Hi Marc,
On 2019/12/24 19:10, Marc Zyngier wrote:
GICv4.1 defines a new VPE table that is potentially shared between
both the ITSs and the redistributors, following complicated affinity
rules.
To make things more confusing, the programming of this table at
the redistributor level is reusing the GICv4.0 GICR_VPROPBASER register
for something completely different.
The code flow is somewhat complexified by the need to respect the
affinities required by the HW, meaning that tables can either be
inherited from a previously discovered ITS or redistributor.
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
Reviewed-by: Zenghui Yu <yuzenghui@xxxxxxxxxx>
With two very minor concerns below.
[...]
+static int allocate_vpe_l1_table(void)
+{
+ void __iomem *vlpi_base = gic_data_rdist_vlpi_base();
+ u64 val, gpsz, npg, pa;
+ unsigned int psz = SZ_64K;
+ unsigned int np, epp, esz;
+ struct page *page;
+
+ if (!gic_rdists->has_rvpeid)
+ return 0;
+
+ /*
+ * if VPENDBASER.Valid is set, disable any previously programmed
+ * VPE by setting PendingLast while clearing Valid. This has the
+ * effect of making sure no doorbell will be generated and we can
+ * then safely clear VPROPBASER.Valid.
+ */
+ if (gits_read_vpendbaser(vlpi_base + GICR_VPENDBASER) & GICR_VPENDBASER_Valid)
+ gits_write_vpendbaser(GICR_VPENDBASER_PendingLast,
+ vlpi_base + GICR_VPENDBASER);
I'm confused here. The Valid field resets to 0. Under which scenario
will the Valid==1 while we're doing initialization for this RD?
+
+ /*
+ * If we can inherit the configuration from another RD, let's do
+ * so. Otherwise, we have to go through the allocation process. We
+ * assume that all RDs have the exact same requirements, as
+ * nothing will work otherwise.
+ */
+ val = inherit_vpe_l1_table_from_rd(&gic_data_rdist()->vpe_table_mask);
+ if (val & GICR_VPROPBASER_4_1_VALID)
+ goto out;
+
+ gic_data_rdist()->vpe_table_mask = kzalloc(sizeof(cpumask_t), GFP_KERNEL);
+ if (!gic_data_rdist()->vpe_table_mask)
+ return -ENOMEM;
+
+ val = inherit_vpe_l1_table_from_its();
+ if (val & GICR_VPROPBASER_4_1_VALID)
+ goto out;
+
+ /* First probe the page size */
+ val = FIELD_PREP(GICR_VPROPBASER_4_1_PAGE_SIZE, GIC_PAGE_SIZE_64K);
+ gits_write_vpropbaser(val, vlpi_base + GICR_VPROPBASER);
+ val = gits_read_vpropbaser(vlpi_base + GICR_VPROPBASER);
+ gpsz = FIELD_GET(GICR_VPROPBASER_4_1_PAGE_SIZE, val);
+ esz = FIELD_GET(GICR_VPROPBASER_4_1_ENTRY_SIZE, val);
+
+ switch (gpsz) {
+ default:
+ gpsz = GIC_PAGE_SIZE_4K;
+ /* fall through */
+ case GIC_PAGE_SIZE_4K:
+ psz = SZ_4K;
+ break;
+ case GIC_PAGE_SIZE_16K:
+ psz = SZ_16K;
+ break;
+ case GIC_PAGE_SIZE_64K:
+ psz = SZ_64K;
+ break;
+ }
+
+ /*
+ * Start populating the register from scratch, including RO fields
+ * (which we want to print in debug cases...)
+ */
+ val = 0;
+ val |= FIELD_PREP(GICR_VPROPBASER_4_1_PAGE_SIZE, gpsz);
+ val |= FIELD_PREP(GICR_VPROPBASER_4_1_ENTRY_SIZE, esz);
+
+ /* How many entries per GIC page? */
+ esz++;
+ epp = psz / (esz * SZ_8);
+
+ /*
+ * If we need more than just a single L1 page, flag the table
+ * as indirect and compute the number of required L1 pages.
+ */
+ if (epp < ITS_MAX_VPEID) {
+ int nl2;
+
+ gic_rdists->flags |= RDIST_FLAGS_VPE_INDIRECT;
This flag is set but not used, can we just drop it?
Thanks,
Zenghui
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