From: thunder.leizhen@huawei•com (Leizhen (ThunderTown))
To: linux-arm-kernel@lists•infradead.org
Subject: [RFC PATCH 05/30] iommu/arm-smmu-v3: Disable tagged pointers when ATS is in use
Date: Mon, 22 May 2017 14:27:35 +0800 [thread overview]
Message-ID: <592284D7.60002@huawei.com> (raw)
In-Reply-To: <20170227195441.5170-6-jean-philippe.brucker@arm.com>
On 2017/2/28 3:54, Jean-Philippe Brucker wrote:
> The ARM architecture has a "Top Byte Ignore" (TBI) option that makes the
> MMU mask out bits [63:56] of an address, allowing a userspace application
> to store data in its pointers.
>
> The ATS doesn't have an architected mechanism to enable TBI, and might
> create ATC entries for addresses that include a tag. Software would then
> have to send ATC invalidation packets for each 255 possible alias of an
> address, or just wipe the whole address space. This is not a viable
> option, so disable TBI when ATS is in use.
>
> It is unclear for the moment how this restriction will affect user
> applications. One example I can imagine (with my complete lack of
> knowledge about JIT engines and their use of tagged pointers) is a JIT
> translating a WebCL applications that uses SVM. Since this kind of
> interpreted language doesn't expose addresses, the interpreter and SVM
> implementations will be given the opportunity to do the right thing and
> remove tags before handing pointers to devices.
>
> Ideally we should remove TBI only for domains that are susceptible to use
> ATS. But at the point we're writing the context descriptor of a domain, we
> are still probing the first device in the group. If that device doesn't
> have an ATC but the next one does, we would then have to clear the TBI
> bit, invalidate the ATCs of previous devices, and notify the drivers that
> their devices cannot use tagged pointers anymore. Such a level of
> complexity doesn't make any sense here since it is unlikely devices will
> use tagged pointers at all.
>
> Signed-off-by: Jean-Philippe Brucker <jean-philippe.brucker@arm•com>
> ---
> drivers/iommu/arm-smmu-v3.c | 7 ++++---
> 1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
> index e7b940146ae3..06b29d4fcf65 100644
> --- a/drivers/iommu/arm-smmu-v3.c
> +++ b/drivers/iommu/arm-smmu-v3.c
> @@ -987,7 +987,7 @@ static void arm_smmu_cmdq_issue_cmd(struct arm_smmu_device *smmu,
> }
>
> /* Context descriptor manipulation functions */
> -static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr)
> +static u64 arm_smmu_cpu_tcr_to_cd(struct arm_smmu_device *smmu, u64 tcr)
> {
> u64 val = 0;
>
> @@ -1000,7 +1000,8 @@ static u64 arm_smmu_cpu_tcr_to_cd(u64 tcr)
> val |= ARM_SMMU_TCR2CD(tcr, EPD0);
> val |= ARM_SMMU_TCR2CD(tcr, EPD1);
> val |= ARM_SMMU_TCR2CD(tcr, IPS);
> - val |= ARM_SMMU_TCR2CD(tcr, TBI0);
> + if (!(smmu->features & ARM_SMMU_FEAT_ATS))
> + val |= ARM_SMMU_TCR2CD(tcr, TBI0);
Maybe we should always disable TBI. Otherwise, a device behind a ATS supported or
non-supported SMMU should use different strategies.
>
> return val;
> }
> @@ -1014,7 +1015,7 @@ static void arm_smmu_write_ctx_desc(struct arm_smmu_device *smmu,
> * We don't need to issue any invalidation here, as we'll invalidate
> * the STE when installing the new entry anyway.
> */
> - val = arm_smmu_cpu_tcr_to_cd(cfg->cd.tcr) |
> + val = arm_smmu_cpu_tcr_to_cd(smmu, cfg->cd.tcr) |
> #ifdef __BIG_ENDIAN
> CTXDESC_CD_0_ENDI |
> #endif
>
--
Thanks!
BestRegards
next prev parent reply other threads:[~2017-05-22 6:27 UTC|newest]
Thread overview: 103+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-27 19:54 [RFC PATCH 00/30] Add PCIe SVM support to ARM SMMUv3 Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 01/30] iommu/arm-smmu-v3: Link groups and devices Jean-Philippe Brucker
2017-03-27 12:18 ` Robin Murphy
2017-04-10 11:02 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 02/30] iommu/arm-smmu-v3: Link groups and domains Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 03/30] PCI: Move ATS declarations outside of CONFIG_PCI Jean-Philippe Brucker
2017-03-03 21:09 ` Bjorn Helgaas
2017-03-06 11:29 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 04/30] iommu/arm-smmu-v3: Add support for PCI ATS Jean-Philippe Brucker
2017-03-01 19:24 ` Sinan Kaya
2017-03-02 10:51 ` Jean-Philippe Brucker
2017-03-02 13:11 ` okaya at codeaurora.org
2017-03-08 15:26 ` Sinan Kaya
2017-03-21 19:38 ` Jean-Philippe Brucker
2017-04-03 8:34 ` Sunil Kovvuri
2017-04-03 10:14 ` Jean-Philippe Brucker
2017-04-03 11:42 ` Sunil Kovvuri
2017-04-03 11:56 ` Jean-Philippe Brucker
2017-05-10 12:54 ` Tomasz Nowicki
2017-05-10 13:35 ` Jean-Philippe Brucker
2017-05-23 8:41 ` Leizhen (ThunderTown)
2017-05-23 11:21 ` Jean-Philippe Brucker
2017-05-25 18:27 ` Roy Franz (Cavium)
2017-02-27 19:54 ` [RFC PATCH 05/30] iommu/arm-smmu-v3: Disable tagged pointers when ATS is in use Jean-Philippe Brucker
2017-05-22 6:27 ` Leizhen (ThunderTown) [this message]
2017-05-22 14:02 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 06/30] iommu/arm-smmu-v3: Add support for Substream IDs Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 07/30] iommu/arm-smmu-v3: Add second level of context descriptor table Jean-Philippe Brucker
2017-05-15 12:47 ` Tomasz Nowicki
2017-05-15 13:57 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 08/30] iommu/arm-smmu-v3: Add support for VHE Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 09/30] iommu/arm-smmu-v3: Support broadcast TLB maintenance Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 10/30] iommu/arm-smmu-v3: Add task contexts Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 11/30] arm64: mm: Pin down ASIDs for sharing contexts with devices Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 12/30] iommu/arm-smmu-v3: Keep track of process address spaces Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 13/30] iommu/io-pgtable-arm: Factor out ARM LPAE register defines Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 14/30] iommu/arm-smmu-v3: Share process page tables Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 15/30] iommu/arm-smmu-v3: Steal private ASID from a domain Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 16/30] iommu/arm-smmu-v3: Use shared ASID set Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 17/30] iommu/arm-smmu-v3: Add SVM feature checking Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 18/30] PCI: Make "PRG Response PASID Required" handling common Jean-Philippe Brucker
2017-03-03 21:11 ` Bjorn Helgaas
2017-03-06 11:31 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 19/30] PCI: Cache PRI and PASID bits in pci_dev Jean-Philippe Brucker
2017-03-03 21:12 ` Bjorn Helgaas
2017-02-27 19:54 ` [RFC PATCH 20/30] iommu/arm-smmu-v3: Enable PCI PASID in masters Jean-Philippe Brucker
2017-05-31 14:10 ` [RFC,20/30] " Sinan Kaya
2017-06-01 12:30 ` Jean-Philippe Brucker
2017-06-01 12:30 ` David Woodhouse
2017-06-23 14:39 ` Sinan Kaya
2017-06-23 15:15 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 21/30] iommu/arm-smmu-v3: Handle device faults from PRI Jean-Philippe Brucker
[not found] ` <8520D5D51A55D047800579B0941471982640F43C@XAP-PVEXMBX02.xlnx.xilinx.com>
2017-03-25 5:16 ` valmiki
2017-03-27 11:05 ` Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 22/30] iommu: Bind/unbind tasks to/from devices Jean-Philippe Brucker
2017-03-02 7:29 ` Tian, Kevin
2017-03-03 9:40 ` David Woodhouse
2017-03-03 17:05 ` Raj, Ashok
2017-03-03 18:39 ` Jean-Philippe Brucker
2017-03-22 15:36 ` Joerg Roedel
2017-03-22 18:30 ` Jean-Philippe Brucker
2017-03-22 15:38 ` Joerg Roedel
2017-02-27 19:54 ` [RFC PATCH 23/30] iommu/arm-smmu-v3: Bind/unbind device and task Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 24/30] iommu: Specify PASID state when unbinding a task Jean-Philippe Brucker
2017-03-22 15:44 ` Joerg Roedel
2017-03-22 18:31 ` Jean-Philippe Brucker
2017-03-22 22:53 ` Joerg Roedel
2017-03-23 13:37 ` Jean-Philippe Brucker
2017-03-23 14:30 ` Joerg Roedel
2017-03-23 15:52 ` Jean-Philippe Brucker
2017-03-23 16:52 ` Joerg Roedel
2017-03-23 17:03 ` Jean-Philippe Brucker
2017-03-24 11:00 ` Joerg Roedel
2017-03-24 19:08 ` Jean-Philippe Brucker
2017-03-27 15:33 ` Joerg Roedel
2017-02-27 19:54 ` [RFC PATCH 25/30] iommu/arm-smmu-v3: Safe invalidation and recycling of PASIDs Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 26/30] iommu/arm-smmu-v3: Fix PRI queue overflow acknowledgement Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 27/30] iommu/arm-smmu-v3: Handle PRI queue overflow Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 28/30] iommu/arm-smmu-v3: Add support for Hardware Translation Table Update at stage 1 Jean-Philippe Brucker
2017-02-27 19:54 ` [RFC PATCH 29/30] vfio: Add support for Shared Virtual Memory Jean-Philippe Brucker
2017-02-28 3:54 ` Alex Williamson
2017-02-28 15:17 ` Jean-Philippe Brucker
2017-03-21 7:04 ` Liu, Yi L
2017-03-21 19:37 ` Jean-Philippe Brucker
2017-03-21 20:56 ` jacob pan
2017-03-23 8:39 ` Liu, Yi L
2017-03-23 13:38 ` Jean-Philippe Brucker
2017-03-24 7:46 ` Liu, Yi L
2017-03-27 10:13 ` Jean-Philippe Brucker
2017-03-29 6:17 ` Liu, Yi L
2017-04-26 6:53 ` Tomasz Nowicki
2017-04-26 10:08 ` Jean-Philippe Brucker
2017-04-26 11:01 ` Tomasz Nowicki
2017-02-27 19:54 ` [RFC PATCH 30/30] vfio: Allow to bind foreign task Jean-Philippe Brucker
2017-02-28 3:54 ` Alex Williamson
2017-02-28 6:43 ` Tian, Kevin
2017-02-28 15:22 ` Jean-Philippe Brucker
2017-03-01 8:02 ` Tian, Kevin
2017-03-02 10:50 ` Jean-Philippe Brucker
2017-04-26 7:25 ` Tomasz Nowicki
2017-04-26 10:08 ` Jean-Philippe Brucker
2017-03-06 8:20 ` [RFC PATCH 00/30] Add PCIe SVM support to ARM SMMUv3 Liu, Yi L
2017-03-06 11:14 ` Jean-Philippe Brucker
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