mem: fix ivshmem freeing

There is no sync between host and guest to allow removal of memzones,
and freeing them result in undefined behavior.

In the guest, we identify IVSHMEM memsegs/memzones by having
ioremap_addr != 0. In the host, nothing is done to the memzone, meaning
ioremap_addr == 0.

As a solution, mark memzones being added to IVSHMEM in the host, by
setting ioremap_addr, then return an error whenever we try to free an
IVSHMEM memzone.

Fixes: ff909fe21f0 ("mem: introduce memzone freeing")

Signed-off-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>

diff --git a/lib/librte_eal/common/eal_common_memzone.c b/lib/librte_eal/common/eal_common_memzone.c
index 7b1d77e..febc56b 100644 (file)
--- a/lib/librte_eal/common/eal_common_memzone.c
+++ b/lib/librte_eal/common/eal_common_memzone.c
@@ -322,6 +322,14 @@ rte_memzone_free(const struct rte_memzone *mz)
        idx = idx / sizeof(struct rte_memzone);
 
        addr = mcfg->memzone[idx].addr;
+#ifdef RTE_LIBRTE_IVSHMEM
+       /*
+        * If ioremap_addr is set, it's an IVSHMEM memzone and we cannot
+        * free it.
+        */
+       if (mcfg->memzone[idx].ioremap_addr != 0)
+               ret = -EINVAL;
+#endif
        if (addr == NULL)
                ret = -EINVAL;
        else if (mcfg->memzone_cnt == 0) {

diff --git a/lib/librte_eal/common/include/rte_memzone.h b/lib/librte_eal/common/include/rte_memzone.h
index 38e5f5b..6a92222 100644 (file)
--- a/lib/librte_eal/common/include/rte_memzone.h
+++ b/lib/librte_eal/common/include/rte_memzone.h
@@ -258,10 +258,12 @@ const struct rte_memzone *rte_memzone_reserve_bounded(const char *name,
 /**
  * Free a memzone.
  *
+ * Note: an IVSHMEM zone cannot be freed.
+ *
  * @param mz
  *   A pointer to the memzone
  * @return
- *  -EINVAL - invalid parameter
+ *  -EINVAL - invalid parameter, IVSHMEM memzone.
  *  0 - success
  */
 int rte_memzone_free(const struct rte_memzone *mz);

diff --git a/lib/librte_ivshmem/rte_ivshmem.c b/lib/librte_ivshmem/rte_ivshmem.c
index 9621906..8fc4b57 100644 (file)
--- a/lib/librte_ivshmem/rte_ivshmem.c
+++ b/lib/librte_ivshmem/rte_ivshmem.c
@@ -504,7 +504,22 @@ add_memzone_to_metadata(const struct rte_memzone * mz,
                                config->metadata->name);
                goto fail;
        }
+#ifdef RTE_LIBRTE_IVSHMEM
+       struct rte_mem_config *mcfg;
+       unsigned int idx;
 
+       mcfg = rte_eal_get_configuration()->mem_config;
+
+       rte_rwlock_write_lock(&mcfg->mlock);
+
+       idx = ((uintptr_t)mz - (uintptr_t)mcfg->memzone);
+       idx = idx / sizeof(struct rte_memzone);
+
+       /* mark the memzone not freeable */
+       mcfg->memzone[idx].ioremap_addr = mz->phys_addr;
+
+       rte_rwlock_write_unlock(&mcfg->mlock);
+#endif
        rte_spinlock_unlock(&config->sl);
        return 0;
 fail: