[Xen-devel] [PATCH 1/7] x86emul: don't special case fetching the immediate of PUSH

["Jan Beulich" <JBeulich@xxxxxxxx>]

These immediates follow the standard patterns in all modes, so they're
better fetched by the generic source operand handling code.

To facilitate testing, instead of adding yet another of these pretty
convoluted individual test cases, simply introduce another blowfish run
with -mno-accumulate-outgoing-args (the additional -Dstatic is to
keep the compiler from converting the calling convention to
"regparm(3)", which I did observe it does).

To make this introduction of a new blowfish pass (and potential further
ones later one) have less impact on the readability of the final code,
abstract all such "binary blob" executions via a table to iterate
through.

The resulting native code execution adjustment also uncovered a lack of
clobbers on the asm() in the 64-bit case, which is being fixed at once.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>

--- a/tools/tests/x86_emulator/Makefile
+++ b/tools/tests/x86_emulator/Makefile
@@ -11,21 +11,21 @@ all: $(TARGET)
 run: $(TARGET)
        ./$(TARGET)
 
-.PHONY: blowfish.h
-blowfish.h:
-       rm -f blowfish.bin
-       XEN_TARGET_ARCH=x86_32 make -f blowfish.mk all
-       (echo "static unsigned int blowfish32_code[] = {"; \
-       od -v -t x blowfish.bin | sed 's/^[0-9]* /0x/' | sed 's/ /, 0x/g' | sed 
's/$$/,/';\
-       echo "};") >$@
-       rm -f blowfish.bin
-ifeq ($(XEN_COMPILE_ARCH),x86_64)
-       XEN_TARGET_ARCH=x86_64 make -f blowfish.mk all
-       (echo "static unsigned int blowfish64_code[] = {"; \
-       od -v -t x blowfish.bin | sed 's/^[0-9]* /0x/' | sed 's/ /, 0x/g' | sed 
's/$$/,/';\
-       echo "};") >>$@
-       rm -f blowfish.bin
-endif
+cflags-x86_32 := "-mno-accumulate-outgoing-args -Dstatic="
+
+blowfish.h: blowfish.c blowfish.mk Makefile
+       rm -f $@.new blowfish.bin
+       $(foreach arch,$(filter-out $(XEN_COMPILE_ARCH),x86_32) 
$(XEN_COMPILE_ARCH), \
+           for cflags in "" $(cflags-$(arch)); do \
+               $(MAKE) -f blowfish.mk XEN_TARGET_ARCH=$(arch) 
BLOWFISH_CFLAGS="$$cflags" all; \
+               flavor=$$(echo $${cflags} | sed -e 's, .*,,' -e 'y,-=,__,') ; \
+               (echo "static unsigned int blowfish_$(arch)$${flavor}[] = {"; \
+                od -v -t x blowfish.bin | sed -e 's/^[0-9]* /0x/' -e 's/ /, 
0x/g' -e 's/$$/,/'; \
+                echo "};") >>$@.new; \
+               rm -f blowfish.bin; \
+           done; \
+       )
+       mv $@.new $@
 
 $(TARGET): x86_emulate.o test_x86_emulator.o
        $(HOSTCC) -o $@ $^
--- a/tools/tests/x86_emulator/blowfish.mk
+++ b/tools/tests/x86_emulator/blowfish.mk
@@ -5,7 +5,7 @@ include $(XEN_ROOT)/tools/Rules.mk
 
 $(call cc-options-add,CFLAGS,CC,$(EMBEDDED_EXTRA_CFLAGS))
 
-CFLAGS += -fno-builtin -msoft-float
+CFLAGS += -fno-builtin -msoft-float $(BLOWFISH_CFLAGS)
 
 .PHONY: all
 all: blowfish.bin
--- a/tools/tests/x86_emulator/test_x86_emulator.c
+++ b/tools/tests/x86_emulator/test_x86_emulator.c
@@ -1,4 +1,5 @@
 #include <errno.h>
+#include <limits.h>
 #include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -12,6 +13,21 @@
 #include "x86_emulate/x86_emulate.h"
 #include "blowfish.h"
 
+static const struct {
+    const void *code;
+    size_t size;
+    unsigned int bitness;
+    const char*name;
+} blobs[] = {
+    { blowfish_x86_32, sizeof(blowfish_x86_32), 32, "blowfish" },
+    { blowfish_x86_32_mno_accumulate_outgoing_args,
+      sizeof(blowfish_x86_32_mno_accumulate_outgoing_args),
+      32, "blowfish (push)" },
+#ifdef __x86_64__
+    { blowfish_x86_64, sizeof(blowfish_x86_64), 64, "blowfish" },
+#endif
+};
+
 #define MMAP_SZ 16384
 
 /* EFLAGS bit definitions. */
@@ -943,25 +959,19 @@ int main(int argc, char **argv)
     else
         printf("skipped\n");
 
