Nouveau - Nov 2023 - [PATCH 3/3] nouveau/gsp: add some basic registry entries.

From: Dave Airlie <airlied at redhat.com>

The nvidia driver sets these two basic registry entries always,
so copy it.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 .../gpu/drm/nouveau/nvkm/subdev/gsp/r535.c    | 45 ++++++++++++++-----
 1 file changed, 35 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
index b6f6b5e747d4..5bd38b1de226 100644
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
@@ -1029,26 +1029,51 @@ r535_gsp_rpc_unloading_guest_driver(struct nvkm_gsp
*gsp, bool suspend)
 	return nvkm_gsp_rpc_wr(gsp, rpc, true);
 }
 
+/* dword only */
+struct nv_gsp_registry_entries {
+	const char *name;
+	uint32_t value;
+};
+
+#define NV_GSP_REG_NUM_ENTRIES 2
+
+static const struct nv_gsp_registry_entries
r535_registry_entries[NV_GSP_REG_NUM_ENTRIES] = {
+	{ "RMSecBusResetEnable", 1 },
+	{ "RMForcePcieConfigSave", 1 },
+};
+
 static int
 r535_gsp_rpc_set_registry(struct nvkm_gsp *gsp)
 {
 	PACKED_REGISTRY_TABLE *rpc;
 	char *strings;
+	int str_offset;
+	int i;
+	size_t rpc_size = sizeof(*rpc) + sizeof(rpc->entries[0]) *
NV_GSP_REG_NUM_ENTRIES;
 
-	rpc = nvkm_gsp_rpc_get(gsp, NV_VGPU_MSG_FUNCTION_SET_REGISTRY,
-			       sizeof(*rpc) + sizeof(rpc->entries[0]) + 1);
+	/* add strings + null terminator */
+	for (i = 0; i < NV_GSP_REG_NUM_ENTRIES; i++)
+		rpc_size += strlen(r535_registry_entries[i].name) + 1;
+
+	rpc = nvkm_gsp_rpc_get(gsp, NV_VGPU_MSG_FUNCTION_SET_REGISTRY, rpc_size);
 	if (IS_ERR(rpc))
 		return PTR_ERR(rpc);
 
 	rpc->size = sizeof(*rpc);
-	rpc->numEntries = 1;
-	rpc->entries[0].nameOffset = offsetof(typeof(*rpc), entries[1]);
-	rpc->entries[0].type = 1;
-	rpc->entries[0].data = 0;
-	rpc->entries[0].length = 4;
-
-	strings = (char *)&rpc->entries[1];
-	strings[0] = '\0';
+	rpc->numEntries = NV_GSP_REG_NUM_ENTRIES;
+
+	str_offset = offsetof(typeof(*rpc), entries[NV_GSP_REG_NUM_ENTRIES]);
+	strings = (char *)&rpc->entries[NV_GSP_REG_NUM_ENTRIES];
+	for (i = 0; i < NV_GSP_REG_NUM_ENTRIES; i++) {
+		int name_len = strlen(r535_registry_entries[i].name) + 1;
+		rpc->entries[i].nameOffset = str_offset;
+		rpc->entries[i].type = 1;
+		rpc->entries[i].data = r535_registry_entries[i].value;
+		rpc->entries[i].length = 4;
+		memcpy(strings, r535_registry_entries[i].name, name_len);
+		strings += name_len;
+		str_offset += name_len;
+	}
 
 	return nvkm_gsp_rpc_wr(gsp, rpc, false);
 }
-- 
2.41.0

On Tue, Oct 31, 2023 at 12:20?AM Dave Airlie <airlied at gmail.com>
wrote:
> +#define NV_GSP_REG_NUM_ENTRIES 2
> +
> +static const struct nv_gsp_registry_entries
r535_registry_entries[NV_GSP_REG_NUM_ENTRIES] = {
> +       { "RMSecBusResetEnable", 1 },
> +       { "RMForcePcieConfigSave", 1 },
> +};
How about :

static const struct nv_gsp_registry_entries r535_registry_entries[] = {
       { "RMSecBusResetEnable", 1 },
       { "RMForcePcieConfigSave", 1 },
};

#define NV_GSP_REG_NUM_ENTRIES ARRAY_SIZE(r535_registry_entries)

