diff options
Diffstat (limited to 'tools/firmware')
| -rw-r--r-- | tools/firmware/hvmloader/pci.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/tools/firmware/hvmloader/pci.c b/tools/firmware/hvmloader/pci.c index 6792ed47a4..1fe250ddc7 100644 --- a/tools/firmware/hvmloader/pci.c +++ b/tools/firmware/hvmloader/pci.c @@ -42,7 +42,6 @@ void pci_setup(void) uint32_t vga_devfn = 256; uint16_t class, vendor_id, device_id; unsigned int bar, pin, link, isa_irq; - int64_t mmio_left; /* Resources assignable to PCI devices via BARs. */ struct resource { @@ -264,8 +263,6 @@ void pci_setup(void) io_resource.base = 0xc000; io_resource.max = 0x10000; - mmio_left = pci_mem_end - pci_mem_start; - /* Assign iomem and ioport resources in descending order of size. */ for ( i = 0; i < nr_bars; i++ ) { @@ -273,7 +270,21 @@ void pci_setup(void) bar_reg = bars[i].bar_reg; bar_sz = bars[i].bar_sz; - using_64bar = bars[i].is_64bar && bar64_relocate && (mmio_left < bar_sz); + /* + * NB: The code here is rather fragile, as the check here to see + * whether bar_sz will fit in the low MMIO region doesn't match the + * real check made below, which involves aligning the base offset of the + * bar with the size of the bar itself. As it happens, this will always + * be satisfied because: + * - The first one will succeed because the MMIO hole can only start at + * 0x{f,e,c,8}00000000. If it fits, it will be aligned properly. + * - All subsequent ones will be aligned because the list is ordered + * large to small, and bar_sz is always a power of 2. (At least + * the code here assumes it to be.) + * Should either of those two conditions change, this code will break. + */ + using_64bar = bars[i].is_64bar && bar64_relocate + && (bar_sz > (mem_resource.max - mem_resource.base)); bar_data = pci_readl(devfn, bar_reg); if ( (bar_data & PCI_BASE_ADDRESS_SPACE) == @@ -295,7 +306,6 @@ void pci_setup(void) resource = &mem_resource; bar_data &= ~PCI_BASE_ADDRESS_MEM_MASK; } - mmio_left -= bar_sz; } else { |