include "hw/i386/pc.h"
 #include "sysemu/tpm_backend_int.h"
 #include "tpm_tis.h"
+#include "tpm_util.h"
 
 #define DEBUG_TPM 0
 
@@ -69,6 +70,8 @@ struct TPMPassthruState {
     bool tpm_op_canceled;
     int cancel_fd;
     bool had_startup_error;
+
+    TPMVersion tpm_version;
 };
 
 typedef struct TPMPassthruState TPMPassthruState;
@@ -333,59 +336,9 @@ static const char *tpm_passthrough_create_desc(void)
 
 static TPMVersion tpm_passthrough_get_tpm_version(TPMBackend *tb)
 {
-    return TPM_VERSION_1_2;
-}
-
-/*
- * A basic test of a TPM device. We expect a well formatted response header
- * (error response is fine) within one second.
- */
-static int tpm_passthrough_test_tpmdev(int fd)
-{
-    struct tpm_req_hdr req = {
-        .tag = cpu_to_be16(TPM_TAG_RQU_COMMAND),
-        .len = cpu_to_be32(sizeof(req)),
-        .ordinal = cpu_to_be32(TPM_ORD_GetTicks),
-    };
-    struct tpm_resp_hdr *resp;
-    fd_set readfds;
-    int n;
-    struct timeval tv = {
-        .tv_sec = 1,
-        .tv_usec = 0,
-    };
-    unsigned char buf[1024];
-
-    n = write(fd, &req, sizeof(req));
-    if (n < 0) {
-        return errno;
-    }
-    if (n != sizeof(req)) {
-        return EFAULT;
-    }
-
-    FD_ZERO(&readfds);
-    FD_SET(fd, &readfds);
-
-    /* wait for a second */
-    n = select(fd + 1, &readfds, NULL, NULL, &tv);
-    if (n != 1) {
-        return errno;
-    }
-
-    n = read(fd, &buf, sizeof(buf));
-    if (n < sizeof(struct tpm_resp_hdr)) {
-        return EFAULT;
-    }
-
-    resp = (struct tpm_resp_hdr *)buf;
-    /* check the header */
-    if (be16_to_cpu(resp->tag) != TPM_TAG_RSP_COMMAND ||
-        be32_to_cpu(resp->len) != n) {
-        return EBADMSG;
-    }
+    TPMPassthruState *tpm_pt = TPM_PASSTHROUGH(tb);
 
-    return 0;
+    return tpm_pt->tpm_version;
 }
 
 /*
@@ -455,7 +408,7 @@ static int tpm_passthrough_handle_device_opts(QemuOpts *opts, TPMBackend *tb)
         goto err_free_parameters;
     }
 
-    if (tpm_passthrough_test_tpmdev(tpm_pt->tpm_fd)) {
+    if (tpm_util_test_tpmdev(tpm_pt->tpm_fd, &tpm_pt->tpm_version)) {
         error_report("'%s' is not a TPM device.",
                      tpm_pt->tpm_dev);
         goto err_close_tpmdev;