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Wed, 11 Sep 2019 11:11:30 +0000 (UTC) To: qemu-devel@nongnu.org References: <20190906075750.14791-1-david@redhat.com> From: David Hildenbrand Openpgp: preference=signencrypt Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzSREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT7CwX4EEwECACgFAljj9eoCGwMFCQlmAYAGCwkI BwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEE3eEPcA/4Na5IIP/3T/FIQMxIfNzZshIq687qgG 8UbspuE/YSUDdv7r5szYTK6KPTlqN8NAcSfheywbuYD9A4ZeSBWD3/NAVUdrCaRP2IvFyELj xoMvfJccbq45BxzgEspg/bVahNbyuBpLBVjVWwRtFCUEXkyazksSv8pdTMAs9IucChvFmmq3 jJ2vlaz9lYt/lxN246fIVceckPMiUveimngvXZw21VOAhfQ+/sofXF8JCFv2mFcBDoa7eYob s0FLpmqFaeNRHAlzMWgSsP80qx5nWWEvRLdKWi533N2vC/EyunN3HcBwVrXH4hxRBMco3jvM m8VKLKao9wKj82qSivUnkPIwsAGNPdFoPbgghCQiBjBe6A75Z2xHFrzo7t1jg7nQfIyNC7ez MZBJ59sqA9EDMEJPlLNIeJmqslXPjmMFnE7Mby/+335WJYDulsRybN+W5rLT5aMvhC6x6POK z55fMNKrMASCzBJum2Fwjf/VnuGRYkhKCqqZ8gJ3OvmR50tInDV2jZ1DQgc3i550T5JDpToh dPBxZocIhzg+MBSRDXcJmHOx/7nQm3iQ6iLuwmXsRC6f5FbFefk9EjuTKcLMvBsEx+2DEx0E UnmJ4hVg7u1PQ+2Oy+Lh/opK/BDiqlQ8Pz2jiXv5xkECvr/3Sv59hlOCZMOaiLTTjtOIU7Tq 7ut6OL64oAq+zsFNBFXLn5EBEADn1959INH2cwYJv0tsxf5MUCghCj/CA/lc/LMthqQ773ga uB9mN+F1rE9cyyXb6jyOGn+GUjMbnq1o121Vm0+neKHUCBtHyseBfDXHA6m4B3mUTWo13nid 0e4AM71r0DS8+KYh6zvweLX/LL5kQS9GQeT+QNroXcC1NzWbitts6TZ+IrPOwT1hfB4WNC+X 2n4AzDqp3+ILiVST2DT4VBc11Gz6jijpC/KI5Al8ZDhRwG47LUiuQmt3yqrmN63V9wzaPhC+ xbwIsNZlLUvuRnmBPkTJwwrFRZvwu5GPHNndBjVpAfaSTOfppyKBTccu2AXJXWAE1Xjh6GOC 8mlFjZwLxWFqdPHR1n2aPVgoiTLk34LR/bXO+e0GpzFXT7enwyvFFFyAS0Nk1q/7EChPcbRb hJqEBpRNZemxmg55zC3GLvgLKd5A09MOM2BrMea+l0FUR+PuTenh2YmnmLRTro6eZ/qYwWkC u8FFIw4pT0OUDMyLgi+GI1aMpVogTZJ70FgV0pUAlpmrzk/bLbRkF3TwgucpyPtcpmQtTkWS gDS50QG9DR/1As3LLLcNkwJBZzBG6PWbvcOyrwMQUF1nl4SSPV0LLH63+BrrHasfJzxKXzqg rW28CTAE2x8qi7e/6M/+XXhrsMYG+uaViM7n2je3qKe7ofum3s4vq7oFCPsOgwARAQABwsFl BBgBAgAPBQJVy5+RAhsMBQkJZgGAAAoJEE3eEPcA/4NagOsP/jPoIBb/iXVbM+fmSHOjEshl KMwEl/m5iLj3iHnHPVLBUWrXPdS7iQijJA/VLxjnFknhaS60hkUNWexDMxVVP/6lbOrs4bDZ NEWDMktAeqJaFtxackPszlcpRVkAs6Msn9tu8hlvB517pyUgvuD7ZS9gGOMmYwFQDyytpepo YApVV00P0u3AaE0Cj/o71STqGJKZxcVhPaZ+LR+UCBZOyKfEyq+ZN311VpOJZ1IvTExf+S/5 lqnciDtbO3I4Wq0ArLX1gs1q1XlXLaVaA3yVqeC8E7kOchDNinD3hJS4OX0e1gdsx/e6COvy qNg5aL5n0Kl4fcVqM0LdIhsubVs4eiNCa5XMSYpXmVi3HAuFyg9dN+x8thSwI836FoMASwOl C7tHsTjnSGufB+D7F7ZBT61BffNBBIm1KdMxcxqLUVXpBQHHlGkbwI+3Ye+nE6HmZH7IwLwV W+Ajl7oYF+jeKaH4DZFtgLYGLtZ1LDwKPjX7VAsa4Yx7S5+EBAaZGxK510MjIx6SGrZWBrrV TEvdV00F2MnQoeXKzD7O4WFbL55hhyGgfWTHwZ457iN9SgYi1JLPqWkZB0JRXIEtjd4JEQcx +8Umfre0Xt4713VxMygW0PnQt5aSQdMD58jHFxTk092mU+yIHj5LeYgvwSgZN4airXk5yRXl SE+xAvmumFBY Organization: Red Hat GmbH Message-ID: <76806ca4-3fca-fbb2-a8ca-f7664f696e15@redhat.com> Date: Wed, 11 Sep 2019 13:11:29 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 MIME-Version: 1.0 In-Reply-To: <20190906075750.14791-1-david@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.70]); Wed, 11 Sep 2019 11:11:32 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [qemu-s390x] [PATCH v2 00/28] s390x/tcg: mem_helper: Fault-safe handling X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Florian Weimer , Thomas Huth , Cornelia Huck , Stefano Brivio , qemu-s390x@nongnu.org, Richard Henderson Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 06.09.19 09:57, David Hildenbrand wrote: > This is the successor of > "[PATCH v1 0/4] s390x/tcg: MOVE (MVC): Fault-safe handling" > > ---- > > This series fixes a bunch of