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2019-02-11cputlb: update TLB entry/index after tlb_fillEmilio G. Cota
We are failing to take into account that tlb_fill() can cause a TLB resize, which renders prior TLB entry pointers/indices stale. Fix it by re-doing the TLB entry lookups immediately after tlb_fill. Fixes: 86e1eff8bc ("tcg: introduce dynamic TLB sizing", 2019-01-28) Reported-by: Max Filippov <jcmvbkbc@gmail.com> Tested-by: Max Filippov <jcmvbkbc@gmail.com> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20190209162745.12668-3-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-30tcg: Fix LGPL version numberThomas Huth
It's either "GNU *Library* General Public version 2" or "GNU Lesser General Public version *2.1*", but there was no "version 2.0" of the "Lesser" library. So assume that version 2.1 is meant here. Cc: Richard Henderson <rth@twiddle.net> Signed-off-by: Thomas Huth <thuth@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <1548252536-6242-5-git-send-email-thuth@redhat.com> Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2019-01-28cputlb: Remove static tlb sizingRichard Henderson
Now that all tcg backends support TCG_TARGET_IMPLEMENTS_DYN_TLB, remove the define and the old code. Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-28tcg: introduce dynamic TLB sizingEmilio G. Cota
Disabled in all TCG backends for now. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20190116170114.26802-3-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2019-01-28cputlb: do not evict empty entries to the vtlbEmilio G. Cota
Currently we evict an entry to the victim TLB when it doesn't match the current address. But it could be that there's no match because the current entry is empty (i.e. all -1's, for instance via tlb_flush). Do not evict the entry to the vtlb in that case. This change will help us keep track of the TLB's use rate, which we'll use to implement a policy for dynamic TLB sizing. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20190116170114.26802-2-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Remove tlb_c.pending_flushesRichard Henderson
This is essentially redundant with tlb_c.dirty. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Filter flushes on already clean tlbsRichard Henderson
Especially for guests with large numbers of tlbs, like ARM or PPC, we may well not use all of them in between flush operations. Remember which tlbs have been used since the last flush, and avoid any useless flushing. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Count "partial" and "elided" tlb flushesRichard Henderson
Our only statistic so far was "full" tlb flushes, where all mmu_idx are flushed at the same time. Now count "partial" tlb flushes where sets of mmu_idx are flushed, but the set is not maximal. Account one per mmu_idx flushed, as that is the unit of work performed. We don't actually count elided flushes yet, but go ahead and change the interface presented to the monitor all at once. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Merge tlb_flush_page into tlb_flush_page_by_mmuidxRichard Henderson
The difference between the two sets of APIs is now miniscule. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Merge tlb_flush_nocheck into tlb_flush_by_mmuidx_async_workRichard Henderson
The difference between the two sets of APIs is now miniscule. This allows tlb_flush, tlb_flush_all_cpus, and tlb_flush_all_cpus_synced to be merged with their corresponding by_mmuidx functions as well. For accounting, consider mmu_idx_bitmask = ALL_MMUIDX_BITS to be a full flush. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Move env->vtlb_index to env->tlb_d.vindexRichard Henderson
The rest of the tlb victim cache is per-tlb, the next use index should be as well. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Split large page tracking per mmu_idxRichard Henderson
The set of large pages in the kernel is probably not the same as the set of large pages in the application. Forcing one range to cover both will flush more often than necessary. This allows tlb_flush_page_async_work to flush just the one mmu_idx implicated, which in turn allows us to remove tlb_check_page_and_flush_by_mmuidx_async_work. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Move cpu->pending_tlb_flush to env->tlb_c.pending_flushRichard Henderson
Protect it with the tlb_lock instead of using atomics. The move puts it in or near the same cacheline as the lock; using the lock means we don't need a second atomic operation in order to perform the update. Which makes it cheap to also update pending_flush in tlb_flush_by_mmuidx_async_work. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Remove tcg_enabled hack from tlb_flush_nocheckRichard Henderson
The bugs this was working around were fixed with commits 022d6378c7fd target/unicore32: remove tlb_flush from uc32_init_fn 6e11beecfde0 target/alpha: remove tlb_flush from alpha_cpu_initfn Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-31cputlb: Move tlb_lock to CPUTLBCommonRichard Henderson
