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[Xen-devel] [PATCH v2 1/2] xen/arm: vgic: Introduce helpers to read/write/clear/set vGIC register ...



From: Julien Grall <julien.grall@xxxxxxxxxx>

and use them in the vGIC emulation.

The GIC registers may support different access sizes. Rather than open
coding the access for every registers, provide a set of helpers to access
them.

The caller will have to call vgic_regN_* where N is the size of the
emulated registers.

The new helpers supports any access size and expect the caller to
validate the access size supported by the emulated registers.

Signed-off-by: Julien Grall <julien.grall@xxxxxxxxxx>
---
v2: - VGIC_REG_MASK macro does not compute mask correctly.
      So replace it with inline function and compute mask
      correctly for all sizes

diff --git a/xen/arch/arm/vgic-v3.c b/xen/arch/arm/vgic-v3.c
index f1c482d..7ef7b16 100644
--- a/xen/arch/arm/vgic-v3.c
+++ b/xen/arch/arm/vgic-v3.c
@@ -109,7 +109,6 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
mmio_info_t *info,
     struct hsr_dabt dabt = info->dabt;
     struct cpu_user_regs *regs = guest_cpu_user_regs();
     register_t *r = select_user_reg(regs, dabt.reg);
-    uint64_t aff;
 
     switch ( gicr_reg )
     {
@@ -118,21 +117,27 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
mmio_info_t *info,
         goto read_as_zero_32;
     case GICR_IIDR:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICR_IIDR_VAL;
+        *r = vgic_reg32_read(GICV3_GICR_IIDR_VAL, info);
         return 1;
     case GICR_TYPER:
+    {
+        uint64_t typer, aff;
+
         if ( dabt.size != DABT_DOUBLE_WORD ) goto bad_width;
         /* TBD: Update processor id in [23:8] when ITS support is added */
         aff = (MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 3) << 56 |
                MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 2) << 48 |
                MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 1) << 40 |
                MPIDR_AFFINITY_LEVEL(v->arch.vmpidr, 0) << 32);
-        *r = aff;
+        typer = aff;
 
         if ( v->arch.vgic.flags & VGIC_V3_RDIST_LAST )
-            *r |= GICR_TYPER_LAST;
+            typer |= GICR_TYPER_LAST;
+
+        *r = vgic_reg64_read(typer, info);
 
         return 1;
+    }
     case GICR_STATUSR:
         /* Not implemented */
         goto read_as_zero_32;
@@ -161,7 +166,7 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
mmio_info_t *info,
     case GICR_SYNCR:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         /* RO . But when read it always returns busy bito bit[0] */
-        *r = GICR_SYNCR_NOT_BUSY;
+        *r = vgic_reg32_read(GICR_SYNCR_NOT_BUSY, info);
         return 1;
     case GICR_MOVLPIR:
         /* WO Read as zero */
@@ -171,22 +176,22 @@ static int __vgic_v3_rdistr_rd_mmio_read(struct vcpu *v, 
mmio_info_t *info,
         goto read_as_zero_64;
     case GICR_PIDR0:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICR_PIDR0;
+        *r = vgic_reg32_read(GICV3_GICR_PIDR0, info);
          return 1;
     case GICR_PIDR1:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICR_PIDR1;
+        *r = vgic_reg32_read(GICV3_GICR_PIDR1, info);
          return 1;
     case GICR_PIDR2:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICR_PIDR2;
+        *r = vgic_reg32_read(GICV3_GICR_PIDR2, info);
          return 1;
     case GICR_PIDR3:
         /* Manufacture/customer defined */
         goto read_as_zero_32;
     case GICR_PIDR4:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICR_PIDR4;
+        *r = vgic_reg32_read(GICV3_GICR_PIDR4, info);
          return 1;
     case GICR_PIDR5 ... GICR_PIDR7:
         /* Reserved0 */
@@ -309,7 +314,7 @@ static int __vgic_v3_distr_common_mmio_read(const char 
*name, struct vcpu *v,
         rank = vgic_rank_offset(v, 1, reg - GICD_ISENABLER, DABT_WORD);
         if ( rank == NULL ) goto read_as_zero;
         vgic_lock_rank(v, rank, flags);
-        *r = rank->ienable;
+        *r = vgic_reg32_read(rank->ienable, info);
         vgic_unlock_rank(v, rank, flags);
         return 1;
     case GICD_ICENABLER ... GICD_ICENABLERN:
@@ -317,7 +322,7 @@ static int __vgic_v3_distr_common_mmio_read(const char 
*name, struct vcpu *v,
         rank = vgic_rank_offset(v, 1, reg - GICD_ICENABLER, DABT_WORD);
         if ( rank == NULL ) goto read_as_zero;
         vgic_lock_rank(v, rank, flags);
-        *r = rank->ienable;
+        *r = vgic_reg32_read(rank->ienable, info);
         vgic_unlock_rank(v, rank, flags);
         return 1;
     /* Read the pending status of an IRQ via GICD/GICR is not supported */
@@ -331,25 +336,37 @@ static int __vgic_v3_distr_common_mmio_read(const char 
*name, struct vcpu *v,
         goto read_as_zero;
 
