lib/test_kho: use kho_preserve_vmalloc instead of storing addresses in fdt

KHO test stores physical addresses of the preserved folios directly in
fdt.  Use kho_preserve_vmalloc() instead of it and kho_restore_vmalloc()
to retrieve the addresses after kexec.

This makes the test more scalable from one side and adds tests coverage
for kho_preserve_vmalloc() from the other.

Link: https://lkml.kernel.org/r/20250921054458.4043761-5-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Alexander Graf <graf@amazon.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Changyuan Lyu <changyuanl@google.com>
Cc: Chris Li <chrisl@kernel.org>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/test_kho.c b/lib/test_kho.c
index fe8504e3407b537b7119e34c3ab4cd5ee727419d..60cd899ea74539b9dfb5d6f9899c1ffe7fcb38c3 100644 (file)
--- a/lib/test_kho.c
+++ b/lib/test_kho.c
@@ -32,6 +32,7 @@ module_param(max_mem, long, 0644);
 struct kho_test_state {
        unsigned int nr_folios;
        struct folio **folios;
+       phys_addr_t *folios_info;
        struct folio *fdt;
        __wsum csum;
 };
@@ -67,18 +68,15 @@ static struct notifier_block kho_test_nb = {
 
 static int kho_test_save_data(struct kho_test_state *state, void *fdt)
 {
-       phys_addr_t *folios_info;
+       phys_addr_t *folios_info __free(kvfree) = NULL;
+       struct kho_vmalloc folios_info_phys;
        int err = 0;
 
-       err |= fdt_begin_node(fdt, "data");
-       err |= fdt_property(fdt, "nr_folios", &state->nr_folios,
-                           sizeof(state->nr_folios));
-       err |= fdt_property_placeholder(fdt, "folios_info",
-                                       state->nr_folios * sizeof(*folios_info),
-                                       (void **)&folios_info);
-       err |= fdt_property(fdt, "csum", &state->csum, sizeof(state->csum));
-       err |= fdt_end_node(fdt);
+       folios_info = vmalloc_array(state->nr_folios, sizeof(*folios_info));
+       if (!folios_info)
+               return -ENOMEM;
 
+       err = kho_preserve_vmalloc(folios_info, &folios_info_phys);
        if (err)
                return err;
 
@@ -93,6 +91,17 @@ static int kho_test_save_data(struct kho_test_state *state, void *fdt)
                        break;
        }
 
+       err |= fdt_begin_node(fdt, "data");
+       err |= fdt_property(fdt, "nr_folios", &state->nr_folios,
+                           sizeof(state->nr_folios));
+       err |= fdt_property(fdt, "folios_info", &folios_info_phys,
+                           sizeof(folios_info_phys));
+       err |= fdt_property(fdt, "csum", &state->csum, sizeof(state->csum));
+       err |= fdt_end_node(fdt);
+
+       if (!err)
+               state->folios_info = no_free_ptr(folios_info);
+
        return err;
 }
 
@@ -209,8 +218,9 @@ err_free_folios:
 
 static int kho_test_restore_data(const void *fdt, int node)
 {
+       const struct kho_vmalloc *folios_info_phys;
        const unsigned int *nr_folios;
-       const phys_addr_t *folios_info;
+       phys_addr_t *folios_info;
        const __wsum *old_csum;
        __wsum csum = 0;
        int len;
@@ -225,8 +235,12 @@ static int kho_test_restore_data(const void *fdt, int node)
        if (!old_csum || len != sizeof(*old_csum))
                return -EINVAL;
 
-       folios_info = fdt_getprop(fdt, node, "folios_info", &len);
-       if (!folios_info || len != sizeof(*folios_info) * *nr_folios)
+       folios_info_phys = fdt_getprop(fdt, node, "folios_info", &len);
+       if (!folios_info_phys || len != sizeof(*folios_info_phys))
+               return -EINVAL;
+
+       folios_info = kho_restore_vmalloc(folios_info_phys);
+       if (!folios_info)
                return -EINVAL;
 
        for (int i = 0; i < *nr_folios; i++) {
@@ -246,6 +260,8 @@ static int kho_test_restore_data(const void *fdt, int node)
                folio_put(folio);
        }
 
+       vfree(folios_info);
+
        if (csum != *old_csum)
                return -EINVAL;
 
@@ -304,6 +320,7 @@ static void kho_test_cleanup(void)
                folio_put(kho_test_state.folios[i]);
 
        kvfree(kho_test_state.folios);
+       vfree(kho_test_state.folios_info);
        folio_put(kho_test_state.fdt);
 }