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Re: [PATCH v6 5/9] xen/arm: smmuv2: Add PCI devices support for SMMUv2
Hi Stewart,
On 09/11/2023 18:27, Stewart Hildebrand wrote:
From: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
In general, we should avoid blank commit. In this case, I think some
details would be useful about the implementation. Some of the details I
am interested in is how the logic works and why we don't handle the same
quarantine options as x86?
Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushchenko@xxxxxxxx>
Signed-off-by: Stewart Hildebrand <stewart.hildebrand@xxxxxxx>
---
v5->v6:
* check for hardware_domain == NULL (dom0less test case)
* locking: assign pdev->domain before list_add()
v4->v5:
* assign device to pdev->domain (usually dom0) by default in add_device() hook
* deassign from hwdom
* rebase on top of ("dynamic node programming using overlay dtbo") series
* remove TODO in comment about device prints
* add TODO regarding locking
* fixup after dropping ("xen/arm: Move is_protected flag to struct device")
v3->v4:
* add new device_is_protected check in add_device hook to match SMMUv3 and
IPMMU-VMSA drivers
v2->v3:
* invoke iommu_add_pci_sideband_ids() from add_device hook
v1->v2:
* ignore add_device/assign_device/reassign_device calls for phantom functions
(i.e. devfn != pdev->devfn)
downstream->v1:
* wrap unused function in #ifdef 0
* remove the remove_device() stub since it was submitted separately to the list
[XEN][PATCH v6 12/19] xen/smmu: Add remove_device callback for smmu_iommu ops
https://lists.xenproject.org/archives/html/xen-devel/2023-05/msg00204.html
* arm_smmu_(de)assign_dev: return error instead of crashing system
* update condition in arm_smmu_reassign_dev
* style fixup
* add && !is_hardware_domain(d) into condition in arm_smmu_assign_dev()
(cherry picked from commit 0c11a7f65f044c26d87d1e27ac6283ef1f9cfb7a from
the downstream branch spider-master from
https://github.com/xen-troops/xen.git)
---
xen/drivers/passthrough/arm/smmu.c | 199 ++++++++++++++++++++++++-----
1 file changed, 169 insertions(+), 30 deletions(-)
diff --git a/xen/drivers/passthrough/arm/smmu.c
b/xen/drivers/passthrough/arm/smmu.c
index 11fc1d22ef0a..24d1c0353025 100644
--- a/xen/drivers/passthrough/arm/smmu.c
+++ b/xen/drivers/passthrough/arm/smmu.c
@@ -131,11 +131,21 @@ enum irqreturn {
typedef enum irqreturn irqreturn_t;
-/* Device logger functions
- * TODO: Handle PCI
- */
-#define dev_print(dev, lvl, fmt, ...)
\
- printk(lvl "smmu: %s: " fmt, dt_node_full_name(dev_to_dt(dev)), ##
__VA_ARGS__)
+/* Device logger functions */
+#ifndef CONFIG_HAS_PCI
+#define dev_print(dev, lvl, fmt, ...) \
+ printk(lvl "smmu: %s: " fmt, dev_name(dev), ## __VA_ARGS__)
+#else
+#define dev_print(dev, lvl, fmt, ...) ({ \
+ if ( !dev_is_pci((dev)) ) \
+ printk(lvl "smmu: %s: " fmt, dev_name((dev)), ## __VA_ARGS__); \
+ else \
+ { \
+ struct pci_dev *pdev = dev_to_pci((dev)); \
+ printk(lvl "smmu: %pp: " fmt, &pdev->sbdf, ## __VA_ARGS__); \
+ } \
+})
+#endif
#define dev_dbg(dev, fmt, ...) dev_print(dev, XENLOG_DEBUG, fmt, ## __VA_ARGS__)
#define dev_notice(dev, fmt, ...) dev_print(dev, XENLOG_INFO, fmt, ##
__VA_ARGS__)
@@ -187,6 +197,7 @@ static void __iomem *devm_ioremap_resource(struct device
*dev,
* Xen: PCI functions
* TODO: It should be implemented when PCI will be supported
*/
+#if 0 /* unused */
#define to_pci_dev(dev) (NULL)
static inline int pci_for_each_dma_alias(struct pci_dev *pdev,
