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drm/xe/guc: Fix h2g_write usage of GUC_CTB_MSG_MAX_LEN

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In the ABI header, GUC_CTB_MSG_MIN_LEN is '1' because
GUC_CTB_HDR_LEN is 1. This aligns with H2G/G2H CTB specification
where all command formats are defined in units of dwords so that '1'
is a dword. Accordingly, GUC_CTB_MSG_MAX_LEN is 256-1 (i.e. 255
dwords). However, h2g_write was incorrectly assuming that
GUC_CTB_MSG_MAX_LEN was in bytes. Fix this.

v3: Fix nit on #define location.(Matt)
v2: By correctly treating GUC_CTB_MSG_MAX_LEN as dwords, it causes
    a local array to consume 4x the stack size. Rework the function
    to avoid consuming stack even if the action size is large. (Matt)

Signed-off-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Reviewed-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
This commit is contained in:
Alan Previn 2023-06-02 11:16:50 -07:00 committed by Rodrigo Vivi
parent 44869c72e8
commit c7fac450dd
1 changed files with 19 additions and 13 deletions
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32
drivers/gpu/drm/xe/xe_guc_ct.c
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@ -396,24 +396,27 @@ static void g2h_release_space(struct xe_guc_ct *ct, u32 g2h_len)
spin_unlock_irq(&ct->fast_lock);
}
#define H2G_CT_HEADERS (GUC_CTB_HDR_LEN + 1) /* one DW CTB header and one DW HxG header */
static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len,
u32 ct_fence_value, bool want_response)
{
struct xe_device *xe = ct_to_xe(ct);
struct guc_ctb *h2g = &ct->ctbs.h2g;
u32 cmd[GUC_CTB_MSG_MAX_LEN / sizeof(u32)];
u32 cmd_len = len + GUC_CTB_HDR_LEN;
u32 cmd_idx = 0, i;
u32 cmd[H2G_CT_HEADERS];
u32 tail = h2g->info.tail;
u32 full_len;
struct iosys_map map = IOSYS_MAP_INIT_OFFSET(&h2g->cmds,
tail * sizeof(u32));
full_len = len + GUC_CTB_HDR_LEN;
lockdep_assert_held(&ct->lock);
XE_BUG_ON(len * sizeof(u32) > GUC_CTB_MSG_MAX_LEN);
XE_BUG_ON(full_len > (GUC_CTB_MSG_MAX_LEN - GUC_CTB_HDR_LEN));
XE_BUG_ON(tail > h2g->info.size);
/* Command will wrap, zero fill (NOPs), return and check credits again */
if (tail + cmd_len > h2g->info.size) {
if (tail + full_len > h2g->info.size) {
xe_map_memset(xe, &map, 0, 0,
(h2g->info.size - tail) * sizeof(u32));
h2g_reserve_space(ct, (h2g->info.size - tail));
@ -428,30 +431,33 @@ static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len,
* dw1: HXG header (including action code)
* dw2+: action data
*/
cmd[cmd_idx++] = FIELD_PREP(GUC_CTB_MSG_0_FORMAT, GUC_CTB_FORMAT_HXG) |
cmd[0] = FIELD_PREP(GUC_CTB_MSG_0_FORMAT, GUC_CTB_FORMAT_HXG) |
FIELD_PREP(GUC_CTB_MSG_0_NUM_DWORDS, len) |
FIELD_PREP(GUC_CTB_MSG_0_FENCE, ct_fence_value);
if (want_response) {
cmd[cmd_idx++] =
cmd[1] =
FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) |
FIELD_PREP(GUC_HXG_EVENT_MSG_0_ACTION |
GUC_HXG_EVENT_MSG_0_DATA0, action[0]);
} else {
cmd[cmd_idx++] =
cmd[1] =
FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_EVENT) |
FIELD_PREP(GUC_HXG_EVENT_MSG_0_ACTION |
GUC_HXG_EVENT_MSG_0_DATA0, action[0]);
}
for (i = 1; i < len; ++i)
cmd[cmd_idx++] = action[i];
/* H2G header in cmd[1] replaces action[0] so: */
--len;
++action;
/* Write H2G ensuring visable before descriptor update */
xe_map_memcpy_to(xe, &map, 0, cmd, cmd_len * sizeof(u32));
xe_map_memcpy_to(xe, &map, 0, cmd, H2G_CT_HEADERS * sizeof(u32));
xe_map_memcpy_to(xe, &map, H2G_CT_HEADERS * sizeof(u32), action, len * sizeof(u32));
xe_device_wmb(ct_to_xe(ct));
/* Update local copies */
h2g->info.tail = (tail + cmd_len) % h2g->info.size;
h2g_reserve_space(ct, cmd_len);
h2g->info.tail = (tail + full_len) % h2g->info.size;
h2g_reserve_space(ct, full_len);
/* Update descriptor */
desc_write(xe, h2g, tail, h2g->info.tail);