[PATCH v11 4/4] drm/xe/vf: Fixup CTB send buffer messages after migration
Lis, Tomasz
tomasz.lis at intel.com
Fri Apr 18 13:28:56 UTC 2025
On 18.04.2025 14:58, Michal Wajdeczko wrote:
>
> On 18.04.2025 01:42, Tomasz Lis wrote:
>> During post-migration recovery of a VF, it is necessary to update
>> GGTT references included in messages which are going to be sent
>> to GuC. GuC will start consuming messages after VF KMD will inform
>> it about fixups being done; before that, the VF KMD is expected
>> to update any H2G messages which are already in send buffer but
>> were not consumed by GuC.
>>
>> Only a small subset of messages allowed for VFs have GGTT references
>> in them. This patch adds the functionality to parse the CTB send
>> ring buffer and shift addresses contained within.
>>
>> While fixing the CTB content, ct->lock is not taken. This means
>> the only barrier taken remains GGTT address lock - which is ok,
>> because only requests with GGTT addresses matter, but it also means
>> tail changes can happen during the CTB fixups execution (which may
>> be ignored as any new messages will not have anything to fix).
>>
>> The GGTT address locking will be introduced in a future series.
>>
>> v2: removed storing shift as that's now done in VMA nodes patch;
>> macros to inlines; warns to asserts; log messages fixes (Michal)
>> v3: removed inline keywords, enums for offsets in CTB messages,
>> less error messages, if return unused then made functs void (Michal)
>> v4: update the cached head before starting fixups
>> v5: removed/updated comments, wrapped lines, converted assert into
>> error, enums for offsets to separate patch, reused xe_map_rd
>> v6: define xe_map_*_array() macros, support CTB wrap which divides
>> a message, updated comments, moved one function to an earlier patch
>> v7: renamed few functions, wider use on previously introduced helper,
>> separate cases in parsing messges, documented a static funct
>> v8: Introduced more helpers, fixed coding style mistakes
>> v9: Move xe_map*() functs to macros, add asserts, add debug print
>> v10: Errors in place of some asserts, style fixes
>>
>> Signed-off-by: Tomasz Lis <tomasz.lis at intel.com>
>> Cc: Michal Wajdeczko <michal.wajdeczko at intel.com>
>> ---
>> drivers/gpu/drm/xe/xe_guc_ct.c | 181 +++++++++++++++++++++++++++++++
>> drivers/gpu/drm/xe/xe_guc_ct.h | 2 +
>> drivers/gpu/drm/xe/xe_map.h | 18 +++
>> drivers/gpu/drm/xe/xe_sriov_vf.c | 18 +++
>> 4 files changed, 219 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
>> index 2447de0ebedf..32a6001c3d25 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.c
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.c
>> @@ -25,6 +25,7 @@
>> #include "xe_gt_printk.h"
>> #include "xe_gt_sriov_pf_control.h"
>> #include "xe_gt_sriov_pf_monitor.h"
>> +#include "xe_gt_sriov_printk.h"
>> #include "xe_gt_tlb_invalidation.h"
>> #include "xe_guc.h"
>> #include "xe_guc_log.h"
>> @@ -84,6 +85,8 @@ struct g2h_fence {
>> bool done;
>> };
>>
>> +#define make_u64(hi, lo) ((u64)((u64)(u32)(hi) << 32 | (u32)(lo)))
>> +
>> static void g2h_fence_init(struct g2h_fence *g2h_fence, u32 *response_buffer)
>> {
>> g2h_fence->response_buffer = response_buffer;
>> @@ -1624,6 +1627,184 @@ static void g2h_worker_func(struct work_struct *w)
>> receive_g2h(ct);
>> }
>>
>> +static void xe_fixup_u64_in_cmds(struct xe_device *xe, struct iosys_map *cmds,
>> + u32 size, u32 idx, s64 shift)
>> +{
>> + u32 hi, lo;
>> + u64 offset;
>> +
>> + lo = xe_map_rd_ring_u32(xe, cmds, idx, size);
>> + hi = xe_map_rd_ring_u32(xe, cmds, idx + 1, size);
>> + offset = make_u64(hi, lo);
>> + offset += shift;
>> + lo = lower_32_bits(offset);
>> + hi = upper_32_bits(offset);
>> + xe_map_wr_ring_u32(xe, cmds, idx, size, lo);
>> + xe_map_wr_ring_u32(xe, cmds, idx + 1, size, hi);
>> +}
>> +
>> +/*
>> + * Shift any GGTT addresses within a single message left within CTB from
>> + * before post-migration recovery.