This is the first of several moves to reduce the size of the CPU_COMMON_TLB macro and improve some locality of refernce. Tested-by: Emilio G. Cota <cota@braap.org> Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18cputlb: read CPUTLBEntry.addr_write atomicallyEmilio G. Cota
Updates can come from other threads, so readers that do not take tlb_lock must use atomic_read to avoid undefined behaviour (UB). This completes the conversion to tlb_lock. This conversion results on average in no performance loss, as the following experiments (run on an Intel i7-6700K CPU @ 4.00GHz) show. 1. aarch64 bootup+shutdown test: - Before: Performance counter stats for 'taskset -c 0 ../img/aarch64/die.sh' (10 runs): 7487.087786 task-clock (msec) # 0.998 CPUs utilized ( +- 0.12% ) 31,574,905,303 cycles # 4.217 GHz ( +- 0.12% ) 57,097,908,812 instructions # 1.81 insns per cycle ( +- 0.08% ) 10,255,415,367 branches # 1369.747 M/sec ( +- 0.08% ) 173,278,962 branch-misses # 1.69% of all branches ( +- 0.18% ) 7.504481349 seconds time elapsed ( +- 0.14% ) - After: Performance counter stats for 'taskset -c 0 ../img/aarch64/die.sh' (10 runs): 7462.441328 task-clock (msec) # 0.998 CPUs utilized ( +- 0.07% ) 31,478,476,520 cycles # 4.218 GHz ( +- 0.07% ) 57,017,330,084 instructions # 1.81 insns per cycle ( +- 0.05% ) 10,251,929,667 branches # 1373.804 M/sec ( +- 0.05% ) 173,023,787 branch-misses # 1.69% of all branches ( +- 0.11% ) 7.474970463 seconds time elapsed ( +- 0.07% ) 2. SPEC06int: SPEC06int (test set) [Y axis: Speedup over master] 1.15 +-+----+------+------+------+------+------+-------+------+------+------+------+------+------+----+-+ | | 1.1 +-+.................................+++.............................+ tlb-lock-v2 (m+++x) +-+ | +++ | +++ tlb-lock-v3 (spinl|ck) | | +++ | | +++ +++ | | | 1.05 +-+....+++...........####.........|####.+++.|......|.....###....+++...........+++....###.........+-+ | ### ++#| # |# |# ***### +++### +++#+# | +++ | #|# ### | 1 +-+++***+#++++####+++#++#++++++++++#++#+*+*++#++++#+#+****+#++++###++++###++++###++++#+#++++#+#+++-+ | *+* # #++# *** # #### *** # * *++# ****+# *| * # ****|# |# # #|# #+# # # | 0.95 +-+..*.*.#....#..#.*|*..#...#..#.*|*..#.*.*..#.*|.*.#.*++*.#.*++*+#.****.#....#+#....#.#..++#.#..+-+ | * * # # # *|* # # # *|* # * * # *++* # * * # * * # * |* # ++# # # # *** # | | * * # ++# # *+* # # # *|* # * * # * * # * * # * * # *++* # **** # ++# # * * # | 0.9 +-+..*.*.#...|#..#.*.*..#.++#..#.*|*..#.*.*..#.*..*.#.*..*.#.*..*.#.*..*.#.*.|*.#...|#.#..*.*.#..+-+ | * * # *** # * * # |# # *+* # * * # * * # * * # * * # * * # *++* # |# # * * # | 0.85 +-+..*.*.#..*|*..#.*.*..#.***..#.*.*..#.*.*..#.*..*.#.*..*.#.*..*.#.*..*.#.*..*.#.****.#..*.*.#..+-+ | * * # *+* # * * # *|* # * * # * * # * * # * * # * * # * * # * * # * |* # * * # | | * * # * * # * * # *+* # * * # * * # * * # * * # * * # * * # * * # * |* # * * # | 0.8 +-+..*.*.#..*.*..#.*.*..#.*.*..#.*.*..#.*.*..#.*..*.#.*..*.#.*..*.#.*..*.#.*..*.#.*++*.#..*.*.#..+-+ | * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # * * # | 0.75 +-+--***##--***###-***###-***###-***###-***###-****##-****##-****##-****##-****##-****##--***##--+-+ 400.perlben401.bzip2403.gcc429.m445.gob456.hmme45462.libqua464.h26471.omnet473483.xalancbmkgeomean png: https://imgur.com/a/BHzpPTW Notes: - tlb-lock-v2 corresponds to an implementation with a mutex. - tlb-lock-v3 corresponds to the current implementation, i.e. a spinlock and a single lock acquisition in tlb_set_page_with_attrs. Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181016153840.25877-1-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18tcg: Split CONFIG_ATOMIC128Richard Henderson
GCC7+ will no longer advertise support for 16-byte __atomic operations if only cmpxchg is supported, as for x86_64. Fortunately, x86_64 still has support for __sync_compare_and_swap_16 and we can make use of that. AArch64 does not have, nor ever has had such support, so open-code it. Reviewed-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18tcg: Add tlb_index and tlb_entry helpersRichard Henderson
Isolate the computation of an index from an address into a helper before we change that function. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> [ cota: convert tlb_vaddr_to_host; use atomic_read on addr_write ] Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181009175129.17888-2-cota@braap.org>
2018-10-18cputlb: serialize tlb updates with env->tlb_lockEmilio G. Cota