     case GICD_IPRIORITYR ... GICD_IPRIORITYRN:
+    {
+        uint32_t ipriority;
+
         if ( dabt.size != DABT_BYTE && dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 8, reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL ) goto read_as_zero;
 
         vgic_lock_rank(v, rank, flags);
-        *r = rank->ipriority[REG_RANK_INDEX(8, reg - GICD_IPRIORITYR,
-                                            DABT_WORD)];
-        if ( dabt.size == DABT_BYTE )
-            *r = vgic_byte_read(*r, dabt.sign, reg);
+        ipriority = rank->ipriority[REG_RANK_INDEX(8, reg - GICD_IPRIORITYR,
+                                                   DABT_WORD)];
         vgic_unlock_rank(v, rank, flags);
+
+        *r = vgic_reg32_read(ipriority, info);
+
         return 1;
+    }
     case GICD_ICFGR ... GICD_ICFGRN:
+    {
+        uint32_t icfgr;
+
         if ( dabt.size != DABT_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 2, reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL ) goto read_as_zero;
         vgic_lock_rank(v, rank, flags);
-        *r = rank->icfg[REG_RANK_INDEX(2, reg - GICD_ICFGR, DABT_WORD)];
+        icfgr = rank->icfg[REG_RANK_INDEX(2, reg - GICD_ICFGR, DABT_WORD)];
         vgic_unlock_rank(v, rank, flags);
+
+        *r = vgic_reg32_read(icfgr, info);
+
         return 1;
+    }
     default:
         printk(XENLOG_G_ERR
                "%pv: %s: unhandled read r%d offset %#08x\n",
@@ -389,7 +406,7 @@ static int __vgic_v3_distr_common_mmio_write(const char 
*name, struct vcpu *v,
         if ( rank == NULL ) goto write_ignore;
         vgic_lock_rank(v, rank, flags);
         tr = rank->ienable;
-        rank->ienable |= *r;
+        vgic_reg32_setbit(&rank->ienable, *r, info);
         /* The irq number is extracted from offset. so shift by register size 
*/
         vgic_enable_irqs(v, (*r) & (~tr), (reg - GICD_ISENABLER) >> DABT_WORD);
         vgic_unlock_rank(v, rank, flags);
@@ -400,6 +417,7 @@ static int __vgic_v3_distr_common_mmio_write(const char 
*name, struct vcpu *v,
         if ( rank == NULL ) goto write_ignore;
         vgic_lock_rank(v, rank, flags);
         tr = rank->ienable;
+        vgic_reg32_clearbit(&rank->ienable, *r, info);
         rank->ienable &= ~*r;
         /* The irq number is extracted from offset. so shift by register size 
*/
         vgic_disable_irqs(v, (*r) & tr, (reg - GICD_ICENABLER) >> DABT_WORD);
@@ -438,12 +456,10 @@ static int __vgic_v3_distr_common_mmio_write(const char 
*name, struct vcpu *v,
