| Message ID | 20190916135806.1269-1-david@redhat.com |
|---|---|
| Headers | show |
| Series | s390x/tcg: mem_helper: Fault-safe handling | expand |
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 <sbrivio@redhat.com> > Cc: Florian Weimer <fweimer@redhat.com> > Cc: Dan Horák <dan@danny.cz> > Cc: Cole Robinson <crobinso@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). Conny, how do you prefer to upstream this stuff? (remembering that you'll be on vacation soon).
On Wed, 18 Sep 2019 10:25:15 +0200 David Hildenbrand <david@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 <sbrivio@redhat.com> > > Cc: Florian Weimer <fweimer@redhat.com> > > Cc: Dan Horák <dan@danny.cz> > > Cc: Cole Robinson <crobinso@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.
On 18.09.19 11:26, Cornelia Huck wrote: > On Wed, 18 Sep 2019 10:25:15 +0200 > David Hildenbrand <david@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 <sbrivio@redhat.com> >>> Cc: Florian Weimer <fweimer@redhat.com> >>> Cc: Dan Horák <dan@danny.cz> >>> Cc: Cole Robinson <crobinso@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!