Currently we rely on atomic operations for cross-CPU invalidations. There are two cases that these atomics miss: cross-CPU invalidations can race with either (1) vCPU threads flushing their TLB, which happens via memset, or (2) vCPUs calling tlb_reset_dirty on their TLB, which updates .addr_write with a regular store. This results in undefined behaviour, since we're mixing regular and atomic ops on concurrent accesses. Fix it by using tlb_lock, a per-vCPU lock. All updaters of tlb_table and the corresponding victim cache now hold the lock. The readers that do not hold tlb_lock must use atomic reads when reading .addr_write, since this field can be updated by other threads; the conversion to atomic reads is done in the next patch. Note that an alternative fix would be to expand the use of atomic ops. However, in the case of TLB flushes this would have a huge performance impact, since (1) TLB flushes can happen very frequently and (2) we currently use a full memory barrier to flush each TLB entry, and a TLB has many entries. Instead, acquiring the lock is barely slower than a full memory barrier since it is uncontended, and with a single lock acquisition we can flush the entire TLB. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181009174557.16125-6-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18cputlb: fix assert_cpu_is_self macroEmilio G. Cota
Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181009174557.16125-5-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-10-18exec: introduce tlb_initEmilio G. Cota
Paves the way for the addition of a per-TLB lock. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <20181009174557.16125-4-cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-08-14accel/tcg: Check whether TLB entry is RAM consistently with how we set it upPeter Maydell
We set up TLB entries in tlb_set_page_with_attrs(), where we have some logic for determining whether the TLB entry is considered to be RAM-backed, and thus has a valid addend field. When we look at the TLB entry in get_page_addr_code(), we use different logic for determining whether to treat the page as RAM-backed and use the addend field. This is confusing, and in fact buggy, because the code in tlb_set_page_with_attrs() correctly decides that rom_device memory regions not in romd mode are not RAM-backed, but the code in get_page_addr_code() thinks they are RAM-backed. This typically results in "Bad ram pointer" assertion if the guest tries to execute from such a memory region. Fix this by making get_page_addr_code() just look at the TLB_MMIO bit in the code_address field of the TLB, which tlb_set_page_with_attrs() sets if and only if the addend field is not valid for code execution. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20180713150945.12348-1-peter.maydell@linaro.org
2018-08-14accel/tcg: Return -1 for execution from MMIO regions in get_page_addr_code()Peter Maydell
Now that all the callers can handle get_page_addr_code() returning -1, remove all the code which tries to handle execution from MMIO regions or small-MMU-region RAM areas. This will mean that we can correctly execute from these areas, rather than ending up either aborting QEMU or delivering an incorrect guest exception. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Cédric Le Goater <clg@kaod.org> Tested-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20180710160013.26559-6-peter.maydell@linaro.org
2018-08-14accel/tcg: Pass read access type through to io_readx()Peter Maydell
The io_readx() function needs to know whether the load it is doing is an MMU_DATA_LOAD or an MMU_INST_FETCH, so that it can pass the right value to the cpu_transaction_failed() function. Plumb this information through from the softmmu code. This is currently not often going to give the wrong answer, because usually instruction fetches go via get_page_addr_code(). However once we switch over to handling execution from non-RAM by creating single-insn TBs, the path for an insn fetch to generate a bus error will be through cpu_ld*_code() and io_readx(), so without this change we will generate a d-side fault when we should generate an i-side fault. We also have to pass the access type via a CPU struct global down to unassigned_mem_read(), for the benefit of the targets which still use the cpu_unassigned_access() hook (m68k, mips, sparc, xtensa). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Tested-by: Cédric Le Goater <clg@kaod.org> Message-id: 20180710160013.26559-2-peter.maydell@linaro.org
2018-07-16accel/tcg: Assert that tlb fill gave us a valid TLB entryPeter Maydell
In commit 4b1a3e1e34ad97 we added a check for whether the TLB entry we had following a tlb_fill had the INVALID bit set. This could happen in some circumstances because a stale or wrong TLB entry was pulled out of the victim cache. However, after commit 68fea038553039e (which prevents stale entries being in the victim cache) and the previous commit (which ensures we don't incorrectly hit in the victim cache)) this should never be possible. Drop the check on TLB_INVALID_MASK from the "is this a TLB_RECHECK?" condition, and instead assert that the tlb fill procedure has given us a valid TLB entry (or longjumped out with a guest exception). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180713141636.18665-3-peter.maydell@linaro.org
