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alistair23-linux
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[PATCH] KVM: MMU: Fix cmpxchg8b emulation 

cmpxchg8b uses edx:eax as the compare operand, not edi:eax.

cmpxchg8b is used by 32-bit pae guests to set page table entries atomically,
and this is emulated touching shadowed guest page tables.

Also, implement it for 32-bit hosts.

Signed-off-by: Avi Kivity <avi@qumranet.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
hifive-unleashed-5.1
Avi Kivity 2007-01-05 16:36:51 -08:00 committed by Linus Torvalds
parent 3bb65a22a4
commit 32b3562735
2 changed files with 28 additions and 1 deletions
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27
drivers/kvm/kvm_main.c
View File

@ -936,6 +936,30 @@ 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);
@ -1010,6 +1034,9 @@ 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,

2
drivers/kvm/x86_emulate.c
View File

@ -1323,7 +1323,7 @@ twobyte_special_insn:
ctxt)) != 0))
goto done;
if ((old_lo != _regs[VCPU_REGS_RAX])
|| (old_hi != _regs[VCPU_REGS_RDI])) {
|| (old_hi != _regs[VCPU_REGS_RDX])) {
_regs[VCPU_REGS_RAX] = old_lo;
_regs[VCPU_REGS_RDX] = old_hi;
_eflags &= ~EFLG_ZF;