diff mbox

[Xen-devel,v9,08/10] xen/arm: take the rank lock before accessing ipriority

Message ID 1406223192-26267-8-git-send-email-stefano.stabellini@eu.citrix.com
State New
Headers show

Commit Message

Stefano Stabellini July 24, 2014, 5:33 p.m. UTC 
Currently we read ipriority from vgic_vcpu_inject_irq without taking the
rank lock. Fix that by taking the rank lock and reading ipriority at the
beginning of the function.

As vgic_vcpu_inject_irq is called from the irq.c upon receiving an
interrupt, we need to change the implementation of vgic_lock/unlock_rank
to spin_lock_irqsave to make it safe in irq context.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

---

Changes in v9:
- add explicit flags paramter to vgic_lock_rank and vgic_unlock_rank.

Changes in v2:
- rebased on ab78724fc5628318b172b4344f7280621a151e1b;
- remove warning on changing priority of active irqs.
---
 xen/arch/arm/vgic-v2.c     |   74 +++++++++++++++++++++++---------------------
 xen/arch/arm/vgic.c        |   10 ++++--
 xen/include/asm-arm/vgic.h |    4 +--
 3 files changed, 47 insertions(+), 41 deletions(-)

Comments

Julien Grall July 28, 2014, 4:22 p.m. UTC | #1 
Hi Stefano,

On 07/24/2014 06:33 PM, Stefano Stabellini wrote:
> Currently we read ipriority from vgic_vcpu_inject_irq without taking the
> rank lock. Fix that by taking the rank lock and reading ipriority at the
> beginning of the function.
> 
> As vgic_vcpu_inject_irq is called from the irq.c upon receiving an
> interrupt, we need to change the implementation of vgic_lock/unlock_rank
> to spin_lock_irqsave to make it safe in irq context.
> 
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

Which series between GICv3 and this one will go first? I suspect this
one, so Vijay will have to rebase his VGICv3 patch on yours.

[..]

> @@ -367,6 +368,10 @@ void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq)
>      unsigned long flags;
>      bool_t running;
>  
> +    vgic_lock_rank(v, rank, flags);
> +    priority = vgic_byte_read(rank->ipriority[REG_RANK_INDEX(8, irq, DABT_WORD)], 0, irq & 0x3);

This line is longer than 80 characters. I would split it, but I'm not
sure if it will be readable.

Anyway:

Acked-by: Julien Grall <julien.grall@linaro.org>

Regards,
diff mbox

Patch

diff --git a/xen/arch/arm/vgic-v2.c b/xen/arch/arm/vgic-v2.c
index f9e357c..8b21a13 100644
--- a/xen/arch/arm/vgic-v2.c
+++ b/xen/arch/arm/vgic-v2.c
@@ -39,6 +39,7 @@  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
     register_t *r = select_user_reg(regs, dabt.reg);
     struct vgic_irq_rank *rank;
     int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
+    unsigned long flags;
 
     switch ( gicd_reg )
     {
@@ -77,54 +78,54 @@  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->ienable;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICENABLER ... GICD_ICENABLERN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->ienable;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ISPENDR ... GICD_ISPENDRN:
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISPENDR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = vgic_byte_read(rank->ipend, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICPENDR ... GICD_ICPENDRN:
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICPENDR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = vgic_byte_read(rank->ipend, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ISACTIVER ... GICD_ISACTIVERN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->iactive;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICACTIVER ... GICD_ICACTIVERN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->iactive;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ITARGETSR ... GICD_ITARGETSRN:
@@ -132,12 +133,12 @@  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         rank = vgic_rank_offset(v, 8, gicd_reg - GICD_ITARGETSR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
 
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->itargets[REG_RANK_INDEX(8, gicd_reg - GICD_ITARGETSR,
                                            DABT_WORD)];
         if ( dabt.size == DABT_BYTE )
             *r = vgic_byte_read(*r, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_IPRIORITYR ... GICD_IPRIORITYRN:
@@ -145,21 +146,21 @@  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
 
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR,
                                             DABT_WORD)];
         if ( dabt.size == DABT_BYTE )
             *r = vgic_byte_read(*r, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICFGR ... GICD_ICFGRN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR, DABT_WORD)];
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_NSACR ... GICD_NSACRN:
@@ -176,18 +177,18 @@  static int vgic_v2_distr_mmio_read(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_CPENDSGIR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = vgic_byte_read(rank->pendsgi, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_SPENDSGIR ... GICD_SPENDSGIRN:
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_SPENDSGIR, DABT_WORD);
         if ( rank == NULL) goto read_as_zero;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         *r = vgic_byte_read(rank->pendsgi, dabt.sign, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     /* Implementation defined -- read as zero */
@@ -269,6 +270,7 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
     struct vgic_irq_rank *rank;
     int gicd_reg = (int)(info->gpa - v->domain->arch.vgic.dbase);
     uint32_t tr;
+    unsigned long flags;
 
