Re: [PATCH RFC v1 05/11] iommu/virtio: Add SVA feature and related enable/disable callbacks
On Fri, Apr 23, 2021 at 03:21:41PM +0530, Vivek Gautam wrote:
> Add a feature flag to virtio iommu for Shared virtual addressing
> (SVA). This feature would indicate the availablily path for handling
> device page faults, and the provision for sending page response.
In this case the feature should probably be called PAGE_REQUEST or
similar. SVA aggregates PF + PASID + shared page tables
Thanks,
Jean
> Also add necessary methods to enable and disable SVA so that the
> masters can enable the SVA path. This also requires enabling the
> PRI capability on the device.
>
> Signed-off-by: Vivek Gautam
> ---
> drivers/iommu/virtio-iommu.c | 268 ++
> include/uapi/linux/virtio_iommu.h | 1 +
> 2 files changed, 269 insertions(+)
>
> diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
> index 3da5f0807711..250c137a211b 100644
> --- a/drivers/iommu/virtio-iommu.c
> +++ b/drivers/iommu/virtio-iommu.c
> @@ -18,6 +18,7 @@
> #include
> #include
> #include
> +#include
> #include
> #include
> #include
> @@ -26,6 +27,7 @@
>
> #include
> #include "iommu-pasid-table.h"
> +#include "iommu-sva-lib.h"
>
> #define MSI_IOVA_BASE0x800
> #define MSI_IOVA_LENGTH 0x10
> @@ -37,6 +39,9 @@
> /* Some architectures need an Address Space ID for each page table */
> DEFINE_XARRAY_ALLOC1(viommu_asid_xa);
>
> +static DEFINE_MUTEX(sva_lock);
> +static DEFINE_MUTEX(iopf_lock);
> +
> struct viommu_dev_pri_work {
> struct work_struct work;
> struct viommu_dev *dev;
> @@ -71,6 +76,7 @@ struct viommu_dev {
>
> boolhas_map:1;
> boolhas_table:1;
> + boolhas_sva:1;
> };
>
> struct viommu_mapping {
> @@ -124,6 +130,12 @@ struct viommu_endpoint {
> void*pstf;
> /* Preferred page table format */
> void*pgtf;
> +
> + /* sva */
> + boolats_supported;
> + boolpri_supported;
> + boolsva_enabled;
> + booliopf_enabled;
> };
>
> struct viommu_ep_entry {
> @@ -582,6 +594,64 @@ static int viommu_add_pstf(struct viommu_endpoint *vdev,
> void *pstf, size_t len)
> return 0;
> }
>
> +static int viommu_init_ats_pri(struct viommu_endpoint *vdev)
> +{
> + struct device *dev = vdev->dev;
> + struct pci_dev *pdev = to_pci_dev(dev);
> +
> + if (!dev_is_pci(vdev->dev))
> + return -EINVAL;
> +
> + if (pci_ats_supported(pdev))
> + vdev->ats_supported = true;
> +
> + if (pci_pri_supported(pdev))
> + vdev->pri_supported = true;
> +
> + return 0;
> +}
> +
> +static int viommu_enable_pri(struct viommu_endpoint *vdev)
> +{
> + int ret;
> + struct pci_dev *pdev;
> +
> + /* Let's allow only 4 requests for PRI right now */
> + size_t max_inflight_pprs = 4;
> +
> + if (!vdev->pri_supported || !vdev->ats_supported)
> + return -ENODEV;
> +
> + pdev = to_pci_dev(vdev->dev);
> +
> + ret = pci_reset_pri(pdev);
> + if (ret)
> + return ret;
> +
> + ret = pci_enable_pri(pdev, max_inflight_pprs);
> + if (ret) {
> + dev_err(vdev->dev, "cannot enable PRI: %d\n", ret);
> + return ret;
> + }
> +
> + return 0;
> +}
> +
> +static void viommu_disable_pri(struct viommu_endpoint *vdev)
> +{
> + struct pci_dev *pdev;
> +
> + if (!dev_is_pci(vdev->dev))
> + return;
> +
> + pdev = to_pci_dev(vdev->dev);
> +
> + if (!pdev->pri_enabled)
> + return;
> +
> + pci_disable_pri(pdev);
> +}
> +
> static int viommu_init_queues(struct viommu_dev *viommu)
> {
> viommu->iopf_pri = iopf_queue_alloc(dev_name(viommu->dev));
> @@ -684,6 +754,10 @@ static int viommu_probe_endpoint(struct viommu_dev
> *viommu, struct device *dev)
> if (ret)
> goto out_free_eps;
>
> + ret = viommu_init_ats_pri(vdev);
> + if (ret)
> + goto out_free_eps;
> +
> kfree(probe);
> return 0;
>
> @@ -1681,6 +1755,194 @@ 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_endpoint_iopf_supported(struct viommu_endpoint *vdev)
> +{
> + /* TODO: support Stall model later */
> + return vdev->pri_supported;
> +}
> +
> +bool viommu_endpoint_sva_supported(struct viommu_endpoint *vdev)
> +{
> + struct viommu_dev *viommu = vdev->viommu;
> +
> + if (!viommu->has_sva)
> + return false;
> +
> + return vdev->pasid_bits;
> +}
> +
> +bool viommu_endpoint_sva_enabled(struct viommu_endpoint *vdev)
> +{
> + bool enabled;
> +
> + mutex_lock(_lock);
> +
[PATCH RFC v1 05/11] iommu/virtio: Add SVA feature and related enable/disable callbacks
Add a feature flag to virtio iommu for Shared virtual addressing
(SVA). This feature would indicate the availablily path for handling
device page faults, and the provision for sending page response.
