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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] x86-64: emulation support for cmpxchg16b
With the x86 instruction emulator no pretty complete, I'd like to
re-submit this patch to support cmpxchg16b on x86-64 and at once rename
the underlying emulator callback function pointer (making clear that if
implemented, it is to operate on two longs rather than two 32-bit
values). At the same time it fixes an apparently wrong emulator context
initialization in the shadow code.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Index: 2008-04-15/tools/tests/test_x86_emulator.c
===================================================================
--- 2008-04-15.orig/tools/tests/test_x86_emulator.c 2008-04-01
11:10:21.000000000 +0200
+++ 2008-04-15/tools/tests/test_x86_emulator.c 2008-04-15 08:48:15.000000000
+0200
@@ -74,7 +74,7 @@ static int cmpxchg(
return X86EMUL_OKAY;
}
-static int cmpxchg8b(
+static int cmpxchg2(
unsigned int seg,
unsigned long offset,
unsigned long old_lo,
@@ -94,7 +94,7 @@ static struct x86_emulate_ops emulops =
.insn_fetch = read,
.write = write,
.cmpxchg = cmpxchg,
- .cmpxchg8b = cmpxchg8b
+ .cmpxchg2 = cmpxchg2
};
int main(int argc, char **argv)
Index: 2008-04-15/tools/tests/x86_emulate.c
===================================================================
--- 2008-04-15.orig/tools/tests/x86_emulate.c 2008-04-01 11:10:21.000000000
+0200
+++ 2008-04-15/tools/tests/x86_emulate.c 2008-04-15 08:48:15.000000000
+0200
@@ -3,6 +3,8 @@
#include <string.h>
#include <public/xen.h>
+#define cpu_has_cmpxchg16b (sizeof(long) == 8)
+
#include "x86_emulate/x86_emulate.h"
#define __emulate_fpu_insn(_op) \
Index: 2008-04-15/xen/arch/x86/mm.c
===================================================================
--- 2008-04-15.orig/xen/arch/x86/mm.c 2008-04-11 14:48:16.000000000 +0200
+++ 2008-04-15/xen/arch/x86/mm.c 2008-04-15 08:48:15.000000000 +0200
@@ -3635,6 +3635,7 @@ static int ptwr_emulated_cmpxchg(
container_of(ctxt, struct ptwr_emulate_ctxt, ctxt));
}
+#ifdef __i386__
static int ptwr_emulated_cmpxchg8b(
enum x86_segment seg,
unsigned long offset,
@@ -3650,13 +3651,16 @@ static int ptwr_emulated_cmpxchg8b(
offset, ((u64)old_hi << 32) | old, ((u64)new_hi << 32) | new, 8, 1,
container_of(ctxt, struct ptwr_emulate_ctxt, ctxt));
}
+#else
+#define ptwr_emulated_cmpxchg8b NULL
+#endif
static struct x86_emulate_ops ptwr_emulate_ops = {
.read = ptwr_emulated_read,
.insn_fetch = ptwr_emulated_read,
.write = ptwr_emulated_write,
.cmpxchg = ptwr_emulated_cmpxchg,
- .cmpxchg8b = ptwr_emulated_cmpxchg8b
+ .cmpxchg2 = ptwr_emulated_cmpxchg8b
};
/* Write page fault handler: check if guest is trying to modify a PTE. */
Index: 2008-04-15/xen/arch/x86/mm/shadow/common.c
===================================================================
--- 2008-04-15.orig/xen/arch/x86/mm/shadow/common.c 2008-04-11
14:48:16.000000000 +0200
+++ 2008-04-15/xen/arch/x86/mm/shadow/common.c 2008-04-15 08:48:15.000000000
+0200
@@ -262,6 +262,7 @@ hvm_emulate_cmpxchg(enum x86_segment seg
v, addr, old, new, bytes, sh_ctxt);
}
+#ifdef __i386__
static int
hvm_emulate_cmpxchg8b(enum x86_segment seg,
unsigned long offset,
@@ -288,13 +289,16 @@ hvm_emulate_cmpxchg8b(enum x86_segment s
return v->arch.paging.mode->shadow.x86_emulate_cmpxchg8b(
v, addr, old_lo, old_hi, new_lo, new_hi, sh_ctxt);
}
+#else
