On Fri, Dec 21, 2018 at 12:29:41PM +0000, Tvrtko Ursulin wrote:
>
> On 14/12/2018 18:20, Lucas De Marchi wrote:
> > From: Tomasz Lis <tomasz.lis@xxxxxxxxx>
> >
> > The table has been unified across OSes to minimize virtualization overhead.
> >
> > The MOCS table is now published as part of bspec, and versioned. Entries
> > are supposed to never be modified, but new ones can be added. Adding
> > entries increases table version. The patch includes version 1 entries.
> >
> > Meaning of each entry is now explained in bspec, and user mode clients
> > are expected to know what each entry means. The 3 entries used for previous
> > platforms are still compatible with their legacy definitions, but that is
> > not guaranteed to be true for future platforms.
> >
> > v2: Fixed SCC values, improved commit comment (Daniele)
> > v3: Improved MOCS table comment (Daniele)
> > v4: Moved new entries below gen9 ones. Put common entries into
> > definition to be used in multiple arrays. (Lucas)
> > v5: Made defines for or-ing flags. Renamed macros from MOCS_TABLE
> > to MOCS_ENTRIES. Switched LE_CoS to upper case. (Joonas)
> > v6: Removed definitions of reserved entries. (Michal)
> > Increased limit of entries sent to the hardware on gen11+.
> > v7: Simplify table as done for previou gens (Lucas)
> >
> > BSpec: 34007
> > BSpec: 560
> >
> > Signed-off-by: Tomasz Lis <tomasz.lis@xxxxxxxxx>
> > Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
> > Reviewed-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> > Signed-off-by: Lucas De Marchi <lucas.demarchi@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/intel_mocs.c | 187 ++++++++++++++++++++++++++----
> > 1 file changed, 162 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_mocs.c b/drivers/gpu/drm/i915/intel_mocs.c
> > index 577633cefb8a..dfc4edea020f 100644
> > --- a/drivers/gpu/drm/i915/intel_mocs.c
> > +++ b/drivers/gpu/drm/i915/intel_mocs.c
> > @@ -44,6 +44,8 @@ struct drm_i915_mocs_table {
> > #define LE_SCC(value) ((value) << 8)
> > #define LE_PFM(value) ((value) << 11)
> > #define LE_SCF(value) ((value) << 14)
> > +#define LE_COS(value) ((value) << 15)
> > +#define LE_SSE(value) ((value) << 17)
> > /* Defines for the tables (LNCFMOCS0 - LNCFMOCS31) - two entries per word */
> > #define L3_ESC(value) ((value) << 0)
> > @@ -52,6 +54,10 @@ struct drm_i915_mocs_table {
> > /* Helper defines */
> > #define GEN9_NUM_MOCS_ENTRIES 62 /* 62 out of 64 - 63 & 64 are reserved. */
> > +#define GEN11_NUM_MOCS_ENTRIES 64 /* 63-64 are reserved, but configured. */
> > +
> > +#define NUM_MOCS_ENTRIES(i915) \
> > + (INTEL_GEN(i915) < 11 ? GEN9_NUM_MOCS_ENTRIES : GEN11_NUM_MOCS_ENTRIES)
> > /* (e)LLC caching options */
> > #define LE_0_PAGETABLE _LE_CACHEABILITY(0)
> > @@ -80,21 +86,21 @@ struct drm_i915_mocs_table {
> > * LNCFCMOCS0 - LNCFCMOCS32 registers.
> > *
> > * These tables are intended to be kept reasonably consistent across
> > - * platforms. However some of the fields are not applicable to all of
> > - * them.
> > + * HW platforms, and for ICL+, be identical across OSes. To achieve
> > + * that, for Icelake and above, list of entries is published as part
> > + * of bspec.
> > *
> > * Entries not part of the following tables are undefined as far as
> > - * userspace is concerned and shouldn't be relied upon. For the time
> > - * being they will be implicitly initialized to the strictest caching
> > - * configuration (uncached) to guarantee forwards compatibility with
> > - * userspace programs written against more recent kernels providing
> > - * additional MOCS entries.
> > + * userspace is concerned and shouldn't be relied upon.
> > + *
> > + * The last two entries are reserved by the hardware. For ICL+ they
> > + * should be initialized according to bspec and never used, for older
> > + * platforms they should never be written to.
> > *
> > - * NOTE: These tables MUST start with being uncached and the length
> > - * MUST be less than 63 as the last two registers are reserved
> > - * by the hardware. These tables are part of the kernel ABI and
> > - * may only be updated incrementally by adding entries at the
> > - * end.
> > + * NOTE: These tables are part of bspec and defined as part of hardware
> > + * interface for ICL+. For older platforms, they are part of kernel
> > + * ABI. It is expected that existing entries will remain constant
> > + * and the tables will only be updated by adding new entries.