>> + * @ct: pointer to CT struct of the target GuC
>> + * @cmds: iomap buffer containing CT messages
>> + * @head: start of the target message within the buffer
>> + * @len: length of the target message
>> + * @size: size of the commands buffer
>> + * @shift: the address shift to be added to each GGTT reference
>> + * Return: true if the message was fixed or needed no fixups, false on failure
>> + */
>> +static bool ct_fixup_ggtt_in_message(struct xe_guc_ct *ct,
>> + struct iosys_map *cmds, u32 head,
>> + u32 len, u32 size, s64 shift)
>> +{
>> + struct xe_gt *gt __maybe_unused = ct_to_gt(ct);
>> + struct xe_device *xe = ct_to_xe(ct);
>> + u32 msg[GUC_HXG_MSG_MIN_LEN];
>> + u32 action, i, n;
>> +
>> + xe_gt_assert(gt, len >= GUC_HXG_MSG_MIN_LEN);
>> +
>> + msg[0] = xe_map_rd_ring_u32(xe, cmds, head, size);
>> + action = FIELD_GET(GUC_HXG_REQUEST_MSG_0_ACTION, msg[0]);
>> +
>> + xe_gt_sriov_dbg_verbose(gt, "fixing H2G %#x\n", action);
>> +
>> + switch (action) {
>> + case XE_GUC_ACTION_REGISTER_CONTEXT:
>> + if (len >= XE_GUC_REGISTER_CONTEXT_MSG_LEN)
> hmm, was this code tested?
>
> IMO this should be:
>
> len != XE_GUC_REGISTER_CONTEXT_MSG_LEN
right, will fix the conditions.
>> + goto err_len;
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_DATA_5_WQ_DESC_ADDR_LOWER,
>> + shift);
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_DATA_7_WQ_BUF_BASE_LOWER,
>> + shift);
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_DATA_10_HW_LRC_ADDR, shift);
>> + break;
>> + case XE_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC:
>> + if (len >= XE_GUC_REGISTER_CONTEXT_MULTI_LRC_MSG_LEN)
> and this should be:
>
> len < XE_GUC_REGISTER_CONTEXT_MULTI_LRC_MSG_LEN
>
>> + goto err_len;
>> + n = xe_map_rd_ring_u32(xe, cmds, head +
>> + XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_10_NUM_CTXS, size);
>> + if (len >= XE_GUC_REGISTER_CONTEXT_MULTI_LRC_MSG_LEN + 2 * n)
> and this should be:
>
> len != XE_GUC_REGISTER_CONTEXT_MULTI_LRC_MSG_LEN + 2*n
>
>> + goto err_len;
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_5_WQ_DESC_ADDR_LOWER,
>> + shift);
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_7_WQ_BUF_BASE_LOWER,
>> + shift);
>> + for (i = 0; i < n; i++)
>> + xe_fixup_u64_in_cmds(xe, cmds, size, head +
>> + XE_GUC_REGISTER_CONTEXT_MULTI_LRC_DATA_11_HW_LRC_ADDR
>> + + 2 * i, shift);
>> + break;
>> + default:
>> + break;
>> + }
>> + return true;
> nit: add empty line here
ok
>
>> +err_len:
>> + xe_gt_err(gt, "Skipped G2G %#x message fixups, length (%u) too small\n", action, len);
>> + return false;
>> +}
>> +
>> +/*
>> + * Apply fixups to the next outgoing CT message within given CTB
>> + * @ct: the &xe_guc_ct struct instance representing the target GuC
>> + * @h2g: the &guc_ctb struct instance of the target buffer
>> + * @shift: shift to be added to all GGTT addresses within the CTB
>> + * @mhead: pointer to an integer storing message start position; the
>> + * position is changed to next message before this function return
>> + * @avail: size of the area available for parsing, that is length
>> + * of all remaining messages stored within the CTB
>> + * Return: size of the area available for parsing after one message
>> + * has been parsed, that is length remaining from the updated mhead
>> + */
>> +static int ct_fixup_ggtt_in_buffer(struct xe_guc_ct *ct, struct guc_ctb *h2g,
>> + s64 shift, u32 *mhead, s32 avail)
>> +{
>> + struct xe_device *xe = ct_to_xe(ct);
> to avoid 2x ct_to_gt() maybe add *gt here ?
ok, can do that.