2018-07-16accel/tcg: Use correct test when looking in victim TLB for codePeter Maydell
In get_page_addr_code(), we were incorrectly looking in the victim TLB for an entry which matched the target address for reads, not for code accesses. This meant that we could hit on a victim TLB entry that indicated that the address was readable but not executable, and incorrectly bypass the call to tlb_fill() which should generate the guest MMU exception. Fix this bug. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180713141636.18665-2-peter.maydell@linaro.org
2018-07-02accel/tcg: Avoid caching overwritten tlb entriesRichard Henderson
When installing a TLB entry, remove any cached version of the same page in the VTLB. If the existing TLB entry matches, do not copy into the VTLB, but overwrite it. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-07-02accel/tcg: Don't treat invalid TLB entries as needing recheckPeter Maydell
In get_page_addr_code() when we check whether the TLB entry is marked as TLB_RECHECK, we should not go down that code path if the TLB entry is not valid at all (ie the TLB_INVALID bit is set). Tested-by: Laurent Vivier <laurent@vivier.eu> Reported-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20180629161731.16239-1-peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-07-02accel/tcg: Correct "is this a TLB miss" check in get_page_addr_code()Peter Maydell
In commit 71b9a45330fe220d1 we changed the condition we use to determine whether we need to refill the TLB in get_page_addr_code() to if (unlikely(env->tlb_table[mmu_idx][index].addr_code != (addr & (TARGET_PAGE_MASK | TLB_INVALID_MASK)))) { This isn't the right check (it will falsely fail if the input addr happens to have the low bit corresponding to TLB_INVALID_MASK set, for instance). Replace it with a use of the new tlb_hit() function, which is the correct test. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20180629162122.19376-3-peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-07-02tcg: Define and use new tlb_hit() and tlb_hit_page() functionsPeter Maydell
The condition to check whether an address has hit against a particular TLB entry is not completely trivial. We do this in various places, and in fact in one place (get_page_addr_code()) we have got the condition wrong. Abstract it out into new tlb_hit() and tlb_hit_page() inline functions (one for a known-page-aligned address and one for an arbitrary address), and use them in all the places where we had the condition correct. This is a no-behaviour-change patch; we leave fixing the buggy code in get_page_addr_code() to a subsequent patch. Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Message-Id: <20180629162122.19376-2-peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-26tcg: Support MMU protection regions smaller than TARGET_PAGE_SIZEPeter Maydell
Add support for MMU protection regions that are smaller than TARGET_PAGE_SIZE. We do this by marking the TLB entry for those pages with a flag TLB_RECHECK. This flag causes us to always take the slow-path for accesses. In the slow path we can then special case them to always call tlb_fill() again, so we have the correct information for the exact address being accessed. This change allows us to handle reading and writing from small regions; we cannot deal with execution from the small region. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180620130619.11362-2-peter.maydell@linaro.org
2018-06-15cputlb: remove tb_lock from tlb_flush functionsEmilio G. Cota
The acquisition of tb_lock was added when the async tlb_flush was introduced in e3b9ca810 ("cputlb: introduce tlb_flush_* async work.") tb_lock was there to allow us to do memset() on the tb_jmp_cache's. However, since f3ced3c5928 ("tcg: consistently access cpu->tb_jmp_cache atomically") all accesses to tb_jmp_cache are atomic, so tb_lock is not needed here. Get rid of it. Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2018-06-15exec.c: Handle IOMMUs in address_space_translate_for_iotlb()Peter Maydell
Currently we don't support board configurations that put an IOMMU in the path of the CPU's memory transactions, and instead just assert() if the memory region fonud in address_space_translate_for_iotlb() is an IOMMUMemoryRegion. Remove this limitation by having the function handle IOMMUs. This is mostly straightforward, but we must make sure we have a notifier registered for every IOMMU that a transaction has passed through, so that we can flush the TLB appropriately when any of the IOMMUs change their mappings. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Message-id: 20180604152941.20374-5-peter.maydell@linaro.org
2018-06-15cputlb: Pass cpu_transaction_failed() the correct physaddrPeter Maydell
