Messages in this thread | | | Subject | Re: [PATCH 20/35] irqchip/gic-v4.1: Allow direct invalidation of VLPIs | From | Zenghui Yu <> | Date | Mon, 30 Sep 2019 17:40:17 +0800 |
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On 2019/9/30 17:20, Marc Zyngier wrote: > On 2019-09-28 03:02, Zenghui Yu wrote: >> On 2019/9/24 2:25, Marc Zyngier wrote: >>> Just like for INVALL, GICv4.1 has grown a VPE-aware INVLPI register. >>> Let's plumb it in and make use of the DirectLPI code in that case. >>> Signed-off-by: Marc Zyngier <maz@kernel.org> >>> --- >>> drivers/irqchip/irq-gic-v3-its.c | 19 +++++++++++++++++-- >>> include/linux/irqchip/arm-gic-v3.h | 1 + >>> 2 files changed, 18 insertions(+), 2 deletions(-) >>> diff --git a/drivers/irqchip/irq-gic-v3-its.c >>> b/drivers/irqchip/irq-gic-v3-its.c >>> index b791c9beddf2..34595a7fcccb 100644 >>> --- a/drivers/irqchip/irq-gic-v3-its.c >>> +++ b/drivers/irqchip/irq-gic-v3-its.c >>> @@ -1200,13 +1200,27 @@ static void wait_for_syncr(void __iomem *rdbase) >>> static void direct_lpi_inv(struct irq_data *d) >>> { >>> + struct its_vlpi_map *map = get_vlpi_map(d); >>> struct its_collection *col; >>> void __iomem *rdbase; >>> + u64 val; >>> + >>> + if (map) { >>> + struct its_device *its_dev = irq_data_get_irq_chip_data(d); >>> + >>> + WARN_ON(!is_v4_1(its_dev->its)); >>> + >>> + val = GICR_INVLPIR_V; >>> + val |= FIELD_PREP(GICR_INVLPIR_VPEID, map->vpe->vpe_id); >>> + val |= FIELD_PREP(GICR_INVLPIR_INTID, map->vintid); >>> + } else { >>> + val = d->hwirq; >>> + } >>> >>> /* Target the redistributor this LPI is currently routed to */ >>> col = irq_to_col(d); >> >> I think irq_to_col() may not work when GICv4.1 VLPIs are involved in. >> >> irq_to_col() gives us col_map[event] as the target redistributor, >> but the correct one for VLPIs should be vlpi_maps[event]->vpe->col_idx. >> These two are not always pointing to the same physical RD. >> For example, if guest issues a MOVI against a VLPI, we will update the >> corresponding vlpi_map->vpe and issue a VMOVI on ITS... but leave the >> col_map[event] unchanged. >> >> col_map[event] usually describes the physical LPI's CPU affinity, but >> when this physical LPI serves as something which the VLPI is backed by, >> we take really little care of it. Did I miss something here? > > You didn't miss anything, and this is indeed another pretty bad bug. > The collection mapping is completely unused when the LPI becomes a > VLPI, and it is only the vpe->col_id that matters (which gets updated > on VMOVP). > > This shows that irq_to_col() is the wrong abstraction, and what we're > interested is something that is more like 'irq to cpuid', allowing us > to directly point to the right distributor. > > Please see the patch I just pushed[1], which does that. > > Thanks, > > M. > > [1] > https://git.kernel.org/pub/scm/linux/kernel/git/maz/arm-platforms.git/commit/?h=irq/gic-v4.1-devel&id=aff363113eb26b6840136b69c2c7db2ea691db20
Yes, I think this makes sense.
Thanks, zenghui
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