Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753237AbbEAD4A (ORCPT ); Thu, 30 Apr 2015 23:56:00 -0400 Received: from ozlabs.org ([103.22.144.67]:48597 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751522AbbEADz7 (ORCPT ); Thu, 30 Apr 2015 23:55:59 -0400 Date: Fri, 1 May 2015 13:36:58 +1000 From: David Gibson To: Alexey Kardashevskiy Cc: linuxppc-dev@lists.ozlabs.org, Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , Gavin Shan , linux-kernel@vger.kernel.org Subject: Re: [PATCH kernel v9 23/32] powerpc/powernv/ioda: Define and implement DMA table/window management callbacks Message-ID: <20150501033658.GI24886@voom.redhat.com> References: <1429964096-11524-1-git-send-email-aik@ozlabs.ru> <1429964096-11524-24-git-send-email-aik@ozlabs.ru> <20150429053051.GT32589@voom.redhat.com> <5540A7F4.70903@ozlabs.ru> <20150430043750.GH15238@voom.redhat.com> <5541FC41.9040409@ozlabs.ru> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="J+eNKFoVC4T1DV3f" Content-Disposition: inline In-Reply-To: <5541FC41.9040409@ozlabs.ru> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 10326 Lines: 264 --J+eNKFoVC4T1DV3f Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Apr 30, 2015 at 07:56:17PM +1000, Alexey Kardashevskiy wrote: > On 04/30/2015 02:37 PM, David Gibson wrote: > >On Wed, Apr 29, 2015 at 07:44:20PM +1000, Alexey Kardashevskiy wrote: > >>On 04/29/2015 03:30 PM, David Gibson wrote: > >>>On Sat, Apr 25, 2015 at 10:14:47PM +1000, Alexey Kardashevskiy wrote: > >>>>This extends iommu_table_group_ops by a set of callbacks to support > >>>>dynamic DMA windows management. > >>>> > >>>>create_table() creates a TCE table with specific parameters. > >>>>it receives iommu_table_group to know nodeid in order to allocate > >>>>TCE table memory closer to the PHB. The exact format of allocated > >>>>multi-level table might be also specific to the PHB model (not > >>>>the case now though). > >>>>This callback calculated the DMA window offset on a PCI bus from @num > >>>>and stores it in a just created table. > >>>> > >>>>set_window() sets the window at specified TVT index + @num on PHB. > >>>> > >>>>unset_window() unsets the window from specified TVT. > >>>> > >>>>This adds a free() callback to iommu_table_ops to free the memory > >>>>(potentially a tree of tables) allocated for the TCE table. > >>> > >>>Doesn't the free callback belong with the previous patch introducing > >>>multi-level tables? > >> > >> > >> > >>If I did that, you would say "why is it here if nothing calls it" on > >>"multilevel" patch and "I see the allocation but I do not see memory > >>release" ;) > > > >Yeah, fair enough ;) > > > >>I need some rule of thumb here. I think it is a bit cleaner if the same > >>patch adds a callback for memory allocation and its counterpart, no? > > > >On further consideration, yes, I think you're right. > > > >>>>create_table() and free() are supposed to be called once per > >>>>VFIO container and set_window()/unset_window() are supposed to be > >>>>called for every group in a container. > >>>> > >>>>This adds IOMMU capabilities to iommu_table_group such as default > >>>>32bit window parameters and others. > >>>> > >>>>Signed-off-by: Alexey Kardashevskiy > >>>>--- > >>>> arch/powerpc/include/asm/iommu.h | 19 ++++++++ > >>>> arch/powerpc/platforms/powernv/pci-ioda.c | 75 ++++++++++++++++++= ++++++++--- > >>>> arch/powerpc/platforms/powernv/pci-p5ioc2.c | 12 +++-- > >>>> 3 files changed, 96 insertions(+), 10 deletions(-) > >>>> > >>>>diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/= asm/iommu.h > >>>>index 