accel/tcg: Add block comment for probe_access

Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20200508154359.7494-4-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 350c4b451b..d656a1f05c 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -330,6 +330,23 @@ static inline void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *cpu,
 {
 }
 #endif
+/**
+ * probe_access:
+ * @env: CPUArchState
+ * @addr: guest virtual address to look up
+ * @size: size of the access
+ * @access_type: read, write or execute permission
+ * @mmu_idx: MMU index to use for lookup
+ * @retaddr: return address for unwinding
+ *
+ * Look up the guest virtual address @addr.  Raise an exception if the
+ * page does not satisfy @access_type.  Raise an exception if the
+ * access (@addr, @size) hits a watchpoint.  For writes, mark a clean
+ * page as dirty.
+ *
+ * Finally, return the host address for a page that is backed by RAM,
+ * or NULL if the page requires I/O.
+ */
 void *probe_access(CPUArchState *env, target_ulong addr, int size,
                    MMUAccessType access_type, int mmu_idx, uintptr_t retaddr);