linux-kernel - Re: [PATCH] iommu/sun50i: Allow page sizes between 4K and 1M

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Message-ID: <5707055.DvuYhMxLoT@archlinux>
Date:   Mon, 11 Sep 2023 21:29:18 +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: Allow page sizes between 4K and 1M

On Monday, September 11, 2023 9:06:12 PM CEST Robin Murphy wrote:
> On 2023-09-11 20:02, Jernej Skrabec wrote:
> > While peripheral supports only 4K page sizes, we can easily emulate
> > support for bigger page sizes, up to 1M. This is done by making multiple
> > entries in map function or clearing multiple entries in unmap.
> 
> No, it's done by converting over to the {map,unmap}_pages ops. There's
> no need to resurrect this horrible bodge.

Missed those, thanks! In any case, logic to implement those isn't that 
different than here.

Best regards,
Jernej

> 
> Thanks,
> Robin.
> 
> > Signed-off-by: Jernej Skrabec <jernej.skrabec@...il.com>
> > ---
> > 
> >   drivers/iommu/sun50i-iommu.c | 49 +++++++++++++++++++++++-------------
> >   1 file changed, 31 insertions(+), 18 deletions(-)
> > 
> > diff --git a/drivers/iommu/sun50i-iommu.c b/drivers/iommu/sun50i-iommu.c
> > index 74c5cb93e900..93077575d60f 100644
> > --- a/drivers/iommu/sun50i-iommu.c
> > +++ b/drivers/iommu/sun50i-iommu.c
> > @@ -95,6 +95,10 @@
> > 
> >   #define SPAGE_SIZE			4096
> > 
> > +#define SUN50I_IOMMU_PGSIZES		(SZ_4K | SZ_8K | SZ_16K | SZ_32K | 
\
> > +					 SZ_64K | SZ_128K | 
SZ_256K | \
> > +					 SZ_512K | SZ_1M)
> > +
> > 
> >   struct sun50i_iommu {
> >   
> >   	struct iommu_device iommu;
> > 
> > @@ -593,10 +597,12 @@ static int sun50i_iommu_map(struct iommu_domain
> > *domain, unsigned long iova,> 
> >   {
> >   
> >   	struct sun50i_iommu_domain *sun50i_domain = 
to_sun50i_domain(domain);
> >   	struct sun50i_iommu *iommu = sun50i_domain->iommu;
> > 
> > -	u32 pte_index;
> > +	u32 pte_index, pages, i;
> > 
> >   	u32 *page_table, *pte_addr;
> >   	int ret = 0;
> > 
> > +	pages = size / SPAGE_SIZE;
> > +
> > 
> >   	page_table = sun50i_dte_get_page_table(sun50i_domain, iova, gfp);
> >   	if (IS_ERR(page_table)) {
> >   	
> >   		ret = PTR_ERR(page_table);
> > 
> > @@ -604,18 +610,22 @@ 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;
> > +	for (i = 0; i < pages; 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], pages);
> > 
> >   out:
> >   	return ret;
> > 
> > @@ -626,8 +636,10 @@ static size_t sun50i_iommu_unmap(struct iommu_domain
> > *domain, unsigned long iova> 
> >   {
> >   
> >   	struct sun50i_iommu_domain *sun50i_domain = 
to_sun50i_domain(domain);
> >   	phys_addr_t pt_phys;
> > 
> > +	u32 dte, pages, i;
> > 
> >   	u32 *pte_addr;
> > 
> > -	u32 dte;
> > +
> > +	pages = size / SPAGE_SIZE;
> > 
> >   	dte = sun50i_domain->dt[sun50i_iova_get_dte_index(iova)];
> >   	if (!sun50i_dte_is_pt_valid(dte))
> > 
> > @@ -636,13 +648,14 @@ static size_t sun50i_iommu_unmap(struct iommu_domain
> > *domain, unsigned long iova> 
> >   	pt_phys = sun50i_dte_get_pt_address(dte);
> >   	pte_addr = (u32 *)phys_to_virt(pt_phys) +
> >   	sun50i_iova_get_pte_index(iova);
> > 
> > -	if (!sun50i_pte_is_page_valid(*pte_addr))
> > -		return 0;
> > +	for (i = 0; i < pages; i++)
> > +		if (!sun50i_pte_is_page_valid(pte_addr[i]))
> > +			return 0;
> > 
> > -	memset(pte_addr, 0, sizeof(*pte_addr));
> > -	sun50i_table_flush(sun50i_domain, pte_addr, 1);
> > +	memset(pte_addr, 0, sizeof(*pte_addr) * pages);
> > +	sun50i_table_flush(sun50i_domain, pte_addr, pages);
> > 
> > -	return SZ_4K;
> > +	return size;
> > 
> >   }
> >   
> >   static phys_addr_t sun50i_iommu_iova_to_phys(struct iommu_domain
> >   *domain,
> > 
> > @@ -827,7 +840,7 @@ static int sun50i_iommu_of_xlate(struct device *dev,
> > 
> >   }
> >   
> >   static const struct iommu_ops sun50i_iommu_ops = {
> > 
> > -	.pgsize_bitmap	= SZ_4K,
> > +	.pgsize_bitmap	= SUN50I_IOMMU_PGSIZES,
> > 
> >   	.device_group	= sun50i_iommu_device_group,
> >   	.domain_alloc	= sun50i_iommu_domain_alloc,
> >   	.of_xlate	= sun50i_iommu_of_xlate,