Hi Robin,
On Wed, Aug 11, 2021 at 2:24 PM Robin Murphy <robin.murphy@xxxxxxx> wrote:
> IO_PGTABLE_QUIRK_NON_STRICT was never a very comfortable fit, since it's
> not a quirk of the pagetable format itself. Now that we have a more
> appropriate way to convey non-strict unmaps, though, this last of the
> non-quirk quirks can also go, and with the flush queue code also now
> enforcing its own ordering we can have a lovely cleanup all round.
>
> Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Thanks for your patch, which is now commit a8e5f04458c4e496
("iommu/io-pgtable: Remove non-strict quirk") in iommu/next.
> --- a/drivers/iommu/io-pgtable-arm-v7s.c
> +++ b/drivers/iommu/io-pgtable-arm-v7s.c
> @@ -700,14 +700,7 @@ static size_t __arm_v7s_unmap(struct arm_v7s_io_pgtable *data,
> ARM_V7S_BLOCK_SIZE(lvl + 1));
> ptep = iopte_deref(pte[i], lvl, data);
> __arm_v7s_free_table(ptep, lvl + 1, data);
> - } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
> - /*
> - * Order the PTE update against queueing the IOVA, to
> - * guarantee that a flush callback from a different CPU
> - * has observed it before the TLBIALL can be issued.
> - */
> - smp_wmb();
> - } else {
> + } else if (!gather->queued) {
If CONFIG_IOMMU_API=n:
error: ‘struct iommu_iotlb_gather’ has no member named ‘queued’
This can be reproduced using e.g. shmobile_defconfig with
CONFIG_IOMMU_SUPPORT=y
CONFIG_IOMMU_IO_PGTABLE_ARMV7S=y
> io_pgtable_tlb_add_page(iop, gather, iova, blk_size);
> }
> iova += blk_size;
> --- a/drivers/iommu/io-pgtable-arm.c
> +++ b/drivers/iommu/io-pgtable-arm.c
> @@ -638,14 +638,7 @@ static size_t __arm_lpae_unmap(struct arm_lpae_io_pgtable *data,
> io_pgtable_tlb_flush_walk(iop, iova + i * size, size,
> ARM_LPAE_GRANULE(data));
> __arm_lpae_free_pgtable(data, lvl + 1, iopte_deref(pte, data));
> - } else if (iop->cfg.quirks & IO_PGTABLE_QUIRK_NON_STRICT) {
> - /*
> - * Order the PTE update against queueing the IOVA, to
> - * guarantee that a flush callback from a different CPU
> - * has observed it before the TLBIALL can be issued.
> - */
> - smp_wmb();
> - } else {
> + } else if (!gather->queued) {
If CONFIG_IOMMU_API=n:
error: ‘struct iommu_iotlb_gather’ has no member named ‘queued’
This can be reproduced using e.g. shmobile_defconfig with
CONFIG_IOMMU_SUPPORT=y
CONFIG_IOMMU_IO_PGTABLE_LPAE=y
> io_pgtable_tlb_add_page(iop, gather, iova + i * size, size);
> }
>
Perhaps "select IOMMU_API" should be added (moved from individual
drivers) to both IOMMU_IO_PGTABLE_ARMV7S and IOMMU_IO_PGTABLE_LPAE?
Or iommu_iotlb_gather.queued should not be accessed here, or the
access wrapped into a static inline helper function with a dummy for
the CONFIG_IOMMU_API=n case?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
