From: Jason Wang <jasowang@redhat.com> To: Lu Baolu <baolu.lu@linux.intel.com>, tglx@linutronix.de, ashok.raj@intel.com, kevin.tian@intel.com, dave.jiang@intel.com, megha.dey@intel.com, dwmw2@infradead.org Cc: alex.williamson@redhat.com, bhelgaas@google.com, dan.j.williams@intel.com, will@kernel.org, joro@8bytes.org, dmaengine@vger.kernel.org, eric.auger@redhat.com, jacob.jun.pan@intel.com, jgg@mellanox.com, kvm@vger.kernel.org, kwankhede@nvidia.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, iommu@lists.linux-foundation.org, maz@kernel.org, mona.hossain@intel.com, netanelg@mellanox.com, parav@mellanox.com, pbonzini@redhat.com, rafael@kernel.org, samuel.ortiz@intel.com, sanjay.k.kumar@intel.com, shahafs@mellanox.com, tony.luck@intel.com, vkoul@kernel.org, yan.y.zhao@linux.intel.com, yi.l.liu@intel.com, leon@kernel.org Subject: Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU Date: Fri, 15 Jan 2021 12:46:28 +0800 [thread overview] Message-ID: <f2a50326-58de-919a-5992-130224c5725a@redhat.com> (raw) In-Reply-To: <20210114013003.297050-2-baolu.lu@linux.intel.com> On 2021/1/14 上午9:30, Lu Baolu wrote: > Some vendor IOMMU drivers are able to declare that it is running in a VM > context. This is very valuable for the features that only want to be > supported on bare metal. Add a capability bit so that it could be used. > > Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> > --- > drivers/iommu/intel/iommu.c | 20 ++++++++++++++++++++ > drivers/iommu/virtio-iommu.c | 9 +++++++++ > include/linux/iommu.h | 1 + > 3 files changed, 30 insertions(+) > > diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c > index cb205a04fe4c..8eb022d0e8aa 100644 > --- a/drivers/iommu/intel/iommu.c > +++ b/drivers/iommu/intel/iommu.c > @@ -5738,12 +5738,32 @@ static inline bool nested_mode_support(void) > return ret; > } > > +static inline bool caching_mode_enabled(void) > +{ > + struct dmar_drhd_unit *drhd; > + struct intel_iommu *iommu; > + bool ret = false; > + > + rcu_read_lock(); > + for_each_active_iommu(iommu, drhd) { > + if (cap_caching_mode(iommu->cap)) { > + ret = true; > + break; > + } > + } > + rcu_read_unlock(); > + > + return ret; > +} > + > static bool intel_iommu_capable(enum iommu_cap cap) > { > if (cap == IOMMU_CAP_CACHE_COHERENCY) > return domain_update_iommu_snooping(NULL) == 1; > if (cap == IOMMU_CAP_INTR_REMAP) > return irq_remapping_enabled == 1; > + if (cap == IOMMU_CAP_VIOMMU) > + return caching_mode_enabled(); This part I don't understand. Does it mean Intel IOMMU can't be used in VM without caching mode? Thanks > > return false; > } > diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c > index 2bfdd5734844..719793e103db 100644 > --- a/drivers/iommu/virtio-iommu.c > +++ b/drivers/iommu/virtio-iommu.c > @@ -931,7 +931,16 @@ static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args) > return iommu_fwspec_add_ids(dev, args->args, 1); > } > > +static bool viommu_capable(enum iommu_cap cap) > +{ > + if (cap == IOMMU_CAP_VIOMMU) > + return true; > + > + return false; > +} > + > static struct iommu_ops viommu_ops = { > + .capable = viommu_capable, > .domain_alloc = viommu_domain_alloc, > .domain_free = viommu_domain_free, > .attach_dev = viommu_attach_dev, > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index b95a6f8db6ff..1d24be667a03 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -94,6 +94,7 @@ enum iommu_cap { > transactions */ > IOMMU_CAP_INTR_REMAP, /* IOMMU supports interrupt isolation */ > IOMMU_CAP_NOEXEC, /* IOMMU_NOEXEC flag */ > + IOMMU_CAP_VIOMMU, /* IOMMU can declar running in a VM */ > }; > > /*
next prev parent reply other threads:[~2021-01-15 4:48 UTC|newest] Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-01-14 1:30 [RFC PATCH v3 0/2] Add platform check for subdevice irq domain Lu Baolu 2021-01-14 1:30 ` [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU Lu Baolu 2021-01-14 13:26 ` Leon Romanovsky 2021-01-14 23:49 ` Lu Baolu 2021-01-15 6:31 ` Leon Romanovsky 2021-01-16 1:20 ` Lu Baolu 2021-01-16 8:39 ` Leon Romanovsky 2021-01-16 8:47 ` Lu Baolu 2021-01-17 5:30 ` Leon Romanovsky 2021-01-15 4:46 ` Jason Wang [this message] 2021-01-14 1:30 ` [RFC PATCH v3 2/2] platform-msi: Add platform check for subdevice irq domain Lu Baolu 2021-01-14 3:03 ` Tian, Kevin
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