[xen staging] xen/dm: Introduce xendevicemodel_set_irq_level DM op

[patchbot@xxxxxxx]

commit 5d752df85f2c8faf87736cba05113435c7e9a9f1
Author:     Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
AuthorDate: Fri Jan 29 03:48:46 2021 +0200
Commit:     Julien Grall <jgrall@xxxxxxxxxx>
CommitDate: Fri Jan 29 16:55:23 2021 +0000

    xen/dm: Introduce xendevicemodel_set_irq_level DM op
    
    This patch adds ability to the device emulator to notify otherend
    (some entity running in the guest) using a SPI and implements Arm
    specific bits for it. Proposed interface allows emulator to set
    the logical level of a one of a domain's IRQ lines.
    
    We can't reuse the existing DM op (xen_dm_op_set_isa_irq_level)
    to inject an interrupt as the "isa_irq" field is only 8-bit and
    able to cover IRQ 0 - 255, whereas we need a wider range (0 - 1020).
    
    Please note, for egde-triggered interrupt (which is used for
    the virtio-mmio emulation) we only trigger the interrupt on Arm
    if the level is asserted (rising edge) and do nothing if the level
    is deasserted (falling edge), so the call could be named "trigger_irq"
    (without the level parameter). But, in order to model the line closely
    (to be able to support level-triggered interrupt) we need to know whether
    the line is low or high, so the proposed interface has been chosen.
    However, it is worth mentioning that in case of the level-triggered
    interrupt, we should keep injecting the interrupt to the guest until
    the line is deasserted (this is not covered by current patch).
    
    Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
    Signed-off-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@xxxxxxxx>
    Acked-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Acked-by: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
    [On Arm only]
    Tested-by: Wei Chen <Wei.Chen@xxxxxxx>
---
 tools/include/xendevicemodel.h               |  4 +++
 tools/libs/devicemodel/core.c                | 18 ++++++++++
 tools/libs/devicemodel/libxendevicemodel.map |  1 +
 xen/arch/arm/dm.c                            | 54 +++++++++++++++++++++++++++-
 xen/include/public/hvm/dm_op.h               | 16 +++++++++
 5 files changed, 92 insertions(+), 1 deletion(-)

diff --git a/tools/include/xendevicemodel.h b/tools/include/xendevicemodel.h
index e877f5c8a6..c06b3c84b9 100644
--- a/tools/include/xendevicemodel.h
+++ b/tools/include/xendevicemodel.h
@@ -209,6 +209,10 @@ int xendevicemodel_set_isa_irq_level(
     xendevicemodel_handle *dmod, domid_t domid, uint8_t irq,
     unsigned int level);
 
+int xendevicemodel_set_irq_level(
+    xendevicemodel_handle *dmod, domid_t domid, unsigned int irq,
+    unsigned int level);
+
 /**
  * This function maps a PCI INTx line to a an IRQ line.
  *
diff --git a/tools/libs/devicemodel/core.c b/tools/libs/devicemodel/core.c
index 4d4063956d..30bd79f8ba 100644
--- a/tools/libs/devicemodel/core.c
+++ b/tools/libs/devicemodel/core.c
@@ -430,6 +430,24 @@ int xendevicemodel_set_isa_irq_level(
     return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
 }
 
+int xendevicemodel_set_irq_level(
+    xendevicemodel_handle *dmod, domid_t domid, uint32_t irq,
+    unsigned int level)
+{
+    struct xen_dm_op op;
+    struct xen_dm_op_set_irq_level *data;
+
+    memset(&op, 0, sizeof(op));
+
+    op.op = XEN_DMOP_set_irq_level;
+    data = &op.u.set_irq_level;
+
+    data->irq = irq;
+    data->level = level;
+
+    return xendevicemodel_op(dmod, domid, 1, &op, sizeof(op));
+}
+
 int xendevicemodel_set_pci_link_route(
     xendevicemodel_handle *dmod, domid_t domid, uint8_t link, uint8_t irq)
 {
diff --git a/tools/libs/devicemodel/libxendevicemodel.map 
b/tools/libs/devicemodel/libxendevicemodel.map
index 561c62deb4..a0c30125de 100644
--- a/tools/libs/devicemodel/libxendevicemodel.map
+++ b/tools/libs/devicemodel/libxendevicemodel.map
@@ -32,6 +32,7 @@ VERS_1.2 {
        global:
                xendevicemodel_relocate_memory;
                xendevicemodel_pin_memory_cacheattr;
+               xendevicemodel_set_irq_level;
 } VERS_1.1;
 
