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Subject[82/82] KVM: x86 emulator: fix regression with cmpxchg8b on i386 hosts
2.6.35-stable review patch.  If anyone has any objections, please let us know.

------------------

From: Avi Kivity <avi@redhat.com>

commit 16518d5ada690643453eb0aef3cc7841d3623c2d upstream.

operand::val and operand::orig_val are 32-bit on i386, whereas cmpxchg8b
operands are 64-bit.

Fix by adding val64 and orig_val64 union members to struct operand, and
using them where needed.

Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/include/asm/kvm_emulate.h | 10 +++++++++-
arch/x86/kvm/emulate.c | 9 ++++-----
2 files changed, 13 insertions(+), 6 deletions(-)

--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -143,7 +143,15 @@ struct x86_emulate_ops {
struct operand {
enum { OP_REG, OP_MEM, OP_IMM, OP_NONE } type;
unsigned int bytes;
- unsigned long val, orig_val, *ptr;
+ union {
+ unsigned long orig_val;
+ u64 orig_val64;
+ };
+ unsigned long *ptr;
+ union {
+ unsigned long val;
+ u64 val64;
+ };
};

struct fetch_cache {
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -1712,17 +1712,16 @@ static inline int emulate_grp9(struct x8
struct x86_emulate_ops *ops)
{
struct decode_cache *c = &ctxt->decode;
- u64 old = c->dst.orig_val;
+ u64 old = c->dst.orig_val64;

if (((u32) (old >> 0) != (u32) c->regs[VCPU_REGS_RAX]) ||
((u32) (old >> 32) != (u32) c->regs[VCPU_REGS_RDX])) {
-
c->regs[VCPU_REGS_RAX] = (u32) (old >> 0);
c->regs[VCPU_REGS_RDX] = (u32) (old >> 32);
ctxt->eflags &= ~EFLG_ZF;
} else {
- c->dst.val = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
- (u32) c->regs[VCPU_REGS_RBX];
+ c->dst.val64 = ((u64)c->regs[VCPU_REGS_RCX] << 32) |
+ (u32) c->regs[VCPU_REGS_RBX];

ctxt->eflags |= EFLG_ZF;
}
@@ -2535,7 +2534,7 @@ x86_emulate_insn(struct x86_emulate_ctxt
ctxt->vcpu);
if (rc != X86EMUL_CONTINUE)
goto done;
- c->src.orig_val = c->src.val;
+ c->src.orig_val64 = c->src.val64;
}

if (c->src2.type == OP_MEM) {



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