> > */
> > #define GEN9_MOCS_ENTRIES \
> > @@ -132,6 +138,132 @@ static const struct drm_i915_mocs_entry broxton_mocs_table[] = {
> > },
> > };
> > +#define GEN11_MOCS_ENTRIES \
> > + [0] = { \
> > + /* Base - Uncached (Deprecated) */ \
> > + .control_value = LE_1_UC | LE_TC_1_LLC, \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [1] = { \
> > + /* Base - L3 + LeCC:PAT (Deprecated) */ \
> > + .control_value = LE_0_PAGETABLE | LE_TC_1_LLC, \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [2] = { \
> > + /* Base - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [3] = { \
> > + /* Base - Uncached */ \
> > + .control_value = LE_1_UC | LE_TC_1_LLC, \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [4] = { \
> > + /* Base - L3 */ \
> > + .control_value = LE_1_UC | LE_TC_1_LLC, \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [5] = { \
> > + /* Base - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [6] = { \
> > + /* Age 0 - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(1), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [7] = { \
> > + /* Age 0 - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(1), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [8] = { \
> > + /* Age: Don't Chg. - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(2), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [9] = { \
> > + /* Age: Don't Chg. - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(2), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [10] = { \
> > + /* No AOM - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_AOM(1), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [11] = { \
> > + /* No AOM - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_AOM(1), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [12] = { \
> > + /* No AOM; Age 0 - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(1) | LE_AOM(1), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [13] = { \
> > + /* No AOM; Age 0 - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(1) | LE_AOM(1), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [14] = { \
> > + /* No AOM; Age:DC - LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(2) | LE_AOM(1), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [15] = { \
> > + /* No AOM; Age:DC - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(2) | LE_AOM(1), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [18] = { \
> > + /* Self-Snoop - L3 + LLC */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_SSE(3), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [19] = { \
> > + /* Skip Caching - L3 + LLC(12.5%) */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_SCC(7), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [20] = { \
> > + /* Skip Caching - L3 + LLC(25%) */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_SCC(3), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [21] = { \
> > + /* Skip Caching - L3 + LLC(50%) */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_SCC(1), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [22] = { \
> > + /* Skip Caching - L3 + LLC(75%) */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_RSC(1) | LE_SCC(3), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
> > + [23] = { \
> > + /* Skip Caching - L3 + LLC(87.5%) */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3) | LE_RSC(1) | LE_SCC(7), \
> > + .l3cc_value = L3_3_WB \
> > + }, \
>
> There is a hole of unused entries here which I think comes to play from the
> emit functions later.
>
> > + [62] = { \
> > + /* HW Reserved - SW program but never use */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3), \
> > + .l3cc_value = L3_1_UC \
> > + }, \
> > + [63] = { \
> > + /* HW Reserved - SW program but never use */ \
> > + .control_value = LE_3_WB | LE_TC_1_LLC | LE_LRUM(3), \
> > + .l3cc_value = L3_1_UC \
> > + },
> > +
> > +static const struct drm_i915_mocs_entry icelake_mocs_table[] = {
> > + GEN11_MOCS_ENTRIES
> > +};
> > +
> > /**
> > * get_mocs_settings()
> > * @dev_priv: i915 device.
> > @@ -149,8 +281,11 @@ static bool get_mocs_settings(struct drm_i915_private *dev_priv,
> > {
> > bool result = false;
> > - if (IS_GEN9_BC(dev_priv) || IS_CANNONLAKE(dev_priv) ||
> > - IS_ICELAKE(dev_priv)) {
> > + if (IS_ICELAKE(dev_priv)) {
> > + table->size = ARRAY_SIZE(icelake_mocs_table);
>
> So effectively this is always 64 due last two reserved entries.
what do you mean by *always* ? It is 64 for icelake.
>
> > + table->table = icelake_mocs_table;
> > + result = true;
> > + } else if (IS_GEN9_BC(dev_priv) || IS_CANNONLAKE(dev_priv)) {
> > table->size = ARRAY_SIZE(skylake_mocs_table);
> > table->table = skylake_mocs_table;
> > result = true;
> > @@ -213,7 +348,7 @@ void intel_mocs_init_engine(struct intel_engine_cs *engine)
> > if (!get_mocs_settings(dev_priv, &table))
> > return;
> > - GEM_BUG_ON(table.size > GEN9_NUM_MOCS_ENTRIES);
> > + GEM_BUG_ON(table.size > NUM_MOCS_ENTRIES(dev_priv));
> > for (index = 0; index < table.size; index++)
> > I915_WRITE(mocs_register(engine->id, index),
> > @@ -227,7 +362,7 @@ void intel_mocs_init_engine(struct intel_engine_cs *engine)
> > * Entry 0 in the table is uncached - so we are just writing
> > * that value to all the used entries.
