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Message-ID: <20191023005859.GD100970@otc-nc-03>
Date: Tue, 22 Oct 2019 17:58:59 -0700
From: "Raj, Ashok" <ashok.raj@...el.com>
To: Jacob Pan <jacob.jun.pan@...ux.intel.com>
Cc: iommu@...ts.linux-foundation.org,
LKML <linux-kernel@...r.kernel.org>,
Joerg Roedel <joro@...tes.org>,
David Woodhouse <dwmw2@...radead.org>,
Alex Williamson <alex.williamson@...hat.com>,
Jean-Philippe Brucker <jean-philippe@...aro.com>,
Yi Liu <yi.l.liu@...el.com>,
"Tian, Kevin" <kevin.tian@...el.com>,
Christoph Hellwig <hch@...radead.org>,
Lu Baolu <baolu.lu@...ux.intel.com>,
Jonathan Cameron <jic23@...nel.org>,
Eric Auger <eric.auger@...hat.com>,
Ashok Raj <ashok.raj@...el.com>
Subject: Re: [PATCH v6 03/10] iommu/vt-d: Replace Intel specific PASID
allocator with IOASID
On Tue, Oct 22, 2019 at 04:53:16PM -0700, Jacob Pan wrote:
> Make use of generic IOASID code to manage PASID allocation,
> free, and lookup. Replace Intel specific code.
>
> Signed-off-by: Jacob Pan <jacob.jun.pan@...ux.intel.com>
> ---
> drivers/iommu/intel-iommu.c | 12 ++++++------
> drivers/iommu/intel-pasid.c | 36 ------------------------------------
> drivers/iommu/intel-svm.c | 37 +++++++++++++++++++++----------------
> 3 files changed, 27 insertions(+), 58 deletions(-)
>
> diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
> index 3aff0141c522..72febcf2c48f 100644
> --- a/drivers/iommu/intel-iommu.c
> +++ b/drivers/iommu/intel-iommu.c
> @@ -5311,7 +5311,7 @@ static void auxiliary_unlink_device(struct dmar_domain *domain,
> domain->auxd_refcnt--;
>
> if (!domain->auxd_refcnt && domain->default_pasid > 0)
> - intel_pasid_free_id(domain->default_pasid);
> + ioasid_free(domain->default_pasid);
if the domain is gauranteed to be torn down, its ok.. but otherwise
do you need to clear domain->default_pasid to avoid accidental reference
in some other code path?
> }
>
> static int aux_domain_add_dev(struct dmar_domain *domain,
> @@ -5329,10 +5329,10 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
> if (domain->default_pasid <= 0) {
> int pasid;
>
> - pasid = intel_pasid_alloc_id(domain, PASID_MIN,
> - pci_max_pasids(to_pci_dev(dev)),
> - GFP_KERNEL);
> - if (pasid <= 0) {
> + /* No private data needed for the default pasid */
> + pasid = ioasid_alloc(NULL, PASID_MIN, pci_max_pasids(to_pci_dev(dev)) - 1,
If we ensure IOMMU max-pasid is full 20bit width, its good. In a vIOMMU
if iommu max pasid is restricted for some kind of partitioning in future
you want to consider limiting to no more than what's provisioned in the vIOMMU
right?
> + NULL);
> + if (pasid == INVALID_IOASID) {
> pr_err("Can't allocate default pasid\n");
> return -ENODEV;
> }
> @@ -5368,7 +5368,7 @@ static int aux_domain_add_dev(struct dmar_domain *domain,
> spin_unlock(&iommu->lock);
> spin_unlock_irqrestore(&device_domain_lock, flags);
> if (!domain->auxd_refcnt && domain->default_pasid > 0)
> - intel_pasid_free_id(domain->default_pasid);
> + ioasid_free(domain->default_pasid);
>
> return ret;
> }
> diff --git a/drivers/iommu/intel-pasid.c b/drivers/iommu/intel-pasid.c
> index 76bcbb21e112..c0d1f28d3412 100644
> --- a/drivers/iommu/intel-pasid.c
> +++ b/drivers/iommu/intel-pasid.c
> @@ -26,42 +26,6 @@
> */
> static DEFINE_SPINLOCK(pasid_lock);
> u32 intel_pasid_max_id = PASID_MAX;
> -static DEFINE_IDR(pasid_idr);
> -
> -int intel_pasid_alloc_id(void *ptr, int start, int end, gfp_t gfp)
> -{
> - int ret, min, max;
> -
> - min = max_t(int, start, PASID_MIN);
> - max = min_t(int, end, intel_pasid_max_id);
> -
> - WARN_ON(in_interrupt());
> - idr_preload(gfp);
> - spin_lock(&pasid_lock);
> - ret = idr_alloc(&pasid_idr, ptr, min, max, GFP_ATOMIC);