The API for cpu_transaction_failed() says that it takes the physical address for the failed transaction. However we were actually passing it the offset within the target MemoryRegion. We don't currently have any target CPU implementations of this hook that require the physical address; fix this bug so we don't get confused if we ever do add one. Suggested-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180611125633.32755-3-peter.maydell@linaro.org
2018-06-15cpu-defs.h: Document CPUIOTLBEntry 'addr' fieldPeter Maydell
The 'addr' field in the CPUIOTLBEntry struct has a rather non-obvious use; add a comment documenting it (reverse-engineered from what the code that sets it is doing). Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 20180611125633.32755-2-peter.maydell@linaro.org
2018-01-25accel/tcg: add size paremeter in tlb_fill()Laurent Vivier
The MC68040 MMU provides the size of the access that triggers the page fault. This size is set in the Special Status Word which is written in the stack frame of the access fault exception. So we need the size in m68k_cpu_unassigned_access() and m68k_cpu_handle_mmu_fault(). To be able to do that, this patch modifies the prototype of handle_mmu_fault handler, tlb_fill() and probe_write(). do_unassigned_access() already includes a size parameter. This patch also updates handle_mmu_fault handlers and tlb_fill() of all targets (only parameter, no code change). Signed-off-by: Laurent Vivier <laurent@vivier.eu> Reviewed-by: David Hildenbrand <david@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-Id: <20180118193846.24953-2-laurent@vivier.eu>
2017-11-21accel/tcg: Handle atomic accesses to notdirty memory correctlyPeter Maydell
To do a write to memory that is marked as notdirty, we need to invalidate any TBs we have cached for that memory, and update the cpu physical memory dirty flags for VGA and migration. The slowpath code in notdirty_mem_write() does all this correctly, but the new atomic handling code in atomic_mmu_lookup() doesn't do anything at all, it just clears the dirty bit in the TLB. The effect of this bug is that if the first write to a notdirty page for which we have cached TBs is by a guest atomic access, we fail to invalidate the TBs and subsequently will execute incorrect code. This can be seen by trying to run 'javac' on AArch64. Use the new notdirty_call_before() and notdirty_call_after() functions to correctly handle the update to notdirty memory in the atomic codepath. Cc: qemu-stable@nongnu.org Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Richard Henderson <richard.henderson@linaro.org> Message-id: 1511201308-23580-3-git-send-email-peter.maydell@linaro.org
2017-11-15tcg: Record code_gen_buffer address for user-only memory helpersRichard Henderson
When we handle a signal from a fault within a user-only memory helper, we cannot cpu_restore_state with the PC found within the signal frame. Use a TLS variable, helper_retaddr, to record the unwind start point to find the faulting guest insn. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Reported-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-10-20accel/tcg: allow to invalidate a write TLB entry immediatelyDavid Hildenbrand
Background: s390x implements Low-Address Protection (LAP). If LAP is enabled, writing to effective addresses (before any translation) 0-511 and 4096-4607 triggers a protection exception. So we have subpage protection on the first two pages of every address space (where the lowcore - the CPU private data resides). By immediately invalidating the write entry but allowing the caller to continue, we force every write access onto these first two pages into the slow path. we will get a tlb fault with the specific accessed addresses and can then evaluate if protection applies or not. We have to make sure to ignore the invalid bit if tlb_fill() succeeds. Signed-off-by: David Hildenbrand <david@redhat.com> Message-Id: <20171016202358.3633-2-david@redhat.com> Signed-off-by: Cornelia Huck <cohuck@redhat.com>
2017-10-10cputlb: bring back tlb_flush_count under !TLB_DEBUGEmilio G. Cota
Commit f0aff0f124 ("cputlb: add assert_cpu_is_self checks") buried the increment of tlb_flush_count under TLB_DEBUG. This results in "info jit" always (mis)reporting 0 TLB flushes when !TLB_DEBUG. Besides, under MTTCG tlb_flush_count is updated by several threads, so in order not to lose counts we'd either have to use atomic ops or distribute the counter, which is more scalable. This patch does the latter by embedding tlb_flush_count in CPUArchState. The global count is then easily obtained by iterating over the CPU list. Note that this change also requires updating the accessors to tlb_flush_count to use atomic_read/set whenever there may be conflicting accesses (as defined in C11) to it. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Emilio G. Cota <cota@braap.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-25accel/tcg/cputlb: avoid recursive BQL (fixes #1706296)Alex Bennée