issues related to some mem helpers and makes > sure that they are fault-safe, meaning no system state is modified in case > a fault is triggered. > > I can spot tons of other issues with other mem helpers that will have > to be fixed later. Also, fault-safe handling for some instructions > (especially TR) might be harder to implement (you don't know what will > actually be accessed upfront - we might need a buffer and go over > inputs twice). Focusing on the MOVE instructions for now. > > ---- > > Newer versions of glibc use memcpy() in memmove() for forward moves. The > implementation makese use of MVC. The TCG implementation of MVC is > currently not able to handle faults reliably when crossing pages. MVC > can cross with 256 bytes at most two pages. > > In case we get a fault on the second page, we already moved data. When > continuing after the fault we might try to move already overwritten data, > which is very bad in case we have overlapping data on a forward move. > > Triggered for now only by rpmbuild (crashes when checking the spec file) > and rpm (database corruptions). This fixes installing Fedora rawhide (31) > under TCG. > > This was horrible to debug as it barely triggers and we fail at completely > different places. > > Cc: Stefano Brivio > Cc: Florian Weimer > > v1 -> v2: > - Include many fixes > - Fix more instructions > - Use the new probe_access() function > - Include "tests/tcg: target/s390x: Test MVO" > > David Hildenbrand (28): > s390x/tcg: Reset exception_index to -1 instead of 0 > s390x/tcg: MVCL: Zero out unused bits of address > s390x/tcg: MVCL: Detect destructive overlaps > s390x/tcg: MVCL: Process max 2k bytes at a time > s390x/tcg: MVC: Increment the length once > s390x/tcg: MVC: Use is_destructive_overlap() > s390x/tcg: MVPG: Check for specification exceptions > s390x/tcg: MVPG: Properly wrap the addresses > s390x/tcg: MVCLU/MVCLE: Process max 4k bytes at a time > s390x/tcg: MVCS/MVCP: Check for special operation exceptions > s390x/tcg: MVCS/MVCP: Properly wrap the length > s390x/tcg: MVST: Check for specification exceptions > s390x/tcg: MVST: Fix storing back the addresses to registers > s390x/tcg: Always use MMU_USER_IDX for CONFIG_USER_ONLY > s390x/tcg: Fault-safe memset > s390x/tcg: Fault-safe memmove > s390x/tcg: MVCS/MVCP: Use access_memmove_idx() > s390x/tcg: MVC: Fault-safe handling on destructive overlaps > s390x/tcg: MVCLU: Fault-safe handling > s390x/tcg: OC: Fault-safe handling > s390x/tcg: XC: Fault-safe handling > s390x/tcg: NC: Fault-safe handling > s390x/tcg: MVCIN: Fault-safe handling > s390x/tcg: MVN: Fault-safe handling > s390x/tcg: MVZ: Fault-safe handling > s390x/tcg: MVST: Fault-safe handling > s390x/tcg: MVO: Fault-safe handling > tests/tcg: target/s390x: Test MVO > > target/s390x/cpu.h | 4 + > target/s390x/helper.h | 2 +- > target/s390x/insn-data.def | 2 +- > target/s390x/mem_helper.c | 672 ++++++++++++++++++++++---------- > target/s390x/translate.c | 12 +- > tests/tcg/s390x/Makefile.target | 1 + > tests/tcg/s390x/mvo.c | 25 ++ > 7 files changed, 507 insertions(+), 211 deletions(-) > create mode 100644 tests/tcg/s390x/mvo.c > I guess, for a minimal review besides the obvious fixes, looking at "s390x/tcg: Fault-safe memset" and "s390x/tcg: Fault-safe memmove" and "s390x/tcg: MVC: Fault-safe handling on destructive overlaps" makes sense. They contain the real magic used within remaining patches. -- Thanks, David / dhildenb