On 5/22/25 10:59, Jan Beulich wrote:
> On 22.05.2025 16:03, Roger Pau Monne wrote:
>> diff --git a/xen/arch/x86/pci.c b/xen/arch/x86/pci.c
>> index 26bb7f6a3c3a..39fd5a16a4aa 100644
>> --- a/xen/arch/x86/pci.c
>> +++ b/xen/arch/x86/pci.c
>> @@ -101,6 +101,15 @@ int pci_conf_write_intercept(unsigned int seg, unsigned
>> int bdf,
>>
>> bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end)
>> {
>> + /*
>> + * Refuse to map BARs at position 0, those are not initialized. This
>> might
>> + * be required by Linux, that can reposition BARs with memory decoding
>> + * enabled. By returning false here bar->enabled will be set to false,
>> and
>> + * bar_write() will work as expected.
>> + */
>> + if ( mfn_eq(start, _mfn(0)) )
>> + return false;
>
> Is this really x86-specific?
No, I think Arm would benefit from this check too. I'm in favor of
moving the check to common.
