Re: [PATCH v8 14/17] vfio-user: handle PCI BAR accesses

[Jag Raman]

> On Apr 25, 2022, at 6:05 AM, Stefan Hajnoczi <stefanha@redhat.com> wrote:
> 
> On Tue, Apr 19, 2022 at 04:44:19PM -0400, Jagannathan Raman wrote:
>> +static size_t vfu_object_bar_rw(PCIDevice *pci_dev, int pci_bar,
>> +                                hwaddr bar_offset, char * const buf,
>> +                                hwaddr len, const bool is_write)
>> +{
>> +    MemoryRegionSection section = { 0 };
>> +    uint8_t *ptr = (uint8_t *)buf;
>> +    MemoryRegion *section_mr = NULL;
>> +    uint64_t section_size;
>> +    hwaddr section_offset;
>> +    hwaddr size = 0;
>> +
>> +    while (len) {
>> +        section = memory_region_find(pci_dev->io_regions[pci_bar].memory,
>> +                                     bar_offset, len);
>> +
>> +        if (!section.mr) {
>> +            warn_report("vfu: invalid address 0x%"PRIx64"", bar_offset);
>> +            return size;
>> +        }
>> +
>> +        section_mr = section.mr;
>> +        section_offset = section.offset_within_region;
>> +        section_size = int128_get64(section.size);
>> +
>> +        if (is_write && section_mr->readonly) {
>> +            warn_report("vfu: attempting to write to readonly region in "
>> +                        "bar %d - [0x%"PRIx64" - 0x%"PRIx64"]",
>> +                        pci_bar, bar_offset,
>> +                        (bar_offset + section_size));
>> +            memory_region_unref(section_mr);
>> +            return size;
>> +        }
>> +
>> +        if (vfu_object_mr_rw(section_mr, ptr, section_offset,
>> +                             section_size, is_write)) {
>> +            warn_report("vfu: failed to %s "
>> +                        "[0x%"PRIx64" - 0x%"PRIx64"] in bar %d",
>> +                        is_write ? "write to" : "read from", bar_offset,
>> +                        (bar_offset + section_size), pci_bar);
>> +            return size;
> 
> Missing memory_region_unref(section_mr).

Ah got it.

Thanks!
--
Jag