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Re: [Xen-devel] [PATCH V5 04/10] xen/arm: Use cpumask_t type for vcpu_mask in vgic_to_sgi



Hi Chen,

On 30/05/2015 12:07, Chen Baozi wrote:
From: Chen Baozi <baozich@xxxxxxxxx>

Use cpumask_t instead of unsigned long which can only express 64 cpus at
the most. Add the {gicv2|gicv3}_sgir_to_cpumask in corresponding vGICs
to translate GICD_SGIR/ICC_SGI1R_EL1 to vcpu_mask for vgic_to_sgi.

Signed-off-by: Chen Baozi <baozich@xxxxxxxxx>
---
  xen/arch/arm/vgic-v2.c            | 16 +++++++++++++---
  xen/arch/arm/vgic-v3.c            | 19 +++++++++++++++----
  xen/arch/arm/vgic.c               | 24 +++++++++++-------------
  xen/include/asm-arm/gic.h         |  1 +
  xen/include/asm-arm/gic_v3_defs.h |  2 ++
  xen/include/asm-arm/vgic.h        |  2 +-
  6 files changed, 43 insertions(+), 21 deletions(-)

diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
index 3be1a51..17a3c9f 100644
--- a/xen/arch/arm/vgic-v2.c
+++ b/xen/arch/arm/vgic-v2.c
@@ -33,6 +33,15 @@
  #include <asm/gic.h>
  #include <asm/vgic.h>

+static inline void gicv2_sgir_to_cpumask(cpumask_t *cpumask,
+                                         const register_t sgir)
+{
+    unsigned long target_list;
+
+    target_list = ((sgir & GICD_SGI_TARGET_MASK) >> GICD_SGI_TARGET_SHIFT);
+    bitmap_copy(cpumask_bits(cpumask), &target_list, GICD_SGI_TARGET_BITS);
+}
+
  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
  {
      struct hsr_dabt dabt = info->dabt;
@@ -201,16 +210,17 @@ static int vgic_v2_to_sgi(struct vcpu *v, register_t sgir)
      int virq;
      int irqmode;
      enum gic_sgi_mode sgi_mode;
-    unsigned long vcpu_mask = 0;
+    cpumask_t vcpu_mask;

+    cpumask_clear(&vcpu_mask);
      irqmode = (sgir & GICD_SGI_TARGET_LIST_MASK) >> 
GICD_SGI_TARGET_LIST_SHIFT;
      virq = (sgir & GICD_SGI_INTID_MASK);
-    vcpu_mask = (sgir & GICD_SGI_TARGET_MASK) >> GICD_SGI_TARGET_SHIFT;

      /* Map GIC sgi value to enum value */
      switch ( irqmode )
      {
      case GICD_SGI_TARGET_LIST_VAL:
+        gicv2_sgir_to_cpumask(&vcpu_mask, sgir);
          sgi_mode = SGI_TARGET_LIST;
          break;
      case GICD_SGI_TARGET_OTHERS_VAL:
@@ -226,7 +236,7 @@ static int vgic_v2_to_sgi(struct vcpu *v, register_t sgir)
          return 0;
      }

-    return vgic_to_sgi(v, sgir, sgi_mode, virq, vcpu_mask);
+    return vgic_to_sgi(v, sgir, sgi_mode, virq, &vcpu_mask);
  }

  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index ef9a71a..a283c8c 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -972,22 +972,33 @@ write_ignore:
      return 1;
  }

+static inline void gicv3_sgir_to_cpumask(cpumask_t *cpumask,
+                                         const register_t sgir)
+{
+    unsigned long target_list;
+
+    target_list = sgir & ICH_SGI_TARGETLIST_MASK;
+    bitmap_copy(cpumask_bits(cpumask), &target_list, ICH_SGI_TARGET_BITS);
+

Spurious line.

+}
+
  static int vgic_v3_to_sgi(struct vcpu *v, register_t sgir)
  {
      int virq;
      int irqmode;
      enum gic_sgi_mode sgi_mode;
-    unsigned long vcpu_mask = 0;
+    cpumask_t vcpu_mask;

+    cpumask_clear(&vcpu_mask);
      irqmode = (sgir >> ICH_SGI_IRQMODE_SHIFT) & ICH_SGI_IRQMODE_MASK;
      virq = (sgir >> ICH_SGI_IRQ_SHIFT ) & ICH_SGI_IRQ_MASK;
-    /* SGI's are injected at Rdist level 0. ignoring affinity 1, 2, 3 */
-    vcpu_mask = sgir & ICH_SGI_TARGETLIST_MASK;

      /* Map GIC sgi value to enum value */
      switch ( irqmode )
      {
      case ICH_SGI_TARGET_LIST:
+        /* SGI's are injected at Rdist level 0. ignoring affinity 1, 2, 3 */
+        gicv3_sgir_to_cpumask(&vcpu_mask, sgir);
          sgi_mode = SGI_TARGET_LIST;
          break;
      case ICH_SGI_TARGET_OTHERS:
@@ -998,7 +1009,7 @@ static int vgic_v3_to_sgi(struct vcpu *v, register_t sgir)
          return 0;
      }

-    return vgic_to_sgi(v, sgir, sgi_mode, virq, vcpu_mask);
+    return vgic_to_sgi(v, sgir, sgi_mode, virq, &vcpu_mask);
  }

  static int vgic_v3_emulate_sysreg(struct cpu_user_regs *regs, union hsr hsr)
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 7b387b7..f9e43f9 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -318,16 +318,12 @@ void vgic_enable_irqs(struct vcpu *v, uint32_t r, int n)
      }
  }

