|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v7 09/34] 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>
Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Reviewed-by: Julien Grall <julien.grall@xxxxxxx>
---
xen/arch/arm/gic-v3-its.c | 346 +++++++++++++++++++++++++++++++++++++++
xen/arch/arm/vgic-v3-its.c | 4 +
xen/include/asm-arm/domain.h | 3 +
xen/include/asm-arm/gic_v3_its.h | 13 ++
4 files changed, 366 insertions(+)
diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
index 0164b96..07280b3 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_device {
+ 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);
@@ -157,6 +179,20 @@ static int its_send_cmd_sync(struct host_its *its,
unsigned int cpu)
return its_send_command(its, cmd);
}
+static int its_send_cmd_mapti(struct host_its *its,
+ uint32_t deviceid, uint32_t eventid,
+ uint32_t pintid, uint16_t icid)
+{
+ uint64_t cmd[4];
+
+ cmd[0] = GITS_CMD_MAPTI | ((uint64_t)deviceid << 32);
+ cmd[1] = eventid | ((uint64_t)pintid << 32);
+ cmd[2] = icid;
+ cmd[3] = 0x00;
+
+ return its_send_command(its, cmd);
+}
+
static int its_send_cmd_mapc(struct host_its *its, uint32_t collection_id,
unsigned int cpu)
{
@@ -171,6 +207,43 @@ 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(size_bits > 0);
+ ASSERT(!(itt_addr & ~GENMASK(51, 8)));
+
+ /* The number of events is encoded as "number of bits minus one". */
+ size_bits--;
+ }
+ cmd[0] = GITS_CMD_MAPD | ((uint64_t)deviceid << 32);
+ cmd[1] = size_bits;
+ 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)
+{
+ uint64_t cmd[4];
+
+ cmd[0] = GITS_CMD_INV | ((uint64_t)deviceid << 32);
+ cmd[1] = eventid;
+ cmd[2] = 0x00;
+ cmd[3] = 0x00;
+
+ return its_send_command(its, cmd);
+}
+
/* Set up the (1:1) collection mapping for the given host CPU. */
int gicv3_its_setup_collection(unsigned int cpu)
{
@@ -450,6 +523,279 @@ int gicv3_its_init(void)
return 0;
}
+/*
+ * TODO: Investigate the interaction when a guest removes a device while
+ * some LPIs are still in flight.
+ */
+static int remove_mapped_guest_device(struct its_device *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, 0, 0, false);
+
+ for ( i = 0; i < 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);
+
+ /* This should never happen, but just in case ... */
+ if ( ret && printk_ratelimit() )
+ printk(XENLOG_WARNING "Can't unmap host ITS device 0x%x\n",
+ dev->host_devid);
+
+ 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_device *dev,
+ paddr_t vdoorbell, uint32_t vdevid)
+{
+ if ( dev->guest_doorbell < vdoorbell )
+ return -1;
+
+ if ( dev->guest_doorbell > vdoorbell )
+ return 1;
+
+ if ( dev->guest_devid < vdevid )
+ return -1;
+
+ if ( dev->guest_devid > vdevid )
+ 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,
+ * increasing both @eventid and @lpi to cover the number of requested LPIs.
+ */
+static int gicv3_its_map_host_events(struct host_its *its,
+ uint32_t devid, uint32_t eventid,
+ uint32_t lpi, uint32_t nr_events)
+{
+ uint32_t i;
+ int ret;
+
+ for ( i = 0; i < nr_events; i++ )
+ {
+ /* For now we map every host LPI to host CPU 0 */
+ ret = its_send_cmd_mapti(its, devid, eventid + i, lpi + i, 0);
+ if ( ret )
+ return ret;
+
+ ret = its_send_cmd_inv(its, devid, eventid + i);
+ if ( ret )
+ return ret;
+ }
+
+ /* TODO: Consider using INVALL here. Didn't work on the model, though. */
+
+ ret = its_send_cmd_sync(its, 0);
+ if ( ret )
+ return ret;
+
+ 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,
+ uint64_t nr_events, bool valid)
+{
+ void *itt_addr = NULL;
+ struct host_its *hw_its;
+ struct its_device *dev = NULL;
+ struct rb_node **new = &d->arch.vgic.its_devices.rb_node, *parent = NULL;
+ int i, ret = -ENOENT; /* "i" must be signed to check for >= 0 below.
