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[PULL,05/21] target/s390x: Fix MVCRL with a large value in R0

Message ID 20230710121543.197250-6-thuth@redhat.com
State New
Headers show
Series [PULL,01/21] hw/s390x: Move KVM specific PV from hw/ to target/s390x/kvm/ | expand

Commit Message

Thomas Huth July 10, 2023, 12:15 p.m. UTC 
From: Ilya Leoshkevich <iii@linux.ibm.com>

Using a large R0 causes an assertion error:

    qemu-s390x: target/s390x/tcg/mem_helper.c:183: access_prepare_nf: Assertion `size > 0 && size <= 4096' failed.

Even though PoP explicitly advises against using more than 8 bits for the
size, an emulator crash is never a good thing.

Fix by truncating the size to 8 bits.

Fixes: ea0a1053e276 ("s390x/tcg: Implement Miscellaneous-Instruction-Extensions Facility 3 for the s390x")
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: qemu-stable@nongnu.org
Message-Id: <20230704081506.276055-5-iii@linux.ibm.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
---
 target/s390x/tcg/mem_helper.c | 1 +
 1 file changed, 1 insertion(+)
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Patch

diff --git a/target/s390x/tcg/mem_helper.c b/target/s390x/tcg/mem_helper.c
index d02ec861d8..84ad85212c 100644
--- a/target/s390x/tcg/mem_helper.c
+++ b/target/s390x/tcg/mem_helper.c
@@ -514,6 +514,7 @@  void HELPER(mvcrl)(CPUS390XState *env, uint64_t l, uint64_t dest, uint64_t src)
     int32_t i;
 
     /* MVCRL always copies one more byte than specified - maximum is 256 */
+    l &= 0xff;
     l++;
 
     access_prepare(&srca, env, src, l, MMU_DATA_LOAD, mmu_idx, ra);