Also add necessary methods to enable and disable SVA so that the
masters can enable the SVA path. This also requires enabling the
PRI capability on the device.
Signed-off-by: Vivek Gautam
---
drivers/iommu/virtio-iommu.c | 268 ++
include/uapi/linux/virtio_iommu.h | 1 +
2 files changed, 269 insertions(+)
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
index 3da5f0807711..250c137a211b 100644
--- a/drivers/iommu/virtio-iommu.c
+++ b/drivers/iommu/virtio-iommu.c
@@ -18,6 +18,7 @@
#include
#include
#include
+#include
#include
#include
#include
@@ -26,6 +27,7 @@
#include
#include "iommu-pasid-table.h"
+#include "iommu-sva-lib.h"
#define MSI_IOVA_BASE 0x800
#define MSI_IOVA_LENGTH0x10
@@ -37,6 +39,9 @@
/* Some architectures need an Address Space ID for each page table */
DEFINE_XARRAY_ALLOC1(viommu_asid_xa);
+static DEFINE_MUTEX(sva_lock);
+static DEFINE_MUTEX(iopf_lock);
+
struct viommu_dev_pri_work {
struct work_struct work;
struct viommu_dev *dev;
@@ -71,6 +76,7 @@ struct viommu_dev {
boolhas_map:1;
boolhas_table:1;
+ boolhas_sva:1;
};
struct viommu_mapping {
@@ -124,6 +130,12 @@ struct viommu_endpoint {
void*pstf;
/* Preferred page table format */
void*pgtf;
+
+ /* sva */
+ boolats_supported;
+ boolpri_supported;
+ boolsva_enabled;
+ booliopf_enabled;
};
struct viommu_ep_entry {
@@ -582,6 +594,64 @@ static int viommu_add_pstf(struct viommu_endpoint *vdev,
void *pstf, size_t len)
return 0;
}
+static int viommu_init_ats_pri(struct viommu_endpoint *vdev)
+{
+ struct device *dev = vdev->dev;
+ struct pci_dev *pdev = to_pci_dev(dev);
+
+ if (!dev_is_pci(vdev->dev))
+ return -EINVAL;
+
+ if (pci_ats_supported(pdev))
+ vdev->ats_supported = true;
+
+ if (pci_pri_supported(pdev))
+ vdev->pri_supported = true;
+
+ return 0;
+}
+
+static int viommu_enable_pri(struct viommu_endpoint *vdev)
+{
+ int ret;
+ struct pci_dev *pdev;
+
+ /* Let's allow only 4 requests for PRI right now */
+ size_t max_inflight_pprs = 4;
+
+ if (!vdev->pri_supported || !vdev->ats_supported)
+ return -ENODEV;
+
+ pdev = to_pci_dev(vdev->dev);
+
+ ret = pci_reset_pri(pdev);
+ if (ret)
+ return ret;
+
+ ret = pci_enable_pri(pdev, max_inflight_pprs);
+ if (ret) {
+ dev_err(vdev->dev, "cannot enable PRI: %d\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static void viommu_disable_pri(struct viommu_endpoint *vdev)
+{
+ struct pci_dev *pdev;
+
+ if (!dev_is_pci(vdev->dev))
+ return;
+
+ pdev = to_pci_dev(vdev->dev);
+
+ if (!pdev->pri_enabled)
+ return;
+
+ pci_disable_pri(pdev);
+}
+
static int viommu_init_queues(struct viommu_dev *viommu)
{
viommu->iopf_pri = iopf_queue_alloc(dev_name(viommu->dev));
@@ -684,6 +754,10 @@ static int viommu_probe_endpoint(struct viommu_dev
*viommu, struct device *dev)
if (ret)
goto out_free_eps;
+ ret = viommu_init_ats_pri(vdev);
+ if (ret)
+ goto out_free_eps;
+
kfree(probe);
return 0;
@@ -1681,6 +1755,194 @@ 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_endpoint_iopf_supported(struct viommu_endpoint *vdev)
+{
+ /* TODO: support Stall model later */
+ return vdev->pri_supported;
+}
+
+bool viommu_endpoint_sva_supported(struct viommu_endpoint *vdev)
+{
+ struct viommu_dev *viommu = vdev->viommu;
+
+ if (!viommu->has_sva)
+ return false;
+
+ return vdev->pasid_bits;
+}
+
+bool viommu_endpoint_sva_enabled(struct viommu_endpoint *vdev)
+{
+ bool enabled;
+
+ mutex_lock(_lock);
+ enabled = vdev->sva_enabled;
+ mutex_unlock(_lock);
+ return enabled;
+}
+
+static int viommu_endpoint_sva_enable_iopf(struct viommu_endpoint *vdev)
+{
+ int ret;
+ struct device *dev = vdev->dev;
+
+ if (!viommu_endpoint_iopf_supported(vdev))
+ return 0;
+
+ if (!vdev->iopf_enabled)
+ return -EINVAL;
+
+ if (vdev->pri_supported) {
+
