| Message ID | 20240215150133.2088-3-Jonathan.Cameron@huawei.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | tcg/i386: Page tables in MMIO memory fixes (CXL) | expand |
On 15/2/24 16:01, Jonathan Cameron via wrote: > From: Gregory Price <gregory.price@memverge.com> > > CXL emulation of interleave requires read and write hooks due to > requirement for subpage granularity. The Linux kernel stack now enables > using this memory as conventional memory in a separate NUMA node. If a > process is deliberately forced to run from that node > $ numactl --membind=1 ls > the page table walk on i386 fails. > > Useful part of backtrace: > > (cpu=cpu@entry=0x555556fd9000, fmt=fmt@entry=0x555555fe3378 "cpu_io_recompile: could not find TB for pc=%p") > at ../../cpu-target.c:359 > (retaddr=0, addr=19595792376, attrs=..., xlat=<optimized out>, cpu=0x555556fd9000, out_offset=<synthetic pointer>) > at ../../accel/tcg/cputlb.c:1339 > (cpu=0x555556fd9000, full=0x7fffee0d96e0, ret_be=ret_be@entry=0, addr=19595792376, size=size@entry=8, mmu_idx=4, type=MMU_DATA_LOAD, ra=0) at ../../accel/tcg/cputlb.c:2030 > (cpu=cpu@entry=0x555556fd9000, p=p@entry=0x7ffff56fddc0, mmu_idx=<optimized out>, type=type@entry=MMU_DATA_LOAD, memop=<optimized out>, ra=ra@entry=0) at ../../accel/tcg/cputlb.c:2356 > (cpu=cpu@entry=0x555556fd9000, addr=addr@entry=19595792376, oi=oi@entry=52, ra=ra@entry=0, access_type=access_type@entry=MMU_DATA_LOAD) at ../../accel/tcg/cputlb.c:2439 > at ../../accel/tcg/ldst_common.c.inc:301 > at ../../target/i386/tcg/sysemu/excp_helper.c:173 > (err=0x7ffff56fdf80, out=0x7ffff56fdf70, mmu_idx=0, access_type=MMU_INST_FETCH, addr=18446744072116178925, env=0x555556fdb7c0) > at ../../target/i386/tcg/sysemu/excp_helper.c:578 > (cs=0x555556fd9000, addr=18446744072116178925, size=<optimized out>, access_type=MMU_INST_FETCH, mmu_idx=0, probe=<optimized out>, retaddr=0) at ../../target/i386/tcg/sysemu/excp_helper.c:604 > > Avoid this by plumbing the address all the way down from > x86_cpu_tlb_fill() where is available as retaddr to the actual accessors > which provide it to probe_access_full() which already handles MMIO accesses. > Suggested-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> > Signed-off-by: Gregory Price <gregory.price@memverge.com> > > --- > Patch posted in reply to thread: > https://lore.kernel.org/qemu-devel/ZbvpSaOXzZkqDd6c@memverge.com/ > > I checked Gregory was fine with me adding Sign-off / author via the CXL discord. > --- > target/i386/tcg/sysemu/excp_helper.c | 57 +++++++++++++++------------- > 1 file changed, 30 insertions(+), 27 deletions(-)
On Thu, 15 Feb 2024 16:31:26 +0100 Philippe Mathieu-Daudé <philmd@linaro.org> wrote: > On 15/2/24 16:01, Jonathan Cameron via wrote: > > From: Gregory Price <gregory.price@memverge.com> > > > > CXL emulation of interleave requires read and write hooks due to > > requirement for subpage granularity. The Linux kernel stack now enables > > using this memory as conventional memory in a separate NUMA node. If a > > process is deliberately forced to run from that node > > $ numactl --membind=1 ls > > the page table walk on i386 fails. > > > > Useful part of backtrace: > > > > (cpu=cpu@entry=0x555556fd9000, fmt=fmt@entry=0x555555fe3378 "cpu_io_recompile: could not find TB for pc=%p") > > at ../../cpu-target.c:359 > > (retaddr=0, addr=19595792376, attrs=..., xlat=<optimized out>, cpu=0x555556fd9000, out_offset=<synthetic pointer>) > > at ../../accel/tcg/cputlb.c:1339 > > (cpu=0x555556fd9000, full=0x7fffee0d96e0, ret_be=ret_be@entry=0, addr=19595792376, size=size@entry=8, mmu_idx=4, type=MMU_DATA_LOAD, ra=0) at ../../accel/tcg/cputlb.c:2030 > > (cpu=cpu@entry=0x555556fd9000, p=p@entry=0x7ffff56fddc0, mmu_idx=<optimized out>, type=type@entry=MMU_DATA_LOAD, memop=<optimized out>, ra=ra@entry=0) at ../../accel/tcg/cputlb.c:2356 > > (cpu=cpu@entry=0x555556fd9000, addr=addr@entry=19595792376, oi=oi@entry=52, ra=ra@entry=0, access_type=access_type@entry=MMU_DATA_LOAD) at ../../accel/tcg/cputlb.c:2439 > > at ../../accel/tcg/ldst_common.c.inc:301 > > at ../../target/i386/tcg/sysemu/excp_helper.c:173 > > (err=0x7ffff56fdf80, out=0x7ffff56fdf70, mmu_idx=0, access_type=MMU_INST_FETCH, addr=18446744072116178925, env=0x555556fdb7c0) > > at ../../target/i386/tcg/sysemu/excp_helper.c:578 > > (cs=0x555556fd9000, addr=18446744072116178925, size=<optimized out>, access_type=MMU_INST_FETCH, mmu_idx=0, probe=<optimized out>, retaddr=0) at ../../target/i386/tcg/sysemu/excp_helper.c:604 > > > > Avoid this by plumbing the address all the way down from > > x86_cpu_tlb_fill() where is available as retaddr to the actual accessors > > which provide it to probe_access_full() which already handles MMIO accesses. > > > > Suggested-by: Peter Maydell <peter.maydell@linaro.org> Good point! Sorry Peter. > Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org> Thanks > > > Signed-off-by: Gregory Price <gregory.price@memverge.com> > > > > --- > > Patch posted in reply to thread: > > https://lore.kernel.org/qemu-devel/ZbvpSaOXzZkqDd6c@memverge.com/ > > > > I checked Gregory was fine with me adding Sign-off / author via the CXL discord. > > --- > > target/i386/tcg/sysemu/excp_helper.c | 57 +++++++++++++++------------- > > 1 file changed, 30 insertions(+), 27 deletions(-) >
On 2/15/24 05:01, Jonathan Cameron wrote: > -static bool ptw_translate(PTETranslate *inout, hwaddr addr) > +static bool ptw_translate(PTETranslate *inout, hwaddr addr, uint64_t ra) You do not need to pass in 'ra' here... > flags = probe_access_full(inout->env, addr, 0, MMU_DATA_STORE, > - inout->ptw_idx, true, &inout->haddr, &full, 0); > + inout->ptw_idx, true, &inout->haddr, &full, ra); ... because this ^^^^ indicates a non-fault probe. A return address is only required for a faulting probe to raise an exception. > -static inline uint32_t ptw_ldl(const PTETranslate *in) > +static inline uint32_t ptw_ldl(const PTETranslate *in, uint64_t ra) > { > if (likely(in->haddr)) { > return ldl_p(in->haddr); > } > - return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0); > + return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, ra); > } However the loads do require 'ra' for the io_recompile, as you saw from the backtrace. r~
On 2/15/24 09:21, Richard Henderson wrote: > On 2/15/24 05:01, Jonathan Cameron wrote: >> -static bool ptw_translate(PTETranslate *inout, hwaddr addr) >> +static bool ptw_translate(PTETranslate *inout, hwaddr addr, uint64_t ra) > > You do not need to pass in 'ra' here... > >> flags = probe_access_full(inout->env, addr, 0, MMU_DATA_STORE, >> - inout->ptw_idx, true, &inout->haddr, &full, 0); >> + inout->ptw_idx, true, &inout->haddr, &full, ra); > > ... because this ^^^^ > indicates a non-fault probe. > A return address is only required for a faulting probe to raise an exception. Bah. We can always recurse and hit the load case too. So: Reviewed-by: Richard Henderson <richard.henderson@linaro.org> r~ > >> -static inline uint32_t ptw_ldl(const PTETranslate *in) >> +static inline uint32_t ptw_ldl(const PTETranslate *in, uint64_t ra) >> { >> if (likely(in->haddr)) { >> return ldl_p(in->haddr); >> } >> - return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0); >> + return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, ra); >> } > > However the loads do require 'ra' for the io_recompile, as you saw from the backtrace. > > > r~
diff --git a/target/i386/tcg/sysemu/excp_helper.c b/target/i386/tcg/sysemu/excp_helper.c index 5b86f439ad..b3bce020f4 100644 --- a/target/i386/tcg/sysemu/excp_helper.c +++ b/target/i386/tcg/sysemu/excp_helper.c @@ -59,14 +59,14 @@ typedef struct PTETranslate { hwaddr gaddr; } PTETranslate; -static bool ptw_translate(PTETranslate *inout, hwaddr addr) +static bool ptw_translate(PTETranslate *inout, hwaddr addr, uint64_t ra) { CPUTLBEntryFull *full; int flags; inout->gaddr = addr; flags = probe_access_full(inout->env, addr, 0, MMU_DATA_STORE, - inout->ptw_idx, true, &inout->haddr, &full, 0); + inout->ptw_idx, true, &inout->haddr, &full, ra); if (unlikely(flags & TLB_INVALID_MASK)) { TranslateFault *err = inout->err; @@ -82,20 +82,20 @@ static bool ptw_translate(PTETranslate *inout, hwaddr addr) return true; } -static inline uint32_t ptw_ldl(const PTETranslate *in) +static inline uint32_t ptw_ldl(const PTETranslate *in, uint64_t ra) { if (likely(in->haddr)) { return ldl_p(in->haddr); } - return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0); + return cpu_ldl_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, ra); } -static inline