Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751318AbbEAELM (ORCPT ); Fri, 1 May 2015 00:11:12 -0400 Received: from mail-pd0-f173.google.com ([209.85.192.173]:36766 "EHLO mail-pd0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750728AbbEAELH (ORCPT ); Fri, 1 May 2015 00:11:07 -0400 Message-ID: <5542FCD2.9000601@ozlabs.ru> Date: Fri, 01 May 2015 14:10:58 +1000 From: Alexey Kardashevskiy User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0 MIME-Version: 1.0 To: David Gibson CC: linuxppc-dev@lists.ozlabs.org, Benjamin Herrenschmidt , Paul Mackerras , Alex Williamson , Gavin Shan , linux-kernel@vger.kernel.org Subject: Re: [PATCH kernel v9 27/32] powerpc/iommu/ioda2: Add get_table_size() to calculate the size of future table References: <1429964096-11524-1-git-send-email-aik@ozlabs.ru> <1429964096-11524-28-git-send-email-aik@ozlabs.ru> <20150429064029.GX32589@voom.redhat.com> In-Reply-To: <20150429064029.GX32589@voom.redhat.com> Content-Type: text/plain; charset=koi8-r; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7438 Lines: 188 On 04/29/2015 04:40 PM, David Gibson wrote: > On Sat, Apr 25, 2015 at 10:14:51PM +1000, Alexey Kardashevskiy wrote: >> This adds a way for the IOMMU user to know how much a new table will >> use so it can be accounted in the locked_vm limit before allocation >> happens. >> >> This stores the allocated table size in pnv_pci_create_table() >> so the locked_vm counter can be updated correctly when a table is >> being disposed. >> >> This defines an iommu_table_group_ops callback to let VFIO know >> how much memory will be locked if a table is created. >> >> Signed-off-by: Alexey Kardashevskiy >> --- >> Changes: >> v9: >> * reimplemented the whole patch >> --- >> arch/powerpc/include/asm/iommu.h | 5 +++++ >> arch/powerpc/platforms/powernv/pci-ioda.c | 14 ++++++++++++ >> arch/powerpc/platforms/powernv/pci.c | 36 +++++++++++++++++++++++++++++++ >> arch/powerpc/platforms/powernv/pci.h | 2 ++ >> 4 files changed, 57 insertions(+) >> >> diff --git a/arch/powerpc/include/asm/iommu.h b/arch/powerpc/include/asm/iommu.h >> index 1472de3..9844c106 100644 >> --- a/arch/powerpc/include/asm/iommu.h >> +++ b/arch/powerpc/include/asm/iommu.h >> @@ -99,6 +99,7 @@ struct iommu_table { >> unsigned long it_size; /* Size of iommu table in entries */ >> unsigned long it_indirect_levels; >> unsigned long it_level_size; >> + unsigned long it_allocated_size; >> unsigned long it_offset; /* Offset into global table */ >> unsigned long it_base; /* mapped address of tce table */ >> unsigned long it_index; /* which iommu table this is */ >> @@ -155,6 +156,10 @@ extern struct iommu_table *iommu_init_table(struct iommu_table * tbl, >> struct iommu_table_group; >> >> struct iommu_table_group_ops { >> + unsigned long (*get_table_size)( >> + __u32 page_shift, >> + __u64 window_size, >> + __u32 levels); >> long (*create_table)(struct iommu_table_group *table_group, >> int num, >> __u32 page_shift, >> diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c >> index e0be556..7f548b4 100644 >> --- a/arch/powerpc/platforms/powernv/pci-ioda.c >> +++ b/arch/powerpc/platforms/powernv/pci-ioda.c >> @@ -2062,6 +2062,18 @@ static void pnv_pci_ioda2_setup_bypass_pe(struct pnv_phb *phb, >> } >> >> #ifdef CONFIG_IOMMU_API >> +static unsigned long pnv_pci_ioda2_get_table_size(__u32 page_shift, >> + __u64 window_size, __u32 levels) >> +{ >> + unsigned long ret = pnv_get_table_size(page_shift, window_size, levels); >> + >> + if (!ret) >> + return ret; >> + >> + /* Add size of it_userspace */ >> + return ret + (window_size >> page_shift) * sizeof(unsigned long); > > This doesn't make much sense. The userspace view can't possibly be a > property of the specific low-level IOMMU model. This it_userspace thing is all about memory preregistration. I need some way to track how many actual mappings the mm_iommu_table_group_mem_t has in order to decide whether to allow unregistering or not. When I clear TCE, I can read the old value which is host physical