     switch ( gicd_reg )
     {
@@ -295,7 +297,7 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISENABLER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         tr = rank->ienable;
         rank->ienable |= *r;
         /* The virtual irq is derived from register offset.
@@ -303,14 +305,14 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
          * to get Virtual irq number */
         vgic_enable_irqs(v, (*r) & (~tr),
                          (gicd_reg - GICD_ISENABLER) >> DABT_WORD);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICENABLER ... GICD_ICENABLERN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICENABLER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         tr = rank->ienable;
         rank->ienable &= ~*r;
         /* The virtual irq is derived from register offset.
@@ -318,7 +320,7 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
          * to get  Virtual irq number */
         vgic_disable_irqs(v, (*r) & tr,
                          (gicd_reg - GICD_ICENABLER) >> DABT_WORD);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ISPENDR ... GICD_ISPENDRN:
@@ -337,18 +339,18 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ISACTIVER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         rank->iactive &= ~*r;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICACTIVER ... GICD_ICACTIVERN:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 1, gicd_reg - GICD_ICACTIVER, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         rank->iactive &= ~*r;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ITARGETSR ... GICD_ITARGETSR + 7:
@@ -379,7 +381,7 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
             !((target & 0xff) && (target & (0xff << 8)) &&
              (target & (0xff << 16)) && (target & (0xff << 24))))
             goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         i = 0;
         while ( (i = find_next_bit(&target, 32, i)) < 32 )
         {
@@ -406,7 +408,7 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         else
             vgic_byte_write(&rank->itargets[REG_RANK_INDEX(8,
                        gicd_reg - GICD_ITARGETSR, DABT_WORD)], target, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
     }
 
@@ -414,14 +416,14 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 8, gicd_reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         if ( dabt.size == DABT_WORD )
             rank->ipriority[REG_RANK_INDEX(8, gicd_reg - GICD_IPRIORITYR,
                                            DABT_WORD)] = *r;
         else
             vgic_byte_write(&rank->ipriority[REG_RANK_INDEX(8,
                         gicd_reg - GICD_IPRIORITYR, DABT_WORD)], *r, gicd_reg);
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_ICFGR: /* SGIs */
@@ -433,9 +435,9 @@  static int vgic_v2_distr_mmio_write(struct vcpu *v, mmio_info_t *info)
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 2, gicd_reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL) goto write_ignore;
-        vgic_lock_rank(v, rank);
+        vgic_lock_rank(v, rank, flags);
         rank->icfg[REG_RANK_INDEX(2, gicd_reg - GICD_ICFGR, DABT_WORD)] = *r;
-        vgic_unlock_rank(v, rank);
+        vgic_unlock_rank(v, rank, flags);
         return 1;
 
     case GICD_NSACR ... GICD_NSACRN:
diff --git a/xen/arch/arm/vgic.c b/xen/arch/arm/vgic.c
index 474eebd..a3df18d 100644
--- a/xen/arch/arm/vgic.c
+++ b/xen/arch/arm/vgic.c
@@ -158,10 +158,11 @@  struct vcpu *vgic_get_target_vcpu(struct vcpu *v, unsigned int irq)
     struct domain *d = v->domain;
     struct vcpu *v_target;
     struct vgic_irq_rank *rank = vgic_rank_irq(v, irq);
+    unsigned long flags;
 
-    vgic_lock_rank(v, rank);
+    vgic_lock_rank(v, rank, flags);
     v_target = d->arch.vgic.handler->get_target_vcpu(v, irq);
-    vgic_unlock_rank(v, rank);
+    vgic_unlock_rank(v, rank, flags);
     return v_target;
 }
 
@@ -367,6 +368,10 @@  void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq)
     unsigned long flags;
     bool_t running;
 
+    vgic_lock_rank(v, rank, flags);
+    priority = vgic_byte_read(rank->ipriority[REG_RANK_INDEX(8, irq, DABT_WORD)], 0, irq & 0x3);
+    vgic_unlock_rank(v, rank, flags);
+
     spin_lock_irqsave(&v->arch.vgic.lock, flags);
 
     /* vcpu offline */
@@ -384,7 +389,6 @@  void vgic_vcpu_inject_irq(struct vcpu *v, unsigned int irq)
         goto out;
     }
  
-    priority = vgic_byte_read(rank->ipriority[REG_RANK_INDEX(8, irq, DABT_WORD)], 0, irq & 0x3);
 
     n->irq = irq;
     n->priority = priority;
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 9b1db04..338ba03 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -107,8 +107,8 @@  struct vgic_ops {
 #define vgic_lock(v)   spin_lock_irq(&(v)->domain->arch.vgic.lock)
 #define vgic_unlock(v) spin_unlock_irq(&(v)->domain->arch.vgic.lock)
 
-#define vgic_lock_rank(v, r) spin_lock(&(r)->lock)
-#define vgic_unlock_rank(v, r) spin_unlock(&(r)->lock)
+#define vgic_lock_rank(v, r, flags)   spin_lock_irqsave(&(r)->lock, flags)
+#define vgic_unlock_rank(v, r, flags) spin_unlock_irqrestore(&(r)->lock, flags)
 
 /*
  * Rank containing GICD_<FOO><n> for GICD_<FOO> with