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[71.212.39.66]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-21de32eb419sm65698135ad.145.2025.02.02.19.18.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 02 Feb 2025 19:18:34 -0800 (PST) From: Richard Henderson To: qemu-devel@nongnu.org Cc: pbonzini@redhat.com, mark.cave-ayland@ilande.co.uk, berrange@redhat.com, philmd@linaro.org, thuth@redhat.com Subject: [PATCH v2 14/14] tcg: Remove TCG_OVERSIZED_GUEST Date: Sun, 2 Feb 2025 19:18:21 -0800 Message-ID: <20250203031821.741477-15-richard.henderson@linaro.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20250203031821.741477-1-richard.henderson@linaro.org> References: <20250203031821.741477-1-richard.henderson@linaro.org> MIME-Version: 1.0 Received-SPF: pass client-ip=2607:f8b0:4864:20::62b; envelope-from=richard.henderson@linaro.org; helo=mail-pl1-x62b.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org This is now prohibited in configuration. Signed-off-by: Richard Henderson Reviewed-by: Alex Bennée --- include/qemu/atomic.h | 18 +++-------------- include/tcg/oversized-guest.h | 23 ---------------------- accel/tcg/cputlb.c | 7 ------- accel/tcg/tcg-all.c | 9 ++++----- target/arm/ptw.c | 34 --------------------------------- target/riscv/cpu_helper.c | 13 +------------ docs/devel/multi-thread-tcg.rst | 1 - 7 files changed, 8 insertions(+), 97 deletions(-) delete mode 100644 include/tcg/oversized-guest.h diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h index 7a3f2e6576..f80cba24cf 100644 --- a/include/qemu/atomic.h +++ b/include/qemu/atomic.h @@ -56,25 +56,13 @@ */ #define signal_barrier() __atomic_signal_fence(__ATOMIC_SEQ_CST) -/* Sanity check that the size of an atomic operation isn't "overly large". +/* + * Sanity check that the size of an atomic operation isn't "overly large". * Despite the fact that e.g. i686 has 64-bit atomic operations, we do not * want to use them because we ought not need them, and this lets us do a * bit of sanity checking that other 32-bit hosts might build. - * - * That said, we have a problem on 64-bit ILP32 hosts in that in order to - * sync with TCG_OVERSIZED_GUEST, this must match TCG_TARGET_REG_BITS. - * We'd prefer not want to pull in everything else TCG related, so handle - * those few cases by hand. - * - * Note that x32 is fully detected with __x86_64__ + _ILP32, and that for - * Sparc we always force the use of sparcv9 in configure. MIPS n32 (ILP32) & - * n64 (LP64) ABIs are both detected using __mips64. */ -#if defined(__x86_64__) || defined(__sparc__) || defined(__mips64) -# define ATOMIC_REG_SIZE 8 -#else -# define ATOMIC_REG_SIZE sizeof(void *) -#endif +#define ATOMIC_REG_SIZE sizeof(void *) /* Weak atomic operations prevent the compiler moving other * loads/stores past the atomic operation load/store. However there is diff --git a/include/tcg/oversized-guest.h b/include/tcg/oversized-guest.h deleted file mode 100644 index 641b9749ff..0000000000 --- a/include/tcg/oversized-guest.h +++ /dev/null @@ -1,23 +0,0 @@ -/* SPDX-License-Identifier: MIT */ -/* - * Define TCG_OVERSIZED_GUEST - * Copyright (c) 2008 Fabrice Bellard - */ - -#ifndef EXEC_TCG_OVERSIZED_GUEST_H -#define EXEC_TCG_OVERSIZED_GUEST_H - -#include "tcg-target-reg-bits.h" -#include "cpu-param.h" - -/* - * Oversized TCG guests make things like MTTCG hard - * as we can't use atomics for cputlb updates. - */ -#if TARGET_LONG_BITS > TCG_TARGET_REG_BITS -#define TCG_OVERSIZED_GUEST 1 -#else -#define TCG_OVERSIZED_GUEST 0 -#endif - -#endif diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index b4ccf0cdcb..17e2251695 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -47,7 +47,6 @@ #include "qemu/plugin-memory.h" #endif #include "tcg/tcg-ldst.h" -#include "tcg/oversized-guest.h" /* DEBUG defines, enable DEBUG_TLB_LOG to log to the CPU_LOG_MMU target */ /* #define DEBUG_TLB */ @@ -118,12 +117,8 @@ static inline uint64_t tlb_read_idx(const CPUTLBEntry *entry, return qatomic_read(ptr); #else const uint64_t *ptr = &entry->addr_idx[access_type]; -# if TCG_OVERSIZED_GUEST - return *ptr; -# else /* ofs might correspond to .addr_write, so use qatomic_read */ return qatomic_read(ptr); -# endif #endif } @@ -908,8 +903,6 @@ static void tlb_reset_dirty_range_locked(CPUTLBEntry *tlb_entry, uint32_t *ptr_write = (uint32_t *)&tlb_entry->addr_write; ptr_write += HOST_BIG_ENDIAN; qatomic_set(ptr_write, *ptr_write | TLB_NOTDIRTY); -#elif