From patchwork Fri Sep 1 06:01:18 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: LIU Zhiwei X-Patchwork-Id: 13372058 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4B18FCA0FE6 for ; Fri, 1 Sep 2023 06:02:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qbxEi-0000X1-Qh; Fri, 01 Sep 2023 02:02:28 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qbxEg-0000Wt-Mp for qemu-devel@nongnu.org; Fri, 01 Sep 2023 02:02:26 -0400 Received: from out30-101.freemail.mail.aliyun.com ([115.124.30.101]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qbxEd-0004Al-HN for qemu-devel@nongnu.org; Fri, 01 Sep 2023 02:02:26 -0400 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R581e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=ay29a033018046051; MF=zhiwei_liu@linux.alibaba.com; NM=1; PH=DS; RN=4; SR=0; TI=SMTPD_---0Vr1M3Ks_1693548128; Received: from L-PF1D6DP4-1208.hz.ali.com(mailfrom:zhiwei_liu@linux.alibaba.com fp:SMTPD_---0Vr1M3Ks_1693548128) by smtp.aliyun-inc.com; Fri, 01 Sep 2023 14:02:09 +0800 From: LIU Zhiwei To: qemu-devel@nongnu.org Cc: richard.henderson@linaro.org, pbonzini@redhat.com, LIU Zhiwei Subject: [PATCH 1/1] accel/tcg: Fix the comment for CPUTLBEntryFull Date: Fri, 1 Sep 2023 14:01:18 +0800 Message-Id: <20230901060118.379-1-zhiwei_liu@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 MIME-Version: 1.0 Received-SPF: pass client-ip=115.124.30.101; envelope-from=zhiwei_liu@linux.alibaba.com; helo=out30-101.freemail.mail.aliyun.com X-Spam_score_int: -98 X-Spam_score: -9.9 X-Spam_bar: --------- X-Spam_report: (-9.9 / 5.0 requ) BAYES_00=-1.9, ENV_AND_HDR_SPF_MATCH=-0.5, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, UNPARSEABLE_RELAY=0.001, USER_IN_DEF_SPF_WL=-7.5 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 When memory region is ram, the lower TARGET_PAGE_BITS is not the physical section number. Instead, its value is always 0. Add comment and assert to make it clear. Signed-off-by: LIU Zhiwei Reviewed-by: Richard Henderson --- accel/tcg/cputlb.c | 11 +++++++---- include/exec/cpu-defs.h | 12 ++++++------ 2 files changed, 13 insertions(+), 10 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index d68fa6867c..a1ebf75068 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -1192,6 +1192,7 @@ void tlb_set_page_full(CPUState *cpu, int mmu_idx, write_flags = read_flags; if (is_ram) { iotlb = memory_region_get_ram_addr(section->mr) + xlat; + assert(!(iotlb & ~TARGET_PAGE_MASK)); /* * Computing is_clean is expensive; avoid all that unless * the page is actually writable. @@ -1254,10 +1255,12 @@ void tlb_set_page_full(CPUState *cpu, int mmu_idx, /* refill the tlb */ /* - * At this point iotlb contains a physical section number in the lower - * TARGET_PAGE_BITS, and either - * + the ram_addr_t of the page base of the target RAM (RAM) - * + the offset within section->mr of the page base (I/O, ROMD) + * When memory region is ram, iotlb contains a TARGET_PAGE_BITS + * aligned ram_addr_t of the page base of the target RAM. + * Otherwise, iotlb contains + * - a physical section number in the lower TARGET_PAGE_BITS + * - the offset within section->mr of the page base (I/O, ROMD) with the + * TARGET_PAGE_BITS masked off. * We subtract addr_page (which is page aligned and thus won't * disturb the low bits) to give an offset which can be added to the * (non-page-aligned) vaddr of the eventual memory access to get diff --git a/include/exec/cpu-defs.h b/include/exec/cpu-defs.h index fb4c8d480f..350287852e 100644 --- a/include/exec/cpu-defs.h +++ b/include/exec/cpu-defs.h @@ -100,12 +100,12 @@ typedef struct CPUTLBEntryFull { /* * @xlat_section contains: - * - in the lower TARGET_PAGE_BITS, a physical section number - * - with the lower TARGET_PAGE_BITS masked off, an offset which - * must be added to the virtual address to obtain: - * + the ram_addr_t of the target RAM (if the physical section - * number is PHYS_SECTION_NOTDIRTY or PHYS_SECTION_ROM) - * + the offset within the target MemoryRegion (otherwise) + * - For ram, an offset which must be added to the virtual address + * to obtain the ram_addr_t of the target RAM + * - For other memory regions, + * + in the lower TARGET_PAGE_BITS, the physical section number + * + with the TARGET_PAGE_BITS masked off, the offset within + * the target MemoryRegion */ hwaddr xlat_section;