[Xen-devel] [PATCH v5 p2 01/19] xen/arm: Let the toolstack configure the number of SPIs

[Julien Grall <julien.grall@xxxxxxxxxx>]

From: Julien Grall <julien.grall@xxxxxxxxxx>

Each domain may have a different number of IRQs depending on the devices
assigned to it.

Rather re-using the number of IRQs used by the hardwared GIC, let the
toolstack specify the number of SPIs when the domain is created. This
will avoid to waste memory.

To calculate the number of SPIs, we take advantage of the fact that the
libxl interface can only expose 1:1 mapping and look for the largest SPI
in the list.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
Cc: Ian Jackson <ian.jackson@xxxxxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Wei Liu <wei.liu2@xxxxxxxxxx>

---
    Changes in v5:
        - Remove stray change
        - Limit the number of SPIs to (1020 - 32) rather than the number
        supported by the hardware

    Changes in v4:
        - Check the number of SPIs supported by the virtual GIC against
        the number supported by the hardware GIC.
        - Use uint32_t rather than int in the toolstack code.
        - Initialize spi after the check in the toolstack code
        - Typoes

    Changes in v3:
        - Fix typoes
        - A separate has been created to extend the DOMCTL create domain

    Changes in v2:
        - Patch added
---
 tools/libxc/xc_domain.c       |  1 +
 tools/libxl/libxl_arm.c       | 21 +++++++++++++++++++++
 xen/arch/arm/domain.c         |  2 +-
 xen/arch/arm/setup.c          |  1 +
 xen/arch/arm/vgic.c           | 11 ++++++-----
 xen/include/asm-arm/vgic.h    |  2 +-
 xen/include/public/arch-arm.h |  2 ++
 7 files changed, 33 insertions(+), 7 deletions(-)

diff --git a/tools/libxc/xc_domain.c b/tools/libxc/xc_domain.c
index 95e3098..1f2c80c 100644
--- a/tools/libxc/xc_domain.c
+++ b/tools/libxc/xc_domain.c
@@ -67,6 +67,7 @@ int xc_domain_create(xc_interface *xch,
     /* No arch-specific configuration for now */
 #elif defined (__arm__) || defined(__aarch64__)
     config.gic_version = XEN_DOMCTL_CONFIG_GIC_DEFAULT;
+    config.nr_spis = 0;
 #else
     errno = ENOSYS;
     return -1;
diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
index 946618c..5a5cb3f 100644
--- a/tools/libxl/libxl_arm.c
+++ b/tools/libxl/libxl_arm.c
@@ -39,6 +39,27 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
                                       libxl_domain_config *d_config,
                                       xc_domain_configuration_t *xc_config)
 {
+    uint32_t nr_spis = 0;
+    unsigned int i;
+
+    for (i = 0; i < d_config->b_info.num_irqs; i++) {
+        uint32_t irq = d_config->b_info.irqs[i];
+        uint32_t spi;
+
+        if (irq < 32)
+            continue;
+
+        spi = irq - 32;
+
+        if (nr_spis <= spi)
+            nr_spis = spi + 1;
+    }
+
+    LOG(DEBUG, "Configure the domain");
+
+    xc_config->nr_spis = nr_spis;
+    LOG(DEBUG, " - Allocate %u SPIs", nr_spis);
+
     xc_config->gic_version = XEN_DOMCTL_CONFIG_GIC_DEFAULT;
 
     return 0;
diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
index e4d6fc8..180bccc 100644
--- a/xen/arch/arm/domain.c
+++ b/xen/arch/arm/domain.c
@@ -590,7 +590,7 @@ int arch_domain_create(struct domain *d, unsigned int 
domcr_flags,
     if ( (rc = gicv_setup(d)) != 0 )
         goto fail;
 
-    if ( (rc = domain_vgic_init(d)) != 0 )
+    if ( (rc = domain_vgic_init(d, config->nr_spis)) != 0 )
         goto fail;
 
     if ( (rc = domain_vtimer_init(d)) != 0 )
diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c
index 4ec7c13..711562cf 100644
--- a/xen/arch/arm/setup.c
+++ b/xen/arch/arm/setup.c
@@ -830,6 +830,7 @@ void __init start_xen(unsigned long boot_phys_offset,
     /* Create initial domain 0. */
     /* The vGIC for DOM0 is exactly emulating the hardware GIC */
     config.gic_version = XEN_DOMCTL_CONFIG_GIC_DEFAULT;
+    config.nr_spis = gic_number_lines() - 32;
 
     dom0 = domain_create(0, 0, 0, &config);
     if ( IS_ERR(dom0) || (alloc_dom0_vcpu0(dom0) == NULL) )
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 8f91962..150624a 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -68,16 +68,17 @@ static void vgic_init_pending_irq(struct pending_irq *p, 
unsigned int virq)
     p->irq = virq;
 }
 
-int domain_vgic_init(struct domain *d)
+int domain_vgic_init(struct domain *d, unsigned int nr_spis)
 {
     int i;
 
     d->arch.vgic.ctlr = 0;
 
-    if ( is_hardware_domain(d) )
-        d->arch.vgic.nr_spis = gic_number_lines() - 32;
-    else
-        d->arch.vgic.nr_spis = 0; /* We don't need SPIs for the guest */
+    /* Limit the number of virtual SPIs supported to (1020 - 32) = 988  */
+    if ( (nr_spis + NR_LOCAL_IRQS) > 1020 )
+        return -EINVAL;
+
+    d->arch.vgic.nr_spis = nr_spis;
 
     switch ( gic_hw_version() )
     {
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index aba0d80..647f2fe 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -177,7 +177,7 @@ enum gic_sgi_mode;
 
 #define vgic_num_irqs(d)        ((d)->arch.vgic.nr_spis + 32)
 
-extern int domain_vgic_init(struct domain *d);
+extern int domain_vgic_init(struct domain *d, unsigned int nr_spis);
 extern void domain_vgic_free(struct domain *d);
 extern int vcpu_vgic_init(struct vcpu *v);
 extern struct vcpu *vgic_get_target_vcpu(struct vcpu *v, unsigned int irq);
diff --git a/xen/include/public/arch-arm.h b/xen/include/public/arch-arm.h
index ed7e98f..c029e0f 100644
--- a/xen/include/public/arch-arm.h
+++ b/xen/include/public/arch-arm.h
@@ -315,6 +315,8 @@ typedef uint64_t xen_callback_t;
 struct xen_arch_domainconfig {
     /* IN/OUT */
     uint8_t gic_version;
+    /* IN */
+    uint32_t nr_spis;
 };
 
 #endif
-- 
2.1.4


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