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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v4 08/27] ARM: GICv3 ITS: introduce device mapping
The ITS uses device IDs to map LPIs to a device. Dom0 will later use
those IDs, which we directly pass on to the host.
For this we have to map each device that Dom0 may request to a host
ITS device with the same identifier.
Allocate the respective memory and enter each device into an rbtree to
later be able to iterate over it or to easily teardown guests.
Because device IDs are per ITS, we need to identify a virtual ITS. We
use the doorbell address for that purpose, as it is a nice architectural
MSI property and spares us handling with opaque pointer or break
the VGIC abstraction.
Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
---
xen/arch/arm/gic-v3-its.c | 266 +++++++++++++++++++++++++++++++++++++++
xen/arch/arm/vgic-v3.c | 4 +
xen/include/asm-arm/domain.h | 3 +
xen/include/asm-arm/gic_v3_its.h | 17 +++
4 files changed, 290 insertions(+)
diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index bd189e8..c7c32b9 100644
--- a/xen/arch/arm/gic-v3-its.c
+++ b/xen/arch/arm/gic-v3-its.c
@@ -21,6 +21,8 @@
#include <xen/lib.h>
#include <xen/delay.h>
#include <xen/mm.h>
+#include <xen/rbtree.h>
+#include <xen/sched.h>
#include <xen/sizes.h>
#include <asm/gic.h>
#include <asm/gic_v3_defs.h>
@@ -36,6 +38,26 @@
*/
LIST_HEAD(host_its_list);
+/*
+ * Describes a device which is using the ITS and is used by a guest.
+ * Since device IDs are per ITS (in contrast to vLPIs, which are per
+ * guest), we have to differentiate between different virtual ITSes.
+ * We use the doorbell address here, since this is a nice architectural
+ * property of MSIs in general and we can easily get to the base address
+ * of the ITS and look that up.
+ */
+struct its_devices {
+ struct rb_node rbnode;
+ struct host_its *hw_its;
+ void *itt_addr;
+ paddr_t guest_doorbell; /* Identifies the virtual ITS */
+ uint32_t host_devid;
+ uint32_t guest_devid;
+ uint32_t eventids; /* Number of event IDs (MSIs) */
+ uint32_t *host_lpi_blocks; /* Which LPIs are used on the host */
+ struct pending_irq *pend_irqs; /* One struct per event */
+};
+
bool gicv3_its_host_has_its(void)
{
return !list_empty(&host_its_list);
@@ -170,6 +192,26 @@ static int its_send_cmd_mapc(struct host_its *its,
uint32_t collection_id,
return its_send_command(its, cmd);
}
+static int its_send_cmd_mapd(struct host_its *its, uint32_t deviceid,
+ uint8_t size_bits, paddr_t itt_addr, bool valid)
+{
+ uint64_t cmd[4];
+
+ if ( valid )
+ {
+ ASSERT(size_bits <= its->evid_bits);
+ ASSERT(!(itt_addr & ~GENMASK_ULL(51, 8)));
+ }
+ cmd[0] = GITS_CMD_MAPD | ((uint64_t)deviceid << 32);
+ cmd[1] = size_bits - 1;
+ cmd[2] = itt_addr;
+ if ( valid )
+ cmd[2] |= GITS_VALID_BIT;
+ cmd[3] = 0x00;
+
+ return its_send_command(its, cmd);
+}
+
static int its_send_cmd_inv(struct host_its *its,
uint32_t deviceid, uint32_t eventid)
{
@@ -464,6 +506,64 @@ int gicv3_its_init(void)
return 0;
}
+static int remove_mapped_guest_device(struct its_devices *dev)
+{
+ int ret = 0;
+ unsigned int i;
+
+ if ( dev->hw_its )
+ /* MAPD also discards all events with this device ID. */
+ ret = its_send_cmd_mapd(dev->hw_its, dev->host_devid, 1, 0, false);
+
+ for ( i = 0; i < DIV_ROUND_UP(dev->eventids, LPI_BLOCK); i++ )
+ gicv3_free_host_lpi_block(dev->host_lpi_blocks[i]);
+
+ /* Make sure the MAPD command above is really executed. */
+ if ( !ret )
+ ret = gicv3_its_wait_commands(dev->hw_its);
+
+ /* We can't free the ITT memory if the MAPD(V=0) failed for any reason. */
+ if ( !ret )
+ xfree(dev->itt_addr);
+
+ xfree(dev->pend_irqs);
+ xfree(dev->host_lpi_blocks);
+ xfree(dev);
+
+ return 0;
+}
+
+static struct host_its *gicv3_its_find_by_doorbell(paddr_t doorbell_address)
+{
+ struct host_its *hw_its;
+
+ list_for_each_entry(hw_its, &host_its_list, entry)
+ {
+ if ( hw_its->addr + ITS_DOORBELL_OFFSET == doorbell_address )
+ return hw_its;
+ }
+
+ return NULL;
+}
+
+static int compare_its_guest_devices(struct its_devices *dev,
+ paddr_t doorbell, uint32_t devid)
+{
+ if ( dev->guest_doorbell < doorbell )
+ return -1;
+
+ if ( dev->guest_doorbell > doorbell )
+ return 1;
+
+ if ( dev->guest_devid < devid )
+ return -1;
+
+ if ( dev->guest_devid > devid )
+ return 1;
+
+ return 0;
+}
+
/*
* On the host ITS @its, map @nr_events consecutive LPIs.