address which I cannot use to find the preregistered region and adjust the mappings counter; I can only use userspace addresses for this (not even guest physical addresses as it is VFIO and probably no KVM). So I have to keep userspace addresses somewhere, one per IOMMU page, and the iommu_table seems a natural place for this. > >> +} >> + >> static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group, >> int num, __u32 page_shift, __u64 window_size, __u32 levels, >> struct iommu_table *tbl) >> @@ -2086,6 +2098,7 @@ static long pnv_pci_ioda2_create_table(struct iommu_table_group *table_group, >> >> BUG_ON(tbl->it_userspace); >> tbl->it_userspace = uas; >> + tbl->it_allocated_size += uas_cb; >> tbl->it_ops = &pnv_ioda2_iommu_ops; >> if (pe->tce_inval_reg) >> tbl->it_type |= (TCE_PCI_SWINV_CREATE | TCE_PCI_SWINV_FREE); >> @@ -2160,6 +2173,7 @@ static void pnv_ioda2_release_ownership(struct iommu_table_group *table_group) >> } >> >> static struct iommu_table_group_ops pnv_pci_ioda2_ops = { >> + .get_table_size = pnv_pci_ioda2_get_table_size, >> .create_table = pnv_pci_ioda2_create_table, >> .set_window = pnv_pci_ioda2_set_window, >> .unset_window = pnv_pci_ioda2_unset_window, >> diff --git a/arch/powerpc/platforms/powernv/pci.c b/arch/powerpc/platforms/powernv/pci.c >> index fc129c4..1b5b48a 100644 >> --- a/arch/powerpc/platforms/powernv/pci.c >> +++ b/arch/powerpc/platforms/powernv/pci.c >> @@ -662,6 +662,38 @@ void pnv_pci_setup_iommu_table(struct iommu_table *tbl, >> tbl->it_type = TCE_PCI; >> } >> >> +unsigned long pnv_get_table_size(__u32 page_shift, >> + __u64 window_size, __u32 levels) >> +{ >> + unsigned long bytes = 0; >> + const unsigned window_shift = ilog2(window_size); >> + unsigned entries_shift = window_shift - page_shift; >> + unsigned table_shift = entries_shift + 3; >> + unsigned long tce_table_size = max(0x1000UL, 1UL << table_shift); >> + unsigned long direct_table_size; >> + >> + if (!levels || (levels > POWERNV_IOMMU_MAX_LEVELS) || >> + (window_size > memory_hotplug_max()) || >> + !is_power_of_2(window_size)) >> + return 0; >> + >> + /* Calculate a direct table size from window_size and levels */ >> + entries_shift = ROUND_UP(entries_shift, levels) / levels; >> + table_shift = entries_shift + 3; >> + table_shift = max_t(unsigned, table_shift, PAGE_SHIFT); >> + direct_table_size = 1UL << table_shift; >> + >> + for ( ; levels; --levels) { >> + bytes += ROUND_UP(tce_table_size, direct_table_size); >> + >> + tce_table_size /= direct_table_size; >> + tce_table_size <<= 3; >> + tce_table_size = ROUND_UP(tce_table_size, direct_table_size); >> + } >> + >> + return bytes; >> +} >> + >> static __be64 *pnv_alloc_tce_table_pages(int nid, unsigned shift, >> unsigned levels, unsigned long limit, >> unsigned long *tce_table_allocated) >> @@ -741,6 +773,10 @@ long pnv_pci_create_table(struct iommu_table_group *table_group, int nid, >> return -ENOMEM; >> } >> >> + tbl->it_allocated_size = pnv_get_table_size(page_shift, window_size, >> + levels); >> + WARN_ON(!tbl->it_allocated_size); >> + >> /* Setup linux iommu table */ >> pnv_pci_setup_iommu_table(tbl, addr, tce_table_size, bus_offset, >> page_shift); >> diff --git a/arch/powerpc/platforms/powernv/pci.h b/arch/powerpc/platforms/powernv/pci.h >> index 3d1ff584..ce4bc3c 100644 >> --- a/arch/powerpc/platforms/powernv/pci.h >> +++ b/arch/powerpc/platforms/powernv/pci.h >> @@ -224,6 +224,8 @@ extern long pnv_pci_create_table(struct iommu_table_group *table_group, int nid, >> __u64 bus_offset, __u32 page_shift, __u64 window_size, >> __u32 levels, struct iommu_table *tbl); >> extern void pnv_pci_free_table(struct iommu_table *tbl); >> +extern unsigned long pnv_get_table_size(__u32 page_shift, >> + __u64 window_size, __u32 levels); >> extern void pnv_pci_init_p5ioc2_hub(struct device_node *np); >> extern void pnv_pci_init_ioda_hub(struct device_node *np); >> extern void pnv_pci_init_ioda2_phb(struct device_node *np); > -- Alexey -- 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/