Messages in this thread | | | Subject | Re: [PATCH v3 05/32] irqchip/gic-v4.1: VPE table (aka GICR_VPROPBASER) allocation | From | Zenghui Yu <> | Date | Mon, 20 Jan 2020 22:03:39 +0800 |
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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@kernel.org>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
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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