This patch adds support for cancelling an executing TPM command.
In Linux for example a user can cancel a command through the TPM's
sysfs 'cancel' entry using
echo "1" > /sysfs/class/misc/tpm0/device/cancel
This patch propagates the cancellation of a command inside a VM
to the host TPM's sysfs entry.
It also uses the possibility to cancel the command before QEMU VM
shutdown or reboot, which helps in preventing QEMU from hanging while
waiting for the completion of the command.
To relieve higher layers or users from having to determine the TPM's
cancel sysfs entry, the driver searches for the entry in well known
locations.
Signed-off-by: Stefan Berger <address@hidden>
---
qemu-options.hx | 9 ++-
tpm/tpm_passthrough.c | 165 ++++++++++++++++++++++++++++++++++++++++++++++----
vl.c | 5 ++
3 files changed, 164 insertions(+), 15 deletions(-)
diff --git a/qemu-options.hx b/qemu-options.hx
index e7e868e..c533c29 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -2193,7 +2193,7 @@ DEFHEADING()
DEFHEADING(TPM device options:)
DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \
- "-tpmdev passthrough,id=id[,path=path]\n"
+ "-tpmdev passthrough,id=id[,path=path][,cancel_path=path]\n"
" use path to provide path to a character device; default is
/dev/tpm0\n",
QEMU_ARCH_ALL)
STEXI
@@ -2216,7 +2216,7 @@ Use ? to print all available TPM backend types.
qemu -tpmdev ?
@end example
address@hidden -tpmdev passthrough, address@hidden, address@hidden
address@hidden -tpmdev passthrough, address@hidden, address@hidden,
address@hidden
(Linux-host only) Enable access to the host's TPM using the passthrough
driver.
@@ -2225,6 +2225,11 @@ driver.
a Linux host this would be @code{/dev/tpm0}.
@option{path} is optional and by default @code{/dev/tpm0} is used.
address@hidden specifies the path to the host TPM device's sysfs
+entry allowing for cancellation of an ongoing TPM command.
address@hidden is optional and by default QEMU will search for the
+sysfs entry to use.
+
Some notes about using the host's TPM with the passthrough driver:
The TPM device accessed by the passthrough driver must not be
diff --git a/tpm/tpm_passthrough.c b/tpm/tpm_passthrough.c
index 7d5de8e..baca21f 100644
--- a/tpm/tpm_passthrough.c
+++ b/tpm/tpm_passthrough.c
@@ -22,6 +22,8 @@
* License along with this library; if not, see <http://www.gnu.org/licenses/>
*/
+#include <dirent.h>
+
#include "qemu-common.h"
#include "qapi/error.h"
#include "qemu/sockets.h"
@@ -57,11 +59,18 @@ struct TPMPassthruState {
char *tpm_dev;
int tpm_fd;
+ bool tpm_executing;
+ bool tpm_op_canceled;
+ int cancel_fd;
bool had_startup_error;
};
#define TPM_PASSTHROUGH_DEFAULT_DEVICE "/dev/tpm0"
+/* functions */
+
+static void tpm_passthrough_cancel_cmd(TPMBackend *tb);
+
static int tpm_passthrough_unix_write(int fd, const uint8_t *buf, uint32_t
len)
{
return send_all(fd, buf, len);
@@ -79,25 +88,36 @@ static uint32_t tpm_passthrough_get_size_from_buffer(const
uint8_t *buf)
return be32_to_cpu(resp->len);
}
-static int tpm_passthrough_unix_tx_bufs(int tpm_fd,
+static int tpm_passthrough_unix_tx_bufs(TPMPassthruState *tpm_pt,
const uint8_t *in, uint32_t in_len,
uint8_t *out, uint32_t out_len)
{
int ret;
- ret = tpm_passthrough_unix_write(tpm_fd, in, in_len);
+ tpm_pt->tpm_op_canceled = false;
+ tpm_pt->tpm_executing = true;
+
+ ret = tpm_passthrough_unix_write(tpm_pt->tpm_fd, in, in_len);
if (ret != in_len) {
- error_report("tpm_passthrough: error while transmitting data "
- "to TPM: %s (%i)\n",
- strerror(errno), errno);
+ if (!tpm_pt->tpm_op_canceled ||
+ (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
+ error_report("tpm_passthrough: error while transmitting data "
+ "to TPM: %s (%i)\n",
+ strerror(errno), errno);
+ }
goto err_exit;
}
- ret = tpm_passthrough_unix_read(tpm_fd, out, out_len);
+ tpm_pt->tpm_executing = false;
+
+ ret = tpm_passthrough_unix_read(tpm_pt->tpm_fd, out, out_len);
if (ret < 0) {
- error_report("tpm_passthrough: error while reading data from "
- "TPM: %s (%i)\n",
- strerror(errno), errno);
+ if (!tpm_pt->tpm_op_canceled ||
+ (tpm_pt->tpm_op_canceled && errno != ECANCELED)) {
+ error_report("tpm_passthrough: error while reading data from "
+ "TPM: %s (%i)\n",
+ strerror(errno), errno);
+ }
} else if (ret < sizeof(struct tpm_resp_hdr) ||
tpm_passthrough_get_size_from_buffer(out) != ret) {
ret = -1;
@@ -110,13 +130,15 @@ err_exit:
tpm_write_fatal_error_response(out, out_len);
}
+ tpm_pt->tpm_executing = false;