> > */
> > - for (; index < GEN9_NUM_MOCS_ENTRIES; index++)
> > + for (; index < NUM_MOCS_ENTRIES(dev_priv); index++)
> > I915_WRITE(mocs_register(engine->id, index),
> > table.table[0].control_value);
> > }
> > @@ -245,18 +380,19 @@ void intel_mocs_init_engine(struct intel_engine_cs *engine)
> > static int emit_mocs_control_table(struct i915_request *rq,
> > const struct drm_i915_mocs_table *table)
> > {
> > + struct drm_i915_private *i915 = rq->i915;
> > enum intel_engine_id engine = rq->engine->id;
> > unsigned int index;
> > u32 *cs;
> > - if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
> > + if (WARN_ON(table->size > NUM_MOCS_ENTRIES(i915)))
> > return -ENODEV;
> > - cs = intel_ring_begin(rq, 2 + 2 * GEN9_NUM_MOCS_ENTRIES);
> > + cs = intel_ring_begin(rq, 2 + 2 * NUM_MOCS_ENTRIES(i915));
> > if (IS_ERR(cs))
> > return PTR_ERR(cs);
> > - *cs++ = MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES);
> > + *cs++ = MI_LOAD_REGISTER_IMM(NUM_MOCS_ENTRIES(i915));
> > for (index = 0; index < table->size; index++) {
> > *cs++ = i915_mmio_reg_offset(mocs_register(engine, index));
> > @@ -271,7 +407,7 @@ static int emit_mocs_control_table(struct i915_request *rq,
> > * Entry 0 in the table is uncached - so we are just writing
> > * that value to all the used entries.
> > */
> > - for (; index < GEN9_NUM_MOCS_ENTRIES; index++) {
> > + for (; index < NUM_MOCS_ENTRIES(i915); index++) {
> > *cs++ = i915_mmio_reg_offset(mocs_register(engine, index));
> > *cs++ = table->table[0].control_value;
>
> So in init and emit functions the behaviour is now different due reserved
> entries.
indeed
>
> Where before (and according the the comment which this patch removes - why?)
humn... but the comment is still there. Are we talking about the same
comment?
/*
* Ok, now set the unused entries to uncached. These entries
* are officially undefined and no contract for the contents
* and settings is given for these entries.
*
* Entry 0 in the table is uncached - so we are just writing
* that value to all the used entries.
*/
> we were setting unused entries to uncached, on Icelake they will be set to
> whatever all zeros is - LE_PAGETABLE?
>
> If that is not desired, we may need to transition to a scheme where struct
> drm_i915_mocs_entry starts holding the table index, and the static array is
> not indexed by it.
agreed
>
> It would also save the unused hole of zeros on Icelake which would probably
> offset the extra used space.
well, but at the expense of the additional field on the used entries and
additional complexity in the code - we would lose the logic here to
override an entry unless we keep track what has already been set.
Lucas De Marchi
>
> So I think someone needs to clarify what is the desired state for unused
> entries on Icelake.
>
> Regards,
>
> Tvrtko
>
> > }
> > @@ -304,17 +440,18 @@ static inline u32 l3cc_combine(const struct drm_i915_mocs_table *table,
> > static int emit_mocs_l3cc_table(struct i915_request *rq,
> > const struct drm_i915_mocs_table *table)
> > {
> > + struct drm_i915_private *i915 = rq->i915;
> > unsigned int i;
> > u32 *cs;
> > - if (WARN_ON(table->size > GEN9_NUM_MOCS_ENTRIES))
> > + if (WARN_ON(table->size > NUM_MOCS_ENTRIES(i915)))
> > return -ENODEV;
> > - cs = intel_ring_begin(rq, 2 + GEN9_NUM_MOCS_ENTRIES);
> > + cs = intel_ring_begin(rq, 2 + NUM_MOCS_ENTRIES(i915));
> > if (IS_ERR(cs))
> > return PTR_ERR(cs);
> > - *cs++ = MI_LOAD_REGISTER_IMM(GEN9_NUM_MOCS_ENTRIES / 2);
> > + *cs++ = MI_LOAD_REGISTER_IMM(NUM_MOCS_ENTRIES(i915) / 2);
> > for (i = 0; i < table->size/2; i++) {
> > *cs++ = i915_mmio_reg_offset(GEN9_LNCFCMOCS(i));
> > @@ -333,7 +470,7 @@ static int emit_mocs_l3cc_table(struct i915_request *rq,
> > * this will be uncached. Leave the last pair uninitialised as
> > * they are reserved by the hardware.
> > */
> > - for (; i < GEN9_NUM_MOCS_ENTRIES / 2; i++) {
> > + for (; i < NUM_MOCS_ENTRIES(i915) / 2; i++) {
> > *cs++ = i915_mmio_reg_offset(GEN9_LNCFCMOCS(i));
> > *cs++ = l3cc_combine(table, 0, 0);
> > }
> > @@ -380,7 +517,7 @@ void intel_mocs_init_l3cc_table(struct drm_i915_private *dev_priv)
> > * this will be uncached. Leave the last pair as initialised as
> > * they are reserved by the hardware.
> > */
> > - for (; i < (GEN9_NUM_MOCS_ENTRIES / 2); i++)
> > + for (; i < (NUM_MOCS_ENTRIES(dev_priv) / 2); i++)
> > I915_WRITE(GEN9_LNCFCMOCS(i), l3cc_combine(&table, 0, 0));
> > }
> >
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