[Qemu-devel] [PATCH] KVM: flush icache after writing to RAM

[Scott Wood]

This is required so that the guest does not execute any stale
instructions.

qemu-kvm does this in cpu_physical_memory_rw, but not in
cpu_physical_memory_write_rom.

Signed-off-by: Scott Wood <address@hidden>
---
 exec.c |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)

diff --git a/exec.c b/exec.c
index 983c0db..055d304 100644
--- a/exec.c
+++ b/exec.c
@@ -33,6 +33,7 @@
 #include "osdep.h"
 #include "kvm.h"
 #include "qemu-timer.h"
+#include "cache-utils.h"
 #if defined(CONFIG_USER_ONLY)
 #include <qemu.h>
 #include <signal.h>
@@ -3768,6 +3769,12 @@ void cpu_physical_memory_rw(target_phys_addr_t addr, 
uint8_t *buf,
                     cpu_physical_memory_set_dirty_flags(
                         addr1, (0xff & ~CODE_DIRTY_FLAG));
                 }
+                /* qemu doesn't execute guest code directly, but kvm does
+                   therefore flush instruction caches */
+                if (kvm_enabled()) {
+                    flush_icache_range((unsigned long)ptr,
+                                       (unsigned long)ptr + l);
+                }
             }
         } else {
             if ((pd & ~TARGET_PAGE_MASK) > IO_MEM_ROM &&
@@ -3838,6 +3845,13 @@ void cpu_physical_memory_write_rom(target_phys_addr_t 
addr,
             /* ROM/RAM case */
             ptr = qemu_get_ram_ptr(addr1);
             memcpy(ptr, buf, l);
+
+            /* qemu doesn't execute guest code directly, but kvm does
+               therefore flush instruction caches */
+            if (kvm_enabled()) {
+                flush_icache_range((unsigned long)ptr,
+                                   (unsigned long)ptr + l);
+            }
         }
         len -= l;
         buf += l;
-- 
1.7.1