* The mapping connects a device @devid and event @eventid pair to LPI @lpi,
@@ -495,6 +595,172 @@ static int gicv3_its_map_host_events(struct host_its *its,
return gicv3_its_wait_commands(its);
}
+/*
+ * Map a hardware device, identified by a certain host ITS and its device ID
+ * to domain d, a guest ITS (identified by its doorbell address) and device ID.
+ * Also provide the number of events (MSIs) needed for that device.
+ * This does not check if this particular hardware device is already mapped
+ * at another domain, it is expected that this would be done by the caller.
+ */
+int gicv3_its_map_guest_device(struct domain *d,
+ paddr_t host_doorbell, uint32_t host_devid,
+ paddr_t guest_doorbell, uint32_t guest_devid,
+ uint32_t nr_events, bool valid)
+{
+ void *itt_addr = NULL;
+ struct host_its *hw_its;
+ struct its_devices *dev = NULL;
+ struct rb_node **new = &d->arch.vgic.its_devices.rb_node, *parent = NULL;
+ unsigned int i;
+ int ret = -ENOENT;
+
+ hw_its = gicv3_its_find_by_doorbell(host_doorbell);
+ if ( !hw_its )
+ return ret;
+
+ /* check for already existing mappings */
+ spin_lock(&d->arch.vgic.its_devices_lock);
+ while ( *new )
+ {
+ struct its_devices *temp;
+ int cmp;
+
+ temp = rb_entry(*new, struct its_devices, rbnode);
+
+ parent = *new;
+ cmp = compare_its_guest_devices(temp, guest_doorbell, guest_devid);
+ if ( !cmp )
+ {
+ if ( !valid )
+ rb_erase(&temp->rbnode, &d->arch.vgic.its_devices);
+
+ spin_unlock(&d->arch.vgic.its_devices_lock);
+
+ if ( valid )
+ {
+ gprintk(XENLOG_DEBUG, "d%d: tried to remap guest ITS device
0x%x to host device 0x%x\n",
+ d->domain_id, guest_devid, host_devid);
+ return -EBUSY;
+ }
+
+ return remove_mapped_guest_device(temp);
+ }
+
+ if ( cmp > 0 )
+ new = &((*new)->rb_left);
+ else
+ new = &((*new)->rb_right);
+ }
+
+ if ( !valid )
+ goto out_unlock;
+
+ ret = -ENOMEM;
+
+ /* An Interrupt Translation Table needs to be 256-byte aligned. */
+ itt_addr = _xzalloc(nr_events * hw_its->itte_size, 256);
+ if ( !itt_addr )
+ goto out_unlock;
+
+ dev = xzalloc(struct its_devices);
+ if ( !dev )
+ goto out_unlock;
+
+ /*
+ * Allocate the pending_irqs for each virtual LPI. They will be put
+ * into the domain's radix tree upon the guest's MAPTI command.
+ */
+ dev->pend_irqs = xzalloc_array(struct pending_irq, nr_events);
+ if ( !dev->pend_irqs )
+ goto out_unlock;
+
+ dev->host_lpi_blocks = xzalloc_array(uint32_t,
+ DIV_ROUND_UP(nr_events, LPI_BLOCK));
+ if ( !dev->host_lpi_blocks )
+ goto out_unlock;
+
+ ret = its_send_cmd_mapd(hw_its, host_devid,
+ fls(ROUNDUP(nr_events, LPI_BLOCK) - 1),
+ virt_to_maddr(itt_addr), true);
+ if ( ret )
+ goto out_unlock;
+
+ dev->itt_addr = itt_addr;
+ dev->hw_its = hw_its;
+ dev->guest_doorbell = guest_doorbell;
+ dev->guest_devid = guest_devid;
+ dev->host_devid = host_devid;
+ dev->eventids = nr_events;
+
+ rb_link_node(&dev->rbnode, parent, new);
+ rb_insert_color(&dev->rbnode, &d->arch.vgic.its_devices);
+
+ spin_unlock(&d->arch.vgic.its_devices_lock);
+
+ /*
+ * Map all host LPIs within this device already. We can't afford to queue
+ * any host ITS commands later on during the guest's runtime.
