On 18.09.19 11:26, Cornelia Huck wrote: > On Wed, 18 Sep 2019 10:25:15 +0200 > David Hildenbrand <da...@redhat.com> wrote: > >> On 16.09.19 15:57, David Hildenbrand wrote: >>> 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 <sbri...@redhat.com> >>> Cc: Florian Weimer <fwei...@redhat.com> >>> Cc: Dan Horák <d...@danny.cz> >>> Cc: Cole Robinson <crobi...@redhat.com> >>> >>> v2 -> v3: >>> - "s390x/tcg: MVCL: Zero out unused bits of address" >>> -- Do single deposit for 24/31-bit >>> - "s390x/tcg: MVCL: Process max 4k bytes at a time" >>> -- Use max of 4k instead of 2k, limiting to single pages >>> - "s390x/tcg: MVCLU/MVCLE: Process max 4k bytes at a time" >>> -- Limit to single pages >>> - "s390x/tcg: MVCOS: Lengths are 32 bit in 24/31-bit mode" >>> -- Added >>> - "s390x/tcg: MVCS/MVCP: Properly wrap the length" >>> -- Properly use 32 instead of 31 bit. >>> - "s390x/tcg: MVST: Fix storing back the addresses to registers" >>> -- Read R0 implicitly >>> - "s390x/tcg: Fault-safe memset" >>> -- Speed up TLB_NOTDIRTY handling >>> -- Move single-page access to helper function >>> -- Pass access structure to access_memset() >>> -- Replace access_prepare() by previous access_prepare_idx() >>> - "s390x/tcg: Fault-safe memmove" >>> -- Pass access structure to access_memmove() >>> -- Speed up TLB_NOTDIRTY handling when accessing single bytes >>> - The other fault-safe handling patches were adapted to work with the >>> changed access functions. mmu_idx is now always passed to >>> access_prepare() from the helpers. >>> >>> v1 -> v2: >>> - Include many fixes >>> - Fix more instructions >>> - Use the new probe_access() function >>> - Include "tests/tcg: target/s390x: Test MVO" >>> >>> David Hildenbrand (29): >>> 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 4k 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: MVCOS: Lengths are 32 bit in 24/31-bit mode >>> 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() >>> 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 | 743 ++++++++++++++++++++++---------- >>> target/s390x/translate.c | 12 +- >>> tests/tcg/s390x/Makefile.target | 1 + >>> tests/tcg/s390x/mvo.c | 25 ++ >>> 7 files changed, 564 insertions(+), 225 deletions(-) >>> create mode 100644 tests/tcg/s390x/mvo.c >>> >> >> As long as there are no further comments, this series is ready to go >> (only one patch description needs a fixup). > > I don't have any :) > >> >> Conny, how do you prefer to upstream this stuff? (remembering that >> you'll be on vacation soon). > > I'll happily process a pull request from you, as long as I can send a > pull request myself on Thu or Fri latest. >
Alright, I'll send on later today. Cheers! -- Thanks, David / dhildenb
