From 795592fef7d5d66a67b95a7f45cc1a84883db6a8 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Mon, 7 Oct 2024 17:29:48 -0700 Subject: [PATCH] accel/tcg: Use the alignment test in tlb_fill_align When we have a tlb miss, defer the alignment check to the new tlb_fill_align hook. Move the existing alignment check so that we only perform it with a tlb hit. Reviewed-by: Helge Deller Signed-off-by: Richard Henderson --- accel/tcg/cputlb.c | 88 ++++++++++++++++++++++++---------------------- 1 file changed, 45 insertions(+), 43 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index d72f454e9e..b76a4eac4e 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -1620,6 +1620,7 @@ typedef struct MMULookupLocals { * mmu_lookup1: translate one page * @cpu: generic cpu state * @data: lookup parameters + * @memop: memory operation for the access, or 0 * @mmu_idx: virtual address context * @access_type: load/store/code * @ra: return address into tcg generated code, or 0 @@ -1629,7 +1630,7 @@ typedef struct MMULookupLocals { * tlb_fill_align will longjmp out. Return true if the softmmu tlb for * @mmu_idx may have resized. */ -static bool mmu_lookup1(CPUState *cpu, MMULookupPageData *data, +static bool mmu_lookup1(CPUState *cpu, MMULookupPageData *data, MemOp memop, int mmu_idx, MMUAccessType access_type, uintptr_t ra) { vaddr addr = data->addr; @@ -1645,7 +1646,7 @@ static bool mmu_lookup1(CPUState *cpu, MMULookupPageData *data, if (!victim_tlb_hit(cpu, mmu_idx, index, access_type, addr & TARGET_PAGE_MASK)) { tlb_fill_align(cpu, addr, access_type, mmu_idx, - 0, data->size, false, ra); + memop, data->size, false, ra); maybe_resized = true; index = tlb_index(cpu, mmu_idx, addr); entry = tlb_entry(cpu, mmu_idx, addr); @@ -1657,6 +1658,25 @@ static bool mmu_lookup1(CPUState *cpu, MMULookupPageData *data, flags = tlb_addr & (TLB_FLAGS_MASK & ~TLB_FORCE_SLOW); flags |= full->slow_flags[access_type]; + if (likely(!maybe_resized)) { + /* Alignment has not been checked by tlb_fill_align. */ + int a_bits = memop_alignment_bits(memop); + + /* + * This alignment check differs from the one above, in that this is + * based on the atomicity of the operation. The intended use case is + * the ARM memory type field of each PTE, where access to pages with + * Device memory type require alignment. + */ + if (unlikely(flags & TLB_CHECK_ALIGNED)) { + int at_bits = memop_atomicity_bits(memop); + a_bits = MAX(a_bits, at_bits); + } + if (unlikely(addr & ((1 << a_bits) - 1))) { + cpu_unaligned_access(cpu, addr, access_type, mmu_idx, ra); + } + } + data->full = full; data->flags = flags; /* Compute haddr speculatively; depending on flags it might be invalid. */ @@ -1713,7 +1733,6 @@ static void mmu_watch_or_dirty(CPUState *cpu, MMULookupPageData *data, static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, uintptr_t ra, MMUAccessType type, MMULookupLocals *l) { - unsigned a_bits; bool crosspage; int flags; @@ -1722,12 +1741,6 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, tcg_debug_assert(l->mmu_idx < NB_MMU_MODES); - /* Handle CPU specific unaligned behaviour */ - a_bits = memop_alignment_bits(l->memop); - if (addr & ((1 << a_bits) - 1)) { - cpu_unaligned_access(cpu, addr, type, l->mmu_idx, ra); - } - l->page[0].addr = addr; l->page[0].size = memop_size(l->memop); l->page[1].addr = (addr + l->page[0].size - 1) & TARGET_PAGE_MASK; @@ -1735,7 +1748,7 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, crosspage = (addr ^ l->page[1].addr) & TARGET_PAGE_MASK; if (likely(!crosspage)) { - mmu_lookup1(cpu, &l->page[0], l->mmu_idx, type, ra); + mmu_lookup1(cpu, &l->page[0], l->memop, l->mmu_idx, type, ra); flags = l->page[0].flags; if (unlikely(flags & (TLB_WATCHPOINT | TLB_NOTDIRTY))) { @@ -1754,8 +1767,8 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, * Lookup both pages, recognizing exceptions from either. If the * second lookup potentially resized, refresh first CPUTLBEntryFull. */ - mmu_lookup1(cpu, &l->page[0], l->mmu_idx, type, ra); - if (mmu_lookup1(cpu, &l->page[1], l->mmu_idx, type, ra)) { + mmu_lookup1(cpu, &l->page[0], l->memop, l->mmu_idx, type, ra); + if (mmu_lookup1(cpu, &l->page[1], 0, l->mmu_idx, type, ra)) { uintptr_t index = tlb_index(cpu, l->mmu_idx, addr); l->page[0].full = &cpu->neg.tlb.d[l->mmu_idx].fulltlb[index]; } @@ -1774,19 +1787,6 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, tcg_debug_assert((flags & TLB_BSWAP) == 0); } - /* - * This alignment check differs from the one above, in that this is - * based on the atomicity of the operation. The intended use case is - * the ARM memory type field of each PTE, where access to pages with - * Device memory type require alignment. - */ - if (unlikely(flags & TLB_CHECK_ALIGNED)) { - a_bits = memop_atomicity_bits(l->memop); - if (addr & ((1 << a_bits) - 1)) { - cpu_unaligned_access(cpu, addr, type, l->mmu_idx, ra); - } - } - return crosspage; } @@ -1799,34 +1799,18 @@ static void *atomic_mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, { uintptr_t mmu_idx = get_mmuidx(oi); MemOp mop = get_memop(oi); - int a_bits = memop_alignment_bits(mop); uintptr_t index; CPUTLBEntry *tlbe; vaddr tlb_addr; void *hostaddr; CPUTLBEntryFull *full; + bool did_tlb_fill = false; tcg_debug_assert(mmu_idx < NB_MMU_MODES); /* Adjust the given return address. */ retaddr -= GETPC_ADJ; - /* Enforce guest required alignment. */ - if (unlikely(a_bits > 0 && (addr & ((1 << a_bits) - 1)))) { - /* ??? Maybe indicate atomic op to cpu_unaligned_access */ - cpu_unaligned_access(cpu, addr, MMU_DATA_STORE, - mmu_idx, retaddr); - } - - /* Enforce qemu required alignment. */ - if (unlikely(addr & (size - 1))) { - /* We get here if guest alignment was not requested, - or was not enforced by cpu_unaligned_access above. - We might widen the access and emulate, but for now - mark an exception and exit the cpu loop. */ - goto stop_the_world; - } - index = tlb_index(cpu, mmu_idx, addr); tlbe = tlb_entry(cpu, mmu_idx, addr); @@ -1836,7 +1820,8 @@ static void *atomic_mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, if (!victim_tlb_hit(cpu, mmu_idx, index, MMU_DATA_STORE, addr & TARGET_PAGE_MASK)) { tlb_fill_align(cpu, addr, MMU_DATA_STORE, mmu_idx, - 0, size, false, retaddr); + mop, size, false, retaddr); + did_tlb_fill = true; index = tlb_index(cpu, mmu_idx, addr); tlbe = tlb_entry(cpu, mmu_idx, addr); } @@ -1859,6 +1844,23 @@ static void *atomic_mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, */ g_assert_not_reached(); } + + /* Enforce guest required alignment, if not handled by tlb_fill_align. */ + if (!did_tlb_fill && (addr & ((1 << memop_alignment_bits(mop)) - 1))) { + cpu_unaligned_access(cpu, addr, MMU_DATA_STORE, mmu_idx, retaddr); + } + + /* Enforce qemu required alignment. */ + if (unlikely(addr & (size - 1))) { + /* + * We get here if guest alignment was not requested, or was not + * enforced by cpu_unaligned_access or tlb_fill_align above. + * We might widen the access and emulate, but for now + * mark an exception and exit the cpu loop. + */ + goto stop_the_world; + } + /* Collect tlb flags for read. */ tlb_addr |= tlbe->addr_read;