         rank = vgic_rank_offset(v, 8, reg - GICD_IPRIORITYR, DABT_WORD);
         if ( rank == NULL ) goto write_ignore;
         vgic_lock_rank(v, rank, flags);
-        if ( dabt.size == DABT_WORD )
-            rank->ipriority[REG_RANK_INDEX(8, reg - GICD_IPRIORITYR,
-                                           DABT_WORD)] = *r;
-        else
-            vgic_byte_write(&rank->ipriority[REG_RANK_INDEX(8,
-                       reg - GICD_IPRIORITYR, DABT_WORD)], *r, reg);
+        vgic_reg32_write(&rank->ipriority[REG_RANK_INDEX(8,
+                                                         reg - GICD_IPRIORITYR,
+                                                         DABT_WORD)],
+                         *r, info);
         vgic_unlock_rank(v, rank, flags);
         return 1;
     case GICD_ICFGR: /* Restricted to configure SGIs */
@@ -455,7 +471,9 @@ static int __vgic_v3_distr_common_mmio_write(const char 
*name, struct vcpu *v,
         rank = vgic_rank_offset(v, 2, reg - GICD_ICFGR, DABT_WORD);
         if ( rank == NULL ) goto write_ignore;
         vgic_lock_rank(v, rank, flags);
-        rank->icfg[REG_RANK_INDEX(2, reg - GICD_ICFGR, DABT_WORD)] = *r;
+        vgic_reg32_write(&rank->icfg[REG_RANK_INDEX(2, reg - GICD_ICFGR,
+                                                    DABT_WORD)],
+                         *r, info);
         vgic_unlock_rank(v, rank, flags);
         return 1;
     default:
@@ -694,7 +712,7 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
     case GICD_CTLR:
         if ( dabt.size != DABT_WORD ) goto bad_width;
         vgic_lock(v);
-        *r = v->domain->arch.vgic.ctlr;
+        *r = vgic_reg32_read(v->domain->arch.vgic.ctlr, info);
         vgic_unlock(v);
         return 1;
     case GICD_TYPER:
@@ -709,13 +727,16 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
          * bit is zero. The maximum is 8.
          */
         unsigned int ncpus = min_t(unsigned int, v->domain->max_vcpus, 8);
+        uint32_t typer;
 
         if ( dabt.size != DABT_WORD ) goto bad_width;
         /* No secure world support for guests. */
-        *r = ((ncpus - 1) << GICD_TYPE_CPUS_SHIFT |
-              DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32));
+        typer = ((ncpus - 1) << GICD_TYPE_CPUS_SHIFT |
+                 DIV_ROUND_UP(v->domain->arch.vgic.nr_spis, 32));
+
+        typer |= (irq_bits - 1) << GICD_TYPE_ID_BITS_SHIFT;
 
-        *r |= (irq_bits - 1) << GICD_TYPE_ID_BITS_SHIFT;
+        *r = vgic_reg32_read(typer, info);
 
