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From: Auger Eric <eric.auger@redhat.com>
To: Jacob Pan <jacob.jun.pan@linux.intel.com>,
	iommu@lists.linux-foundation.org,
	LKML <linux-kernel@vger.kernel.org>,
	 Joerg Roedel <joro@8bytes.org>,
	David Woodhouse <dwmw2@infradead.org>,
	 Alex Williamson <alex.williamson@redhat.com>,
	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
Cc: "Tian, Kevin" <kevin.tian@intel.com>,
	Raj Ashok <ashok.raj@intel.com>,
	Andriy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: Re: [PATCH v4 14/22] iommu/vt-d: Add custom allocator for IOASID
Date: Tue, 16 Jul 2019 11:30:14 +0200
Message-ID: <2f2ba561-793f-a6a0-5765-ef8e9a5a3ab6@redhat.com> (raw)
In-Reply-To: <1560087862-57608-15-git-send-email-jacob.jun.pan@linux.intel.com>

Hi Jacob,

On 6/9/19 3:44 PM, Jacob Pan wrote:
> When VT-d driver runs in the guest, PASID allocation must be
> performed via virtual command interface. This patch registers a
> custom IOASID allocator which takes precedence over the default
> XArray based allocator. The resulting IOASID allocation will always
> come from the host. This ensures that PASID namespace is system-
> wide.
> 
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Signed-off-by: Liu, Yi L <yi.l.liu@intel.com>
> Signed-off-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
> ---
>  drivers/iommu/Kconfig       |  1 +
>  drivers/iommu/intel-iommu.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/intel-iommu.h |  2 ++
>  3 files changed, 63 insertions(+)
> 
> diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
> index c40c4b5..5d1bc2a 100644
> --- a/drivers/iommu/Kconfig
> +++ b/drivers/iommu/Kconfig
> @@ -213,6 +213,7 @@ config INTEL_IOMMU_SVM
>  	bool "Support for Shared Virtual Memory with Intel IOMMU"
>  	depends on INTEL_IOMMU && X86
>  	select PCI_PASID
> +	select IOASID
>  	select MMU_NOTIFIER
>  	select IOASID
>  	help
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 09b8ff0..5b84994 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -1711,6 +1711,8 @@ static void free_dmar_iommu(struct intel_iommu *iommu)
>  		if (ecap_prs(iommu->ecap))
>  			intel_svm_finish_prq(iommu);
>  	}
> +	ioasid_unregister_allocator(&iommu->pasid_allocator);
> +
>  #endif
>  }
>  
> @@ -4820,6 +4822,46 @@ static int __init platform_optin_force_iommu(void)
>  	return 1;
>  }
>  
> +#ifdef CONFIG_INTEL_IOMMU_SVM
> +static ioasid_t intel_ioasid_alloc(ioasid_t min, ioasid_t max, void *data)
> +{
> +	struct intel_iommu *iommu = data;
> +	ioasid_t ioasid;
> +
> +	/*
> +	 * VT-d virtual command interface always uses the full 20 bit
> +	 * PASID range. Host can partition guest PASID range based on
> +	 * policies but it is out of guest's control.
> +	 */
> +	if (min < PASID_MIN || max > PASID_MAX)
> +		return -EINVAL;
ioasid_alloc() does not handle that error value, use INVALID_IOASID?
> +
> +	if (vcmd_alloc_pasid(iommu, &ioasid))
> +		return INVALID_IOASID;
> +
> +	return ioasid;
> +}
> +
> +static void intel_ioasid_free(ioasid_t ioasid, void *data)
> +{
> +	struct iommu_pasid_alloc_info *svm;
> +	struct intel_iommu *iommu = data;
> +
> +	if (!iommu)
> +		return;
> +	/*
> +	 * Sanity check the ioasid owner is done at upper layer, e.g. VFIO
> +	 * We can only free the PASID when all the devices are unbond.
> +	 */
> +	svm = ioasid_find(NULL, ioasid, NULL);
> +	if (!svm) {
> +		pr_warn("Freeing unbond IOASID %d\n", ioasid);
> +		return;
> +	}
> +	vcmd_free_pasid(iommu, ioasid);
> +}
> +#endif
> +
>  int __init intel_iommu_init(void)
>  {
>  	int ret = -ENODEV;
> @@ -4924,6 +4966,24 @@ int __init intel_iommu_init(void)
>  				       "%s", iommu->name);
>  		iommu_device_set_ops(&iommu->iommu, &intel_iommu_ops);
>  		iommu_device_register(&iommu->iommu);
> +#ifdef CONFIG_INTEL_IOMMU_SVM
> +		if (cap_caching_mode(iommu->cap) && sm_supported(iommu)) {
> +			/*
> +			 * Register a custom ASID allocator if we are running
> +			 * in a guest, the purpose is to have a system wide PASID
> +			 * namespace among all PASID users.
> +			 * There can be multiple vIOMMUs in each guest but only
> +			 * one allocator is active. All vIOMMU allocators will
> +			 * eventually be calling the same host allocator.
> +			 */
> +			iommu->pasid_allocator.alloc = intel_ioasid_alloc;
> +			iommu->pasid_allocator.free = intel_ioasid_free;
> +			iommu->pasid_allocator.pdata = (void *)iommu;
> +			ret = ioasid_register_allocator(&iommu->pasid_allocator);
> +			if (ret)
> +				pr_warn("Custom PASID allocator registeration failed\n");
what if it fails, don't you want a tear down path?