+ */
+ for ( i = 0; i < DIV_ROUND_UP(nr_events, LPI_BLOCK); i++ )
+ {
+ ret = gicv3_allocate_host_lpi_block(d, &dev->host_lpi_blocks[i]);
+ if ( ret < 0 )
+ goto out;
+
+ ret = gicv3_its_map_host_events(hw_its, host_devid, i * LPI_BLOCK,
+ dev->host_lpi_blocks[i], LPI_BLOCK);
+ if ( ret < 0 )
+ goto out;
+ }
+
+ return 0;
+
+out_unlock:
+ spin_unlock(&d->arch.vgic.its_devices_lock);
+
+out:
+ if ( dev )
+ {
+ xfree(dev->pend_irqs);
+ xfree(dev->host_lpi_blocks);
+ }
+ xfree(itt_addr);
+ xfree(dev);
+ return ret;
+}
+
+/* Removing any connections a domain had to any ITS in the system. */
+void gicv3_its_unmap_all_devices(struct domain *d)
+{
+ struct rb_node *victim;
+ struct its_devices *dev;
+
+ /*
+ * This is an easily readable, but sub-optimal implementation.
+ * It uses the provided iteration wrapper and erases each node, which
+ * possibly triggers rebalancing.
+ * This seems overkill since we are going to abolish the whole tree, but
+ * avoids an open-coded re-implementation of the traversal functions with
+ * some recursive function calls.
+ */
+ do {
+ spin_lock(&d->arch.vgic.its_devices_lock);
+
+ if ( (victim = rb_first(&d->arch.vgic.its_devices)) )
+ {
+
+ dev = rb_entry(victim, struct its_devices, rbnode);
+ rb_erase(victim, &d->arch.vgic.its_devices);
+
+ spin_unlock(&d->arch.vgic.its_devices_lock);
+
+ remove_mapped_guest_device(dev);
+ }
+ } while ( victim );
+
+ spin_unlock(&d->arch.vgic.its_devices_lock);
+}
+
/* Scan the DT for any ITS nodes and create a list of host ITSes out of it. */
void gicv3_its_dt_init(const struct dt_device_node *node)
{
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index 0679e76..3c7161b 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -1449,6 +1449,9 @@ static int vgic_v3_domain_init(struct domain *d)
d->arch.vgic.nr_regions = rdist_count;
d->arch.vgic.rdist_regions = rdist_regions;
+ spin_lock_init(&d->arch.vgic.its_devices_lock);
+ d->arch.vgic.its_devices = RB_ROOT;
+
/*
* Domain 0 gets the hardware address.
* Guests get the virtual platform layout.
@@ -1521,6 +1524,7 @@ static int vgic_v3_domain_init(struct domain *d)
static void vgic_v3_domain_free(struct domain *d)
{
+ gicv3_its_unmap_all_devices(d);
xfree(d->arch.vgic.rdist_regions);
}
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 09fe502..503a3cf 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -10,6 +10,7 @@
#include <asm/gic.h>
#include <public/hvm/params.h>
#include <xen/serial.h>
+#include <xen/rbtree.h>
struct hvm_domain
{
@@ -108,6 +109,8 @@ struct arch_domain
} *rdist_regions;
int nr_regions; /* Number of rdist regions */
uint32_t rdist_stride; /* Re-Distributor stride */
+ struct rb_root its_devices; /* Devices mapped to an ITS */
+ spinlock_t its_devices_lock; /* Protects the its_devices tree */
#endif
} vgic;
diff --git a/xen/include/asm-arm/gic_v3_its.h b/xen/include/asm-arm/gic_v3_its.h
index 0a96723..d8165c4 100644
--- a/xen/include/asm-arm/gic_v3_its.h
+++ b/xen/include/asm-arm/gic_v3_its.h
@@ -102,7 +102,10 @@
#define GITS_CMD_MOVALL 0x0e
#define GITS_CMD_DISCARD 0x0f
+#define ITS_DOORBELL_OFFSET 0x10040
+
#include <xen/device_tree.h>
+#include <xen/rbtree.h>
#define HOST_ITS_FLUSH_CMD_QUEUE (1U << 0)
#define HOST_ITS_USES_PTA (1U << 1)
@@ -148,6 +151,16 @@ uint64_t gicv3_get_redist_address(unsigned int cpu, bool
use_pta);
/* Map a collection for this host CPU to each host ITS. */
int gicv3_its_setup_collection(unsigned int cpu);
+/*
+ * Map a device on the host by allocating an ITT on the host (ITS).
+ * "nr_event" specifies how many events (interrupts) this device will need.
+ * Setting "valid" to false deallocates the device.
+ */
+int gicv3_its_map_guest_device(struct domain *d,
+ paddr_t host_doorbell, uint32_t host_devid,
+ paddr_t guest_doorbell, uint32_t guest_devid,
+ uint32_t nr_events, bool valid);
+void gicv3_its_unmap_all_devices(struct domain *d);
int gicv3_allocate_host_lpi_block(struct domain *d, uint32_t *first_lpi);
void gicv3_free_host_lpi_block(uint32_t first_lpi);
@@ -190,6 +203,10 @@ static inline int gicv3_its_setup_collection(unsigned int
cpu)
BUG();
}
+static inline void gicv3_its_unmap_all_devices(struct domain *d)
+{
+}
+
#endif /* CONFIG_HAS_ITS */
#endif
--
2.9.0
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