{"id":2215427,"url":"http://patchwork.ozlabs.org/api/patches/2215427/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324151323.74473-11-mohamed@unpredictable.fr/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20260324151323.74473-11-mohamed@unpredictable.fr>","list_archive_url":null,"date":"2026-03-24T15:13:21","name":"[v3,10/12] target/i386: emulate: segmentation rework","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"559464fcbdb05f9d3b4030dad4c157e4c0656287","submitter":{"id":91318,"url":"http://patchwork.ozlabs.org/api/people/91318/?format=json","name":"Mohamed Mediouni","email":"mohamed@unpredictable.fr"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20260324151323.74473-11-mohamed@unpredictable.fr/mbox/","series":[{"id":497303,"url":"http://patchwork.ozlabs.org/api/series/497303/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=497303","date":"2026-03-24T15:13:13","name":"whpx: i386: Windows 10 and performance fixes","version":3,"mbox":"http://patchwork.ozlabs.org/series/497303/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2215427/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2215427/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@legolas.ozlabs.org","Authentication-Results":["legolas.ozlabs.org;\n\tdkim=pass (2048-bit key;\n unprotected) header.d=unpredictable.fr header.i=@unpredictable.fr\n header.a=rsa-sha256 header.s=sig1 header.b=eEZLsnY4;\n\tdkim-atps=neutral","legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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helo=outbound.st.icloud.com","X-Spam_score_int":"-27","X-Spam_score":"-2.8","X-Spam_bar":"--","X-Spam_report":"(-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001,\n RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-0.001,\n 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":"qemu development ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org"},"content":"Make accesses to segments all go through read_segment_descriptor\nto be able to fetch segment state on-demand.\n\nSwitch away from SegmentCache to the x86_segment_descriptor\nthat is already used by read_segment_descriptor.\n\nSigned-off-by: Mohamed Mediouni \n---\n target/i386/emulate/x86_helpers.c | 50 ++++++++++++-------------------\n 1 file changed, 19 insertions(+), 31 deletions(-)","diff":"diff --git a/target/i386/emulate/x86_helpers.c b/target/i386/emulate/x86_helpers.c\nindex c817015ef9..63bae3582f 100644\n--- a/target/i386/emulate/x86_helpers.c\n+++ b/target/i386/emulate/x86_helpers.c\n@@ -43,49 +43,37 @@ static CpuMode cpu_mode(CPUState *cpu)\n return m;\n }\n \n-static bool segment_type_ro(const SegmentCache *seg)\n+static bool segment_type_ro(const x86_segment_descriptor desc)\n {\n- uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15;\n+ uint32_t type_ = desc.type;\n return (type_ & (~RWRX_SEGMENT_TYPE)) == 0;\n }\n \n-static bool segment_type_code(const SegmentCache *seg)\n+static bool segment_type_code(const x86_segment_descriptor desc)\n {\n- uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15;\n+ uint32_t type_ = desc.type;\n return (type_ & CODE_SEGMENT_TYPE) != 0;\n }\n \n-static bool segment_expands_down(const SegmentCache *seg)\n+static bool segment_expands_down(const x86_segment_descriptor desc)\n {\n- uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15;\n+ uint32_t type_ = desc.type;\n \n- if (segment_type_code(seg)) {\n+ if (segment_type_code(desc)) {\n return false;\n }\n \n return (type_ & EXPAND_DOWN_SEGMENT_TYPE) != 0;\n }\n \n-static uint32_t segment_limit(const SegmentCache *seg)\n+static uint8_t segment_db(const x86_segment_descriptor desc)\n {\n- uint32_t limit = seg->limit;\n- uint32_t granularity = (seg->flags & DESC_G_MASK) != 0;\n-\n- if (granularity != 0) {\n- limit = (limit << 12) | 0xFFF;\n- }\n-\n- return limit;\n+ return desc.db;\n }\n \n-static uint8_t segment_db(const SegmentCache *seg)\n+static uint32_t segment_max_limit(const x86_segment_descriptor desc)\n {\n- return (seg->flags >> DESC_B_SHIFT) & 1;\n-}\n-\n-static uint32_t segment_max_limit(const SegmentCache *seg)\n-{\n- if (segment_db(seg) != 0) {\n+ if (segment_db(desc) != 0) {\n return 0xFFFFFFFF;\n }\n return 0xFFFF;\n@@ -96,15 +84,15 @@ static int linearize(CPUState *cpu,\n X86Seg seg_idx)\n {\n enum CpuMode mode;\n- X86CPU *x86_cpu = X86_CPU(cpu);\n- CPUX86State *env = &x86_cpu->env;\n- SegmentCache *seg = &env->segs[seg_idx];\n- target_ulong base = seg->base;\n+ struct x86_segment_descriptor desc;\n+ target_ulong base;\n target_ulong logical_addr_32b;\n uint32_t limit;\n /* TODO: the emulator will not pass us \"write\" indicator yet */\n bool write = false;\n \n+ emul_ops->read_segment_descriptor(cpu, &desc, seg_idx);\n+ base = x86_segment_base(&desc);\n mode = cpu_mode(cpu);\n \n switch (mode) {\n@@ -116,21 +104,21 @@ static int linearize(CPUState *cpu,\n break;\n case PROTECTED_MODE:\n case REAL_MODE:\n- if (segment_type_ro(seg) && write) {\n+ if (segment_type_ro(desc) && write) {\n error_report(\"Cannot write to read-only segment\");\n return -1;\n }\n \n logical_addr_32b = logical_addr & 0xFFFFFFFF;\n- limit = segment_limit(seg);\n+ limit = x86_segment_limit(&desc);\n \n- if (segment_expands_down(seg)) {\n+ if (segment_expands_down(desc)) {\n if (logical_addr_32b >= limit) {\n error_report(\"Address exceeds limit (expands down)\");\n return -1;\n }\n \n- limit = segment_max_limit(seg);\n+ limit = segment_max_limit(desc);\n }\n \n if (logical_addr_32b > limit) {\n","prefixes":["v3","10/12"]}