-/* TODO: unsigned long is used to fit vcpu_mask.*/
  int vgic_to_sgi(struct vcpu *v, register_t sgir, enum gic_sgi_mode irqmode, 
int virq,
-                unsigned long vcpu_mask)
+                cpumask_t *vcpu_mask)
  {
      struct domain *d = v->domain;
-    int vcpuid;
      int i;

-    ASSERT(d->max_vcpus < 8*sizeof(vcpu_mask));
-

As said in the previous version, cpumask_t is based on NR_CPUS and there is no relation between NR_CPUS and MAX_VIRT_CPUS. Furthermore, NR_CPUS which can be configured at build time by the user (see MAX_PHYS_CPUS). We need to catch at build time possible when the cpumask_t would be smaller in order to avoid insecure hypervisor.

      ASSERT( virq < 16 );

      switch ( irqmode )
@@ -341,12 +337,12 @@ int vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode, int
           * SGI_TARGET_SELF mode. So Force vcpu_mask to 0
           */
          perfc_incr(vgic_sgi_others);
-        vcpu_mask = 0;
+        cpumask_clear(vcpu_mask);

Given that you already clear the cpumask on the caller of this function, I think we can consider that it will be nice with us rather than wasting CPU time to clear twice. That would require to update the comment above.

          for ( i = 0; i < d->max_vcpus; i++ )
          {
              if ( i != current->vcpu_id && d->vcpu[i] != NULL &&
                   is_vcpu_online(d->vcpu[i]) )
-                set_bit(i, &vcpu_mask);
+                cpumask_set_cpu(i, vcpu_mask);
          }
          break;
      case SGI_TARGET_SELF:
@@ -355,8 +351,8 @@ int vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode, int
           * SGI_TARGET_SELF mode. So Force vcpu_mask to 0
           */
          perfc_incr(vgic_sgi_self);
-        vcpu_mask = 0;
-        set_bit(current->vcpu_id, &vcpu_mask);
+        cpumask_clear(vcpu_mask);

Ditto.

+        cpumask_set_cpu(current->vcpu_id, vcpu_mask);
          break;
      default:
          gprintk(XENLOG_WARNING,
@@ -365,15 +361,17 @@ int vgic_to_sgi(struct vcpu *v, register_t sgir, enum 
gic_sgi_mode irqmode, int
          return 0;
      }

-    for_each_set_bit( vcpuid, &vcpu_mask, d->max_vcpus )
+       for ( i = cpumask_first(vcpu_mask);
+             i < d->max_vcpus;
+             i = cpumask_next(i, vcpu_mask))

The indentation looks wrong here. And why don't you use vcpuid? It would have avoid the renaming vcpuid/i below which increase the path size for nothing.

      {
-        if ( d->vcpu[vcpuid] != NULL && !is_vcpu_online(d->vcpu[vcpuid]) )
+        if ( d->vcpu[i] != NULL && !is_vcpu_online(d->vcpu[i]) )
          {
              gprintk(XENLOG_WARNING, "VGIC: write r=%"PRIregister" \
-                    vcpu_mask=%lx, wrong CPUTargetList\n", sgir, vcpu_mask);
+                    , wrong CPUTargetList\n", sgir);
              continue;
          }
-        vgic_vcpu_inject_irq(d->vcpu[vcpuid], virq);
+        vgic_vcpu_inject_irq(d->vcpu[i], virq);
      }
      return 1;
  }
diff --git a/xen/include/asm-arm/gic.h b/xen/include/asm-arm/gic.h
index 463fffb..c6ef4bf 100644
--- a/xen/include/asm-arm/gic.h
+++ b/xen/include/asm-arm/gic.h
@@ -64,6 +64,7 @@
  #define GICD_SGI_TARGET_SELF_VAL     (2)
  #define GICD_SGI_TARGET_SHIFT        (16)
  #define GICD_SGI_TARGET_MASK         (0xFFUL<<GICD_SGI_TARGET_SHIFT)
+#define GICD_SGI_TARGET_BITS         (8)
  #define GICD_SGI_GROUP1              (1UL<<15)
  #define GICD_SGI_INTID_MASK          (0xFUL)

diff --git a/xen/include/asm-arm/gic_v3_defs.h 
b/xen/include/asm-arm/gic_v3_defs.h
index 556f114..e106e67 100644
--- a/xen/include/asm-arm/gic_v3_defs.h
+++ b/xen/include/asm-arm/gic_v3_defs.h
@@ -152,6 +152,8 @@
  #define ICH_SGI_IRQ_SHIFT            24
  #define ICH_SGI_IRQ_MASK             0xf
  #define ICH_SGI_TARGETLIST_MASK      0xffff
+#define ICH_SGI_TARGET_BITS          16
+
  #endif /* __ASM_ARM_GIC_V3_DEFS_H__ */

  /*
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 6dcdf9f..2f413e1 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -201,7 +201,7 @@ DEFINE_VGIC_OPS(3)
  extern int vcpu_vgic_free(struct vcpu *v);
  extern int vgic_to_sgi(struct vcpu *v, register_t sgir,
                         enum gic_sgi_mode irqmode, int virq,
-                       unsigned long vcpu_mask);
+                       cpumask_t *vcpu_mask);
  extern void vgic_migrate_irq(struct vcpu *old, struct vcpu *new, unsigned int 
irq);

  /* Reserve a specific guest vIRQ */


Regards,

--
Julien Grall

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