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KVM: Allow passing 64-bit values to the emulated read/write API
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This simplifies the API somewhat (by eliminating the special-case
cmpxchg8b on i386).

Signed-off-by: Avi Kivity <avi@qumranet.com>
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Avi Kivity committed May 3, 2007
1 parent 1165f5f commit 4c690a1
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Showing 3 changed files with 24 additions and 99 deletions.
45 changes: 9 additions & 36 deletions drivers/kvm/kvm_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -970,7 +970,7 @@ void mark_page_dirty(struct kvm *kvm, gfn_t gfn)
}

static int emulator_read_std(unsigned long addr,
unsigned long *val,
void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
Expand Down Expand Up @@ -1006,7 +1006,7 @@ static int emulator_read_std(unsigned long addr,
}

static int emulator_write_std(unsigned long addr,
unsigned long val,
const void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
Expand All @@ -1016,7 +1016,7 @@ static int emulator_write_std(unsigned long addr,
}

static int emulator_read_emulated(unsigned long addr,
unsigned long *val,
void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
Expand Down Expand Up @@ -1044,7 +1044,7 @@ static int emulator_read_emulated(unsigned long addr,
}

static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
unsigned long val, int bytes)
const void *val, int bytes)
{
struct page *page;
void *virt;
Expand All @@ -1057,14 +1057,14 @@ static int emulator_write_phys(struct kvm_vcpu *vcpu, gpa_t gpa,
kvm_mmu_pre_write(vcpu, gpa, bytes);
mark_page_dirty(vcpu->kvm, gpa >> PAGE_SHIFT);
virt = kmap_atomic(page, KM_USER0);
memcpy(virt + offset_in_page(gpa), &val, bytes);
memcpy(virt + offset_in_page(gpa), val, bytes);
kunmap_atomic(virt, KM_USER0);
kvm_mmu_post_write(vcpu, gpa, bytes);
return 1;
}

static int emulator_write_emulated(unsigned long addr,
unsigned long val,
const void *val,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
Expand All @@ -1083,14 +1083,14 @@ static int emulator_write_emulated(unsigned long addr,
vcpu->mmio_phys_addr = gpa;
vcpu->mmio_size = bytes;
vcpu->mmio_is_write = 1;
memcpy(vcpu->mmio_data, &val, bytes);
memcpy(vcpu->mmio_data, val, bytes);

return X86EMUL_CONTINUE;
}

static int emulator_cmpxchg_emulated(unsigned long addr,
unsigned long old,
unsigned long new,
const void *old,
const void *new,
unsigned int bytes,
struct x86_emulate_ctxt *ctxt)
{
Expand All @@ -1103,30 +1103,6 @@ static int emulator_cmpxchg_emulated(unsigned long addr,
return emulator_write_emulated(addr, new, bytes, ctxt);
}

#ifdef CONFIG_X86_32

static int emulator_cmpxchg8b_emulated(unsigned long addr,
unsigned long old_lo,
unsigned long old_hi,
unsigned long new_lo,
unsigned long new_hi,
struct x86_emulate_ctxt *ctxt)
{
static int reported;
int r;

if (!reported) {
reported = 1;
printk(KERN_WARNING "kvm: emulating exchange8b as write\n");
}
r = emulator_write_emulated(addr, new_lo, 4, ctxt);
if (r != X86EMUL_CONTINUE)
return r;
return emulator_write_emulated(addr+4, new_hi, 4, ctxt);
}

#endif

static unsigned long get_segment_base(struct kvm_vcpu *vcpu, int seg)
{
return kvm_arch_ops->get_segment_base(vcpu, seg);
Expand Down Expand Up @@ -1201,9 +1177,6 @@ struct x86_emulate_ops emulate_ops = {
.read_emulated = emulator_read_emulated,
.write_emulated = emulator_write_emulated,
.cmpxchg_emulated = emulator_cmpxchg_emulated,
#ifdef CONFIG_X86_32
.cmpxchg8b_emulated = emulator_cmpxchg8b_emulated,
#endif
};