int (*fn) (struct pci_dev *pdev,
@@ -196,6 +207,7 @@ static inline int pci_for_each_dma_alias(struct pci_dev
*pdev,
BUG();
return 0;
}
+#endif
/* Xen: misc */
#define PHYS_MASK_SHIFT PADDR_BITS
@@ -631,7 +643,7 @@ struct arm_smmu_master_cfg {
for (i = 0; idx = cfg->smendx[i], i < num; ++i)
struct arm_smmu_master {
- struct device_node *of_node;
+ struct device *dev;
struct rb_node node;
struct arm_smmu_master_cfg cfg;
};
@@ -723,7 +735,7 @@ arm_smmu_get_fwspec(struct arm_smmu_master_cfg *cfg)
{
struct arm_smmu_master *master = container_of(cfg,
struct
arm_smmu_master, cfg);
- return dev_iommu_fwspec_get(&master->of_node->dev);
+ return dev_iommu_fwspec_get(master->dev);
}
static void parse_driver_options(struct arm_smmu_device *smmu)
@@ -756,7 +768,7 @@ static struct device_node *dev_get_dev_node(struct device
*dev)
}
static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
- struct device_node *dev_node)
+ struct device *dev)
{
struct rb_node *node = smmu->masters.rb_node;
@@ -765,9 +777,9 @@ static struct arm_smmu_master *find_smmu_master(struct arm_smmu_device *smmu,
master = container_of(node, struct arm_smmu_master, node);
- if (dev_node < master->of_node)
+ if (dev < master->dev)
node = node->rb_left;
- else if (dev_node > master->of_node)
+ else if (dev > master->dev)
node = node->rb_right;
else
return master;
@@ -802,9 +814,9 @@ static int insert_smmu_master(struct arm_smmu_device *smmu,
= container_of(*new, struct arm_smmu_master, node);
parent = *new;
- if (master->of_node < this->of_node)
+ if (master->dev < this->dev)
new = &((*new)->rb_left);
- else if (master->of_node > this->of_node)
+ else if (master->dev > this->dev)
new = &((*new)->rb_right);
else
return -EEXIST;
@@ -836,28 +848,37 @@ static int arm_smmu_dt_add_device_legacy(struct
arm_smmu_device *smmu,
struct arm_smmu_master *master;
struct device_node *dev_node = dev_get_dev_node(dev);
Looking at this call, there is a Todo "Add support of PCI". If this
function is now only meant to be used for platform device, then should
we remove the TODO in it?
- master = find_smmu_master(smmu, dev_node);
+ master = find_smmu_master(smmu, dev);
if (master) {
dev_err(dev,
"rejecting multiple registrations for master device
%s\n",
- dev_node->name);
+ dev_node ? dev_node->name : "");
Printing "" looks a bit odd. But I wonder if this is actually redundant
with the content printed by dev_err()?
return -EBUSY;
}
master = devm_kzalloc(dev, sizeof(*master), GFP_KERNEL);
if (!master)
return -ENOMEM;
- master->of_node = dev_node;
+ master->dev = dev;
- /* Xen: Let Xen know that the device is protected by an SMMU */
- dt_device_set_protected(dev_node);
+ if ( !dev_is_pci(dev) )
I think a comment should stay to explain how someone known that the PCI
device will be protected by an IOMMU.
+ {
+ if ( dt_device_is_protected(dev_node) )
+ {
+ dev_err(dev, "Already added to SMMU\n");
+ return -EEXIST;
+ }
This checks seems to be unrelated with the rest of the patch. Can you
explain?
+
+ /* Xen: Let Xen know that the device is protected by an SMMU */
+ dt_device_set_protected(dev_node);
+ }
for (i = 0; i < fwspec->num_ids; ++i) {
if (!(smmu->features & ARM_SMMU_FEAT_STREAM_MATCH) &&
(fwspec->ids[i] >= smmu->num_mapping_groups)) {
dev_err(dev,
"stream ID for master device %s greater than maximum
allowed (%d)\n",
- dev_node->name, smmu->num_mapping_groups);
+ dev_node ? dev_node->name : "",
smmu->num_mapping_groups);
Same remark as above for "".
