Whenever we modify a storage key, we shuld flush the TLBs of all CPUs,
so the MMU fault handling code can properly consider the changed storage
key (to e.g., properly set the reference and change bit on the next
accesses).

These functions are barely used in modern Linux guests, so the performance
implications are neglectable for now.

This is a preparation for better reference and change bit handling for
TCG, which will require more MMU changes.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 target/s390x/mem_helper.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
index 29d9eaa5b7..ed54265e03 100644
--- a/target/s390x/mem_helper.c
+++ b/target/s390x/mem_helper.c
@@ -1815,6 +1815,8 @@ void HELPER(sske)(CPUS390XState *env, uint64_t r1, uint64_t r2)
 
     key = (uint8_t) r1;
     skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
+    /* TODO: Flush only entries with this target address */
+    tlb_flush_all_cpus_synced(env_cpu(env));
 }
 
 /* reset reference bit extended */
@@ -1843,6 +1845,8 @@ uint32_t HELPER(rrbe)(CPUS390XState *env, uint64_t r2)
     if (skeyclass->set_skeys(ss, r2 / TARGET_PAGE_SIZE, 1, &key)) {
         return 0;
     }
+    /* TODO: Flush only entries with this target address */
+    tlb_flush_all_cpus_synced(env_cpu(env));
 
     /*
      * cc
-- 
2.21.0

On Mon, 12 Aug 2019 13:27:34 +0200
David Hildenbrand <david@redhat.com> wrote:

> Whenever we modify a storage key, we shuld flush the TLBs of all CPUs,
> so the MMU fault handling code can properly consider the changed storage
> key (to e.g., properly set the reference and change bit on the next
> accesses).
> 
> These functions are barely used in modern Linux guests, so the performance
> implications are neglectable for now.
> 
> This is a preparation for better reference and change bit handling for
> TCG, which will require more MMU changes.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  target/s390x/mem_helper.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/target/s390x/mem_helper.c b/target/s390x/mem_helper.c
> index 29d9eaa5b7..ed54265e03 100644
> --- a/target/s390x/mem_helper.c
> +++ b/target/s390x/mem_helper.c
> @@ -1815,6 +1815,8 @@ void HELPER(sske)(CPUS390XState *env, uint64_t r1, uint64_t r2)
>  
>      key = (uint8_t) r1;
>      skeyclass->set_skeys(ss, addr / TARGET_PAGE_SIZE, 1, &key);
> +    /* TODO: Flush only entries with this target address */
> +    tlb_flush_all_cpus_synced(env_cpu(env));
>  }
>  
>  /* reset reference bit extended */
> @@ -1843,6 +1845,8 @@ uint32_t HELPER(rrbe)(CPUS390XState *env, uint64_t r2)
>      if (skeyclass->set_skeys(ss, r2 / TARGET_PAGE_SIZE, 1, &key)) {
>          return 0;
>      }
> +    /* TODO: Flush only entries with this target address */
> +    tlb_flush_all_cpus_synced(env_cpu(env));
>  
>      /*
>       * cc

Seems reasonable.

Reviewed-by: Cornelia Huck <cohuck@redhat.com>