@@ -212,7 +212,7 @@ with the following properties:
enable only selected interfaces.
Under the "xen,domain" compatible node, one or more sub-nodes are present
-for the DomU kernel and ramdisk.
+for the DomU kernel, ramdisk and static event channel.
The kernel sub-node has the following properties:
@@ -254,11 +254,42 @@ The ramdisk sub-node has the following properties:
property because it will be created by the UEFI stub on boot.
This option is needed only when UEFI boot is used.
+The static event channel sub-node has the following properties:
+
+- compatible
+
+ "xen,evtchn"
+
+- xen,evtchn
+
+ The property is tuples of two numbers
+ (local-evtchn link-to-foreign-evtchn) where:
+
+ local-evtchn is an integer value that will be used to allocate local port
+ for a domain to send and receive event notifications to/from the remote
+ domain. Maximum supported value is 2^17 for FIFO ABI and 4096 for 2L ABI.
+
+ link-to-foreign-evtchn is a single phandle to a remote evtchn to which
+ local-evtchn will be connected.
Example
=======
chosen {
+
+ module@0 {
+ compatible = "multiboot,kernel", "multiboot,module";
+ xen,uefi-binary = "...";
+ bootargs = "...";
+
+ /* one sub-node per local event channel */
+ ec1: evtchn@1 {
+ compatible = "xen,evtchn-v1";
+ /* local-evtchn link-to-foreign-evtchn */
+ xen,evtchn = <0xa &ec2>;
+ };
+ };
+
domU1 {
compatible = "xen,domain";
#address-cells = <0x2>;
@@ -277,6 +308,23 @@ chosen {
compatible = "multiboot,ramdisk", "multiboot,module";
reg = <0x0 0x4b000000 0xffffff>;
};
+
+ /* one sub-node per local event channel */
+ ec2: evtchn@2 {
+ compatible = "xen,evtchn-v1";
+ /* local-evtchn link-to-foreign-evtchn */
+ xen,evtchn = <0xa &ec1>;
+ };
+
+ ec3: evtchn@3 {
+ compatible = "xen,evtchn-v1";
+ xen,evtchn = <0xb &ec5>;
+ };
+
+ ec4: evtchn@4 {
+ compatible = "xen,evtchn-v1";
+ xen,evtchn = <0xc &ec6>;
+ };
};
domU2 {
@@ -296,6 +344,18 @@ chosen {
compatible = "multiboot,ramdisk", "multiboot,module";
reg = <0x0 0x4d000000 0xffffff>;
};
+
+ /* one sub-node per local event channel */
+ ec5: evtchn@5 {
+ compatible = "xen,evtchn-v1";
+ /* local-evtchn link-to-foreign-evtchn */
+ xen,evtchn = <0xb &ec3>;
+ };
+
+ ec6: evtchn@6 {
+ compatible = "xen,evtchn-v1";
+ xen,evtchn = <0xd &ec4>;
+ };
};
};
@@ -3052,6 +3052,144 @@ void __init evtchn_allocate(struct domain *d)
d->arch.hvm.params[HVM_PARAM_CALLBACK_IRQ] = val;
}
+static int __init allocate_domain_evtchn(const struct dt_device_node *node)
+{
+ const void *prop = NULL;
+ const __be32 *cell;
+ uint32_t len, domU1_port, domU2_port, remote_phandle;
+ const struct dt_device_node *evtchn_node, *remote_node;
+ struct evtchn_alloc_unbound alloc_unbound;
+ struct evtchn_bind_interdomain bind_interdomain;
+ int rc;
+
+ dt_for_each_child_node(node, evtchn_node)
+ {
+ struct domain *d, *d1 = NULL, *d2 = NULL;
+
+ if ( !dt_device_is_compatible(evtchn_node, "xen,evtchn-v1") )
+ continue;
+
+ prop = dt_get_property(evtchn_node, "xen,evtchn", &len);
+ /* If the property is not found, return without errors */
+ if ( !prop )
+ return 0;
+
+ if ( !len )
+ {
+ printk(XENLOG_ERR "xen,evtchn property cannot be empty.\n");
+ return -EINVAL;
+ }
+
+ cell = (const __be32 *)prop;
+ domU1_port = dt_next_cell(1, &cell);
+ remote_phandle = dt_next_cell(1, &cell);
+
+ remote_node = dt_find_node_by_phandle(remote_phandle);
+ if ( !remote_node )
+ {
+ printk(XENLOG_ERR
+ "evtchn: could not find remote evtchn phandle\n");
+ return -EINVAL;
+ }
+
+ prop = dt_get_property(remote_node, "xen,evtchn", &len);
+ /* If the property is not found, return without errors */