Thanks

Eric
> +		}
> +#endif
>  	}
>  
>  	bus_set_iommu(&pci_bus_type, &intel_iommu_ops);
> diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h
> index bff907b..8605c74 100644
> --- a/include/linux/intel-iommu.h
> +++ b/include/linux/intel-iommu.h
> @@ -31,6 +31,7 @@
>  #include <linux/iommu.h>
>  #include <linux/io-64-nonatomic-lo-hi.h>
>  #include <linux/dmar.h>
> +#include <linux/ioasid.h>
>  
>  #include <asm/cacheflush.h>
>  #include <asm/iommu.h>
> @@ -549,6 +550,7 @@ struct intel_iommu {
>  #ifdef CONFIG_INTEL_IOMMU_SVM
>  	struct page_req_dsc *prq;
>  	unsigned char prq_name[16];    /* Name for PRQ interrupt */
> +	struct ioasid_allocator_ops pasid_allocator; /* Custom allocator for PASIDs */
>  #endif
>  	struct q_inval  *qi;            /* Queued invalidation info */
>  	u32 *iommu_state; /* Store iommu states between suspend and resume.*/
> 
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  reply index

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-09 13:44 [PATCH v4 00/22] Shared virtual address IOMMU and VT-d support Jacob Pan
2019-06-09 13:44 ` [PATCH v4 01/22] driver core: Add per device iommu param Jacob Pan
2019-06-09 13:44 ` [PATCH v4 02/22] iommu: Introduce device fault data Jacob Pan
2019-06-18 15:42   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 03/22] iommu: Introduce device fault report API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 04/22] iommu: Add recoverable fault reporting Jacob Pan
2019-06-18 15:44   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 05/22] iommu: Add a timeout parameter for PRQ response Jacob Pan
2019-06-09 13:44 ` [PATCH v4 06/22] trace/iommu: Add sva trace events Jacob Pan
2019-06-09 13:44 ` [PATCH v4 07/22] iommu: Use device fault trace event Jacob Pan
2019-06-09 13:44 ` [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-24 15:06     ` Auger Eric
2019-06-24 15:23       ` Jean-Philippe Brucker
2019-06-09 13:44 ` [PATCH v4 09/22] iommu: Introduce cache_invalidate API Jacob Pan
2019-06-18 15:41   ` Jonathan Cameron
2019-06-09 13:44 ` [PATCH v4 10/22] iommu: Fix compile error without IOMMU_API Jacob Pan
2019-06-18 14:10   ` Jonathan Cameron
2019-06-24 22:28     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 11/22] iommu: Introduce guest PASID bind function Jacob Pan
2019-06-18 15:36   ` Jean-Philippe Brucker
2019-06-24 22:24     ` Jacob Pan
2019-07-16 16:44   ` Auger Eric
2019-08-05 21:02     ` Jacob Pan
2019-08-05 23:13     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 12/22] iommu: Add I/O ASID allocator Jacob Pan
2019-06-18 16:50   ` Jonathan Cameron
2019-06-25 18:55     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 13/22] iommu/vt-d: Enlightened PASID allocation Jacob Pan
2019-07-16  9:29   ` Auger Eric
2019-08-13 16:57     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 14/22] iommu/vt-d: Add custom allocator for IOASID Jacob Pan
2019-07-16  9:30   ` Auger Eric [this message]
2019-08-05 20:02     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 15/22] iommu/vt-d: Replace Intel specific PASID allocator with IOASID Jacob Pan
2019-06-18 15:57   ` Jonathan Cameron
2019-06-24 21:36     ` Jacob Pan
2019-06-27  1:53   ` Lu Baolu
2019-06-27 15:40     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 16/22] iommu/vt-d: Move domain helper to header Jacob Pan
2019-07-16  9:33   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 17/22] iommu/vt-d: Avoid duplicated code for PASID setup Jacob Pan
2019-06-18 16:03   ` Jonathan Cameron
2019-06-24 23:44     ` Jacob Pan
2019-07-16  9:52   ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 18/22] iommu/vt-d: Add nested translation helper function Jacob Pan
2019-06-09 13:44 ` [PATCH v4 19/22] iommu/vt-d: Clean up for SVM device list Jacob Pan
2019-06-18 16:42   ` Jonathan Cameron
2019-06-24 23:59     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 20/22] iommu/vt-d: Add bind guest PASID support Jacob Pan
2019-06-18 16:44   ` Jonathan Cameron
2019-06-24 22:41     ` Jacob Pan
2019-06-27  2:50   ` Lu Baolu
2019-06-27 20:22     ` Jacob Pan
2019-07-05  2:21       ` Lu Baolu
2019-08-14 17:20         ` Jacob Pan
2019-07-16 16:45   ` Auger Eric
2019-07-16 17:04     ` Raj, Ashok
2019-07-18  7:47       ` Auger Eric
2019-06-09 13:44 ` [PATCH v4 21/22] iommu/vt-d: Support flushing more translation cache types Jacob Pan
2019-07-18  8:35   ` Auger Eric
2019-08-14 20:17     ` Jacob Pan
2019-06-09 13:44 ` [PATCH v4 22/22] iommu/vt-d: Add svm/sva invalidate function Jacob Pan

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