+#define hvm_emulate_cmpxchg8b NULL
+#endif
static struct x86_emulate_ops hvm_shadow_emulator_ops = {
.read = hvm_emulate_read,
.insn_fetch = hvm_emulate_insn_fetch,
.write = hvm_emulate_write,
.cmpxchg = hvm_emulate_cmpxchg,
- .cmpxchg8b = hvm_emulate_cmpxchg8b,
+ .cmpxchg2 = hvm_emulate_cmpxchg8b,
};
static int
@@ -352,6 +356,7 @@ pv_emulate_cmpxchg(enum x86_segment seg,
v, offset, old, new, bytes, sh_ctxt);
}
+#ifdef __i386__
static int
pv_emulate_cmpxchg8b(enum x86_segment seg,
unsigned long offset,
@@ -369,13 +374,16 @@ pv_emulate_cmpxchg8b(enum x86_segment se
return v->arch.paging.mode->shadow.x86_emulate_cmpxchg8b(
v, offset, old_lo, old_hi, new_lo, new_hi, sh_ctxt);
}
+#else
+#define pv_emulate_cmpxchg8b NULL
+#endif
static struct x86_emulate_ops pv_shadow_emulator_ops = {
.read = pv_emulate_read,
.insn_fetch = pv_emulate_read,
.write = pv_emulate_write,
.cmpxchg = pv_emulate_cmpxchg,
- .cmpxchg8b = pv_emulate_cmpxchg8b,
+ .cmpxchg2 = pv_emulate_cmpxchg8b,
};
struct x86_emulate_ops *shadow_init_emulation(
@@ -390,7 +398,12 @@ struct x86_emulate_ops *shadow_init_emul
if ( !is_hvm_vcpu(v) )
{
+#ifndef CONFIG_COMPAT
sh_ctxt->ctxt.addr_size = sh_ctxt->ctxt.sp_size = BITS_PER_LONG;
+#else
+ sh_ctxt->ctxt.addr_size = sh_ctxt->ctxt.sp_size =
+ !is_pv_32on64_vcpu(v) ? BITS_PER_LONG : COMPAT_BITS_PER_LONG;
+#endif
return &pv_shadow_emulator_ops;
}
Index: 2008-04-15/xen/arch/x86/mm/shadow/multi.c
===================================================================
--- 2008-04-15.orig/xen/arch/x86/mm/shadow/multi.c 2008-04-01
14:20:52.000000000 +0200
+++ 2008-04-15/xen/arch/x86/mm/shadow/multi.c 2008-04-15 08:48:15.000000000
+0200
@@ -4432,7 +4432,8 @@ sh_x86_emulate_cmpxchg(struct vcpu *v, u
return rv;
}
-int
+#ifdef __i386__
+static int
sh_x86_emulate_cmpxchg8b(struct vcpu *v, unsigned long vaddr,
unsigned long old_lo, unsigned long old_hi,
unsigned long new_lo, unsigned long new_hi,
@@ -4465,6 +4466,7 @@ sh_x86_emulate_cmpxchg8b(struct vcpu *v,
shadow_unlock(v->domain);
return rv;
}
+#endif
/**************************************************************************/
@@ -4738,7 +4740,9 @@ struct paging_mode sh_paging_mode = {
.shadow.detach_old_tables = sh_detach_old_tables,
.shadow.x86_emulate_write = sh_x86_emulate_write,
.shadow.x86_emulate_cmpxchg = sh_x86_emulate_cmpxchg,
+#ifdef __i386__
.shadow.x86_emulate_cmpxchg8b = sh_x86_emulate_cmpxchg8b,
+#endif
.shadow.make_monitor_table = sh_make_monitor_table,
.shadow.destroy_monitor_table = sh_destroy_monitor_table,
#if SHADOW_OPTIMIZATIONS & SHOPT_WRITABLE_HEURISTIC
Index: 2008-04-15/xen/arch/x86/x86_emulate/x86_emulate.c
===================================================================
--- 2008-04-15.orig/xen/arch/x86/x86_emulate/x86_emulate.c 2008-04-01
11:10:21.000000000 +0200
+++ 2008-04-15/xen/arch/x86/x86_emulate/x86_emulate.c 2008-04-15
08:48:15.000000000 +0200
@@ -3346,60 +3346,64 @@ x86_emulate(
src.val = x86_seg_gs;
goto pop_seg;
- case 0xc7: /* Grp9 (cmpxchg8b) */
-#if defined(__i386__)
- {
- unsigned long old_lo, old_hi;
+ case 0xc7: /* Grp9 (cmpxchg{8,16}b) */
generate_exception_if((modrm_reg & 7) != 1, EXC_UD, -1);
generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off+0, &old_lo, 4, ctxt)) ||
- (rc = ops->read(ea.mem.seg, ea.mem.off+4, &old_hi, 4, ctxt)) )
- goto done;
- if ( (old_lo != _regs.eax) || (old_hi != _regs.edx) )
- {
- _regs.eax = old_lo;
