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Message-ID: <20191022211930.2ef8138f@jacob-builder>
Date: Tue, 22 Oct 2019 21:19:30 -0700
From: Jacob Pan <jacob.jun.pan@...ux.intel.com>
To: "Raj, Ashok" <ashok.raj@...el.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>,
jacob.jun.pan@...ux.intel.com
Subject: Re: [PATCH v6 03/10] iommu/vt-d: Replace Intel specific PASID
allocator with IOASID
On Tue, 22 Oct 2019 17:58:59 -0700
"Raj, Ashok" <ashok.raj@...el.com> wrote:
> 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?
>
Good point, but i think it is out of the scope of this patch. Perhaps
another patch to fix that.
> > }
> >
> > 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?
>
Yes, I agree we should double check IOMMU ecap PSS.
But it is outside the scope of this patch, which is merely replacing the
current logic with a different API.
Also, unless we do nested mdev, this code should run in host only,
no 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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