return -ERANGE;
}
master->cfg.smendx[i] = INVALID_SMENDX;
@@ -872,7 +893,7 @@ static int arm_smmu_dt_remove_device_legacy(struct
arm_smmu_device *smmu,
struct device_node *dev_node = dev_get_dev_node(dev);
int ret;
- master = find_smmu_master(smmu, dev_node);
+ master = find_smmu_master(smmu, dev);
if (master == NULL) {
dev_err(dev,
"No registrations found for master device %s\n",
@@ -884,8 +905,9 @@ static int arm_smmu_dt_remove_device_legacy(struct
arm_smmu_device *smmu,
if (ret)
return ret;
- /* Protected by dt_host_lock and dtdevs_lock as caller holds these locks. */
- dev_node->is_protected = false;
+ if ( !dev_is_pci(dev) )
+ /* Protected by dt_host_lock and dtdevs_lock as caller holds
these locks. */
+ dev_node->is_protected = false;
kfree(master);
return 0;
@@ -914,6 +936,12 @@ static int register_smmu_master(struct arm_smmu_device
*smmu,
fwspec);
}
+/* Forward declaration */
+static int arm_smmu_assign_dev(struct domain *d, u8 devfn,
+ struct device *dev, u32 flag);
+static int arm_smmu_deassign_dev(struct domain *d, uint8_t devfn,
+ struct device *dev);
+
/*
* The driver which supports generic IOMMU DT bindings must have this
* callback implemented.
@@ -938,6 +966,22 @@ static int arm_smmu_dt_add_device_generic(u8 devfn, struct
device *dev)
{
struct arm_smmu_device *smmu;
struct iommu_fwspec *fwspec;
+ int ret;
+
+#ifdef CONFIG_HAS_PCI
+ if ( dev_is_pci(dev) )
+ {
+ struct pci_dev *pdev = dev_to_pci(dev);
+ int ret;
+
+ if ( devfn != pdev->devfn )
+ return 0;
+
+ ret = iommu_add_pci_sideband_ids(pdev);
+ if ( ret < 0 )
+ iommu_fwspec_free(dev);
+ }
+#endif
fwspec = dev_iommu_fwspec_get(dev);
if (fwspec == NULL)
@@ -947,7 +991,24 @@ static int arm_smmu_dt_add_device_generic(u8 devfn, struct
device *dev)
if (smmu == NULL)
return -ENXIO;
- return arm_smmu_dt_add_device_legacy(smmu, dev, fwspec);
+ ret = arm_smmu_dt_add_device_legacy(smmu, dev, fwspec);
+ if ( ret )
axc> + return ret;
+
+#ifdef CONFIG_HAS_PCI
+ if ( dev_is_pci(dev) )
+ {
+ struct pci_dev *pdev = dev_to_pci(dev);
+
+ /*
+ * During PHYSDEVOP_pci_device_add, Xen does not assign the
+ * device, so we must do it here.
+ */
In the context of dom0less, the hardware domain may not exist at all.
And even if it exists, you will first assign the device to the hardware
domain and then re-assign to the guest just after.
This looks wrong.
+ ret = arm_smmu_assign_dev(pdev->domain, devfn, dev, 0);
+ }
+#endif
+
+ return ret;
}
static int arm_smmu_dt_xlate_generic(struct device *dev,
@@ -970,11 +1031,10 @@ static struct arm_smmu_device
*find_smmu_for_device(struct device *dev)
{
struct arm_smmu_device *smmu;
struct arm_smmu_master *master = NULL;
- struct device_node *dev_node = dev_get_dev_node(dev);
spin_lock(&arm_smmu_devices_lock);
list_for_each_entry(smmu, &arm_smmu_devices, list) {
- master = find_smmu_master(smmu, dev_node);
+ master = find_smmu_master(smmu, dev);
if (master)
break;
}
@@ -2066,6 +2126,7 @@ static bool arm_smmu_capable(enum iommu_cap cap)
}
#endif
+#if 0 /* Not used */
static int __arm_smmu_get_pci_sid(struct pci_dev *pdev, u16 alias, void *data)
{
*((u16 *)data) = alias;
@@ -2076,6 +2137,7 @@ static void __arm_smmu_release_pci_iommudata(void *data)
{
kfree(data);
}
+#endif
static int arm_smmu_add_device(struct device *dev)
{
@@ -2083,12 +2145,13 @@ static int arm_smmu_add_device(struct device *dev)
struct arm_smmu_master_cfg *cfg;
struct iommu_group *group;
void (*releasefn)(void *data) = NULL;
- int ret;
smmu = find_smmu_for_device(dev);
if (!smmu)
return -ENODEV;
+ /* There is no need to distinguish here, thanks to PCI-IOMMU DT bindings */
+#if 0
if (dev_is_pci(dev)) {
struct pci_dev *pdev = to_pci_dev(dev);
struct iommu_fwspec *fwspec;
@@ -2113,10 +2176,12 @@ static int arm_smmu_add_device(struct device *dev)
&fwspec->ids[0]);
releasefn = __arm_smmu_release_pci_iommudata;
cfg->smmu = smmu;
- } else {
+ } else
+#endif
+ {
struct arm_smmu_master *master;
- master = find_smmu_master(smmu, dev->of_node);
+ master = find_smmu_master(smmu, dev);
if (!master) {
return -ENODEV;
}
@@ -2784,6 +2849,61 @@ static int arm_smmu_assign_dev(struct domain *d, u8
devfn,
return -ENOMEM;
}
+#ifdef CONFIG_HAS_PCI
+ if ( dev_is_pci(dev) && !is_hardware_domain(d) )
+ {
+ struct pci_dev *pdev = dev_to_pci(dev);
+
+ printk(XENLOG_INFO "Assigning device %04x:%02x:%02x.%u to
dom%d\n",
+ pdev->seg, pdev->bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+ d->domain_id);
Is this a left-over debug? If not, shouldn't this happen in a caller
instead because this is quite generic?
