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

Nikunj A Dadhania nikunj at linux.vnet.ibm.com
Mon Feb 27 17:00:23 AEDT 2017

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 ?


More information about the SLOF mailing list