diff mbox series

[v8,1/8] memory: Introduce memory region fetch operation

Message ID 20240715095702.1222213-2-ethan84@andestech.com (mailing list archive)
State New, archived
Headers show
Series Support RISC-V IOPMP | expand

Commit Message

Ethan Chen July 15, 2024, 9:56 a.m. UTC
Allow memory regions to have different behaviors for read and fetch
operations.

For example, the RISC-V IOPMP could raise an interrupt when the CPU
tries to fetch from a non-executable region.

If the fetch operation for a memory region is not implemented, the read
operation will still be used for fetch operations.

Signed-off-by: Ethan Chen <ethan84@andestech.com>
---
 accel/tcg/cputlb.c    |   9 +++-
 include/exec/memory.h |  30 ++++++++++++
 system/memory.c       | 104 ++++++++++++++++++++++++++++++++++++++++++
 system/trace-events   |   2 +
 4 files changed, 143 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
index 117b516739..edb3715017 100644
--- a/accel/tcg/cputlb.c
+++ b/accel/tcg/cputlb.c
@@ -1942,8 +1942,13 @@  static uint64_t int_ld_mmio_beN(CPUState *cpu, CPUTLBEntryFull *full,
         this_size = 1 << this_mop;
         this_mop |= MO_BE;
 
-        r = memory_region_dispatch_read(mr, mr_offset, &val,
-                                        this_mop, full->attrs);
+        if (type == MMU_INST_FETCH) {
+            r = memory_region_dispatch_fetch(mr, mr_offset, &val,
+                                             this_mop, full->attrs);
+        } else {
+            r = memory_region_dispatch_read(mr, mr_offset, &val,
+                                            this_mop, full->attrs);
+        }
         if (unlikely(r != MEMTX_OK)) {
             io_failed(cpu, full, addr, this_size, type, mmu_idx, r, ra);
         }
diff --git a/include/exec/memory.h b/include/exec/memory.h
index 02f7528ec0..d837d7d7eb 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -274,6 +274,13 @@  struct MemoryRegionOps {
                   uint64_t data,
                   unsigned size);
 
+    /* Fetch from the memory region. @addr is relative to @mr; @size is
+     * in bytes. */
+    uint64_t (*fetch)(void *opaque,
+                      hwaddr addr,
+                      unsigned size);
+
+
     MemTxResult (*read_with_attrs)(void *opaque,
                                    hwaddr addr,
                                    uint64_t *data,
@@ -284,6 +291,12 @@  struct MemoryRegionOps {
                                     uint64_t data,
                                     unsigned size,
                                     MemTxAttrs attrs);
+    MemTxResult (*fetch_with_attrs)(void *opaque,
+                                    hwaddr addr,
+                                    uint64_t *data,
+                                    unsigned size,
+                                    MemTxAttrs attrs);
+
 
     enum device_endian endianness;
     /* Guest-visible constraints: */
@@ -2602,6 +2615,23 @@  MemTxResult memory_region_dispatch_write(MemoryRegion *mr,
                                          MemOp op,
                                          MemTxAttrs attrs);
 
+
+/**
+ * memory_region_dispatch_fetch: perform a fetch directly to the specified
+ * MemoryRegion.
+ *
+ * @mr: #MemoryRegion to access
+ * @addr: address within that region
+ * @pval: pointer to uint64_t which the data is written to
+ * @op: size, sign, and endianness of the memory operation
+ * @attrs: memory transaction attributes to use for the access
+ */
+MemTxResult memory_region_dispatch_fetch(MemoryRegion *mr,
+                                         hwaddr addr,
+                                         uint64_t *pval,
+                                         MemOp op,
+                                         MemTxAttrs attrs);
+
 /**
  * address_space_init: initializes an address space
  *
diff --git a/system/memory.c b/system/memory.c
index 5e6eb459d5..b46721446c 100644
--- a/system/memory.c
+++ b/system/memory.c
@@ -477,6 +477,51 @@  static MemTxResult memory_region_read_with_attrs_accessor(MemoryRegion *mr,
     return r;
 }
 
+static MemTxResult memory_region_fetch_accessor(MemoryRegion *mr,
+                                                hwaddr addr,
+                                                uint64_t *value,
+                                                unsigned size,
+                                                signed shift,
+                                                uint64_t mask,
+                                                MemTxAttrs attrs)
+{
+    uint64_t tmp;
+
+    tmp = mr->ops->fetch(mr->opaque, addr, size);
+    if (mr->subpage) {
+        trace_memory_region_subpage_fetch(get_cpu_index(), mr, addr, tmp, size);
+    } else if (trace_event_get_state_backends(TRACE_MEMORY_REGION_OPS_FETCH)) {
+        hwaddr abs_addr = memory_region_to_absolute_addr(mr, addr);
+        trace_memory_region_ops_fetch(get_cpu_index(), mr, abs_addr, tmp, size,
+                                     memory_region_name(mr));
+    }
+    memory_region_shift_read_access(value, shift, mask, tmp);
+    return MEMTX_OK;
+}
+
+static MemTxResult memory_region_fetch_with_attrs_accessor(MemoryRegion *mr,
+                                                          hwaddr addr,
+                                                          uint64_t *value,
+                                                          unsigned size,
+                                                          signed shift,
+                                                          uint64_t mask,
+                                                          MemTxAttrs attrs)
+{
+    uint64_t tmp = 0;
+    MemTxResult r;
+
+    r = mr->ops->fetch_with_attrs(mr->opaque, addr, &tmp, size, attrs);
+    if (mr->subpage) {
+        trace_memory_region_subpage_fetch(get_cpu_index(), mr, addr, tmp, size);
+    } else if (trace_event_get_state_backends(TRACE_MEMORY_REGION_OPS_FETCH)) {
+        hwaddr abs_addr = memory_region_to_absolute_addr(mr, addr);
+        trace_memory_region_ops_fetch(get_cpu_index(), mr, abs_addr, tmp, size,
+                                      memory_region_name(mr));
+    }
+    memory_region_shift_read_access(value, shift, mask, tmp);
+    return r;
+}
+
 static MemTxResult memory_region_write_accessor(MemoryRegion *mr,
                                                 hwaddr addr,
                                                 uint64_t *value,
@@ -1461,6 +1506,65 @@  MemTxResult memory_region_dispatch_read(MemoryRegion *mr,
     return r;
 }
 