*/
+
+ hw_its = gicv3_its_find_by_doorbell(host_doorbell);
+ if ( !hw_its )
+ return ret;
+
+ /* Sanitise the provided hardware values against the host ITS. */
+ if ( host_devid >= BIT(hw_its->devid_bits) )
+ return -EINVAL;
+
+ /*
+ * The ITS requires the number of events to be a power of 2. We allocate
+ * events and LPIs in chunks of LPI_BLOCK (=32), so make sure we
+ * allocate at least that many.
+ * TODO: Investigate if the number of events can be limited to smaller
+ * values if the guest does not require that many.
+ */
+ nr_events = BIT(fls(nr_events - 1));
+ if ( nr_events < LPI_BLOCK )
+ nr_events = LPI_BLOCK;
+ if ( nr_events >= BIT(hw_its->evid_bits) )
+ return -EINVAL;
+
+ /* check for already existing mappings */
+ spin_lock(&d->arch.vgic.its_devices_lock);
+ while ( *new )
+ {
+ struct its_device *temp;
+ int cmp;
+
+ temp = rb_entry(*new, struct its_device, 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 )
+ {
+ printk(XENLOG_G_WARNING "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_device);
+ 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.
+ * Pre-allocating memory for each *possible* LPI would be using way
+ * too much memory (they can be sparsely used by the guest), also
+ * allocating them on demand requires memory allocation in the interrupt
+ * injection code path, which is not really desired.
+ * So we compromise here by pre-allocating memory for each possible event
+ * up to the max specified by MAPD.
+ * See the mailing list discussion for some background:
+ * https://lists.xen.org/archives/html/xen-devel/2017-03/msg03645.html
+ */
+ 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, nr_events);
+ if ( !dev->host_lpi_blocks )
+ goto out_unlock;
+
+ ret = its_send_cmd_mapd(hw_its, host_devid, fls(nr_events - 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 < nr_events / LPI_BLOCK; i++ )
+ {
+ ret = gicv3_allocate_host_lpi_block(d, &dev->host_lpi_blocks[i]);
+ if ( ret < 0 )
+ break;
+
+ ret = gicv3_its_map_host_events(hw_its, host_devid, i * LPI_BLOCK,
+ dev->host_lpi_blocks[i], LPI_BLOCK);
+ if ( ret < 0 )
+ break;
+ }
+
+ if ( ret )
+ {
+ /* Clean up all allocated host LPI blocks. */
+ for ( ; i >= 0; i-- )
+ {
+ if ( dev->host_lpi_blocks[i] )
+ gicv3_free_host_lpi_block(dev->host_lpi_blocks[i]);
+ }
+
+ /*
+ * Unmapping the device will discard all LPIs mapped so far.
+ * We are already on the failing path, so no error checking to
+ * not mask the original error value. This should never fail anyway.
+ */
+ its_send_cmd_mapd(hw_its, host_devid, 0, 0, false);
+
+ 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;
+}
+
/* 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-its.c b/xen/arch/arm/vgic-v3-its.c
index 2f1a255..065ffe2 100644
--- a/xen/arch/arm/vgic-v3-its.c
+++ b/xen/arch/arm/vgic-v3-its.c
@@ -69,11 +69,15 @@ struct vits_itte
int vgic_v3_its_init_domain(struct domain *d)
{
+ spin_lock_init(&d->arch.vgic.its_devices_lock);
+ d->arch.vgic.its_devices = RB_ROOT;
+
return 0;
}
void vgic_v3_its_free_domain(struct domain *d)
{
+ ASSERT(RB_EMPTY_ROOT(&d->arch.vgic.its_devices));
}
/*
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 68185e2..6de8082 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 84d1692..29559a3 100644
--- a/xen/include/asm-arm/gic_v3_its.h
+++ b/xen/include/asm-arm/gic_v3_its.h
@@ -98,7 +98,10 @@
#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 @@ int gicv3_its_setup_collection(unsigned int cpu);
int vgic_v3_its_init_domain(struct domain *d);
void vgic_v3_its_free_domain(struct domain *d);
+/*
+ * 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,
+ uint64_t nr_events, bool valid);
+
int gicv3_allocate_host_lpi_block(struct domain *d, uint32_t *first_lpi);
void gicv3_free_host_lpi_block(uint32_t first_lpi);
--
2.8.2
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |