From: Philippe Mathieu-Daudé <philmd@linaro.org>
Date: Mon, 22 Dec 2025 09:08:50 +0000 (+0100)
Subject: system/ioport: Declare x86-specific I/O port in little-endian order
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=35ddb78b65802a9ea0166ea494b829529fadbbf4;p=thirdparty%2Fqemu.git

system/ioport: Declare x86-specific I/O port in little-endian order

X86 in/out port (related to ISA bus) uses little endianness:
- enforce little endianness in x86 cpu_in/out() accessors,
- serialize QTest in/out port accesses as little-endian.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-ID: <20260109165058.59144-22-philmd@linaro.org>
---

diff --git a/system/ioport.c b/system/ioport.c
index 801e2490c3..4b94f2f811 100644
--- a/system/ioport.c
+++ b/system/ioport.c
@@ -56,7 +56,7 @@ static void unassigned_io_write(void *opaque, hwaddr addr, uint64_t val,
 const MemoryRegionOps unassigned_io_ops = {
     .read = unassigned_io_read,
     .write = unassigned_io_write,
-    .endianness = DEVICE_NATIVE_ENDIAN,
+    .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
 void cpu_outb(uint32_t addr, uint8_t val)
@@ -71,7 +71,7 @@ void cpu_outw(uint32_t addr, uint16_t val)
     uint8_t buf[2];
 
     trace_cpu_out(addr, 'w', val);
-    stw_p(buf, val);
+    stw_le_p(buf, val);
     address_space_write(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
                         buf, 2);
 }
@@ -81,7 +81,7 @@ void cpu_outl(uint32_t addr, uint32_t val)
     uint8_t buf[4];
 
     trace_cpu_out(addr, 'l', val);
-    stl_p(buf, val);
+    stl_le_p(buf, val);
     address_space_write(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED,
                         buf, 4);
 }
@@ -102,7 +102,7 @@ uint16_t cpu_inw(uint32_t addr)
     uint16_t val;
 
     address_space_read(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED, buf, 2);
-    val = lduw_p(buf);
+    val = lduw_le_p(buf);
     trace_cpu_in(addr, 'w', val);
     return val;
 }
@@ -113,7 +113,7 @@ uint32_t cpu_inl(uint32_t addr)
     uint32_t val;
 
     address_space_read(&address_space_io, addr, MEMTXATTRS_UNSPECIFIED, buf, 4);
-    val = ldl_p(buf);
+    val = ldl_le_p(buf);
     trace_cpu_in(addr, 'l', val);
     return val;
 }
diff --git a/tests/qtest/endianness-test.c b/tests/qtest/endianness-test.c
index 222d116fae..2b2f92099d 100644
--- a/tests/qtest/endianness-test.c
+++ b/tests/qtest/endianness-test.c
@@ -65,8 +65,9 @@ static uint16_t isa_inw(QTestState *qts, const TestCase *test, uint16_t addr)
         value = qtest_inw(qts, addr);
     } else {
         value = qtest_readw(qts, test->isa_base + addr);
+        value = test->bswap ? bswap16(value) : value;
     }
-    return test->bswap ? bswap16(value) : value;
+    return value;
 }
 
 static uint32_t isa_inl(QTestState *qts, const TestCase *test, uint16_t addr)
@@ -76,8 +77,9 @@ static uint32_t isa_inl(QTestState *qts, const TestCase *test, uint16_t addr)
         value = qtest_inl(qts, addr);
     } else {
         value = qtest_readl(qts, test->isa_base + addr);
+        value = test->bswap ? bswap32(value) : value;
     }
-    return test->bswap ? bswap32(value) : value;
+    return value;
 }
 
 static void isa_outb(QTestState *qts, const TestCase *test, uint16_t addr,
@@ -93,10 +95,10 @@ static void isa_outb(QTestState *qts, const TestCase *test, uint16_t addr,
 static void isa_outw(QTestState *qts, const TestCase *test, uint16_t addr,
                      uint16_t value)
 {
-    value = test->bswap ? bswap16(value) : value;
     if (test->isa_base == -1) {
         qtest_outw(qts, addr, value);
     } else {
+        value = test->bswap ? bswap16(value) : value;
         qtest_writew(qts, test->isa_base + addr, value);
     }
 }
@@ -104,10 +106,10 @@ static void isa_outw(QTestState *qts, const TestCase *test, uint16_t addr,
 static void isa_outl(QTestState *qts, const TestCase *test, uint16_t addr,
                      uint32_t value)
 {
-    value = test->bswap ? bswap32(value) : value;
     if (test->isa_base == -1) {
         qtest_outl(qts, addr, value);
     } else {
+        value = test->bswap ? bswap32(value) : value;
         qtest_writel(qts, test->isa_base + addr, value);
     }
 }
diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 622464e365..132aa51137 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -31,6 +31,7 @@
 #include "libqtest.h"
 #include "libqmp.h"
 #include "qemu/accel.h"
+#include "qemu/bswap.h"
 #include "qemu/ctype.h"
 #include "qemu/cutils.h"
 #include "qemu/exit-with-parent.h"
@@ -1190,12 +1191,12 @@ void qtest_outb(QTestState *s, uint16_t addr, uint8_t value)
 
 void qtest_outw(QTestState *s, uint16_t addr, uint16_t value)
 {
-    qtest_out(s, "outw", addr, value);
+    qtest_out(s, "outw", addr, qtest_big_endian(s) ? bswap16(value) : value);
 }
 
 void qtest_outl(QTestState *s, uint16_t addr, uint32_t value)
 {
-    qtest_out(s, "outl", addr, value);
+    qtest_out(s, "outl", addr, qtest_big_endian(s) ? bswap32(value) : value);
 }
 
 static uint32_t qtest_in(QTestState *s, const char *cmd, uint16_t addr)
@@ -1220,12 +1221,16 @@ uint8_t qtest_inb(QTestState *s, uint16_t addr)
 
 uint16_t qtest_inw(QTestState *s, uint16_t addr)
 {
-    return qtest_in(s, "inw", addr);
+    uint16_t v = qtest_in(s, "inw", addr);
+
+    return qtest_big_endian(s) ? bswap16(v) : v;
 }
 
 uint32_t qtest_inl(QTestState *s, uint16_t addr)
 {
-    return qtest_in(s, "inl", addr);
+    uint32_t v = qtest_in(s, "inl", addr);
+
+    return qtest_big_endian(s) ? bswap32(v) : v;
 }
 
 static void qtest_write(QTestState *s, const char *cmd, uint64_t addr,