+static MemTxResult memory_region_dispatch_fetch1(MemoryRegion *mr,
+                                                hwaddr addr,
+                                                uint64_t *pval,
+                                                unsigned size,
+                                                MemTxAttrs attrs)
+{
+    *pval = 0;
+
+    if (mr->ops->fetch) {
+        return access_with_adjusted_size(addr, pval, size,
+                                         mr->ops->impl.min_access_size,
+                                         mr->ops->impl.max_access_size,
+                                         memory_region_fetch_accessor,
+                                         mr, attrs);
+    } else if (mr->ops->fetch_with_attrs) {
+        return access_with_adjusted_size(addr, pval, size,
+            mr->ops->impl.min_access_size,
+            mr->ops->impl.max_access_size,
+            memory_region_fetch_with_attrs_accessor,
+            mr, attrs);
+    } else if (mr->ops->read) {
+        return access_with_adjusted_size(addr, pval, size,
+                                         mr->ops->impl.min_access_size,
+                                         mr->ops->impl.max_access_size,
+                                         memory_region_read_accessor,
+                                         mr, attrs);
+    } else {
+        return access_with_adjusted_size(addr, pval, size,
+                                         mr->ops->impl.min_access_size,
+                                         mr->ops->impl.max_access_size,
+                                         memory_region_read_with_attrs_accessor,
+                                         mr, attrs);
+    }
+}
+
+MemTxResult memory_region_dispatch_fetch(MemoryRegion *mr,
+                                        hwaddr addr,
+                                        uint64_t *pval,
+                                        MemOp op,
+                                        MemTxAttrs attrs)
+{
+    unsigned size = memop_size(op);
+    MemTxResult r;
+
+    if (mr->alias) {
+        return memory_region_dispatch_fetch(mr->alias,
+                                           mr->alias_offset + addr,
+                                           pval, op, attrs);
+    }
+    if (!memory_region_access_valid(mr, addr, size, false, attrs)) {
+        *pval = unassigned_mem_read(mr, addr, size);
+        return MEMTX_DECODE_ERROR;
+    }
+
+    r = memory_region_dispatch_fetch1(mr, addr, pval, size, attrs);
+    adjust_endianness(mr, pval, op);
+    return r;
+}
+
 /* Return true if an eventfd was signalled */
 static bool memory_region_dispatch_write_eventfds(MemoryRegion *mr,
                                                     hwaddr addr,
diff --git a/system/trace-events b/system/trace-events
index 2ed1d59b1f..a8fc70f28f 100644
--- a/system/trace-events
+++ b/system/trace-events
@@ -11,8 +11,10 @@  cpu_out(unsigned int addr, char size, unsigned int val) "addr 0x%x(%c) value %u"
 # memory.c
 memory_region_ops_read(int cpu_index, void *mr, uint64_t addr, uint64_t value, unsigned size, const char *name) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %u name '%s'"
 memory_region_ops_write(int cpu_index, void *mr, uint64_t addr, uint64_t value, unsigned size, const char *name) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %u name '%s'"
+memory_region_ops_fetch(int cpu_index, void *mr, uint64_t addr, uint64_t value, unsigned size, const char *name) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %u name '%s'"
 memory_region_subpage_read(int cpu_index, void *mr, uint64_t offset, uint64_t value, unsigned size) "cpu %d mr %p offset 0x%"PRIx64" value 0x%"PRIx64" size %u"
 memory_region_subpage_write(int cpu_index, void *mr, uint64_t offset, uint64_t value, unsigned size) "cpu %d mr %p offset 0x%"PRIx64" value 0x%"PRIx64" size %u"
+memory_region_subpage_fetch(int cpu_index, void *mr, uint64_t offset, uint64_t value, unsigned size) "cpu %d mr %p offset 0x%"PRIx64" value 0x%"PRIx64" size %u"
 memory_region_ram_device_read(int cpu_index, void *mr, uint64_t addr, uint64_t value, unsigned size) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %u"
 memory_region_ram_device_write(int cpu_index, void *mr, uint64_t addr, uint64_t value, unsigned size) "cpu %d mr %p addr 0x%"PRIx64" value 0x%"PRIx64" size %u"
 memory_region_sync_dirty(const char *mr, const char *listener, int global) "mr '%s' listener '%s' synced (global=%d)"