Re: [PATCH 2/4] powerpc: Prepare to support kernel handling of IOMMU map/unmap

2013-06-17 Thread Alexey Kardashevskiy
On 06/16/2013 02:26 PM, Benjamin Herrenschmidt wrote: >> +#if defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_FLATMEM) >> +int realmode_get_page(struct page *page) >> +{ >> +if (PageCompound(page)) >> +return -EAGAIN; >> + >> +get_page(page); >> + >> +return 0; >> +} >>

Re: [PATCH 2/4] powerpc: Prepare to support kernel handling of IOMMU map/unmap

2013-06-15 Thread Benjamin Herrenschmidt
On Sun, 2013-06-16 at 14:26 +1000, Benjamin Herrenschmidt wrote: > > +int realmode_get_page(struct page *page) > > +{ > > + if (PageCompound(page)) > > + return -EAGAIN; > > + > > + get_page(page); > > + > > + return 0; > > +} Shouldn't it be get_page_unless_zero ? Cheers,

Re: [PATCH 2/4] powerpc: Prepare to support kernel handling of IOMMU map/unmap

2013-06-15 Thread Benjamin Herrenschmidt
> +#if defined(CONFIG_SPARSEMEM_VMEMMAP) || defined(CONFIG_FLATMEM) > +int realmode_get_page(struct page *page) > +{ > + if (PageCompound(page)) > + return -EAGAIN; > + > + get_page(page); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(realmode_get_page); > + > +int realmode_pu

[PATCH 2/4] powerpc: Prepare to support kernel handling of IOMMU map/unmap

2013-06-04 Thread Alexey Kardashevskiy
The current VFIO-on-POWER implementation supports only user mode driven mapping, i.e. QEMU is sending requests to map/unmap pages. However this approach is really slow, so we want to move that to KVM. Since H_PUT_TCE can be extremely performance sensitive (especially with network adapters where eac

[PATCH 2/4] powerpc: Prepare to support kernel handling of IOMMU map/unmap

2013-05-20 Thread Alexey Kardashevskiy
The current VFIO-on-POWER implementation supports only user mode driven mapping, i.e. QEMU is sending requests to map/unmap pages. However this approach is really slow, so we want to move that to KVM. Since H_PUT_TCE can be extremely performance sensitive (especially with network adapters where eac