[PATCH v3 3/3] arm64: Sync guest instruction patches for GDB breakpoints

[vince <liuwf0302@gmail.com>]

---
 arm/aarch64/gdb.c |  8 ++++++++
 include/kvm/gdb.h | 10 ++++++++++
 x86/gdb.c         |  4 ++++
 3 files changed, 22 insertions(+)

diff --git a/arm/aarch64/gdb.c b/arm/aarch64/gdb.c
index cbe854b..7872686 100644
--- a/arm/aarch64/gdb.c
+++ b/arm/aarch64/gdb.c
@@ -203,6 +203,14 @@ size_t kvm_gdb__arch_reg_pkt_size(void)
 	return GDB_REGS_SIZE;
 }
 
+void kvm_gdb__arch_sync_guest_insn(void *host, size_t len)
+{
+	char *start = host;
+	char *end = start + len;
+
+	__builtin___clear_cache(start, end);
+}
+
 /* ------------------------------------------------------------------ */
 /* Helpers: which SP to expose as GDB register 31                     */
 /* ------------------------------------------------------------------ */
diff --git a/include/kvm/gdb.h b/include/kvm/gdb.h
index 623dad0..8e10cd7 100644
--- a/include/kvm/gdb.h
+++ b/include/kvm/gdb.h
@@ -90,6 +90,12 @@ size_t kvm_gdb__arch_reg_pkt_size(void);
 /* GDB signal number to report on stop (SIGTRAP=5) */
 int kvm_gdb__arch_signal(struct kvm_cpu *vcpu);
 
+/*
+ * Make a guest instruction patch visible to later instruction fetches.
+ * host points at the host virtual address backing the patched guest bytes.
+ */
+void kvm_gdb__arch_sync_guest_insn(void *host, size_t len);
+
 /*
  * Returns true if the KVM_EXIT_DEBUG exit was caused by a software
  * breakpoint (INT3 / #BP exception), as opposed to a hardware debug
@@ -133,6 +139,10 @@ static inline bool kvm_gdb__active(struct kvm *kvm)
 	return false;
 }
 
+static inline void kvm_gdb__arch_sync_guest_insn(void *host, size_t len)
+{
+}
+
 #endif
 
 #endif /* KVM__GDB_H */
diff --git a/x86/gdb.c b/x86/gdb.c
index f0fa941..91d8a5a 100644
--- a/x86/gdb.c
+++ b/x86/gdb.c
@@ -107,6 +107,10 @@ size_t kvm_gdb__arch_reg_pkt_size(void)
 	return GDB_REGS_SIZE;
 }
 
+void kvm_gdb__arch_sync_guest_insn(void *host, size_t len)
+{
+}
+
 /* ------------------------------------------------------------------ */
 /* Helpers: read/write KVM register structures                        */
 /* ------------------------------------------------------------------ */
-- 
2.34.1