0f50ee2..7694546 100644 > >>>>--- a/arch/powerpc/include/asm/iommu.h > >>>>+++ b/arch/powerpc/include/asm/iommu.h > >>>>@@ -70,6 +70,7 @@ struct iommu_table_ops { > >>>> /* get() returns a physical address */ > >>>> unsigned long (*get)(struct iommu_table *tbl, long index); > >>>> void (*flush)(struct iommu_table *tbl); > >>>>+ void (*free)(struct iommu_table *tbl); > >>>> }; > >>>> > >>>> /* These are used by VIO */ > >>>>@@ -148,6 +149,17 @@ extern struct iommu_table *iommu_init_table(stru= ct iommu_table * tbl, > >>>> struct iommu_table_group; > >>>> > >>>> struct iommu_table_group_ops { > >>>>+ long (*create_table)(struct iommu_table_group *table_group, > >>>>+ int num, > >>>>+ __u32 page_shift, > >>>>+ __u64 window_size, > >>>>+ __u32 levels, > >>>>+ struct iommu_table *tbl); > >>>>+ long (*set_window)(struct iommu_table_group *table_group, > >>>>+ int num, > >>>>+ struct iommu_table *tblnew); > >>>>+ long (*unset_window)(struct iommu_table_group *table_group, > >>>>+ int num); > >>>> /* > >>>> * Switches ownership from the kernel itself to an external > >>>> * user. While onwership is taken, the kernel cannot use IOMMU its= elf. > >>>>@@ -160,6 +172,13 @@ struct iommu_table_group { > >>>> #ifdef CONFIG_IOMMU_API > >>>> struct iommu_group *group; > >>>> #endif > >>>>+ /* Some key properties of IOMMU */ > >>>>+ __u32 tce32_start; > >>>>+ __u32 tce32_size; > >>>>+ __u64 pgsizes; /* Bitmap of supported page sizes */ > >>>>+ __u32 max_dynamic_windows_supported; > >>>>+ __u32 max_levels; > >>> > >>>With this information, table_group seems even more like a bad name. > >>>"iommu_state" maybe? > >> > >> > >>Please, no. We will never come to agreement then :( And "iommu_state" i= s too > >>general anyway, it won't pass. > >> > >> > >>>> struct iommu_table tables[IOMMU_TABLE_GROUP_MAX_TABLES]; > >>>> struct iommu_table_group_ops *ops; > >>>> }; > >>>>diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc= /platforms/powernv/pci-ioda.c > >>>>index cc1d09c..4828837 100644 > >>>>--- a/arch/powerpc/platforms/powernv/pci-ioda.c > >>>>+++ b/arch/powerpc/platforms/powernv/pci-ioda.c > >>>>@@ -24,6 +24,7 @@ > >>>> #include > >>>> #include > >>>> #include > >>>>+#include > >>>> > >>>> #include > >>>> #include > >>>>@@ -1846,6 +1847,7 @@ static struct iommu_table_ops pnv_ioda2_iommu_o= ps =3D { > >>>> #endif > >>>> .clear =3D pnv_ioda2_tce_free, > >>>> .get =3D pnv_tce_get, > >>>>+ .free =3D pnv_pci_free_table, > >>>> }; > >>>> > >>>> static void pnv_pci_ioda_setup_opal_tce_kill(struct pnv_phb *phb, > >>>>@@ -1936,6 +1938,8 @@ static void pnv_pci_ioda_setup_dma_pe(struct pn= v_phb *phb, > >>>> TCE_PCI_SWINV_PAIR); > >>>> > >>>> tbl->it_ops =3D &pnv_ioda1_iommu_ops; > >>>>+ pe->table_group.tce32_start =3D tbl->it_offset << tbl->it_page_shif= t; > >>>>+ pe->table_group.tce32_size =3D tbl->it_size << tbl->it_page_shift; > >>>> iommu_init_table(tbl, phb->hose->node); > >>>> > >>>> if (pe->flags & PNV_IODA_PE_DEV) { > >>>>@@ -1961,7 +1965,7 @@ static void pnv_pci_ioda_setup_dma_pe(struct pn= v_phb *phb, > >>>> } > >>>> > >>>> static long pnv_pci_ioda2_set_window(struct iommu_table_group *tabl= e_group, > >>>>- struct iommu_table *tbl) > >>>>+ int num, struct iommu_table *tbl) > >>>> { > >>>> struct pnv_ioda_pe *pe =3D container_of(table_group, struct pnv_io= da_pe, > >>>> table_group); > >>>>@@ -1972,9 +1976,10 @@ static long pnv_pci_ioda2_set_window(struct io= mmu_table_group *table_group, > >>>> const __u64 start_addr =3D tbl->it_offset << tbl->it_page_shift; > >>>> const __u64 win_size =3D tbl->it_size << tbl->it_page_shift; > >>>> > >>>>- pe_info(pe, "Setting up window at %llx..