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[81.40.121.121]) by smtp.gmail.com with ESMTPSA id v7sm12235768wmj.28.2020.08.22.09.14.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Aug 2020 09:14:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=CBBc5h0tlO9pcuO/0Fz1v/rNWxpnjyRFGDHAJePNn6M=; b=OojEY/06VpV/0PmASrO7KboUB+1xdg5rc3ARFw508oZOQZz+jZtRf2l0NPvbyQbWa4 u3QLp0oWr+Sv0iB/4ljT28X9p9dZLgFqVryBxQ47RI5gIGspOSCwQP8VFdfnKht6HjYf pmzMbymj4NFg5VAx6chIKbUBnZq80jsQddwOo+646ll5oGnnnJFM/HF39O7pv8+5SP+L cQt/gqsEmkUbzYasruuLG5bDVyS2FNbnGEN6Iy6rWUcPsrkyoa/OA9JjyN9CAj8kKoE4 Cmt95WzeeTCzUb82/d/IccdGQLxxdGTyLwe8oRsVPlV5ubJDfyVqDaff177wRuSbB3qu FNlQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:to:cc:subject:date:message-id :mime-version:content-transfer-encoding; bh=CBBc5h0tlO9pcuO/0Fz1v/rNWxpnjyRFGDHAJePNn6M=; b=JE2yxsinG7+J1QsxjWykrMlT8nSBK3CvchktGEVbVmL5GzXmTVd6rPG8Xc7OWvW7wu tx+6BcV8fNOvliS5r0syDe1wXtviHkCTgAc1lW9GgJh9KVFmTO1NXXJZJfz9bMxgNL81 fbULLukiJXFwuqLRCcSr5v8ZvaApAIlT1n21qouAzWJdWXPRk3m+o9V1IU1jOwSIAJm9 Hfv/tF3RQUDGFLytarWT6pa1XuA/uw8tkY2S4BXt+GT+NQXgcZja+eBFPZH1o74Ecm9B UHOZyXUN91mbWELjtXvQAG0GS1BkSr5cJXex12LA1+pVUHFjn2JMS065FxT+qWdA9aR0 0BxA== X-Gm-Message-State: AOAM5312b5RwEXmgn9SEhS0eCJ/hoBTL7i9dq0aYRQVLQzmUB4uUdT00 BctrrVEV+/ZI8ODSdVEG2bhSC2FqNzg= X-Google-Smtp-Source: ABdhPJwwJYMztRnJTVi6ryJ5MSC/gJR09KoHPVEy2mVpqiEn4ICco2mE3RTr8fI4FyeOJ5BZ9drlbw== X-Received: by 2002:adf:d4c6:: with SMTP id w6mr3033493wrk.314.1598112892715; Sat, 22 Aug 2020 09:14:52 -0700 (PDT) From: =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= To: qemu-devel@nongnu.org Subject: [PATCH v2] memory: Directly dispatch alias accesses on origin memory region Date: Sat, 22 Aug 2020 18:14:49 +0200 Message-Id: <20200822161449.1327517-1-f4bug@amsat.org> X-Mailer: git-send-email 2.26.2 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=2a00:1450:4864:20::442; envelope-from=philippe.mathieu.daude@gmail.com; helo=mail-wr1-x442.google.com X-detected-operating-system: by eggs.gnu.org: No matching host in p0f cache. That's all we know. X-Spam_score_int: 0 X-Spam_score: 0.0 X-Spam_bar: / X-Spam_report: (0.0 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FORGED_FROMDOMAIN=1, FREEMAIL_FROM=0.001, HEADER_FROM_DIFFERENT_DOMAINS=1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Richard Henderson , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Paolo Bonzini Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail-DKIM: fail (Header signature does not verify) There is an issue when accessing an alias memory region via the memory_region_dispatch_read() / memory_region_dispatch_write() calls. Since commit 2cdfcf272d ("memory: assign MemoryRegionOps to all regions") we assign &unassigned_mem_ops to all MemoryRegions. The memory_region_init_alias() flow is: memory_region_init_alias() -> memory_region_init() -> object_initialize(TYPE_MEMORY_REGION) -> memory_region_initfn() -> mr->ops =3D &unassigned_mem_ops; When accessing the alias using memory_region_dispatch_read(), flow is: memory_region_dispatch_read() -> memory_region_access_valid(mr) -> mr->ops->valid.accepts() -> unassigned_mem_accepts() <- false <- false <- MEMTX_DECODE_ERROR The caller gets a MEMTX_DECODE_ERROR while the access is OK. Fix by directly dispatching aliases accesses to its origin region. Fixes: 2cdfcf272d ("memory: assign MemoryRegionOps to all regions") Signed-off-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Richard Henderson --- Since v1: - reword as not a bugfix (Paolo) - access the aliases recursively (Paolo) --- softmmu/memory.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/softmmu/memory.c b/softmmu/memory.c index 70b93104e8c..3627985bf9f 100644 --- a/softmmu/memory.c +++ b/softmmu/memory.c @@ -1405,6 +1405,10 @@ MemTxResult memory_region_dispatch_read(MemoryRegion= *mr, unsigned size =3D memop_size(op); MemTxResult r; =20 + while (mr->alias) { + addr +=3D mr->alias_offset; + mr =3D mr->alias; + } if (!memory_region_access_valid(mr, addr, size, false, attrs)) { *pval =3D unassigned_mem_read(mr, addr, size); return MEMTX_DECODE_ERROR; @@ -1449,6 +1453,10 @@ MemTxResult memory_region_dispatch_write(MemoryRegio= n *mr, { unsigned size =3D memop_size(op); =20 + while (mr->alias) { + addr +=3D mr->alias_offset; + mr =3D mr->alias; + } if (!memory_region_access_valid(mr, addr, size, true, attrs)) { unassigned_mem_write(mr, addr, data, size); return MEMTX_DECODE_ERROR; --=20 2.26.2