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Wed, 25 Mar 2026 09:45:20 -0700 (PDT) X-Received: by 2002:a05:600c:3d90:b0:485:2a4b:7bc3 with SMTP id 5b1f17b1804b1-48715fc38f3mr62050135e9.4.1774457120072; Wed, 25 Mar 2026 09:45:20 -0700 (PDT) Received: from [192.168.10.48] ([151.49.85.67]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4871e6cb664sm7908065e9.12.2026.03.25.09.45.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 25 Mar 2026 09:45:17 -0700 (PDT) From: Paolo Bonzini To: qemu-devel@nongnu.org Cc: Mohamed Mediouni Subject: [PULL 13/19] target/i386: emulate: segmentation rework Date: Wed, 25 Mar 2026 17:44:47 +0100 Message-ID: <20260325164453.72127-14-pbonzini@redhat.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260325164453.72127-1-pbonzini@redhat.com> References: <20260325164453.72127-1-pbonzini@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.129.124; envelope-from=pbonzini@redhat.com; helo=us-smtp-delivery-124.mimecast.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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_PASS=-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: qemu development 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 From: Mohamed Mediouni Make accesses to segments all go through read_segment_descriptor to be able to fetch segment state on-demand. Switch away from SegmentCache to the x86_segment_descriptor that is already used by read_segment_descriptor. Signed-off-by: Mohamed Mediouni Link: https://lore.kernel.org/r/20260324151323.74473-11-mohamed@unpredictable.fr Signed-off-by: Paolo Bonzini --- target/i386/emulate/x86_helpers.c | 50 ++++++++++++------------------- 1 file changed, 19 insertions(+), 31 deletions(-) diff --git a/target/i386/emulate/x86_helpers.c b/target/i386/emulate/x86_helpers.c index c817015ef92..63bae3582fe 100644 --- a/target/i386/emulate/x86_helpers.c +++ b/target/i386/emulate/x86_helpers.c @@ -43,49 +43,37 @@ static CpuMode cpu_mode(CPUState *cpu) return m; } -static bool segment_type_ro(const SegmentCache *seg) +static bool segment_type_ro(const x86_segment_descriptor desc) { - uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15; + uint32_t type_ = desc.type; return (type_ & (~RWRX_SEGMENT_TYPE)) == 0; } -static bool segment_type_code(const SegmentCache *seg) +static bool segment_type_code(const x86_segment_descriptor desc) { - uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15; + uint32_t type_ = desc.type; return (type_ & CODE_SEGMENT_TYPE) != 0; } -static bool segment_expands_down(const SegmentCache *seg) +static bool segment_expands_down(const x86_segment_descriptor desc) { - uint32_t type_ = (seg->flags >> DESC_TYPE_SHIFT) & 15; + uint32_t type_ = desc.type; - if (segment_type_code(seg)) { + if (segment_type_code(desc)) { return false; } return (type_ & EXPAND_DOWN_SEGMENT_TYPE) != 0; } -static uint32_t segment_limit(const SegmentCache *seg) +static uint8_t segment_db(const x86_segment_descriptor desc) { - uint32_t limit = seg->limit; - uint32_t granularity = (seg->flags & DESC_G_MASK) != 0; - - if (granularity != 0) { - limit = (limit << 12) | 0xFFF; - } - - return limit; + return desc.db; } -static uint8_t segment_db(const SegmentCache *seg) +static uint32_t segment_max_limit(const x86_segment_descriptor desc) { - return (seg->flags >> DESC_B_SHIFT) & 1; -} - -static uint32_t segment_max_limit(const SegmentCache *seg) -{ - if (segment_db(seg) != 0) { + if (segment_db(desc) != 0) { return 0xFFFFFFFF; } return 0xFFFF; @@ -96,15 +84,15 @@ static int linearize(CPUState *cpu, X86Seg seg_idx) { enum CpuMode mode; - X86CPU *x86_cpu = X86_CPU(cpu); - CPUX86State *env = &x86_cpu->env; - SegmentCache *seg = &env->segs[seg_idx]; - target_ulong base = seg->base; + struct x86_segment_descriptor desc; + target_ulong base; target_ulong logical_addr_32b; uint32_t limit; /* TODO: the emulator will not pass us "write" indicator yet */ bool write = false; + emul_ops->read_segment_descriptor(cpu, &desc, seg_idx); + base = x86_segment_base(&desc); mode = cpu_mode(cpu); switch (mode) { @@ -116,21 +104,21 @@ static int linearize(CPUState *cpu, break; case PROTECTED_MODE: case REAL_MODE: - if (segment_type_ro(seg) && write) { + if (segment_type_ro(desc) && write) { error_report("Cannot write to read-only segment"); return -1; } logical_addr_32b = logical_addr & 0xFFFFFFFF; - limit = segment_limit(seg); + limit = x86_segment_limit(&desc); - if (segment_expands_down(seg)) { + if (segment_expands_down(desc)) { if (logical_addr_32b >= limit) { error_report("Address exceeds limit (expands down)"); return -1; } - limit = segment_max_limit(seg); + limit = segment_max_limit(desc); } if (logical_addr_32b > limit) { -- 2.53.0