[02/12] s390: Lowcore mapping helper.

Commit Message

Cornelia Huck Jan. 17, 2013, 2:23 p.m. UTC

Create a lowcore mapping helper that includes a check for sufficient
length.

Signed-off-by: Cornelia Huck <[e-mail]>
---
 target-s390x/helper.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

Comments

Alexander Graf Jan. 18, 2013, 4:54 p.m. UTC | #1

On 17.01.2013, at 15:23, Cornelia Huck wrote:

> Create a lowcore mapping helper that includes a check for sufficient
> length.
> 
> Signed-off-by: Cornelia Huck <[e-mail]>
> ---
> target-s390x/helper.c | 31 +++++++++++++++++++++++++------
> 1 file changed, 25 insertions(+), 6 deletions(-)
> 
> diff --git a/target-s390x/helper.c b/target-s390x/helper.c
> index 9a132e6..bf2b4d3 100644
> --- a/target-s390x/helper.c
> +++ b/target-s390x/helper.c
> @@ -471,13 +471,32 @@ static uint64_t get_psw_mask(CPUS390XState *env)
>     return r;
> }
> 
> +static LowCore *cpu_map_lowcore(CPUS390XState *env, hwaddr *len)

Just declare len to PAGE_SIZE * 2, like you do in kvm. Or to sizeof(LowCore). Then don't pass it in as parameter, but basically guarantee that the function always returns a full LowCore struct.

> +{
> +    LowCore *lowcore;
> +
> +    if (*len < sizeof(LowCore)) {
> +        cpu_abort(env, "Insufficient length %d for mapping lowcore\n",
> +                  (int) *len);
> +    }
> +
> +    lowcore = cpu_physical_memory_map(env->psa, len, 1);

Here is the place where the size check should be really :).


Alex

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Patch

diff --git a/target-s390x/helper.c b/target-s390x/helper.c
index 9a132e6..bf2b4d3 100644
--- a/target-s390x/helper.c
+++ b/target-s390x/helper.c
@@ -471,13 +471,32 @@  static uint64_t get_psw_mask(CPUS390XState *env)
     return r;
 }
 
+static LowCore *cpu_map_lowcore(CPUS390XState *env, hwaddr *len)
+{
+    LowCore *lowcore;
+
+    if (*len < sizeof(LowCore)) {
+        cpu_abort(env, "Insufficient length %d for mapping lowcore\n",
+                  (int) *len);
+    }
+
+    lowcore = cpu_physical_memory_map(env->psa, len, 1);
+
+    return lowcore;
+}
+
+static void cpu_unmap_lowcore(LowCore *lowcore, hwaddr len)
+{
+    cpu_physical_memory_unmap(lowcore, len, 1, len);
+}
+
 static void do_svc_interrupt(CPUS390XState *env)
 {
     uint64_t mask, addr;
     LowCore *lowcore;
     hwaddr len = TARGET_PAGE_SIZE;
 
-    lowcore = cpu_physical_memory_map(env->psa, &len, 1);
+    lowcore = cpu_map_lowcore(env, &len);
 
     lowcore->svc_code = cpu_to_be16(env->int_svc_code);
     lowcore->svc_ilen = cpu_to_be16(env->int_svc_ilen);
@@ -486,7 +505,7 @@  static void do_svc_interrupt(CPUS390XState *env)
     mask = be64_to_cpu(lowcore->svc_new_psw.mask);
     addr = be64_to_cpu(lowcore->svc_new_psw.addr);
 
-    cpu_physical_memory_unmap(lowcore, len, 1, len);
+    cpu_unmap_lowcore(lowcore, len);
 
     load_psw(env, mask, addr);
 }
@@ -513,7 +532,7 @@  static void do_program_interrupt(CPUS390XState *env)
     qemu_log_mask(CPU_LOG_INT, "%s: code=0x%x ilen=%d\n",
                   __func__, env->int_pgm_code, ilen);
 
-    lowcore = cpu_physical_memory_map(env->psa, &len, 1);
+    lowcore = cpu_map_lowcore(env, &len);
 
     lowcore->pgm_ilen = cpu_to_be16(ilen);
     lowcore->pgm_code = cpu_to_be16(env->int_pgm_code);
@@ -522,7 +541,7 @@  static void do_program_interrupt(CPUS390XState *env)
     mask = be64_to_cpu(lowcore->program_new_psw.mask);
     addr = be64_to_cpu(lowcore->program_new_psw.addr);
 
-    cpu_physical_memory_unmap(lowcore, len, 1, len);
+    cpu_unmap_lowcore(lowcore, len);
 
     DPRINTF("%s: %x %x %" PRIx64 " %" PRIx64 "\n", __func__,
             env->int_pgm_code, ilen, env->psw.mask,
@@ -549,7 +568,7 @@  static void do_ext_interrupt(CPUS390XState *env)
     }
 
     q = &env->ext_queue[env->ext_index];
-    lowcore = cpu_physical_memory_map(env->psa, &len, 1);
+    lowcore = cpu_map_lowcore(env, &len);
 
     lowcore->ext_int_code = cpu_to_be16(q->code);
     lowcore->ext_params = cpu_to_be32(q->param);
@@ -560,7 +579,7 @@  static void do_ext_interrupt(CPUS390XState *env)
     mask = be64_to_cpu(lowcore->external_new_psw.mask);
     addr = be64_to_cpu(lowcore->external_new_psw.addr);
 
-    cpu_physical_memory_unmap(lowcore, len, 1, len);
+    cpu_unmap_lowcore(lowcore, len);
 
     env->ext_index--;
     if (env->ext_index == -1) {