TCG_OVERSIZED_GUEST - tlb_entry->addr_write |= TLB_NOTDIRTY; #else qatomic_set(&tlb_entry->addr_write, tlb_entry->addr_write | TLB_NOTDIRTY); diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c index 95adaacee8..c1a30b0121 100644 --- a/accel/tcg/tcg-all.c +++ b/accel/tcg/tcg-all.c @@ -28,7 +28,6 @@ #include "exec/replay-core.h" #include "system/cpu-timers.h" #include "tcg/startup.h" -#include "tcg/oversized-guest.h" #include "qapi/error.h" #include "qemu/error-report.h" #include "qemu/accel.h" @@ -41,6 +40,8 @@ #include "hw/boards.h" #endif #include "internal-common.h" +#include "cpu-param.h" + struct TCGState { AccelState parent_obj; @@ -72,7 +73,7 @@ DECLARE_INSTANCE_CHECKER(TCGState, TCG_STATE, static bool default_mttcg_enabled(void) { - if (icount_enabled() || TCG_OVERSIZED_GUEST) { + if (icount_enabled()) { return false; } #ifdef TARGET_SUPPORTS_MTTCG @@ -145,9 +146,7 @@ static void tcg_set_thread(Object *obj, const char *value, Error **errp) TCGState *s = TCG_STATE(obj); if (strcmp(value, "multi") == 0) { - if (TCG_OVERSIZED_GUEST) { - error_setg(errp, "No MTTCG when guest word size > hosts"); - } else if (icount_enabled()) { + if (icount_enabled()) { error_setg(errp, "No MTTCG when icount is enabled"); } else { #ifndef TARGET_SUPPORTS_MTTCG diff --git a/target/arm/ptw.c b/target/arm/ptw.c index 64bb6878a4..4330900348 100644 --- a/target/arm/ptw.c +++ b/target/arm/ptw.c @@ -16,9 +16,6 @@ #include "internals.h" #include "cpu-features.h" #include "idau.h" -#ifdef CONFIG_TCG -# include "tcg/oversized-guest.h" -#endif typedef struct S1Translate { /* @@ -840,7 +837,6 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val, ptw->out_rw = true; } -#ifdef CONFIG_ATOMIC64 if (ptw->out_be) { old_val = cpu_to_be64(old_val); new_val = cpu_to_be64(new_val); @@ -852,36 +848,6 @@ static uint64_t arm_casq_ptw(CPUARMState *env, uint64_t old_val, cur_val = qatomic_cmpxchg__nocheck((uint64_t *)host, old_val, new_val); cur_val = le64_to_cpu(cur_val); } -#else - /* - * We can't support the full 64-bit atomic cmpxchg on the host. - * Because this is only used for FEAT_HAFDBS, which is only for AA64, - * we know that TCG_OVERSIZED_GUEST is set, which means that we are - * running in round-robin mode and could only race with dma i/o. - */ -#if !TCG_OVERSIZED_GUEST -# error "Unexpected configuration" -#endif - bool locked = bql_locked(); - if (!locked) { - bql_lock(); - } - if (ptw->out_be) { - cur_val = ldq_be_p(host); - if (cur_val == old_val) { - stq_be_p(host, new_val); - } - } else { - cur_val = ldq_le_p(host); - if (cur_val == old_val) { - stq_le_p(host, new_val); - } - } - if (!locked) { - bql_unlock(); - } -#endif - return cur_val; #else /* AArch32 does not have FEAT_HADFS; non-TCG guests only use debug-mode. */ diff --git a/target/riscv/cpu_helper.c b/target/riscv/cpu_helper.c index e1dfc4ecbf..8ff6d900f2 100644 --- a/target/riscv/cpu_helper.c +++ b/target/riscv/cpu_helper.c @@ -32,7 +32,6 @@ #include "system/cpu-timers.h" #include "cpu_bits.h" #include "debug.h" -#include "tcg/oversized-guest.h" #include "pmp.h" int riscv_env_mmu_index(CPURISCVState *env, bool ifetch) @@ -1167,9 +1166,7 @@ static int get_physical_address(CPURISCVState *env, hwaddr *physical, hwaddr pte_addr; int i; -#if !TCG_OVERSIZED_GUEST -restart: -#endif + restart: for (i = 0; i < levels; i++, ptshift -= ptidxbits) { target_ulong idx; if (i == 0) { @@ -1388,13 +1385,6 @@ restart: false, MEMTXATTRS_UNSPECIFIED); if (memory_region_is_ram(mr)) { target_ulong *pte_pa = qemu_map_ram_ptr(mr->ram_block, addr1); -#if TCG_OVERSIZED_GUEST - /* - * MTTCG is not enabled on oversized TCG guests so - * page table updates do not need to be atomic - */ - *pte_pa = pte = updated_pte; -#else target_ulong old_pte; if (riscv_cpu_sxl(env) == MXL_RV32) { old_pte = qatomic_cmpxchg((uint32_t *)pte_pa, pte, updated_pte); @@ -1405,7 +1395,6 @@ restart: goto restart; } pte = updated_pte; -#endif } else { /* * Misconfigured PTE in ROM (AD bits are not preset) or diff --git a/docs/devel/multi-thread-tcg.rst b/docs/devel/multi-thread-tcg.rst index 7fd0a07633..b0f473961d 100644 --- a/docs/devel/multi-thread-tcg.rst +++ b/docs/devel/multi-thread-tcg.rst @@ -37,7 +37,6 @@ if: * forced by --accel tcg,thread=single * enabling --icount mode -* 64 bit guests on 32 bit hosts (TCG_OVERSIZED_GUEST) In the general case of running translated code there should be no inter-vCPU dependencies and all vCPUs should be able to run at full