-Tomasz
>
>> + u32 msg[GUC_HXG_MSG_MIN_LEN];
>> + u32 size = h2g->info.size;
>> + u32 head = *mhead;
>> + u32 len;
>> +
>> + xe_gt_assert(ct_to_gt(ct), avail >= (s32)GUC_CTB_MSG_MIN_LEN);
>> +
>> + /* Read header */
>> + msg[0] = xe_map_rd_ring_u32(xe, &h2g->cmds, head, size);
>> + len = FIELD_GET(GUC_CTB_MSG_0_NUM_DWORDS, msg[0]) + GUC_CTB_MSG_MIN_LEN;
>> +
>> + if (unlikely(len > (u32)avail)) {
>> + xe_gt_err(ct_to_gt(ct), "H2G channel broken on read, avail=%d, len=%d, fixups skipped\n",
>> + avail, len);
>> + return 0;
>> + }
>> +
>> + head = (head + GUC_CTB_MSG_MIN_LEN) % size;
>> + if (!ct_fixup_ggtt_in_message(ct, &h2g->cmds, head, msg_len_to_hxg_len(len), size, shift))
>> + return 0;
>> + *mhead = (head + msg_len_to_hxg_len(len)) % size;
>> +
>> + return avail - len;
>> +}
>> +
>> +/**
>> + * xe_guc_ct_fixup_messages_with_ggtt - Fixup any pending H2G CTB messages
>> + * @ct: pointer to CT struct of the target GuC
>> + * @ggtt_shift: shift to be added to all GGTT addresses within the CTB
>> + *
>> + * Messages in GuC to Host CTB are owned by GuC and any fixups in them
>> + * are made by GuC. But content of the Host to GuC CTB is owned by the
>> + * KMD, so fixups to GGTT references in any pending messages need to be
>> + * applied here.
>> + * This function updates GGTT offsets in payloads of pending H2G CTB
>> + * messages (messages which were not consumed by GuC before the VF got
>> + * paused).
>> + */
>> +void xe_guc_ct_fixup_messages_with_ggtt(struct xe_guc_ct *ct, s64 ggtt_shift)
>> +{
>> + struct guc_ctb *h2g = &ct->ctbs.h2g;
>> + struct xe_guc *guc = ct_to_guc(ct);
>> + struct xe_gt *gt = guc_to_gt(guc);
>> + u32 head, tail, size;
>> + s32 avail;
>> +
>> + if (unlikely(h2g->info.broken))
>> + return;
>> +
>> + h2g->info.head = desc_read(ct_to_xe(ct), h2g, head);
>> + head = h2g->info.head;
>> + tail = READ_ONCE(h2g->info.tail);
>> + size = h2g->info.size;
>> +
>> + if (unlikely(head > size))
>> + goto corrupted;
>> +
>> + if (unlikely(tail >= size))
>> + goto corrupted;
>> +
>> + avail = tail - head;
>> +
>> + /* beware of buffer wrap case */
>> + if (unlikely(avail < 0))
>> + avail += size;
>> + xe_gt_dbg(gt, "available %d (%u:%u:%u)\n", avail, head, tail, size);
>> + xe_gt_assert(gt, avail >= 0);
>> +
>> + while (avail > 0)
>> + avail = ct_fixup_ggtt_in_buffer(ct, h2g, ggtt_shift, &head, avail);
>> +
>> + return;
>> +
>> +corrupted:
>> + xe_gt_err(gt, "Corrupted H2G descriptor head=%u tail=%u size=%u, fixups not applied\n",
>> + head, tail, size);
>> + h2g->info.broken = true;
>> +}
>> +
>> static struct xe_guc_ct_snapshot *guc_ct_snapshot_alloc(struct xe_guc_ct *ct, bool atomic,
>> bool want_ctb)
>> {
>> diff --git a/drivers/gpu/drm/xe/xe_guc_ct.h b/drivers/gpu/drm/xe/xe_guc_ct.h
>> index 82c4ae458dda..5649bda82823 100644
>> --- a/drivers/gpu/drm/xe/xe_guc_ct.h
>> +++ b/drivers/gpu/drm/xe/xe_guc_ct.h
>> @@ -22,6 +22,8 @@ void xe_guc_ct_snapshot_print(struct xe_guc_ct_snapshot *snapshot, struct drm_pr
>> void xe_guc_ct_snapshot_free(struct xe_guc_ct_snapshot *snapshot);
