Re: [PATCH 04/10] powerpc: Map & release OpenCAPI LPC memory

[Frederic Barrat <fbarrat@linux.ibm.com>]

Le 25/10/2019 à 06:46, Alastair D'Silva a écrit :
> From: Alastair D'Silva <alastair@d-silva.org>
> 
> This patch adds platform support to map & release LPC memory.
> 
> Signed-off-by: Alastair D'Silva <alastair@d-silva.org>
> ---
>   arch/powerpc/include/asm/pnv-ocxl.h   |  2 ++
>   arch/powerpc/platforms/powernv/ocxl.c | 41 +++++++++++++++++++++++++++
>   include/linux/memory_hotplug.h        |  5 ++++
>   mm/memory_hotplug.c                   |  3 +-
>   4 files changed, 50 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/powerpc/include/asm/pnv-ocxl.h b/arch/powerpc/include/asm/pnv-ocxl.h
> index 7de82647e761..f8f8ffb48aa8 100644
> --- a/arch/powerpc/include/asm/pnv-ocxl.h
> +++ b/arch/powerpc/include/asm/pnv-ocxl.h
> @@ -32,5 +32,7 @@ extern int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
>   
>   extern int pnv_ocxl_alloc_xive_irq(u32 *irq, u64 *trigger_addr);
>   extern void pnv_ocxl_free_xive_irq(u32 irq);
> +extern u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64 size);
> +extern void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev);
>   
>   #endif /* _ASM_PNV_OCXL_H */
> diff --git a/arch/powerpc/platforms/powernv/ocxl.c b/arch/powerpc/platforms/powernv/ocxl.c
> index 8c65aacda9c8..c6d4234e0aba 100644
> --- a/arch/powerpc/platforms/powernv/ocxl.c
> +++ b/arch/powerpc/platforms/powernv/ocxl.c
> @@ -475,6 +475,47 @@ void pnv_ocxl_spa_release(void *platform_data)
>   }
>   EXPORT_SYMBOL_GPL(pnv_ocxl_spa_release);
>   
> +u64 pnv_ocxl_platform_lpc_setup(struct pci_dev *pdev, u64 size)
> +{
> +	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
> +	struct pnv_phb *phb = hose->private_data;
> +	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
> +	u64 base_addr = 0;
> +	int rc;
> +
> +	rc = opal_npu_mem_alloc(phb->opal_id, bdfn, size, &base_addr);
> +	if (rc) {
> +		dev_warn(&pdev->dev,
> +			 "OPAL could not allocate LPC memory, rc=%d\n", rc);
> +		return 0;
> +	}
> +
> +	base_addr = be64_to_cpu(base_addr);
> +
> +	rc = check_hotplug_memory_addressable(base_addr >> PAGE_SHIFT,
> +					      size >> PAGE_SHIFT);
> +	if (rc)
> +		return 0;
> +
> +	return base_addr;
> +}
> +EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_setup);
> +
> +void pnv_ocxl_platform_lpc_release(struct pci_dev *pdev)
> +{
> +	struct pci_controller *hose = pci_bus_to_host(pdev->bus);
> +	struct pnv_phb *phb = hose->private_data;
> +	u32 bdfn = (pdev->bus->number << 8) | pdev->devfn;
> +	int rc;
> +
> +	rc = opal_npu_mem_release(phb->opal_id, bdfn);
> +	if (rc)
> +		dev_warn(&pdev->dev,
> +			 "OPAL reported rc=%d when releasing LPC memory\n", rc);
> +}
> +EXPORT_SYMBOL_GPL(pnv_ocxl_platform_lpc_release);
> +
> +
>   int pnv_ocxl_spa_remove_pe_from_cache(void *platform_data, int pe_handle)
>   {
>   	struct spa_data *data = (struct spa_data *) platform_data;
> diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
> index f46ea71b4ffd..3f5f1a642abe 100644
> --- a/include/linux/memory_hotplug.h
> +++ b/include/linux/memory_hotplug.h
> @@ -339,6 +339,11 @@ static inline int remove_memory(int nid, u64 start, u64 size)
>   static inline void __remove_memory(int nid, u64 start, u64 size) {}
>   #endif /* CONFIG_MEMORY_HOTREMOVE */
>   
> +#if CONFIG_MEMORY_HOTPLUG_SPARSE
> +int check_hotplug_memory_addressable(unsigned long pfn,
> +		unsigned long nr_pages);
> +#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
> +
>   extern void __ref free_area_init_core_hotplug(int nid);
>   extern int __add_memory(int nid, u64 start, u64 size);
>   extern int add_memory(int nid, u64 start, u64 size);
> diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
> index 2cecf07b396f..b39827dbd071 100644
> --- a/mm/memory_hotplug.c
> +++ b/mm/memory_hotplug.c
> @@ -278,7 +278,7 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
>   	return 0;
>   }
>   
> -static int check_hotplug_memory_addressable(unsigned long pfn,
> +int check_hotplug_memory_addressable(unsigned long pfn,
>   					    unsigned long nr_pages)
>   {
>   	const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1;
> @@ -294,6 +294,7 @@ static int check_hotplug_memory_addressable(unsigned long pfn,
>   
>   	return 0;
>   }
> +EXPORT_SYMBOL_GPL(check_hotplug_memory_addressable);


Making check_hotplug_memory_addressable() visible in the kernel could be 
a separate patch, to make sure it gets the proper attention instead of 
being buried in a powerpc patch.
Also, already mentioned, but it shouldn't be exported.


>   
>   /*
>    * Reasonably generic function for adding memory.  It is
>