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Commit d2bd05d8 authored by Jan Beulich's avatar Jan Beulich Committed by David Vrabel
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xen-pciback: return proper values during BAR sizing 



Reads following writes with all address bits set to 1 should return all
changeable address bits as one, not the BAR size (nor, as was the case
for the upper half of 64-bit BARs, the high half of the region's end
address). Presumably this didn't cause any problems so far because
consumers use the value to calculate the size (usually via val & -val),
and do nothing else with it.

But also consider the exception here: Unimplemented BARs should always
return all zeroes.

And finally, the check for whether to return the sizing address on read
for the ROM BAR should ignore all non-address bits, not just the ROM
Enable one.

Signed-off-by: default avatarJan Beulich <jbeulich@suse.com>
Reviewed-by: default avatarBoris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
parent d6b186c1

drivers/xen/xen-pciback/conf_space_header.c

+11 −7
Original line number Diff line number Diff line
@@ -145,7 +145,7 @@ static int rom_write(struct pci_dev *dev, int offset, u32 value, void *data) 
	/* A write to obtain the length must happen as a 32-bit write.

	 * This does not (yet) support writing individual bytes

	 */

	if (value == ~PCI_ROM_ADDRESS_ENABLE)

	if ((value | ~PCI_ROM_ADDRESS_MASK) == ~0U)

		bar->which = 1;

	else {

		u32 tmpval;
@@ -225,38 +225,42 @@ static inline void read_dev_bar(struct pci_dev *dev, 
			   (PCI_BASE_ADDRESS_SPACE_MEMORY |

				PCI_BASE_ADDRESS_MEM_TYPE_64))) {

			bar_info->val = res[pos - 1].start >> 32;

			bar_info->len_val = res[pos - 1].end >> 32;

			bar_info->len_val = -resource_size(&res[pos - 1]) >> 32;

			return;

		}

	}



	if (!res[pos].flags ||

	    (res[pos].flags & (IORESOURCE_DISABLED | IORESOURCE_UNSET |

			       IORESOURCE_BUSY)))

		return;



	bar_info->val = res[pos].start |

			(res[pos].flags & PCI_REGION_FLAG_MASK);

	bar_info->len_val = resource_size(&res[pos]);

	bar_info->len_val = -resource_size(&res[pos]) |

			    (res[pos].flags & PCI_REGION_FLAG_MASK);

}



static void *bar_init(struct pci_dev *dev, int offset)

{

	struct pci_bar_info *bar = kmalloc(sizeof(*bar), GFP_KERNEL);

	struct pci_bar_info *bar = kzalloc(sizeof(*bar), GFP_KERNEL);



	if (!bar)

		return ERR_PTR(-ENOMEM);



	read_dev_bar(dev, bar, offset, ~0);

	bar->which = 0;



	return bar;

}



static void *rom_init(struct pci_dev *dev, int offset)

{

	struct pci_bar_info *bar = kmalloc(sizeof(*bar), GFP_KERNEL);

	struct pci_bar_info *bar = kzalloc(sizeof(*bar), GFP_KERNEL);



	if (!bar)

		return ERR_PTR(-ENOMEM);



	read_dev_bar(dev, bar, offset, ~PCI_ROM_ADDRESS_ENABLE);

	bar->which = 0;



	return bar;

}