[SLOF] [PATCH slof] pci-properties: Enforce all MMIO BARs to be 64K page aligned

Alexey Kardashevskiy aik at ozlabs.ru
Mon Feb 27 17:03:10 AEDT 2017

On 27/02/17 17:00, Nikunj A Dadhania wrote:
> Alexey Kardashevskiy <aik at ozlabs.ru> writes:
>> From: Yongji Xie <xyjxie at linux.vnet.ibm.com>
>> QEMU may passthrough a pci device of which BARs are smaller than
>> 64KB(PAGE_SIZE) to guest if the BARs are in an exclusive page.
>> But these passthru-BARs' mmio page may be shared with other
>> BARs in guest. This would cause the pci-passthrough fail and mmio
>> emulation happens in host.
>> To solve this performance issue, this patch enforces the alignment
>> of all MMIO BARs allocations to be at least 64K page aligned so that
>> the mmio page of one BAR would not be shared with other BARs in guest.
>> Signed-off-by: Yongji Xie <xyjxie at linux.vnet.ibm.com>
>> Signed-off-by: Nikunj A Dadhania <nikunj at linux.vnet.ibm.com>
>> ---
>> I am choosing between this and Michael's version or neither. Opinions?
> Can you give pointer to Michael's version ?

Sorry, here it is:



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