On Wed, 1 Nov 2023 at 01:53, Timur Tabi <timur at kernel.org>
wrote:
>
> On Tue, Oct 31, 2023 at 12:20?AM Dave Airlie <airlied at gmail.com>
wrote:
> > +#define NV_GSP_REG_NUM_ENTRIES 2
> > +
> > +static const struct nv_gsp_registry_entries
r535_registry_entries[NV_GSP_REG_NUM_ENTRIES] = {
> > +       { "RMSecBusResetEnable", 1 },
> > +       { "RMForcePcieConfigSave", 1 },
> > +};
>
> How about :
>
> static const struct nv_gsp_registry_entries r535_registry_entries[] = {
>        { "RMSecBusResetEnable", 1 },
>        { "RMForcePcieConfigSave", 1 },
> };
>
> #define NV_GSP_REG_NUM_ENTRIES ARRAY_SIZE(r535_registry_entries)
Good plan. I'll change that now.

Dave.

On Tue, 2023-10-31 at 15:18 +1000, Dave Airlie wrote:
+       strings = (char *)&rpc->entries[NV_GSP_REG_NUM_ENTRIES];

I get a UBSAN index-out-of-bounds error on boot at this line.

[ 17.765746] nouveau 0000:65:00.0: gsp: cmdq: wptr 1
[ 17.765748]
===============================================================================[
17.774170] UBSAN: array-index-out-of-bounds in
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1065:33
[ 17.783449] index 2 is out of range for type 'PACKED_REGISTRY_ENTRY
[*]'
[ 17.790132] CPU: 0 PID: 234 Comm: kworker/0:4 Not tainted 6.6.0-rc5+ #1
[ 17.790135] Hardware name: ASUS X299-A/PRIME X299-A, BIOS 2002 09/25/2019
[ 17.790136] Workqueue: events work_for_cpu_fn
[ 17.790143] Call Trace:
[ 17.790145] <TASK>
[ 17.790148] dump_stack_lvl+0x48/0x70
[ 17.790155] dump_stack+0x10/0x20
[ 17.790156] __ubsan_handle_out_of_bounds+0xc6/0x110
[ 17.790160] r535_gsp_oneinit+0xf81/0x1530 [nouveau]
[ 17.790292] ? __dev_printk+0x39/0xa0
[ 17.790295] ? _dev_info+0x75/0xa0
[ 17.790298] tu102_gsp_oneinit+0x9b/0xd0 [nouveau]

I'm not sure what the fix is.  Do we need
__attribute__((no_sanitize("array-bounds"))) on PACKED_REGISTRY_TABLE?

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On Tue, Oct 31, 2023 at 12:20?AM Dave Airlie <airlied at gmail.com>
wrote:
>         rpc->size = sizeof(*rpc);
> -       rpc->numEntries = 1;
> -       rpc->entries[0].nameOffset = offsetof(typeof(*rpc), entries[1]);
> -       rpc->entries[0].type = 1;
> -       rpc->entries[0].data = 0;
> -       rpc->entries[0].length = 4;
> -
> -       strings = (char *)&rpc->entries[1];
> -       strings[0] = '\0';
> +       rpc->numEntries = NV_GSP_REG_NUM_ENTRIES;
> +
> +       str_offset = offsetof(typeof(*rpc),
entries[NV_GSP_REG_NUM_ENTRIES]);
> +       strings = (char *)&rpc->entries[NV_GSP_REG_NUM_ENTRIES];
> +       for (i = 0; i < NV_GSP_REG_NUM_ENTRIES; i++) {
> +               int name_len = strlen(r535_registry_entries[i].name) + 1;
> +               rpc->entries[i].nameOffset = str_offset;
> +               rpc->entries[i].type = 1;
> +               rpc->entries[i].data = r535_registry_entries[i].value;
> +               rpc->entries[i].length = 4;
> +               memcpy(strings, r535_registry_entries[i].name, name_len);
> +               strings += name_len;
> +               str_offset += name_len;
> +       }
I'm working on a patch that replaces this code with a
dynamically-generated registry so that we can set registry keys via
the driver's command-line (like the Nvidia driver).  However, you have
a bug here.  rpc->size must be the total size of the RPC, including
all the PACKED_REGISTRY_ENTRY structs and the strings that follow
them.  You can see this by looking at RmPackageRegistry() and
regCountEntriesAndSize() in OpenRM.