Messages in this thread | | | Date | Wed, 13 May 2015 17:30:18 +1000 | From | Alexey Kardashevskiy <> | Subject | Re: [PATCH kernel v10 11/34] vfio: powerpc/spapr: Moving pinning/unpinning to helpers |
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On 05/13/2015 04:32 PM, Gavin Shan wrote: > On Tue, May 12, 2015 at 01:39:00AM +1000, Alexey Kardashevskiy wrote: >> This is a pretty mechanical patch to make next patches simpler. >> >> New tce_iommu_unuse_page() helper does put_page() now but it might skip >> that after the memory registering patch applied. >> >> As we are here, this removes unnecessary checks for a value returned >> by pfn_to_page() as it cannot possibly return NULL. >> >> This moves tce_iommu_disable() later to let tce_iommu_clear() know if >> the container has been enabled because if it has not been, then >> put_page() must not be called on TCEs from the TCE table. This situation >> is not yet possible but it will after KVM acceleration patchset is >> applied. >> >> This changes code to work with physical addresses rather than linear >> mapping addresses for better code readability. Following patches will >> add an xchg() callback for an IOMMU table which will accept/return >> physical addresses (unlike current tce_build()) which will eliminate >> redundant conversions. >> >> Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> >> [aw: for the vfio related changes] >> Acked-by: Alex Williamson <alex.williamson@redhat.com> >> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > > Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com> > >> --- >> Changes: >> v9: >> * changed helpers to work with physical addresses rather than linear >> (for simplicity - later ::xchg() will receive physical and avoid >> additional convertions) >> >> v6: >> * tce_get_hva() returns hva via a pointer >> --- >> drivers/vfio/vfio_iommu_spapr_tce.c | 61 +++++++++++++++++++++++++------------ >> 1 file changed, 41 insertions(+), 20 deletions(-) >> >> diff --git a/drivers/vfio/vfio_iommu_spapr_tce.c b/drivers/vfio/vfio_iommu_spapr_tce.c >> index e21479c..115d5e6 100644 >> --- a/drivers/vfio/vfio_iommu_spapr_tce.c >> +++ b/drivers/vfio/vfio_iommu_spapr_tce.c >> @@ -191,69 +191,90 @@ static void tce_iommu_release(void *iommu_data) >> struct tce_container *container = iommu_data; >> >> WARN_ON(container->tbl && !container->tbl->it_group); >> - tce_iommu_disable(container); >> >> if (container->tbl && container->tbl->it_group) >> tce_iommu_detach_group(iommu_data, container->tbl->it_group); >> >> + tce_iommu_disable(container); >> mutex_destroy(&container->lock); >> >> kfree(container); >> } >> >> +static void tce_iommu_unuse_page(struct tce_container *container, >> + unsigned long oldtce) >> +{ >> + struct page *page; >> + >> + if (!(oldtce & (TCE_PCI_READ | TCE_PCI_WRITE))) >> + return; >> + > > It might be worthy to have a global helper function in iommu.h to check > if the given TCE entry is empty or not, for better readability. I would > think the helper function is used here and there :-)
The patchset adds one later, called iommu_tce_direction() ;)
In general, I removed TCE_PCI_READ, TCE_PCI_WRITE from everywhere but powernv code and used enum dma_data_direction instead as these bits are SPAPR TCE protocol specific and VFIO IOMMU API or arch/powerpc/kernel/iommu.c do not receive/handle these bits, they have their own, platform independent.
-- Alexey
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