+
+ if ( devfn != pdev->devfn || pdev->domain == d )
+ return 0;
+
+ ASSERT(pcidevs_locked());
+
+ /* TODO: acquire pci_lock */
What's the plan for this TODO? (The commit message is blank).
+#if 0
+ write_lock(&pdev->domain->pci_lock);
+#endif
+ list_del(&pdev->domain_list);
+#if 0
+ write_unlock(&pdev->domain->pci_lock);
+#endif
+
+ pdev->domain = d;
+
+#if 0
+ write_lock(&d->pci_lock);
+#endif
+ list_add(&pdev->domain_list, &d->pdev_list);
+#if 0
+ write_unlock(&d->pci_lock);
+#endif
+
+ if ( hardware_domain )
+ {
+ domain = dev_iommu_domain(dev);
+
+ /*
+ * Xen may not deassign the device from hwdom before
+ * assigning it elsewhere.
+ */
This comment leave more question than it really answer. Why can't Xen
call reassign? IOW, it feels wrong to reimplement re-assign within
assign. At mimimum, this should be consolidated.
+ if ( domain &&
is_hardware_domain(domain->priv->cfg.domain) )
+ {
+ ret = arm_smmu_deassign_dev(hardware_domain,
devfn, dev);
+ if ( ret )
+ return ret;
+ }
+ }
+
+ /* dom_io is used as a sentinel for quarantined devices */
+ if ( d == dom_io )
+ return 0;
+ }
+#endif
+
if (!dev_iommu_group(dev)) {
ret = arm_smmu_add_device(dev);
if (ret)
@@ -2833,11 +2953,30 @@ out:
return ret;
}
-static int arm_smmu_deassign_dev(struct domain *d, struct device *dev)
+static int arm_smmu_deassign_dev(struct domain *d, uint8_t devfn,
+ struct device *dev)
{
struct iommu_domain *domain = dev_iommu_domain(dev);
struct arm_smmu_xen_domain *xen_domain;
+#ifdef CONFIG_HAS_PCI
+ if ( dev_is_pci(dev) )
+ {
+ struct pci_dev *pdev = dev_to_pci(dev);
+
+ printk(XENLOG_INFO "Deassigning device %04x:%02x:%02x.%u from
dom%d\n",
+ pdev->seg, pdev->bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+ d->domain_id);
Same questions as above for the printk.
+
+ if ( devfn != pdev->devfn )
+ return 0;
I don't understand this check. Are you sanity checking pdev->devfn, and
if so shouldn't not this return an error?
+
+ /* dom_io is used as a sentinel for quarantined devices */
+ if ( d == dom_io )
+ return 0;
+ }
+#endif
+
xen_domain = dom_iommu(d)->arch.priv;
if (!domain || domain->priv->cfg.domain != d) {
@@ -2865,13 +3004,13 @@ static int arm_smmu_reassign_dev(struct domain *s,
struct domain *t,
int ret = 0;
/* Don't allow remapping on other domain than hwdom */
This comment now ...
- if ( t && !is_hardware_domain(t) )
+ if ( t && !is_hardware_domain(t) && t != dom_io )
... now doesn't match the check. You are also relaxing for everyone but
don't really explain why.
return -EPERM;
if (t == s)
return 0;
- ret = arm_smmu_deassign_dev(s, dev);
+ ret = arm_smmu_deassign_dev(s, devfn, dev);
if (ret)
return ret;
Cheers,
--
Julien Grall
|
