Re: [PATCH v2] ACPI: PCI: check if the io space is page aligned

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On Wed, 14 Aug 2024, Miao Wang via B4 Relay wrote:

> From: Miao Wang <shankerwangmiao@xxxxxxxxx>
> 
> When the IO resource given by _CRS method is not page aligned, serious

Is this seen on some system? Could that be documented for future 
reference.

Also, I suggest you add "root" into the shortlog and desciption to 
explain the limited scope of this change because IIRC, somebody wanted to 
allow <4k aligned IO resources under certain conditions.

> problems will happen because the mis-aligend address is passed down to

aligned

> pci_remap_iospace, then to vmap_page_range, and finally to

Add () to any function names.

> vmap_pte_range, where the length bewteen addr and end is expected to be

between

> divisible by PAGE_SIZE, or the loop will overrun till the pfn_none check
> fails.
> 
> Signed-off-by: Miao Wang <shankerwangmiao@xxxxxxxxx>
> ---
> Changes in v2:
> - Sorry for posting out the draft version in V1, fixed a silly compiling issue.
> - Link to v1: https://lore.kernel.org/r/20240814-check_pci_probe_res-v1-1-122ee07821ab@xxxxxxxxx
> ---
>  drivers/acpi/pci_root.c | 14 +++++++++++---
>  1 file changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
> index d0bfb3706801..706449e5f29b 100644
> --- a/drivers/acpi/pci_root.c
> +++ b/drivers/acpi/pci_root.c
> @@ -858,7 +858,7 @@ static void acpi_pci_root_validate_resources(struct device *dev,
>  	}
>  }
>  
> -static void acpi_pci_root_remap_iospace(struct fwnode_handle *fwnode,
> +static void acpi_pci_root_remap_iospace(struct acpi_device *device,
>  			struct resource_entry *entry)
>  {
>  #ifdef PCI_IOBASE
> @@ -868,7 +868,15 @@ static void acpi_pci_root_remap_iospace(struct fwnode_handle *fwnode,
>  	resource_size_t length = resource_size(res);
>  	unsigned long port;
>  
> -	if (pci_register_io_range(fwnode, cpu_addr, length))
> +	if (!PAGE_ALIGNED(cpu_addr) || !PAGE_ALIGNED(length) ||
> +		!PAGE_ALIGNED(pci_addr)) {

Align this line so that ! are under each other. As is, it 
misleadingly looks on a quick glance to belong into the code block.

> +		dev_err(&device->dev,
> +			FW_BUG "I/O resource %pR or its offset %pa is not page aligned\n",
> +			res, &entry->offset);
> +		goto err;
> +	}
> +
> +	if (pci_register_io_range(&device->fwnode, cpu_addr, length))
>  		goto err;
>  
>  	port = pci_address_to_pio(cpu_addr);
> @@ -910,7 +918,7 @@ int acpi_pci_probe_root_resources(struct acpi_pci_root_info *info)
>  	else {
>  		resource_list_for_each_entry_safe(entry, tmp, list) {
>  			if (entry->res->flags & IORESOURCE_IO)
> -				acpi_pci_root_remap_iospace(&device->fwnode,
> +				acpi_pci_root_remap_iospace(device,
>  						entry);
>  
>  			if (entry->res->flags & IORESOURCE_DISABLED)


-- 
 i.





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