From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD452779E8 for ; Thu, 1 Feb 2024 17:08:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.176.79.56 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706807310; cv=none; b=UHZdnkBW5x4vsvf61xR8AnYZll42+FhHLbxvobmkxcywcVk5vGyft+UeaTRH/ZoHfhaap0F6vB8RRgF7zjDiX6MgHwztJvVws+ZjMNveoxm/ooRH/PUOj+ny5caj7ucVViP46N1r0FRXmsAErPUGwjX4jENQlGLPwJLGr3iv7Gs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706807310; c=relaxed/simple; bh=no9a/RWjVe56is27R3S8VIadO7S/WAeI7x34GMG2+g4=; h=Date:From:To:CC:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=XPSKRsFc65L8x9cDF3wiJHlChVbP7TCKlksGSCZYIo/1302oQiTXxoJebFBTR73QZMo3y5XwqUr64Th0trOdreK0J1/dtXuMl37REK/k9ffJaFEcgF4mJH2b/UNLu0LBOWCXRKVTYaSvZbdQTVeqhqSx1cFXc2nDMyKu/SElRP4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=185.176.79.56 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=Huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.18.186.231]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4TQldl4sK6z6K90M; Fri, 2 Feb 2024 01:05:15 +0800 (CST) Received: from lhrpeml500005.china.huawei.com (unknown [7.191.163.240]) by mail.maildlp.com (Postfix) with ESMTPS id 0909E140A9C; Fri, 2 Feb 2024 01:08:24 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.35; Thu, 1 Feb 2024 17:08:23 +0000 Date: Thu, 1 Feb 2024 17:08:22 +0000 From: Jonathan Cameron To: Alex =?ISO-8859-1?Q?Benn=E9e?= CC: Peter Maydell , Sajjan Rao , Gregory Price , "Dimitrios Palyvos" , , , Subject: Re: Crash with CXL + TCG on 8.2: Was Re: qemu cxl memory expander shows numa_node -1 Message-ID: <20240201170822.00005bad@Huawei.com> In-Reply-To: <87h6iskuad.fsf@draig.linaro.org> References: <20230823175056.00001a84@Huawei.com> <20240126123926.000051bd@Huawei.com> <20240126171233.00002a2e@Huawei.com> <20240201130438.00001384@Huawei.com> <20240201140100.000016ce@huawei.com> <87msskkyce.fsf@draig.linaro.org> <20240201162150.000022cf@huawei.com> <87h6iskuad.fsf@draig.linaro.org> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) Precedence: bulk X-Mailing-List: linux-cxl@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: lhrpeml500003.china.huawei.com (7.191.162.67) To lhrpeml500005.china.huawei.com (7.191.163.240) On Thu, 01 Feb 2024 16:45:30 +0000 Alex Benn=E9e wrote: > Jonathan Cameron writes: >=20 > > On Thu, 1 Feb 2024 16:00:56 +0000 > > Peter Maydell wrote: > > =20 > >> On Thu, 1 Feb 2024 at 15:17, Alex Benn=E9e wr= ote: =20 > >> > > >> > Peter Maydell writes: =20 > >> > > So, that looks like: > >> > > * we call cpu_tb_exec(), which executes some generated code > >> > > * that generated code calls the lookup_tb_ptr helper to see > >> > > if we have a generated TB already for the address we're going > >> > > to execute next > >> > > * lookup_tb_ptr probes the TLB to see if we know the host RAM > >> > > address for the guest address > >> > > * this results in a TLB walk for an instruction fetch > >> > > * the page table descriptor load is to IO memory > >> > > * io_prepare assumes it needs to do a TLB recompile, because > >> > > can_do_io is clear > >> > > > >> > > I am not surprised that the corner case of "the guest put its > >> > > page tables in an MMIO device" has not yet come up :-) > >> > > > >> > > I'm really not sure how the icount handling should interact > >> > > with that... =20 > >> > > >> > Its not just icount - we need to handle it for all modes now. That s= aid > >> > seeing