backends/tpm: Avoid using g_alloca()

tpm_emulator_ctrlcmd() is not in hot path.
Use the heap instead of the stack, removing
the g_alloca() call.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.ibm.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20250605193540.59874-3-philmd@linaro.org>

diff --git a/backends/tpm/tpm_emulator.c b/backends/tpm/tpm_emulator.c
index 43d350e895dd8ad92d03d392d4aad6ebac8018d2..4a234ab2c0b19b2604bf0dd8cb5f4540c72a9438 100644 (file)
--- a/backends/tpm/tpm_emulator.c
+++ b/backends/tpm/tpm_emulator.c
@@ -129,11 +129,11 @@ static int tpm_emulator_ctrlcmd(TPMEmulator *tpm, unsigned long cmd, void *msg,
     CharBackend *dev = &tpm->ctrl_chr;
     uint32_t cmd_no = cpu_to_be32(cmd);
     ssize_t n = sizeof(uint32_t) + msg_len_in;
-    uint8_t *buf = NULL;
     ptm_res res;
 
     WITH_QEMU_LOCK_GUARD(&tpm->mutex) {
-        buf = g_alloca(n);
+        g_autofree uint8_t *buf = g_malloc(n);
+
         memcpy(buf, &cmd_no, sizeof(cmd_no));
         memcpy(buf + sizeof(cmd_no), msg, msg_len_in);