diff --git a/usr.sbin/bhyve/tpm_ppi_qemu.c b/usr.sbin/bhyve/tpm_ppi_qemu.c
index 8bea45ea320..11a30607710 100644
--- a/usr.sbin/bhyve/tpm_ppi_qemu.c
+++ b/usr.sbin/bhyve/tpm_ppi_qemu.c
@@ -26,7 +26,7 @@
 #include "tpm_ppi.h"
 
 #define TPM_PPI_ADDRESS 0xFED45000
-#define TPM_PPI_SIZE 0x1000
+#define TPM_PPI_SIZE 0x400
 
 #define TPM_PPI_FWCFG_FILE "etc/tpm/config"
 
@@ -101,7 +101,7 @@ tpm_ppi_init(void **sc)
 	struct tpm_ppi_fwcfg *fwcfg = NULL;
 	int error;
 
-	ppi = calloc(1, sizeof(*ppi));
+	ppi = calloc(1, TPM_PPI_SIZE);
 	if (ppi == NULL) {
 		warnx("%s: failed to allocate acpi region for ppi", __func__);
 		error = ENOMEM;