> - spin_unlock(&pasid_lock);
> - idr_preload_end();
> -
> - return ret;
> -}
> -
> -void intel_pasid_free_id(int pasid)
> -{
> - spin_lock(&pasid_lock);
> - idr_remove(&pasid_idr, pasid);
> - spin_unlock(&pasid_lock);
> -}
> -
> -void *intel_pasid_lookup_id(int pasid)
> -{
> - void *p;
> -
> - spin_lock(&pasid_lock);
> - p = idr_find(&pasid_idr, pasid);
> - spin_unlock(&pasid_lock);
> -
> - return p;
> -}
>
> static int check_vcmd_pasid(struct intel_iommu *iommu)
> {
> diff --git a/drivers/iommu/intel-svm.c b/drivers/iommu/intel-svm.c
> index 9b159132405d..5aef5b7bf561 100644
> --- a/drivers/iommu/intel-svm.c
> +++ b/drivers/iommu/intel-svm.c
> @@ -17,6 +17,7 @@
> #include <linux/dmar.h>
> #include <linux/interrupt.h>
> #include <linux/mm_types.h>
> +#include <linux/ioasid.h>
> #include <asm/page.h>
>
> #include "intel-pasid.h"
> @@ -318,16 +319,15 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
> if (pasid_max > intel_pasid_max_id)
> pasid_max = intel_pasid_max_id;
>
> - /* Do not use PASID 0 in caching mode (virtualised IOMMU) */
> - ret = intel_pasid_alloc_id(svm,
> - !!cap_caching_mode(iommu->cap),
> - pasid_max - 1, GFP_KERNEL);
> - if (ret < 0) {
> + /* Do not use PASID 0, reserved for RID to PASID */
> + svm->pasid = ioasid_alloc(NULL, PASID_MIN,
> + pasid_max - 1, svm);
> + if (svm->pasid == INVALID_IOASID) {
> kfree(svm);
> kfree(sdev);
> + ret = ENOSPC;
> goto out;
> }
> - svm->pasid = ret;
> svm->notifier.ops = &intel_mmuops;
> svm->mm = mm;
> svm->flags = flags;
> @@ -337,7 +337,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
> if (mm) {
> ret = mmu_notifier_register(&svm->notifier, mm);
> if (ret) {
> - intel_pasid_free_id(svm->pasid);
> + ioasid_free(svm->pasid);
> kfree(svm);
> kfree(sdev);
> goto out;
> @@ -353,7 +353,7 @@ int intel_svm_bind_mm(struct device *dev, int *pasid, int flags, struct svm_dev_
> if (ret) {
> if (mm)
> mmu_notifier_unregister(&svm->notifier, mm);
> - intel_pasid_free_id(svm->pasid);
> + ioasid_free(svm->pasid);
> kfree(svm);
> kfree(sdev);
> goto out;
> @@ -401,7 +401,12 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
> if (!iommu)
> goto out;
>
> - svm = intel_pasid_lookup_id(pasid);
> + svm = ioasid_find(NULL, pasid, NULL);
> + if (IS_ERR(svm)) {
> + ret = PTR_ERR(svm);
> + goto out;
> + }
> +
> if (!svm)
> goto out;
>
> @@ -423,7 +428,7 @@ int intel_svm_unbind_mm(struct device *dev, int pasid)
> kfree_rcu(sdev, rcu);
>
> if (list_empty(&svm->devs)) {
> - intel_pasid_free_id(svm->pasid);
> + ioasid_free(svm->pasid);
> if (svm->mm)
> mmu_notifier_unregister(&svm->notifier, svm->mm);
>
> @@ -458,10 +463,11 @@ int intel_svm_is_pasid_valid(struct device *dev, int pasid)
> if (!iommu)
> goto out;
>
> - svm = intel_pasid_lookup_id(pasid);
> - if (!svm)
> + svm = ioasid_find(NULL, pasid, NULL);
> + if (IS_ERR(svm)) {
> + ret = PTR_ERR(svm);
> goto out;
> -
> + }
> /* init_mm is used in this case */
> if (!svm->mm)
> ret = 1;
> @@ -568,13 +574,12 @@ static irqreturn_t prq_event_thread(int irq, void *d)
>
> if (!svm || svm->pasid != req->pasid) {
> rcu_read_lock();
> - svm = intel_pasid_lookup_id(req->pasid);
> + svm = ioasid_find(NULL, req->pasid, NULL);
> /* It *can't* go away, because the driver is not permitted
> * to unbind the mm while any page faults are outstanding.
> * So we only need RCU to protect the internal idr code. */
> rcu_read_unlock();
> -
> - if (!svm) {
> + if (IS_ERR(svm) || !svm) {
> pr_err("%s: Page request for invalid PASID %d: %08llx %08llx\n",
> iommu->name, req->pasid, ((unsigned long long *)req)[0],
> ((unsigned long long *)req)[1]);
> --
> 2.7.4
>
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