From: Leon Romanovsky <leon@kernel.org>
To: Lu Baolu <baolu.lu@linux.intel.com>
Cc: tglx@linutronix.de, ashok.raj@intel.com, kevin.tian@intel.com,
dave.jiang@intel.com, megha.dey@intel.com, dwmw2@infradead.org,
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
Subject: Re: [RFC PATCH v3 1/2] iommu: Add capability IOMMU_CAP_VIOMMU
Date: Thu, 14 Jan 2021 15:26:27 +0200 [thread overview]
Message-ID: <20210114132627.GA944463@unreal> (raw)
In-Reply-To: <20210114013003.297050-2-baolu.lu@linux.intel.com>
On Thu, Jan 14, 2021 at 09:30:02AM +0800, 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.
And how is it used? Who and how will set it?
>
> 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)
> +{
Kernel coding style is not in favour of inline functions in *.c files.
> + 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();
>
> 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 */
> };
>
> /*
> --
> 2.25.1
>
next prev parent reply other threads:[~2021-01-14 13:27 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 [this message]
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
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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