>> void xe_guc_ct_print(struct xe_guc_ct *ct, struct drm_printer *p, bool want_ctb);
>>
>> +void xe_guc_ct_fixup_messages_with_ggtt(struct xe_guc_ct *ct, s64 ggtt_shift);
>> +
>> static inline bool xe_guc_ct_enabled(struct xe_guc_ct *ct)
>> {
>> return ct->state == XE_GUC_CT_STATE_ENABLED;
>> diff --git a/drivers/gpu/drm/xe/xe_map.h b/drivers/gpu/drm/xe/xe_map.h
>> index f62e0c8b67ab..8d67f6ba2d95 100644
>> --- a/drivers/gpu/drm/xe/xe_map.h
>> +++ b/drivers/gpu/drm/xe/xe_map.h
>> @@ -78,6 +78,24 @@ static inline void xe_map_write32(struct xe_device *xe, struct iosys_map *map,
>> iosys_map_wr(map__, offset__, type__, val__); \
>> })
>>
>> +#define xe_map_rd_array(xe__, map__, index__, type__) \
>> + xe_map_rd(xe__, map__, (index__) * sizeof(type__), type__)
>> +
>> +#define xe_map_wr_array(xe__, map__, index__, type__, val__) \
>> + xe_map_wr(xe__, map__, (index__) * sizeof(type__), type__, val__)
>> +
>> +#define xe_map_rd_array_u32(xe__, map__, index__) \
>> + xe_map_rd_array(xe__, map__, index__, u32)
>> +
>> +#define xe_map_wr_array_u32(xe__, map__, index__, val__) \
>> + xe_map_wr_array(xe__, map__, index__, u32, val__)
>> +
>> +#define xe_map_rd_ring_u32(xe__, map__, index__, size__) \
>> + xe_map_rd_array_u32(xe__, map__, (index__) % (size__))
>> +
>> +#define xe_map_wr_ring_u32(xe__, map__, index__, size__, val__) \
>> + xe_map_wr_array_u32(xe__, map__, (index__) % (size__), val__)
>> +
>> #define xe_map_rd_field(xe__, map__, struct_offset__, struct_type__, field__) ({ \
>> struct xe_device *__xe = xe__; \
>> xe_device_assert_mem_access(__xe); \
>> diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
>> index e70f1ceabbb3..2674fa948fda 100644
>> --- a/drivers/gpu/drm/xe/xe_sriov_vf.c
>> +++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
>> @@ -10,6 +10,7 @@
>> #include "xe_gt.h"
>> #include "xe_gt_sriov_printk.h"
>> #include "xe_gt_sriov_vf.h"
>> +#include "xe_guc_ct.h"
>> #include "xe_pm.h"
>> #include "xe_sriov.h"
>> #include "xe_sriov_printk.h"
>> @@ -158,6 +159,20 @@ static int vf_post_migration_requery_guc(struct xe_device *xe)
>> return ret;
>> }
>>
>> +static void vf_post_migration_fixup_ctb(struct xe_device *xe)
>> +{
>> + struct xe_gt *gt;
>> + unsigned int id;
>> +
>> + xe_assert(xe, IS_SRIOV_VF(xe));
>> +
>> + for_each_gt(gt, xe, id) {
>> + s32 shift = xe_gt_sriov_vf_ggtt_shift(gt);
>> +
>> + xe_guc_ct_fixup_messages_with_ggtt(>->uc.guc.ct, shift);
>> + }
>> +}
>> +
>> /*
>> * vf_post_migration_imminent - Check if post-restore recovery is coming.
>> * @xe: the &xe_device struct instance
>> @@ -224,6 +239,9 @@ static void vf_post_migration_recovery(struct xe_device *xe)
>>
>> need_fixups = vf_post_migration_fixup_ggtt_nodes(xe);
>> /* FIXME: add the recovery steps */
>> + if (need_fixups)
>> + vf_post_migration_fixup_ctb(xe);
>> +
>> vf_post_migration_notify_resfix_done(xe);
>> xe_pm_runtime_put(xe);
>> drm_notice(&xe->drm, "migration recovery ended\n");
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