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Message-ID: <5708623.DvuYhMxLoT@jernej-laptop>
Date: Thu, 14 Sep 2023 17:09:28 +0200
From: Jernej Škrabec <jernej.skrabec@...il.com>
To: joro@...tes.org, will@...nel.org,
Robin Murphy <robin.murphy@....com>
Cc: wens@...e.org, samuel@...lland.org, iommu@...ts.linux.dev,
linux-arm-kernel@...ts.infradead.org, linux-sunxi@...ts.linux.dev,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH] iommu/sun50i: Convert to map_pages/unmap_pages
Dne sreda, 13. september 2023 ob 22:20:15 CEST je Robin Murphy napisal(a):
> On 2023-09-12 19:19, Jernej Skrabec wrote:
> > Convert driver to use map_pages and unmap_pages. Since functions operate
> > on page table, extend them to be able to operate on whole table, not
> > just one entry.
> >
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
> > ---
> > Hi!
> >
> > I'm not sure if it makes sense to check validity of page table entry when
> > unmaping pages makes sense. What do you think?
>
> As things currently stand it's largely a matter of opinion - some
> drivers consider that unmapping something which hasn't been mapped is
> nonsensical, and almost always represents the caller having gone wrong,
> thus report it as an error; others take the view that as long as they
> can achieve the requested end result, they're not going to think too
> hard about how they got there. The same arguments apply to whether you'd
> quietly replace an existing PTE or not when mapping, so I'd say the main
> thing is to at least be self-consistent one way or the other.
Ok, I preserved strict checks in this update, which is consistent and same as
before.
Best regards,
Jernej
>
> Cheers,
> Robin.
>
> > Best regards,
> > Jernej
> >
> > drivers/iommu/sun50i-iommu.c | 55 +++++++++++++++++++++---------------
> > 1 file changed, 33 insertions(+), 22 deletions(-)
> >
> > diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
> > index 74c5cb93e900..be6102730a56 100644
> > --- a/drivers/iommu/sun50i-iommu.c
> > +++ b/drivers/iommu/sun50i-iommu.c
> > @@ -589,11 +589,12 @@ static u32 *sun50i_dte_get_page_table(struct
> > sun50i_iommu_domain *sun50i_domain,>
> > }
> >
> > static int sun50i_iommu_map(struct iommu_domain *domain, unsigned long
> > iova,>
> > - phys_addr_t paddr, size_t size, int
prot, gfp_t gfp)
> > + phys_addr_t paddr, size_t pgsize, size_t
pgcount,
> > + int prot, gfp_t gfp, size_t *mapped)
> >
> > {
> >
> > struct sun50i_iommu_domain *sun50i_domain =
to_sun50i_domain(domain);
> > struct sun50i_iommu *iommu = sun50i_domain->iommu;
> >
> > - u32 pte_index;
> > + u32 pte_index, count, i;
> >
> > u32 *page_table, *pte_addr;
> > int ret = 0;
> >
> > @@ -604,45 +605,55 @@ static int sun50i_iommu_map(struct iommu_domain
> > *domain, unsigned long iova,>
> > }
> >
> > pte_index = sun50i_iova_get_pte_index(iova);
> >
> > - pte_addr = &page_table[pte_index];
> > - if (unlikely(sun50i_pte_is_page_valid(*pte_addr))) {
> > - phys_addr_t page_phys =
sun50i_pte_get_page_address(*pte_addr);
> > - dev_err(iommu->dev,
> > - "iova %pad already mapped to %pa cannot
remap to %pa prot: %#x\n",
> > - &iova, &page_phys, &paddr, prot);
> > - ret = -EBUSY;
> > - goto out;
> > + count = min(pgcount, (size_t)NUM_PT_ENTRIES - pte_index);
> > + for (i = 0; i < count; i++) {
> > + pte_addr = &page_table[pte_index + i];
> > + if (unlikely(sun50i_pte_is_page_valid(*pte_addr))) {
> > + phys_addr_t page_phys =
sun50i_pte_get_page_address(*pte_addr);
> > +
> > + dev_err(iommu->dev,
> > + "iova %pad already mapped to %pa
cannot remap to %pa prot: %#x\n",
> > + &iova, &page_phys, &paddr, prot);
> > + ret = -EBUSY;
> > + goto out;
> > + }
> > + *pte_addr = sun50i_mk_pte(paddr, prot);
> > + paddr += SPAGE_SIZE;
> >
> > }
> >
> > - *pte_addr = sun50i_mk_pte(paddr, prot);
> > - sun50i_table_flush(sun50i_domain, pte_addr, 1);
> > + sun50i_table_flush(sun50i_domain, &page_table[pte_index], i);
> > + *mapped = i * SPAGE_SIZE;
> >
> > out:
> > return ret;
> >
> > }
> >
> > static size_t sun50i_iommu_unmap(struct iommu_domain *domain, unsigned
> > long iova,>
> > - size_t size, struct
iommu_iotlb_gather *gather)
> > + size_t pgsize, size_t pgcount,
> > + struct iommu_iotlb_gather
*gather)
> >
> > {
> >
> > struct sun50i_iommu_domain *sun50i_domain =
to_sun50i_domain(domain);
> >
> > + u32 dte, count, i, pte_index;
> >
> > phys_addr_t pt_phys;
> > u32 *pte_addr;
> >
> > - u32 dte;
> >
> > dte = sun50i_domain->dt[sun50i_iova_get_dte_index(iova)];
> > if (!sun50i_dte_is_pt_valid(dte))
> >
> > return 0;
> >
> > pt_phys = sun50i_dte_get_pt_address(dte);
> >
> > - pte_addr = (u32 *)phys_to_virt(pt_phys) +
> > sun50i_iova_get_pte_index(iova); + pte_index =
> > sun50i_iova_get_pte_index(iova);
> > + pte_addr = (u32 *)phys_to_virt(pt_phys) + pte_index;
> >
> > - if (!sun50i_pte_is_page_valid(*pte_addr))
> > - return 0;
> > + count = min(pgcount, (size_t)NUM_PT_ENTRIES - pte_index);
> > + for (i = 0; i < count; i++)
> > + if (!sun50i_pte_is_page_valid(pte_addr[i]))
> > + break;
> >
> > - memset(pte_addr, 0, sizeof(*pte_addr));
> > - sun50i_table_flush(sun50i_domain, pte_addr, 1);
> > + memset(pte_addr, 0, sizeof(*pte_addr) * i);
> > + sun50i_table_flush(sun50i_domain, pte_addr, i);
> >
> > - return SZ_4K;
> > + return i * SPAGE_SIZE;
> >
> > }
> >
> > static phys_addr_t sun50i_iommu_iova_to_phys(struct iommu_domain
> > *domain,
> >
> > @@ -838,8 +849,8 @@ static const struct iommu_ops sun50i_iommu_ops = {
> >
> > .iotlb_sync_map = sun50i_iommu_iotlb_sync_map,
> > .iotlb_sync = sun50i_iommu_iotlb_sync,
> > .iova_to_phys = sun50i_iommu_iova_to_phys,
> >
> > - .map = sun50i_iommu_map,
> > - .unmap = sun50i_iommu_unmap,
> > + .map_pages = sun50i_iommu_map,
> > + .unmap_pages = sun50i_iommu_unmap,
> >
> > .free = sun50i_iommu_domain_free,
> >
> > }
> >
> > };
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