+ if ( !prop )
+ return 0;
+
+ if ( !len )
+ {
+ printk(XENLOG_ERR "xen,evtchn property cannot be empty.\n");
+ return -EINVAL;
+ }
+
+ cell = (const __be32 *)prop;
+ domU2_port = dt_next_cell(1, &cell);
+ remote_phandle = dt_next_cell(1, &cell);
+
+ if ( evtchn_node->phandle != remote_phandle )
+ {
+ printk(XENLOG_ERR "xen,evtchn property is not setup correctly.\n");
+ return -EINVAL;
+ }
+
+ for_each_domain ( d )
+ {
+ if ( d->arch.node == node )
+ {
+ d1 = d;
+ continue;
+ }
+ if ( d->arch.node == dt_get_parent(remote_node) )
+ d2 = d;
+ }
+
+ if ( d1 == NULL )
+ {
+ if ( dt_device_is_compatible(node, "multiboot,kernel") )
+ d1 = hardware_domain;
+ else
+ {
+ printk(XENLOG_ERR "evtchn: could not find domain\n" );
+ return -EINVAL;
+ }
+ }
+
+ if ( d2 == NULL )
+ {
+ if ( dt_device_is_compatible(dt_get_parent(remote_node),
+ "multiboot,kernel") )
+ d2 = hardware_domain;
+ else
+ {
+ printk(XENLOG_ERR "evtchn: could not find domain\n" );
+ return -EINVAL;
+ }
+ }
+
+ alloc_unbound.dom = d1->domain_id;
+ alloc_unbound.remote_dom = d2->domain_id;
+
+ rc = evtchn_alloc_unbound(&alloc_unbound, domU1_port, true);
+ if ( rc < 0 && rc != -EBUSY )
+ {
+ printk(XENLOG_ERR
+ "evtchn_alloc_unbound() failure (Error %d) \n", rc);
+ return rc;
+ }
+
+ bind_interdomain.remote_dom = d1->domain_id;
+ bind_interdomain.remote_port = domU1_port;
+
+ rc = evtchn_bind_interdomain(&bind_interdomain, d2, domU2_port, true);
+ if ( rc < 0 && rc != -EBUSY )
+ {
+ printk(XENLOG_ERR
+ "evtchn_bind_interdomain() failure (Error %d) \n", rc);
+ return rc;
+ }
+ }
+
+ return 0;
+}
+
+void __init allocate_static_evtchn(void)
+{
+ struct dt_device_node *node;
+ const struct dt_device_node *chosen = dt_find_node_by_path("/chosen");
+
+ BUG_ON(chosen == NULL);
+ dt_for_each_child_node(chosen, node)
+ {
+ if ( dt_device_is_compatible(node, "xen,domain") ||
+ dt_device_is_compatible(node, "multiboot,kernel") )
+ {
+ if ( allocate_domain_evtchn(node) != 0 )
+ panic("Could not set up domains evtchn\n");
+ }
+ }
+}
+
static void __init find_gnttab_region(struct domain *d,
struct kernel_info *kinfo)
{
@@ -3358,6 +3496,7 @@ void __init create_domUs(void)
panic("Error creating domain %s\n", dt_node_name(node));
d->is_console = true;
+ d->arch.node = node;
if ( construct_domU(d, node) != 0 )
panic("Could not set up domain %s\n", dt_node_name(node));
@@ -104,6 +104,7 @@ struct arch_domain
#endif
bool directmap;
+ struct dt_device_node *node;
} __cacheline_aligned;
struct arch_vcpu
@@ -106,6 +106,7 @@ int acpi_make_efi_nodes(void *fdt, struct membank tbl_add[]);
void create_domUs(void);
void create_dom0(void);
+void allocate_static_evtchn(void);
void discard_initial_modules(void);
void fw_unreserved_regions(paddr_t s, paddr_t e,
@@ -1046,6 +1046,8 @@ void __init start_xen(unsigned long boot_phys_offset,
if ( acpi_disabled )
create_domUs();
+ allocate_static_evtchn();
+
/*
* This needs to be called **before** heap_init_late() so modules
* will be scrubbed (unless suppressed).
Introduce a new sub-node under /chosen node to establish static event channel communication between domains on dom0less systems. An event channel will be created beforehand to allow the domains to send notifications to each other. Signed-off-by: Rahul Singh <rahul.singh@arm.com> --- docs/misc/arm/device-tree/booting.txt | 62 +++++++++++- xen/arch/arm/domain_build.c | 139 ++++++++++++++++++++++++++ xen/arch/arm/include/asm/domain.h | 1 + xen/arch/arm/include/asm/setup.h | 1 + xen/arch/arm/setup.c | 2 + 5 files changed, 204 insertions(+), 1 deletion(-)