int emulate_instruction(struct kvm_vcpu *vcpu,
Expand Down
46 changes: 9 additions & 37 deletions drivers/kvm/x86_emulate.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1045,7 +1045,7 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
if ((rc = ops->write_std(
register_address(ctxt->ss_base,
_regs[VCPU_REGS_RSP]),
dst.val, dst.bytes, ctxt)) != 0)
&dst.val, dst.bytes, ctxt)) != 0)
goto done;
dst.val = dst.orig_val; /* skanky: disable writeback */
break;
Expand Down Expand Up @@ -1078,12 +1078,12 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
case OP_MEM:
if (lock_prefix)
rc = ops->cmpxchg_emulated((unsigned long)dst.
ptr, dst.orig_val,
dst.val, dst.bytes,
ptr, &dst.orig_val,
&dst.val, dst.bytes,
ctxt);
else
rc = ops->write_emulated((unsigned long)dst.ptr,
dst.val, dst.bytes,
&dst.val, dst.bytes,
ctxt);
if (rc != 0)
goto done;
Expand Down Expand Up @@ -1321,36 +1321,8 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
realmode_set_cr(ctxt->vcpu, modrm_reg, modrm_val, &_eflags);
break;
case 0xc7: /* Grp9 (cmpxchg8b) */
#if defined(__i386__)
{
unsigned long old_lo, old_hi;
if (((rc = ops->read_emulated(cr2 + 0, &old_lo, 4,
ctxt)) != 0)
|| ((rc = ops->read_emulated(cr2 + 4, &old_hi, 4,
ctxt)) != 0))
goto done;
if ((old_lo != _regs[VCPU_REGS_RAX])
|| (old_hi != _regs[VCPU_REGS_RDX])) {
_regs[VCPU_REGS_RAX] = old_lo;
_regs[VCPU_REGS_RDX] = old_hi;
_eflags &= ~EFLG_ZF;
} else if (ops->cmpxchg8b_emulated == NULL) {
rc = X86EMUL_UNHANDLEABLE;
goto done;
} else {
if ((rc = ops->cmpxchg8b_emulated(cr2, old_lo,
old_hi,
_regs[VCPU_REGS_RBX],
_regs[VCPU_REGS_RCX],
ctxt)) != 0)
goto done;
_eflags |= EFLG_ZF;
}
break;
}
#elif defined(CONFIG_X86_64)
{
unsigned long old, new;
u64 old, new;
if ((rc = ops->read_emulated(cr2, &old, 8, ctxt)) != 0)
goto done;
if (((u32) (old >> 0) != (u32) _regs[VCPU_REGS_RAX]) ||
Expand All @@ -1359,15 +1331,15 @@ x86_emulate_memop(struct x86_emulate_ctxt *ctxt, struct x86_emulate_ops *ops)
_regs[VCPU_REGS_RDX] = (u32) (old >> 32);
_eflags &= ~EFLG_ZF;
} else {
new = (_regs[VCPU_REGS_RCX] << 32) | (u32) _regs[VCPU_REGS_RBX];
if ((rc = ops->cmpxchg_emulated(cr2, old,
new, 8, ctxt)) != 0)
new = ((u64)_regs[VCPU_REGS_RCX] << 32)
| (u32) _regs[VCPU_REGS_RBX];
if ((rc = ops->cmpxchg_emulated(cr2, &old,
&new, 8, ctxt)) != 0)
goto done;
_eflags |= EFLG_ZF;
}
break;
}
#endif
}
goto writeback;

Expand Down
32 changes: 6 additions & 26 deletions drivers/kvm/x86_emulate.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -59,8 +59,7 @@ struct x86_emulate_ops {
* @val: [OUT] Value read from memory, zero-extended to 'u_long'.
* @bytes: [IN ] Number of bytes to read from memory.
*/
int (*read_std)(unsigned long addr,
unsigned long *val,
int (*read_std)(unsigned long addr, void *val,
unsigned int bytes, struct x86_emulate_ctxt * ctxt);

/*
Expand All @@ -71,8 +70,7 @@ struct x86_emulate_ops {
* required).
* @bytes: [IN ] Number of bytes to write to memory.
*/
int (*write_std)(unsigned long addr,
unsigned long val,
int (*write_std)(unsigned long addr, const void *val,
unsigned int bytes, struct x86_emulate_ctxt * ctxt);

/*
Expand All @@ -82,7 +80,7 @@ struct x86_emulate_ops {
* @bytes: [IN ] Number of bytes to read from memory.
*/
int (*read_emulated) (unsigned long addr,
unsigned long *val,
void *val,
unsigned int bytes,
struct x86_emulate_ctxt * ctxt);

Expand All @@ -94,7 +92,7 @@ struct x86_emulate_ops {
* @bytes: [IN ] Number of bytes to write to memory.
*/
int (*write_emulated) (unsigned long addr,
unsigned long val,
const void *val,
unsigned int bytes,
struct x86_emulate_ctxt * ctxt);

Expand All @@ -107,29 +105,11 @@ struct x86_emulate_ops {
* @bytes: [IN ] Number of bytes to access using CMPXCHG.
*/
int (*cmpxchg_emulated) (unsigned long addr,
unsigned long old,
unsigned long new,
const void *old,
const void *new,
unsigned int bytes,
struct x86_emulate_ctxt * ctxt);

/*
* cmpxchg8b_emulated: Emulate an atomic (LOCKed) CMPXCHG8B operation on an
* emulated/special memory area.
* @addr: [IN ] Linear address to access.
* @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
* to defining a function that always returns X86EMUL_UNHANDLEABLE.
*/
int (*cmpxchg8b_emulated) (unsigned long addr,
unsigned long old_lo,
unsigned long old_hi,
unsigned long new_lo,
unsigned long new_hi,
struct x86_emulate_ctxt * ctxt);
};

struct cpu_user_regs;
Expand Down

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