as we are at the end of a block shouldn't can_do_io be set? = =20 > >>=20 > >> The lookup_tb_ptr helper gets called from tcg_gen_goto_tb(), > >> which happens earlier than the tb_stop callback (it can > >> happen in the trans function for branch etc insns, for > >> example). > >>=20 > >> I think it should be OK to clear can_do_io at the start > >> of the lookup_tb_ptr helper, something like: > >> diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c > >> index 977576ca143..7818537f318 100644 > >> --- a/accel/tcg/cpu-exec.c > >> +++ b/accel/tcg/cpu-exec.c > >> @@ -396,6 +396,15 @@ const void *HELPER(lookup_tb_ptr)(CPUArchState *e= nv) > >> uint64_t cs_base; > >> uint32_t flags, cflags; > >>=20 > >> + /* > >> + * By definition we've just finished a TB, so I/O is OK. > >> + * Avoid the possibility of calling cpu_io_recompile() if > >> + * a page table walk triggered by tb_lookup() calling > >> + * probe_access_internal() happens to touch an MMIO device. > >> + * The next TB, if we chain to it, will clear the flag again. > >> + */ > >> + cpu->neg.can_do_io =3D true; > >> + > >> cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags); > >>=20 > >> cflags =3D curr_cflags(cpu); > >>=20 > >> -- PMM =20 > > > > No joy. Seems like a very similar backtrace. > > > > Thread 5 "qemu-system-x86" received signal SIGABRT, Aborted. > > [Switching to Thread 0x7ffff4efe6c0 (LWP 23937)] > > __pthread_kill_implementation (no_tid=3D0, signo=3D6, threadid=3D) at ./nptl/pthread_kill.c:44 > > 44 ./nptl/pthread_kill.c: No such file or directory. > > (gdb) bt > > #0 __pthread_kill_implementation (no_tid=3D0, signo=3D6, threadid=3D) at ./nptl/pthread_kill.c:44 > > #1 __pthread_kill_internal (signo=3D6, threadid=3D) at = ./nptl/pthread_kill.c:78 > > #2 __GI___pthread_kill (threadid=3D, signo=3Dsigno@entr= y=3D6) at ./nptl/pthread_kill.c:89 > > #3 0x00007ffff77c43b6 in __GI_raise (sig=3Dsig@entry=3D6) at ../sysdep= s/posix/raise.c:26 > > #4 0x00007ffff77aa87c in __GI_abort () at ./stdlib/abort.c:79 > > #5 0x0000555555c4d19e in cpu_abort (cpu=3Dcpu@entry=3D0x5555578e0cb0, = fmt=3Dfmt@entry=3D0x555556048ee8 "cpu_io_recompile: could not find TB for p= c=3D%p") at ../../cpu-target.c:373 > > #6 0x0000555555c9cb25 in cpu_io_recompile (cpu=3Dcpu@entry=3D0x5555578= e0cb0, retaddr=3Dretaddr@entry=3D0) at ../../accel/tcg/translate-all.c:611 > > #7 0x0000555555c9f744 in io_prepare (retaddr=3D0, addr=3D19595790664, = attrs=3D..., xlat=3D, cpu=3D0x5555578e0cb0, out_offset=3D) at ../../accel/tcg/cputlb.c:1339 > > #8 do_ld_mmio_beN (cpu=3D0x5555578e0cb0, full=3D0x7ffe88012890, ret_be= =3Dret_be@entry=3D0, addr=3D19595790664, size=3Dsize@entry=3D8, mmu_idx=3D4= , type=3DMMU_DATA_LOAD, ra=3D0) at ../../accel/tcg/cputlb.c:2030 > > #9 0x0000555555ca0ecd in do_ld_8 (cpu=3Dcpu@entry=3D0x5555578e0cb0, p= =3Dp@entry=3D0x7ffff4efcdd0, mmu_idx=3D, type=3Dtype@entry= =3DMMU_DATA_LOAD, memop=3D, ra=3Dra@entry=3D0) at ../../acce= l/tcg/cputlb.c:2356 > > #10 0x0000555555ca332f in do_ld8_mmu (cpu=3Dcpu@entry=3D0x5555578e0cb0,= addr=3Daddr@entry=3D19595790664, oi=3Doi@entry=3D52, ra=3Dra@entry=3D0, ac= cess_type=3Daccess_type@entry=3DMMU_DATA_LOAD) at ../../accel/tcg/cputlb.c:= 2439 > > #11 0x0000555555ca5e69 in cpu_ldq_mmu (ra=3D0, oi=3D52, addr=3D19595790= 664, env=3D0x5555578e3470) at ../../accel/tcg/ldst_common.c.inc:169 > > #12 cpu_ldq_le_mmuidx_ra (env=3D0x5555578e3470, addr=3D19595790664, mmu= _idx=3D, ra=3Dra@entry=3D0) at ../../accel/tcg/ldst_common.c= .inc:301 > > #13 0x0000555555b4b5de in ptw_ldq (in=3D0x7ffff4efcf10) at ../../target= /i386/tcg/sysemu/excp_helper.c:98 > > #14 ptw_ldq (in=3D0x7ffff4efcf10) at ../../target/i386/tcg/sysemu/excp_= helper.c:93 > > #15 mmu_translate (env=3Denv@entry=3D0x5555578e3470, in=3D0x7ffff4efcfd= 0, out=3D0x7ffff4efcfa0, err=3Derr@entry=3D0x7ffff4efcfb0) at ../../target/= i386/tcg/sysemu/excp_helper.c:173 > > #16 0x0000555555b4c3f3 in get_physical_address (err=3D0x7ffff4efcfb0, o= ut=3D0x7ffff4efcfa0, mmu_idx=3D0, access_type=3DMMU_DATA_STORE, addr=3D1838= 6491786698339392, env=3D0x5555578e3470) at ../../target/i386/tcg/sysemu/exc= p_helper.c:578 > > #17 x86_cpu_tlb_fill (cs=3D0x5555578e0cb0, addr=3D18386491786698339392,= size=3D, access_type=3DMMU_DATA_STORE, mmu_idx=3D0, probe= =3D, retaddr=3D140736029817822) at ../../target/i386/tcg/sys= emu/excp_helper.c:604 > > #18 0x0000555555ca0df9 in tlb_fill (retaddr=3D140736029817822, mmu_idx= =3D0, access_type=3DMMU_DATA_STORE, size=3D, addr=3D18386491= 786698339392, cpu=3D0x7ffff4efd120) at ../../accel/tcg/cputlb.c:1315 > > #19 mmu_lookup1 (cpu=3Dcpu@entry=3D0x5555578e0cb0, data=3Ddata@entry=3D= 0x7ffff4efd120, mmu_idx=3D0, access_type=3Daccess_type@entry=3DMMU_DATA_STO= RE, ra=3Dra@entry=3D140736029817822) at ../../accel/tcg/cputlb.c:1713 > > #20 0x0000555555ca2b71 in mmu_lookup (cpu=3D0x5555578e0cb0, addr=3D1838= 6491786698339392, oi=3D, ra=3D140736029817822, type=3DMMU_DA= TA_STORE, l=3D0x7ffff4efd120) at ../../accel/tcg/cputlb.c:1803 > > #21 0x0000555555ca3e5d in do_st8_mmu (cpu=3D0x5555578e0cb0, addr=3D2393= 7, val=3D18386491784638059520, oi=3D6, ra=3D140736029817822) at ../../accel= /tcg/cputlb.c:2853 > > #22 0x00007fffa9107c63 in code_gen_buffer () =20 >=20 > No thats different - we are actually writing to the MMIO region here. > But the fact we hit cpu_abort because we can't find the TB we are > executing is a little problematic. >=20 > Does ra properly point to the code buffer here? Err. How would I tell? I'll confess I have almost no idea what is going on in TCG :( Can learn but it won't be quick. J >=20 > > #23 0x0000555555c9395b in cpu_tb_exec (cpu=3Dcpu@entry=3D0x5555578e0cb0= , itb=3Ditb@entry=3D0x7fffa9107980 , tb_exit=3Dtb= _exit@entry=3D0x7ffff4efd718) at ../../accel/tcg/cpu-exec.c:442 > > #24 0x0000555555c93ec0 in cpu_loop_exec_tb (tb_exit=3D0x7ffff4efd718, l= ast_tb=3D, pc=3D, tb=3D0x7fffa9107980 , cpu=3D0x5555578e0cb0) at ../../accel/tcg/cpu-exec.= c:897 > > #25 cpu_exec_loop (cpu=3Dcpu@entry=3D0x5555578e0cb0, sc=3Dsc@entry=3D0x= 7ffff4efd7b0) at ../../accel/tcg/cpu-exec.c:1012 > > #26 0x0000555555c946d1 in cpu_exec_setjmp (cpu=3Dcpu@entry=3D0x5555578e= 0cb0, sc=3Dsc@entry=3D0x7ffff4efd7b0) at ../../accel/tcg/cpu-exec.c:1029 > > #27 0x0000555555c94ebc in cpu_exec (cpu=3Dcpu@entry=3D0x5555578e0cb0) a= t ../../accel/tcg/cpu-exec.c:1055 > > #28 0x0000555555cb8f53 in tcg_cpu_exec (cpu=3Dcpu@entry=3D0x5555578e0cb= 0) at ../../accel/tcg/tcg-accel-ops.c:76 > > #29 0x0000555555cb90b0 in mttcg_cpu_thread_fn (arg=3Darg@entry=3D0x5555= 578e0cb0) at ../../accel/tcg/tcg-accel-ops-mttcg.c:95 > > #30 0x0000555555e57180 in qemu_thread_start (args=3D0x555557956000) at = ../../util/qemu-thread-posix.c:541 > > #31 0x00007ffff78176ba in start_thread (arg=3D) at ./npt= l/pthread_create.c:444 > > #32 0x00007ffff78a60d0 in clone3 () at ../sysdeps/unix/sysv/linux/x86_6= 4/clone3.S:81 =20 >=20