tpm-ppi: page-align PPI RAM

post-copy migration fails on destination with error such as:
2019-12-26T10:22:44.714644Z qemu-kvm: ram_block_discard_range:
Unaligned start address: 0x559d2afae9a0

Use qemu_memalign() to constrain the PPI RAM memory alignment.

Cc: qemu-stable@nongnu.org
Signed-off-by: NMarc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: NPhilippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: NDr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: NStefan Berger <stefanb@linux.ibm.com>
Signed-off-by: NStefan Berger <stefanb@linux.ibm.com>
Message-id: 20200103074000.1006389-3-marcandre.lureau@redhat.com
(cherry picked from commit 71e415c8)
Signed-off-by: NMichael Roth <mdroth@linux.vnet.ibm.com>

hw/tpm/tpm_ppi.c

@@ -43,7 +43,8 @@ void tpm_ppi_reset(TPMPPI *tpmppi)
 void tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
                   hwaddr addr, Object *obj)
 {
-    tpmppi->buf = g_malloc0(HOST_PAGE_ALIGN(TPM_PPI_ADDR_SIZE));
+    tpmppi->buf = qemu_memalign(qemu_real_host_page_size,
+                                HOST_PAGE_ALIGN(TPM_PPI_ADDR_SIZE));
     memory_region_init_ram_device_ptr(&tpmppi->ram, obj, "tpm-ppi",
                                       TPM_PPI_ADDR_SIZE, tpmppi->buf);
     vmstate_register_ram(&tpmppi->ram, DEVICE(obj));