linux-kernel - Re: [PATCH v2 2/6] powerpc/pseries/iommu: Update call to ibm,query-pe-dma-windows

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Message-ID: <5411e8a1-02a3-1287-40bf-ccc9db7a4f88@ozlabs.ru>
Date:   Wed, 1 Jul 2020 18:17:18 +1000
From:   Alexey Kardashevskiy <aik@...abs.ru>
To:     Leonardo Bras <leobras.c@...il.com>,
        Michael Ellerman <mpe@...erman.id.au>,
        Benjamin Herrenschmidt <benh@...nel.crashing.org>,
        Paul Mackerras <paulus@...ba.org>,
        Thiago Jung Bauermann <bauerman@...ux.ibm.com>,
        Ram Pai <linuxram@...ibm.com>
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/6] powerpc/pseries/iommu: Update call to
 ibm,query-pe-dma-windows



On 24/06/2020 16:24, Leonardo Bras wrote:
> From LoPAR level 2.8, "ibm,ddw-extensions" index 3 can make the number of
> outputs from "ibm,query-pe-dma-windows" go from 5 to 6.
> 
> This change of output size is meant to expand the address size of
> largest_available_block PE TCE from 32-bit to 64-bit, which ends up
> shifting page_size and migration_capable.
> 
> This ends up requiring the update of
> ddw_query_response->largest_available_block from u32 to u64, and manually
> assigning the values from the buffer into this struct, according to
> output size.
> 
> Signed-off-by: Leonardo Bras <leobras.c@...il.com>
> ---
>  arch/powerpc/platforms/pseries/iommu.c | 57 +++++++++++++++++++++-----
>  1 file changed, 47 insertions(+), 10 deletions(-)
> 
> diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
> index 68d2aa9c71a8..558e5441c355 100644
> --- a/arch/powerpc/platforms/pseries/iommu.c
> +++ b/arch/powerpc/platforms/pseries/iommu.c
> @@ -44,6 +44,10 @@
>  #define DDW_REMOVE_PE_DMA_WIN	2
>  #define DDW_APPLICABLE_SIZE	3
>  
> +#define DDW_EXT_SIZE		0
> +#define DDW_EXT_RESET_DMA_WIN	1
> +#define DDW_EXT_QUERY_OUT_SIZE	2


#define DDW_EXT_LAST (DDW_EXT_QUERY_OUT_SIZE + 1)
...


> +
>  static struct iommu_table_group *iommu_pseries_alloc_group(int node)
>  {
>  	struct iommu_table_group *table_group;
> @@ -339,7 +343,7 @@ struct direct_window {
>  /* Dynamic DMA Window support */
>  struct ddw_query_response {
>  	u32 windows_available;
> -	u32 largest_available_block;
> +	u64 largest_available_block;
>  	u32 page_size;
>  	u32 migration_capable;
>  };
> @@ -875,13 +879,29 @@ static int find_existing_ddw_windows(void)
>  machine_arch_initcall(pseries, find_existing_ddw_windows);
>  
>  static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
> -			struct ddw_query_response *query)
> +		     struct ddw_query_response *query,
> +		     struct device_node *parent)
>  {
>  	struct device_node *dn;
>  	struct pci_dn *pdn;
> -	u32 cfg_addr;
> +	u32 cfg_addr, query_out[5], ddw_ext[DDW_EXT_QUERY_OUT_SIZE + 1];


... and use DDW_EXT_LAST here.


>  	u64 buid;
> -	int ret;
> +	int ret, out_sz;
> +
> +	/*
> +	 * From LoPAR level 2.8, "ibm,ddw-extensions" index 3 can rule how many
> +	 * output parameters ibm,query-pe-dma-windows will have, ranging from
> +	 * 5 to 6.
> +	 */
> +
> +	ret = of_property_read_u32_array(parent, "ibm,ddw-extensions",
> +					 &ddw_ext[0],
> +					 DDW_EXT_QUERY_OUT_SIZE + 1);
> +	if (ret && ddw_ext[DDW_EXT_SIZE] > 1 &&

>= DDW_EXT_QUERY_OUT_SIZE ?  Thanks,


> +	    ddw_ext[DDW_EXT_QUERY_OUT_SIZE] == 1)
> +		out_sz = 6;
> +	else
> +		out_sz = 5;
>  
>  	/*
>  	 * Get the config address and phb buid of the PE window.
> @@ -894,11 +914,28 @@ static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
>  	buid = pdn->phb->buid;
>  	cfg_addr = ((pdn->busno << 16) | (pdn->devfn << 8));
>  
> -	ret = rtas_call(ddw_avail[DDW_QUERY_PE_DMA_WIN], 3, 5, (u32 *)query,
> +	ret = rtas_call(ddw_avail[DDW_QUERY_PE_DMA_WIN], 3, out_sz, query_out,
>  			cfg_addr, BUID_HI(buid), BUID_LO(buid));
> -	dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x"
> -		" returned %d\n", ddw_avail[DDW_QUERY_PE_DMA_WIN], cfg_addr,
> -		 BUID_HI(buid), BUID_LO(buid), ret);
> +	dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x returned %d\n",
> +		 ddw_avail[DDW_QUERY_PE_DMA_WIN], cfg_addr, BUID_HI(buid),
> +		 BUID_LO(buid), ret);
> +
> +	switch (out_sz) {
> +	case 5:
> +		query->windows_available = query_out[0];
> +		query->largest_available_block = query_out[1];
> +		query->page_size = query_out[2];
> +		query->migration_capable = query_out[3];
> +		break;
> +	case 6:
> +		query->windows_available = query_out[0];
> +		query->largest_available_block = ((u64)query_out[1] << 32) |
> +						 query_out[2];
> +		query->page_size = query_out[3];
> +		query->migration_capable = query_out[4];
> +		break;
> +	}
> +
>  	return ret;
>  }
>  
> @@ -1046,7 +1083,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>  	 * of page sizes: supported and supported for migrate-dma.
>  	 */
>  	dn = pci_device_to_OF_node(dev);
> -	ret = query_ddw(dev, ddw_avail, &query);
> +	ret = query_ddw(dev, ddw_avail, &query, pdn);
>  	if (ret != 0)
>  		goto out_failed;
>  
> @@ -1074,7 +1111,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
>  	/* check largest block * page size > max memory hotplug addr */
>  	max_addr = ddw_memory_hotplug_max();
>  	if (query.largest_available_block < (max_addr >> page_shift)) {
> -		dev_dbg(&dev->dev, "can't map partition max 0x%llx with %u "
> +		dev_dbg(&dev->dev, "can't map partition max 0x%llx with %llu "
>  			  "%llu-sized pages\n", max_addr,  query.largest_available_block,
>  			  1ULL << page_shift);
>  		goto out_failed;
> 

-- 
Alexey