uint64_t ptw_ldq(const PTETranslate *in) +static inline uint64_t ptw_ldq(const PTETranslate *in, uint64_t ra) { if (likely(in->haddr)) { return ldq_p(in->haddr); } - return cpu_ldq_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, 0); + return cpu_ldq_mmuidx_ra(in->env, in->gaddr, in->ptw_idx, ra); } /* @@ -132,7 +132,8 @@ static inline bool ptw_setl(const PTETranslate *in, uint32_t old, uint32_t set) } static bool mmu_translate(CPUX86State *env, const TranslateParams *in, - TranslateResult *out, TranslateFault *err) + TranslateResult *out, TranslateFault *err, + uint64_t ra) { const int32_t a20_mask = x86_get_a20_mask(env); const target_ulong addr = in->addr; @@ -166,11 +167,11 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, */ pte_addr = ((in->cr3 & ~0xfff) + (((addr >> 48) & 0x1ff) << 3)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } restart_5: - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -191,11 +192,11 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, */ pte_addr = ((pte & PG_ADDRESS_MASK) + (((addr >> 39) & 0x1ff) << 3)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } restart_4: - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -212,11 +213,11 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, */ pte_addr = ((pte & PG_ADDRESS_MASK) + (((addr >> 30) & 0x1ff) << 3)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } restart_3_lma: - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -239,12 +240,12 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, * Page table level 3 */ pte_addr = ((in->cr3 & ~0x1f) + ((addr >> 27) & 0x18)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } rsvd_mask |= PG_HI_USER_MASK; restart_3_nolma: - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -262,11 +263,11 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, */ pte_addr = ((pte & PG_ADDRESS_MASK) + (((addr >> 21) & 0x1ff) << 3)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } restart_2_pae: - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -289,10 +290,10 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, */ pte_addr = ((pte & PG_ADDRESS_MASK) + (((addr >> 12) & 0x1ff) << 3)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } - pte = ptw_ldq(&pte_trans); + pte = ptw_ldq(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -307,11 +308,11 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, * Page table level 2 */ pte_addr = ((in->cr3 & ~0xfff) + ((addr >> 20) & 0xffc)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } restart_2_nopae: - pte = ptw_ldl(&pte_trans); + pte = ptw_ldl(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -336,10 +337,10 @@ static bool mmu_translate(CPUX86State *env, const TranslateParams *in, * Page table level 1 */ pte_addr = ((pte & ~0xfffu) + ((addr >> 10) & 0xffc)) & a20_mask; - if (!ptw_translate(&pte_trans, pte_addr)) { + if (!ptw_translate(&pte_trans, pte_addr, ra)) { return false; } - pte = ptw_ldl(&pte_trans); + pte = ptw_ldl(&pte_trans, ra); if (!(pte & PG_PRESENT_MASK)) { goto do_fault; } @@ -529,7 +530,8 @@ static G_NORETURN void raise_stage2(CPUX86State *env, TranslateFault *err, static bool get_physical_address(CPUX86State *env, vaddr addr, MMUAccessType access_type, int mmu_idx, - TranslateResult *out, TranslateFault *err) + TranslateResult *out, TranslateFault *err, + uint64_t ra) { TranslateParams in; bool use_stage2 = env->hflags2 & HF2_NPT_MASK; @@ -548,7 +550,7 @@ static bool get_physical_address(CPUX86State *env, vaddr addr, in.mmu_idx = MMU_USER_IDX; in.ptw_idx = MMU_PHYS_IDX; - if (!mmu_translate(env, &in, out, err)) { + if (!mmu_translate(env, &in, out, err, ra)) { err->stage2 = S2_GPA; return false; } @@ -575,7 +577,7 @@ static bool get_physical_address(CPUX86State *env, vaddr addr, return false; } } - return mmu_translate(env, &in, out, err); + return mmu_translate(env, &in, out, err, ra); } break; } @@ -601,7 +603,8 @@ bool x86_cpu_tlb_fill(CPUState *cs, vaddr addr, int size, TranslateResult out; TranslateFault err; - if (get_physical_address(env, addr, access_type, mmu_idx, &out, &err)) { + if (get_physical_address(env, addr, access_type, mmu_idx, &out, &err, + retaddr)) { /* * Even if 4MB pages, we map only one 4KB page in the cache to * avoid filling it too fast.