From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55037) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fYVFo-00023n-II for qemu-devel@nongnu.org; Thu, 28 Jun 2018 07:38:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fYVFm-0008KI-6p for qemu-devel@nongnu.org; Thu, 28 Jun 2018 07:38:24 -0400 From: David Hildenbrand Date: Thu, 28 Jun 2018 13:38:16 +0200 Message-Id: <20180628113817.30814-2-david@redhat.com> In-Reply-To: <20180628113817.30814-1-david@redhat.com> References: <20180628113817.30814-1-david@redhat.com> Subject: [Qemu-devel] [PATCH v1 1/2] s390x/kvm: legacy_s390_alloc() only supports one allocation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-s390x@nongnu.org Cc: qemu-devel@nongnu.org, Richard Henderson , Alexander Graf , Cornelia Huck , Christian Borntraeger , Thomas Huth , David Hildenbrand We always allocate at a fixed address, a second allocation can therefore of course never work. We would simply overwrite mappings. This can e.g. happen in s390_memory_init(), if trying to allocate more than > 8TB. Let's just bail out, as there is no need for supporting it (legacy handling for z/VM). Signed-off-by: David Hildenbrand --- target/s390x/kvm.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/target/s390x/kvm.c b/target/s390x/kvm.c index ac370da281..bbac3454e3 100644 --- a/target/s390x/kvm.c +++ b/target/s390x/kvm.c @@ -752,12 +752,20 @@ int kvm_s390_mem_op(S390CPU *cpu, vaddr addr, uint8_t ar, void *hostbuf, */ static void *legacy_s390_alloc(size_t size, uint64_t *align, bool shared) { - void *mem; + static void *mem; + + if (mem) { + /* we only support one allocation, which is enough for initial ram */ + return NULL; + } mem = mmap((void *) 0x800000000ULL, size, PROT_EXEC|PROT_READ|PROT_WRITE, MAP_SHARED | MAP_ANONYMOUS | MAP_FIXED, -1, 0); - return mem == MAP_FAILED ? NULL : mem; + if (mem == MAP_FAILED) { + mem = NULL; + } + return mem; } static uint8_t const *sw_bp_inst; -- 2.17.1