tpm: Virtio tpm device

This CL adds a "tpm" Cargo cfg to crosvm which enables a TPM device
backed by libtpm2 simulator.

Tested by running the following inside cros_sdk:

    LIBRARY_PATH=~/src/minijail LD_LIBRARY_PATH=~/src/minijail \
        cargo run --release \
        --features tpm \
        -- \
        run \
        -r rootfs.ext4 \
        --seccomp-policy-dir seccomp/x86_64/ \
        -p init=/bin/bash \
        -p panic=-1 \
        --disable-sandbox \
        vmlinux.bin

with a Linux image built from CL:1387655.

The TPM self test completes successfully with the following output:

    https://paste.googleplex.com/5996075978588160?raw

Justin's TPM playground runs with the following trace output.

    https://paste.googleplex.com/4909751007707136?raw

Design doc: go/vtpm-for-glinux

TEST=ran TPM playground program inside crosvm
TEST=local kokoro
BUG=chromium:911799

Change-Id: I2feb24a3e38cba91f62c6d2cd1f378de4dd03ecf
Reviewed-on: https://chromium-review.googlesource.com/1387624
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Dylan Reid <dgreid@chromium.org>

2 files changed, 1 insertions, 5 deletions

diff --git a/tpm2/Cargo.toml b/tpm2/Cargo.toml
index 80a43bc..56ee5fb 100644
--- a/tpm2/Cargo.toml
+++ b/tpm2/Cargo.toml
@@ -6,5 +6,3 @@ edition = "2018"
 
 [dependencies]
 tpm2-sys = { path = "../tpm2-sys" }
-
-[workspace]
diff --git a/tpm2/src/lib.rs b/tpm2/src/lib.rs
index 53022c6..4de849c 100644
--- a/tpm2/src/lib.rs
+++ b/tpm2/src/lib.rs
@@ -165,9 +165,7 @@ fn tpm_manufacture(first_time: bool) {
     // Unsafe only because this is over FFI and we need to know that the
     // signature declared by tpm2-sys is ABI-compatible with the symbol provided
     // by libtpm2. There are no other invariants to uphold.
-    let ret: c_int = unsafe {
-        tpm2_sys::TPM_Manufacture(first_time as c_int)
-    };
+    let ret: c_int = unsafe { tpm2_sys::TPM_Manufacture(first_time as c_int) };
 
     // We expect that the TPM must not already have been manufactured. The
     // SIMULATOR_EXISTS atomic flag guards calls to this function such that only