         return 1;
     }
@@ -727,7 +748,7 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
         goto read_as_zero_32;
     case GICD_IIDR:
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICD_IIDR_VAL;
+        *r = vgic_reg32_read(GICV3_GICD_IIDR_VAL, info);
         return 1;
     case 0x020 ... 0x03c:
     case 0xc000 ... 0xffcc:
@@ -750,15 +771,23 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
         /* SGI/PPI is RES0 */
         goto read_as_zero_64;
     case GICD_IROUTER32 ... GICD_IROUTERN:
+    {
+        uint64_t irouter;
+
         if ( dabt.size != DABT_DOUBLE_WORD ) goto bad_width;
         rank = vgic_rank_offset(v, 64, gicd_reg - GICD_IROUTER,
                                 DABT_DOUBLE_WORD);
         if ( rank == NULL ) goto read_as_zero;
         vgic_lock_rank(v, rank, flags);
-        *r = rank->v3.irouter[REG_RANK_INDEX(64,
-                              (gicd_reg - GICD_IROUTER), DABT_DOUBLE_WORD)];
+        irouter = rank->v3.irouter[REG_RANK_INDEX(64,
+                                                  (gicd_reg - GICD_IROUTER),
+                                                  DABT_DOUBLE_WORD)];
         vgic_unlock_rank(v, rank, flags);
+
+        *r = vgic_reg64_read(irouter, info);
+
         return 1;
+    }
     case GICD_NSACR ... GICD_NSACRN:
         /* We do not implement security extensions for guests, read zero */
         goto read_as_zero_32;
@@ -774,17 +803,17 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
     case GICD_PIDR0:
         /* GICv3 identification value */
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICD_PIDR0;
+        *r = vgic_reg32_read(GICV3_GICD_PIDR0, info);
         return 1;
     case GICD_PIDR1:
         /* GICv3 identification value */
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICD_PIDR1;
+        *r = vgic_reg32_read(GICV3_GICD_PIDR1, info);
         return 1;
     case GICD_PIDR2:
         /* GICv3 identification value */
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICD_PIDR2;
+        *r = vgic_reg32_read(GICV3_GICD_PIDR2, info);
         return 1;
     case GICD_PIDR3:
         /* GICv3 identification value. Manufacturer/Customer defined */
@@ -792,7 +821,7 @@ static int vgic_v3_distr_mmio_read(struct vcpu *v, 
mmio_info_t *info)
     case GICD_PIDR4:
         /* GICv3 identification value */
         if ( dabt.size != DABT_WORD ) goto bad_width;
-        *r = GICV3_GICD_PIDR4;
+        *r = vgic_reg32_read(GICV3_GICD_PIDR4, info);
         return 1;
     case GICD_PIDR5 ... GICD_PIDR7:
         /* Reserved0 */
@@ -910,12 +939,14 @@ static int vgic_v3_distr_mmio_write(struct vcpu *v, 
mmio_info_t *info)
         rank = vgic_rank_offset(v, 64, gicd_reg - GICD_IROUTER,
                                 DABT_DOUBLE_WORD);
         if ( rank == NULL ) goto write_ignore;
-        new_irouter = *r;
         vgic_lock_rank(v, rank, flags);
 
         old_irouter = rank->v3.irouter[REG_RANK_INDEX(64,
                                        (gicd_reg - GICD_IROUTER),
                                        DABT_DOUBLE_WORD)];
+        new_irouter = old_irouter;
+        vgic_reg64_write(&new_irouter, *r, info);
+
         old_vcpu = vgic_v3_irouter_to_vcpu(v->domain, old_irouter);
         new_vcpu = vgic_v3_irouter_to_vcpu(v->domain, new_irouter);
 
diff --git a/xen/include/asm-arm/vgic.h b/xen/include/asm-arm/vgic.h
index 41cadb1..af1fa17 100644
--- a/xen/include/asm-arm/vgic.h
+++ b/xen/include/asm-arm/vgic.h
@@ -19,6 +19,7 @@
 #define __ASM_ARM_VGIC_H__
 
 #include <xen/bitops.h>
+#include <asm/mmio.h>
 
 struct pending_irq
 {
@@ -180,6 +181,115 @@ static inline void vgic_byte_write(uint32_t *reg, 
uint32_t var, int offset)
     *reg |= var;
 }
 