-    for ( j = 1; j <= 2; j++ )
+    for ( j = 0; j < sizeof(blobs) / sizeof(*blobs); j++ )
     {
-#if defined(__i386__)
-        if ( j == 2 ) break;
-        memcpy(res, blowfish32_code, sizeof(blowfish32_code));
-#else
-        ctxt.addr_size = 16 << j;
-        ctxt.sp_size   = 16 << j;
-        memcpy(res, (j == 1) ? blowfish32_code : blowfish64_code,
-               (j == 1) ? sizeof(blowfish32_code) : sizeof(blowfish64_code));
-#endif
-        printf("Testing blowfish %u-bit code sequence", j*32);
+        memcpy(res, blobs[j].code, blobs[j].size);
+        ctxt.addr_size = ctxt.sp_size = blobs[j].bitness;
+
+        printf("Testing %s %u-bit code sequence",
+               blobs[j].name, ctxt.addr_size);
         regs.eax = 2;
         regs.edx = 1;
         regs.eip = (unsigned long)res;
         regs.esp = (unsigned long)res + MMAP_SZ - 4;
-        if ( j == 2 )
+        if ( ctxt.addr_size == 64 )
         {
-            ctxt.addr_size = ctxt.sp_size = 64;
             *(uint32_t *)(unsigned long)regs.esp = 0;
             regs.esp -= 4;
         }
@@ -983,20 +993,27 @@ int main(int argc, char **argv)
              (regs.eax != 2) || (regs.edx != 1) )
             goto fail;
         printf("okay\n");
-    }
 
-    printf("%-40s", "Testing blowfish native execution...");    
-    asm volatile (
+        if ( ctxt.addr_size != sizeof(void *) * CHAR_BIT )
+            continue;
+
+        i = printf("Testing %s native execution...", blobs[j].name);
+        asm volatile (
 #if defined(__i386__)
-        "movl $0x100000,%%ecx; call *%%ecx"
+            "movl $0x100000,%%ecx; call *%%ecx"
 #else
-        "movl $0x100000,%%ecx; call *%%rcx"
+            "movl $0x100000,%%ecx; call *%%rcx"
 #endif
-        : "=a" (regs.eax), "=d" (regs.edx)
-        : "0" (2), "1" (1) : "ecx" );
-    if ( (regs.eax != 2) || (regs.edx != 1) )
-        goto fail;
-    printf("okay\n");
+            : "=a" (regs.eax), "=d" (regs.edx)
+            : "0" (2), "1" (1) : "ecx"
+#ifdef __x86_64__
+              , "rsi", "rdi", "r8", "r9", "r10", "r11"
+#endif
+        );
+        if ( (regs.eax != 2) || (regs.edx != 1) )
+            goto fail;
+        printf("%*sokay\n", i < 40 ? 40 - i : 0, "");
+    }
 
     return 0;
 
--- a/xen/arch/x86/x86_emulate/x86_emulate.c
+++ b/xen/arch/x86/x86_emulate/x86_emulate.c
@@ -94,8 +94,8 @@ static uint8_t opcode_table[256] = {
     ImplicitOps, ImplicitOps, DstReg|SrcMem|ModRM, DstReg|SrcNone|ModRM|Mov,
     0, 0, 0, 0,
     /* 0x68 - 0x6F */
-    ImplicitOps|Mov, DstReg|SrcImm|ModRM|Mov,
-    ImplicitOps|Mov, DstReg|SrcImmByte|ModRM|Mov,
+    DstImplicit|SrcImm|Mov, DstReg|SrcImm|ModRM|Mov,
+    DstImplicit|SrcImmByte|Mov, DstReg|SrcImmByte|ModRM|Mov,
     ImplicitOps|Mov, ImplicitOps|Mov, ImplicitOps|Mov, ImplicitOps|Mov,
     /* 0x70 - 0x77 */
     ImplicitOps, ImplicitOps, ImplicitOps, ImplicitOps,
@@ -2335,10 +2335,15 @@ x86_emulate(
         break;
 
     case 0x68: /* push imm{16,32,64} */
-        src.val = ((op_bytes == 2)
-                   ? (int32_t)insn_fetch_type(int16_t)
-                   : insn_fetch_type(int32_t));
-        goto push;
+    case 0x6a: /* push imm8 */
+    push:
+        d |= Mov; /* force writeback */
+        dst.type  = OP_MEM;
+        dst.bytes = mode_64bit() && (op_bytes == 4) ? 8 : op_bytes;
+        dst.val = src.val;
+        dst.mem.seg = x86_seg_ss;
+        dst.mem.off = sp_pre_dec(dst.bytes);
+        break;
 
     case 0x69: /* imul imm16/32 */
     case 0x6b: /* imul imm8 */
@@ -2349,19 +2354,6 @@ x86_emulate(
             goto done;
         goto imul;
 
-    case 0x6a: /* push imm8 */
-        src.val = insn_fetch_type(int8_t);
-    push:
-        d |= Mov; /* force writeback */
-        dst.type  = OP_MEM;
-        dst.bytes = op_bytes;
-        if ( mode_64bit() && (dst.bytes == 4) )
-            dst.bytes = 8;
-        dst.val = src.val;
-        dst.mem.seg = x86_seg_ss;
-        dst.mem.off = sp_pre_dec(dst.bytes);
-        break;
-
     case 0x6c ... 0x6d: /* ins %dx,%es:%edi */ {
         unsigned long nr_reps = get_rep_prefix();
         unsigned int port = (uint16_t)_regs.edx;

Attachment: x86emul-push-imm-generic.patch
Description: Text document

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