%llx " > >>>>+ pe_info(pe, "Setting up window#%d at %llx..%llx " > >>>> "pgsize=3D0x%x tablesize=3D0x%lx " > >>>> "levels=3D%d levelsize=3D%x\n", > >>>>+ num, > >>>> start_addr, start_addr + win_size - 1, > >>>> 1UL << tbl->it_page_shift, tbl->it_size << 3, > >>>> tbl->it_indirect_levels + 1, tbl->it_level_size << 3); > >>>>@@ -1987,7 +1992,7 @@ static long pnv_pci_ioda2_set_window(struct iom= mu_table_group *table_group, > >>>> */ > >>>> rc =3D opal_pci_map_pe_dma_window(phb->opal_id, > >>>> pe->pe_number, > >>>>- pe->pe_number << 1, > >>>>+ (pe->pe_number << 1) + num, > >>> > >>>Heh, yes, well, that makes it rather clear that only 2 tables are poss= ible. > >>> > >>>> tbl->it_indirect_levels + 1, > >>>> __pa(tbl->it_base), > >>>> size << 3, > >>>>@@ -2000,7 +2005,7 @@ static long pnv_pci_ioda2_set_window(struct iom= mu_table_group *table_group, > >>>> pnv_pci_ioda2_tvt_invalidate(pe); > >>>> > >>>> /* Store fully initialized *tbl (may be external) in PE */ > >>>>- pe->table_group.tables[0] =3D *tbl; > >>>>+ pe->table_group.tables[num] =3D *tbl; > >>> > >>>I'm a bit confused by this whole set_window thing. Is the idea that > >>>with multiple groups in a container you have multiple table_group s > >>>each with different copies of the iommu_table structures, but pointing > >>>to the same actual TCE entries (it_base)? > >> > >>Yes. > >> > >>>It seems to me not terribly > >>>obvious when you "create" a table and when you "set" a window. > >> > >> > >>A table is not attached anywhere until its address is programmed (in > >>set_window()) to the hardware, it is just a table in memory. For > >>POWER8/IODA2, I create a table before I attach any group to a container, > >>then I program this table to every attached container, right now it is = done > >>in container's attach_group(). So later we can hotplug any host PCI dev= ice > >>to a container - it will program same TCE table to every new group in t= he > >>container. > > > >So you "create" once, then "set" it to one or more table_groups? It > >seems odd that "create" is a table_group callback in that case. >=20 >=20 > Where else could it be? ppc_md? We are getting rid of these. Some global > function? We do not want VFIO to know about this. I run out of ideas here. Yeah, I guess it has to be in table_group, despite the oddness. I guess the point is that it's the first group that determines the type of IOMMU you're using for this container. IIRC you already check on set_window that any additional groups have a compatible (i.e. identical) IOMMU. --=20 David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/~dgibson --J+eNKFoVC4T1DV3f Content-Type: application/pgp-signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJVQvTZAAoJEGw4ysog2bOS6BYQAIgK2jJg2ssz5bH9KxBr7jnr Hr5SJ3MaLsvZ+tARMjHSvlJcZcmGS5Ypm7C0g0tl315sit0sTYzeCwOMWfZ9BSB0 EjfPh+0E/DSLaU1l0owp3oqRvvAXpOA19bLSKxHQpJjjDWjVHGEWoRpFxfzaDIiH tUF8PKmLJr2LMGYDelGqgLPyetAnXpMZmrab74lSTe1exUIuHtRvuKQGZx+tiDW4 LQAo7caGMeggDzHblplGoSCi50u3T59TRISPXg3d+gEdukWY/dmG7QeJhDrpunUY 0/FQ3+bR2YLmYy012wtqzNfEw9JUvsJl4qZTvib5ceH0VBRQC1k1l2qc1RuK2obB VjyiH9ZcixKNePqGiFmBJreYTPdCvsa9GkS5sL8hSNo0V6QXmmhWtRFqsAZfXbBU GlttljgABx+pi626lYSRO1EU0c96m0IvUOAbk3CO4HnDQItdJrIggDgywsa14mDO jIcYUiiwkF+Vd3UnG9VOXlgKv2RwkYGi3dKiLtU0ZvA/vSimXXMXxCCXaJ+ahQF4 Lp5GMYD/qmf4O/y4Ijd8QMW30MZ1kenZboy5BOqJqV7ZnswDm4v8+iqcuMay+T+G +lcAxs4l7BVle875Dbc5ySRVFTvx0Slu2xEREZbIJyXZcDwcS/5i0mkFOaLK08Gj XziaoOdw4/OKr294cjIU =F3Sm -----END PGP SIGNATURE----- --J+eNKFoVC4T1DV3f-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/