 VERS_1.3 {
diff --git a/xen/arch/arm/dm.c b/xen/arch/arm/dm.c
index f254ed7a14..785413372c 100644
--- a/xen/arch/arm/dm.c
+++ b/xen/arch/arm/dm.c
@@ -20,6 +20,8 @@
 #include <xen/ioreq.h>
 #include <xen/nospec.h>
 
+#include <asm/vgic.h>
+
 int dm_op(const struct dmop_args *op_args)
 {
     struct domain *d;
@@ -35,6 +37,7 @@ int dm_op(const struct dmop_args *op_args)
         [XEN_DMOP_unmap_io_range_from_ioreq_server] = sizeof(struct 
xen_dm_op_ioreq_server_range),
         [XEN_DMOP_set_ioreq_server_state]           = sizeof(struct 
xen_dm_op_set_ioreq_server_state),
         [XEN_DMOP_destroy_ioreq_server]             = sizeof(struct 
xen_dm_op_destroy_ioreq_server),
+        [XEN_DMOP_set_irq_level]                    = sizeof(struct 
xen_dm_op_set_irq_level),
     };
 
     rc = rcu_lock_remote_domain_by_id(op_args->domid, &d);
@@ -73,7 +76,56 @@ int dm_op(const struct dmop_args *op_args)
     if ( op.pad )
         goto out;
 
-    rc = ioreq_server_dm_op(&op, d, &const_op);
+    switch ( op.op )
+    {
+    case XEN_DMOP_set_irq_level:
+    {
+        const struct xen_dm_op_set_irq_level *data =
+            &op.u.set_irq_level;
+        unsigned int i;
+
+        /* Only SPIs are supported */
+        if ( (data->irq < NR_LOCAL_IRQS) || (data->irq >= vgic_num_irqs(d)) )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        if ( data->level != 0 && data->level != 1 )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        /* Check that padding is always 0 */
+        for ( i = 0; i < sizeof(data->pad); i++ )
+        {
+            if ( data->pad[i] )
+            {
+                rc = -EINVAL;
+                break;
+            }
+        }
+
+        /*
+         * Allow to set the logical level of a line for non-allocated
+         * interrupts only.
+         */
+        if ( test_bit(data->irq, d->arch.vgic.allocated_irqs) )
+        {
+            rc = -EINVAL;
+            break;
+        }
+
+        vgic_inject_irq(d, NULL, data->irq, data->level);
+        rc = 0;
+        break;
+    }
+
+    default:
+        rc = ioreq_server_dm_op(&op, d, &const_op);
+        break;
+    }
 
     if ( (!rc || rc == -ERESTART) &&
          !const_op && copy_to_guest_offset(op_args->buf[0].h, offset,
diff --git a/xen/include/public/hvm/dm_op.h b/xen/include/public/hvm/dm_op.h
index 66cae1afbd..1f70d58caa 100644
--- a/xen/include/public/hvm/dm_op.h
+++ b/xen/include/public/hvm/dm_op.h
@@ -434,6 +434,21 @@ struct xen_dm_op_pin_memory_cacheattr {
 };
 typedef struct xen_dm_op_pin_memory_cacheattr xen_dm_op_pin_memory_cacheattr_t;
 
+/*
+ * XEN_DMOP_set_irq_level: Set the logical level of a one of a domain's
+ *                         IRQ lines (currently Arm only).
+ * Only SPIs are supported.
+ */
+#define XEN_DMOP_set_irq_level 19
+
+struct xen_dm_op_set_irq_level {
+    uint32_t irq;
+    /* IN - Level: 0 -> deasserted, 1 -> asserted */
+    uint8_t level;
+    uint8_t pad[3];
+};
+typedef struct xen_dm_op_set_irq_level xen_dm_op_set_irq_level_t;
+
 struct xen_dm_op {
     uint32_t op;
     uint32_t pad;
@@ -447,6 +462,7 @@ struct xen_dm_op {
         xen_dm_op_track_dirty_vram_t track_dirty_vram;
         xen_dm_op_set_pci_intx_level_t set_pci_intx_level;
         xen_dm_op_set_isa_irq_level_t set_isa_irq_level;
+        xen_dm_op_set_irq_level_t set_irq_level;
         xen_dm_op_set_pci_link_route_t set_pci_link_route;
         xen_dm_op_modified_memory_t modified_memory;
         xen_dm_op_set_mem_type_t set_mem_type;
--
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