hw/ppc/spapr_tpm_proxy: skip automatic zero-init of large arrays

The 'tpm_execute' method has a pair of 4k arrays used for copying
data between guest and host. Skip the automatic zero-init of these
arrays to eliminate the performance overhead in the I/O hot path.

The two arrays will be fully initialized when reading data from
guest memory or reading data from the proxy FD.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Klaus Jensen <k.jensen@samsung.com>
Reviewed-by: Harsh Prateek Bora <harshpb@linux.ibm.com>
Message-id: 20250610123709.835102-26-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

diff --git a/hw/ppc/spapr_tpm_proxy.c b/hw/ppc/spapr_tpm_proxy.c
index 862eeaa50a36e9d417256510bff617b4899007f3..1297b3ad569c23200190172ab0a22e744341bb3d 100644 (file)
--- a/hw/ppc/spapr_tpm_proxy.c
+++ b/hw/ppc/spapr_tpm_proxy.c
@@ -41,8 +41,8 @@ static ssize_t tpm_execute(SpaprTpmProxy *tpm_proxy, target_ulong *args)
     target_ulong data_in_size = args[2];
     uint64_t data_out = ppc64_phys_to_real(args[3]);
     target_ulong data_out_size = args[4];
-    uint8_t buf_in[TPM_SPAPR_BUFSIZE];
-    uint8_t buf_out[TPM_SPAPR_BUFSIZE];
+    QEMU_UNINITIALIZED uint8_t buf_in[TPM_SPAPR_BUFSIZE];
+    QEMU_UNINITIALIZED uint8_t buf_out[TPM_SPAPR_BUFSIZE];
     ssize_t ret;
 
     trace_spapr_tpm_execute(data_in, data_in_size, data_out, data_out_size);