From e14614fe78bca37e8bdfa472ccf9b8aa49ec6e9e Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Sat, 4 Oct 2025 12:10:52 -0700 Subject: [PATCH] accel/tcg: Hoist first page lookup above pointer_wrap MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit For strict alignment targets we registered cpu_pointer_wrap_notreached, but generic code used it before recognizing the alignment exception. Hoist the first page lookup, so that the alignment exception happens first. Cc: qemu-stable@nongnu.org Buglink: https://bugs.debian.org/1112285 Fixes: a4027ed7d4be ("target: Use cpu_pointer_wrap_notreached for strict align targets") Signed-off-by: Richard Henderson Reviewed-by: Philippe Mathieu-Daudé (cherry picked from commit ec03dd9723781c7e9d4b4f70c7f54d12da9459d5) Signed-off-by: Michael Tokarev --- accel/tcg/cputlb.c | 23 +++++++++++++---------- 1 file changed, 13 insertions(+), 10 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 87e14bde4f2..b063a572e70 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -1744,6 +1744,7 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, uintptr_t ra, MMUAccessType type, MMULookupLocals *l) { bool crosspage; + vaddr last; int flags; l->memop = get_memop(oi); @@ -1753,13 +1754,15 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, 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; + l->page[1].addr = 0; l->page[1].size = 0; - crosspage = (addr ^ l->page[1].addr) & TARGET_PAGE_MASK; - if (likely(!crosspage)) { - mmu_lookup1(cpu, &l->page[0], l->memop, l->mmu_idx, type, ra); + /* Lookup and recognize exceptions from the first page. */ + mmu_lookup1(cpu, &l->page[0], l->memop, l->mmu_idx, type, ra); + last = addr + l->page[0].size - 1; + crosspage = (addr ^ last) & TARGET_PAGE_MASK; + if (likely(!crosspage)) { flags = l->page[0].flags; if (unlikely(flags & (TLB_WATCHPOINT | TLB_NOTDIRTY))) { mmu_watch_or_dirty(cpu, &l->page[0], type, ra); @@ -1769,18 +1772,18 @@ static bool mmu_lookup(CPUState *cpu, vaddr addr, MemOpIdx oi, } } else { /* Finish compute of page crossing. */ - int size0 = l->page[1].addr - addr; + vaddr addr1 = last & TARGET_PAGE_MASK; + int size0 = addr1 - addr; l->page[1].size = l->page[0].size - size0; l->page[0].size = size0; - l->page[1].addr = cpu->cc->tcg_ops->pointer_wrap(cpu, l->mmu_idx, - l->page[1].addr, addr); + addr1, addr); /* - * Lookup both pages, recognizing exceptions from either. If the - * second lookup potentially resized, refresh first CPUTLBEntryFull. + * Lookup and recognize exceptions from the second page. + * If the lookup potentially resized the table, refresh the + * first CPUTLBEntryFull pointer. */ - 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]; -- 2.47.3