+static inline uint64_t vgic_reg_mask(enum dabt_size size)
+{
+    if ( size == DABT_DOUBLE_WORD )
+        return ~0ULL;
+    else
+        return ((1ULL << ((1 << size) * 8)) - 1);
+}
+
+/*
+ * The check on the size supported by the register has to be done by
+ * the caller of vgic_regN_*.
+ *
+ * vgic_reg_* should never be called directly. Instead use the vgic_regN_*
+ * according to size of the emulated register
+ *
+ * Note that the alignment fault will always be taken in the guest
+ * (see B3.12.7 DDI0406.b).
+ */
+static inline register_t vgic_reg_read(uint64_t reg,
+                                       unsigned int offset,
+                                       enum dabt_size size)
+{
+    reg >>= 8 * offset;
+    reg &= vgic_reg_mask(size);
+
+    return reg;
+}
+
+static inline void vgic_reg_write(uint64_t *reg, register_t val,
+                                  unsigned int offset,
+                                  enum dabt_size size)
+{
+    uint64_t mask = vgic_reg_mask(size);
+    int shift = offset * 8;
+
+    *reg &= ~(mask << shift);
+    *reg |= ((uint64_t)val & mask) << shift;
+}
+
+static inline void vgic_reg_setbit(uint64_t *reg, register_t bits,
+                                   unsigned int offset,
+                                   enum dabt_size size)
+{
+    uint64_t mask = vgic_reg_mask(size);
+    int shift = offset * 8;
+
+    *reg |= ((uint64_t)bits & mask) << shift;
+}
+
+static inline void vgic_reg_clearbit(uint64_t *reg, register_t bits,
+                                     unsigned int offset,
+                                     enum dabt_size size)
+{
+    uint64_t mask = vgic_reg_mask(size);
+    int shift = offset * 8;
+
+    *reg &= ~(((uint64_t)bits & mask) << shift);
+}
+
+/* N-bit register helpers */
+#define VGIC_REG_HELPERS(sz, offmask)                                   \
+static inline register_t vgic_reg##sz##_read(uint##sz##_t reg,          \
+                                             const mmio_info_t *info)   \
+{                                                                       \
+    return vgic_reg_read(reg, info->gpa & offmask,                      \
+                         info->dabt.size);                              \
+}                                                                       \
+                                                                        \
+static inline void vgic_reg##sz##_write(uint##sz##_t *reg,              \
+                                        register_t val,                 \
+                                        const mmio_info_t *info)        \
+{                                                                       \
+    uint64_t tmp = *reg;                                                \
+                                                                        \
+    vgic_reg_write(&tmp, val, info->gpa & offmask,                      \
+                   info->dabt.size);                                    \
+                                                                        \
+    *reg = tmp;                                                         \
+}                                                                       \
+                                                                        \
+static inline void vgic_reg##sz##_setbit(uint##sz##_t *reg,             \
+                                         register_t bits,               \
+                                         const mmio_info_t *info)       \
+{                                                                       \
+    uint64_t tmp = *reg;                                                \
+                                                                        \
+    vgic_reg_setbit(&tmp, bits, info->gpa & offmask,                    \
+                    info->dabt.size);                                   \
+                                                                        \
+    *reg = tmp;                                                         \
+}                                                                       \
+                                                                        \
+static inline void vgic_reg##sz##_clearbit(uint##sz##_t *reg,           \
+                                           register_t bits,             \
+                                           const mmio_info_t *info)     \
+{                                                                       \
+    uint64_t tmp = *reg;                                                \
+                                                                        \
+    vgic_reg_clearbit(&tmp, bits, info->gpa & offmask,                  \
+                    info->dabt.size);                                   \
+                                                                        \
+    *reg = tmp;                                                         \
+}
+
+VGIC_REG_HELPERS(64, 0x7);
+VGIC_REG_HELPERS(32, 0x3);
+
+#undef VGIC_REG_HELPERS
+
 enum gic_sgi_mode;
 
 /*
-- 
1.7.9.5


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