The mmio path (see exec.c:prepare_mmio_access) already protects itself against recursive locking and it makes sense to do the same for io_readx/writex. Otherwise any helper running in the BQL context will assert when it attempts to write to device memory as in the case of the bug report. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Signed-off-by: Alex Bennée <alex.bennee@linaro.org> CC: Richard Jones <rjones@redhat.com> CC: Paolo Bonzini <bonzini@gnu.org> CC: qemu-stable@nongnu.org Message-Id: <20170921110625.9500-1-alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2017-09-04cputlb: Support generating CPU exceptions on memory transaction failuresPeter Maydell
Call the new cpu_transaction_failed() hook at the places where CPU generated code interacts with the memory system: io_readx() io_writex() get_page_addr_code() Any access from C code (eg via cpu_physical_memory_rw(), address_space_rw(), ld/st_*_phys()) will *not* trigger CPU exceptions via cpu_transaction_failed(). Handling for transactions failures for this kind of call should be done by using a function which returns a MemTxResult and treating the failure case appropriately in the calling code. In an ideal world we would not generate CPU exceptions for instruction fetch failures in get_page_addr_code() but instead wait until the code translation process tried a load and it failed; however that change would require too great a restructuring and redesign to attempt at this point. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2017-06-30tcg: consistently access cpu->tb_jmp_cache atomicallyEmilio G. Cota
Some code paths can lead to atomic accesses racing with memset() on cpu->tb_jmp_cache, which can result in torn reads/writes and is undefined behaviour in C11. These torn accesses are unlikely to show up as bugs, but from code inspection they seem possible. For example, tb_phys_invalidate does: /* remove the TB from the hash list */ h = tb_jmp_cache_hash_func(tb->pc); CPU_FOREACH(cpu) { if (atomic_read(&cpu->tb_jmp_cache[h]) == tb) { atomic_set(&cpu->tb_jmp_cache[h], NULL); } } Here atomic_set might race with a concurrent memset (such as the ones scheduled via "unsafe" async work, e.g. tlb_flush_page) and therefore we might end up with a torn pointer (or who knows what, because we are under undefined behaviour). This patch converts parallel accesses to cpu->tb_jmp_cache to use atomic primitives, thereby bringing these accesses back to defined behaviour. The price to pay is to potentially execute more instructions when clearing cpu->tb_jmp_cache, but given how infrequently they happen and the small size of the cache, the performance impact I have measured is within noise range when booting debian-arm. Note that under "safe async" work (e.g. do_tb_flush) we could use memset because no other vcpus are running. However I'm keeping these accesses atomic as well to keep things simple and to avoid confusing analysis tools such as ThreadSanitizer. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net> Signed-off-by: Emilio G. Cota <cota@braap.org> Message-Id: <1497486973-25845-1-git-send-email-cota@braap.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
2017-06-27exec: allow to get a pointer for some mmio memory regionKONRAD Frederic
This introduces a special callback which allows to run code from some MMIO devices. SysBusDevice with a MemoryRegion which implements the request_ptr callback will be notified when the guest try to execute code from their offset. Then it will be able to eg: pre-load some code from an SPI device or ask a pointer from an external simulator, etc.. When the pointer or the data in it are no longer valid the device has to invalidate it. Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2017-06-27cputlb: fix the way get_page_addr_code fills the tlbKONRAD Frederic
get_page_addr_code(..) does a cpu_ldub_code to fill the tlb: This can lead to some side effects if a device is mapped at this address. So this patch replaces the cpu_memory_ld by a tlb_fill. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2017-06-27cputlb: move get_page_addr_codeKONRAD Frederic
This just moves the code before VICTIM_TLB_HIT macro definition so we can use it. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2017-06-27cputlb: cleanup get_page_addr_code to use VICTIM_TLB_HITKONRAD Frederic
This replaces env1 and page_index variables by env and index so we can use VICTIM_TLB_HIT macro later. Reviewed-by: Richard Henderson <rth@twiddle.net> Reviewed-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com> Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
2017-06-15tcg: move tcg related files into accel/tcg/ subdirectoryYang Zhong
move cputlb.c, cpu-exec-common.c and cpu-exec.c related tcg exec file into accel/tcg/ subdirectory. Signed-off-by: Yang Zhong <yang.zhong@intel.com> Message-Id: <1496383606-18060-3-git-send-email-yang.zhong@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>