- _regs.edx = old_hi;
- _regs.eflags &= ~EFLG_ZF;
- }
- else if ( ops->cmpxchg8b == NULL )
- {
- rc = X86EMUL_UNHANDLEABLE;
- goto done;
- }
- else
+#ifdef __x86_64__
+ if ( op_bytes != 8 )
{
- if ( (rc = ops->cmpxchg8b(ea.mem.seg, ea.mem.off, old_lo, old_hi,
- _regs.ebx, _regs.ecx, ctxt)) != 0 )
+ unsigned long old, new;
+
+ if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &old, 8, ctxt)) != 0 )
goto done;
- _regs.eflags |= EFLG_ZF;
- }
- break;
- }
-#elif defined(__x86_64__)
- {
- unsigned long old, new;
- generate_exception_if((modrm_reg & 7) != 1, EXC_UD, -1);
- generate_exception_if(ea.type != OP_MEM, EXC_UD, -1);
- if ( (rc = ops->read(ea.mem.seg, ea.mem.off, &old, 8, ctxt)) != 0 )
- goto done;
- if ( ((uint32_t)(old>>0) != (uint32_t)_regs.eax) ||
- ((uint32_t)(old>>32) != (uint32_t)_regs.edx) )
- {
- _regs.eax = (uint32_t)(old>>0);
- _regs.edx = (uint32_t)(old>>32);
- _regs.eflags &= ~EFLG_ZF;
+ if ( ((uint32_t)(old>>0) != (uint32_t)_regs.eax) ||
+ ((uint32_t)(old>>32) != (uint32_t)_regs.edx) )
+ {
+ _regs.eax = (uint32_t)(old>>0);
+ _regs.edx = (uint32_t)(old>>32);
+ _regs.eflags &= ~EFLG_ZF;
+ }
+ else
+ {
+ new = (_regs.ecx<<32)|(uint32_t)_regs.ebx;
+ if ( (rc = ops->cmpxchg(ea.mem.seg, ea.mem.off, old,
+ new, 8, ctxt)) != 0 )
+ goto done;
+ _regs.eflags |= EFLG_ZF;
+ }
}
+ else if ( !cpu_has_cmpxchg16b )
+ generate_exception_if(1, EXC_UD, -1);
else
+#endif
{
- new = (_regs.ecx<<32)|(uint32_t)_regs.ebx;
- if ( (rc = ops->cmpxchg(ea.mem.seg, ea.mem.off, old,
- new, 8, ctxt)) != 0 )
+ unsigned long old_lo, old_hi;
+
+ if ( (rc = ops->read(ea.mem.seg, ea.mem.off,
+ &old_lo, sizeof(old_lo), ctxt)) ||
+ (rc = ops->read(ea.mem.seg, ea.mem.off+sizeof(old_lo),
+ &old_hi, sizeof(old_lo), ctxt)) )
+ goto done;
+ if ( (old_lo != _regs.eax) || (old_hi != _regs.edx) )
+ {
+ _regs.eax = old_lo;
+ _regs.edx = old_hi;
+ _regs.eflags &= ~EFLG_ZF;
+ }
+ else if ( ops->cmpxchg2 == NULL )
+ {
+ rc = X86EMUL_UNHANDLEABLE;
goto done;
- _regs.eflags |= EFLG_ZF;
+ }
+ else
+ {
+ if ( (rc = ops->cmpxchg2(ea.mem.seg, ea.mem.off, old_lo,
old_hi,
+ _regs.ebx, _regs.ecx, ctxt)) != 0 )
+ goto done;
+ _regs.eflags |= EFLG_ZF;
+ }
}
break;
- }
-#endif
case 0xc8 ... 0xcf: /* bswap */
dst.type = OP_REG;
@@ -3409,7 +3413,7 @@ x86_emulate(
{
default: /* case 2: */
/* Undefined behaviour. Writes zero on all tested CPUs. */
- dst.val = 0;
+ __asm__("data16 bswap %k0" : "+r" (dst.val));
break;
case 4:
#ifdef __x86_64__
Index: 2008-04-15/xen/arch/x86/x86_emulate/x86_emulate.h
===================================================================
--- 2008-04-15.orig/xen/arch/x86/x86_emulate/x86_emulate.h 2008-04-01
11:10:21.000000000 +0200
+++ 2008-04-15/xen/arch/x86/x86_emulate/x86_emulate.h 2008-04-15
08:48:15.000000000 +0200
@@ -104,8 +104,9 @@ struct segment_register {
* some out-of-band mechanism, unknown to the emulator. The memop signals
* failure by returning X86EMUL_EXCEPTION to the emulator, which will
* then immediately bail.
- * 2. Valid access sizes are 1, 2, 4 and 8 bytes. On x86/32 systems only
- * cmpxchg8b_emulated need support 8-byte accesses.
+ * 2. Valid access sizes are 1, 2, 4, 8, and 16 bytes. On x86/32 systems only
+ * cmpxchg2_emulated need support 8-byte accesses. On x86/64 systems only
+ * cmpxchg2_emulated need support 16-byte accesses.
* 3. The emulator cannot handle 64-bit mode emulation on an x86/32 system.
*/
struct x86_emulate_ops
@@ -165,16 +166,17 @@ struct x86_emulate_ops
struct x86_emulate_ctxt *ctxt);
/*
- * cmpxchg8b: Emulate an atomic (LOCKed) CMPXCHG8B operation.
+ * cmpxchg2: Emulate an atomic (LOCKed) CMPXCHG{8,16}B operation.
* @old: [IN ] Value expected to be current at @addr.
* @new: [IN ] Value to write to @addr.
* NOTES:
- * 1. This function is only ever called when emulating a real CMPXCHG8B.
- * 2. This function is *never* called on x86/64 systems.
- * 2. Not defining this function (i.e., specifying NULL) is equivalent
+ * 1. This function is only ever called when emulating a real
CMPXCHG{8,16}B.
+ * 2. This function is *never* called on x86/64 systems for emulating
+ * CMPXCHG8B.
+ * 3. Not defining this function (i.e., specifying NULL) is equivalent
* to defining a function that always returns X86EMUL_UNHANDLEABLE.
*/
- int (*cmpxchg8b)(
+ int (*cmpxchg2)(
enum x86_segment seg,
unsigned long offset,
unsigned long old_lo,
Index: 2008-04-15/xen/arch/x86/x86_emulate.c
===================================================================
--- 2008-04-15.orig/xen/arch/x86/x86_emulate.c 2008-04-01 14:20:52.000000000
+0200
+++ 2008-04-15/xen/arch/x86/x86_emulate.c 2008-04-15 08:48:15.000000000
+0200
@@ -12,6 +12,8 @@
#include <asm/x86_emulate.h>
#undef cmpxchg
+#undef cpuid
+#undef wbinvd
#define __emulate_fpu_insn(_op) \
do{ int _exn; \
Index: 2008-04-15/xen/include/asm-x86/cpufeature.h
===================================================================
--- 2008-04-15.orig/xen/include/asm-x86/cpufeature.h 2008-04-01
14:20:52.000000000 +0200
+++ 2008-04-15/xen/include/asm-x86/cpufeature.h 2008-04-15 08:48:15.000000000
+0200
@@ -149,6 +149,7 @@
#define cpu_has_cyrix_arr boot_cpu_has(X86_FEATURE_CYRIX_ARR)
#define cpu_has_centaur_mcr boot_cpu_has(X86_FEATURE_CENTAUR_MCR)
#define cpu_has_clflush boot_cpu_has(X86_FEATURE_CLFLSH)
+#define cpu_has_cmpxchg16b 0
#define cpu_has_page1gb 0
#define cpu_has_efer (boot_cpu_data.x86_capability[1] & 0x20100800)
#else /* __x86_64__ */
@@ -175,6 +176,7 @@
#define cpu_has_cyrix_arr 0
#define cpu_has_centaur_mcr 0
#define cpu_has_clflush boot_cpu_has(X86_FEATURE_CLFLSH)
+#define cpu_has_cmpxchg16b boot_cpu_has(X86_FEATURE_CX16)
#define cpu_has_page1gb boot_cpu_has(X86_FEATURE_PAGE1GB)
#define cpu_has_efer 1
#endif
Index: 2008-04-15/xen/include/asm-x86/paging.h
===================================================================
--- 2008-04-15.orig/xen/include/asm-x86/paging.h 2008-04-11
14:48:16.000000000 +0200
+++ 2008-04-15/xen/include/asm-x86/paging.h 2008-04-15 08:48:15.000000000
+0200
@@ -83,12 +83,14 @@ struct shadow_paging_mode {
unsigned long new,
unsigned int bytes,
struct sh_emulate_ctxt *sh_ctxt);
+#ifdef __i386__
int (*x86_emulate_cmpxchg8b )(struct vcpu *v, unsigned long va,
unsigned long old_lo,
unsigned long old_hi,
unsigned long new_lo,
unsigned long new_hi,
struct sh_emulate_ctxt *sh_ctxt);
+#endif
mfn_t (*make_monitor_table )(struct vcpu *v);
void (*destroy_monitor_table )(struct vcpu *v, mfn_t mmfn);
int (*guess_wrmap )(struct vcpu *v,
Index: 2008-04-15/xen/include/asm-x86/x86_emulate.h
===================================================================
--- 2008-04-15.orig/xen/include/asm-x86/x86_emulate.h 2008-04-01
14:20:52.000000000 +0200
+++ 2008-04-15/xen/include/asm-x86/x86_emulate.h 2008-04-15
08:48:15.000000000 +0200
@@ -16,6 +16,7 @@
#include <xen/types.h>
#include <xen/lib.h>
#include <asm/regs.h>
+#include <asm/processor.h>
#include "../../arch/x86/x86_emulate/x86_emulate.h"
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