On Wed, Jul 14, 2010 at 01:15:09PM +0800, Wei Yongjun wrote: > If the destination is a memory operand and the memory > cannot map to a valid page, the xchg instruction emulation > will fail. If so, we should emulate exchange as write > to fix it. > > Signed-off-by: Wei Yongjun <yjwei@xxxxxxxxxxxxxx> Acked-by: Gleb Natapov <gleb@xxxxxxxxxx> Without this patch locked instruction does not work on io regions. They don't just fail, they stuck in endless loop. > --- > arch/x86/kvm/x86.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c > index d94811e..ac63f6f 100644 > --- a/arch/x86/kvm/x86.c > +++ b/arch/x86/kvm/x86.c > @@ -3560,6 +3560,8 @@ static int emulator_cmpxchg_emulated(unsigned long addr, > goto emul_write; > > page = gfn_to_page(vcpu->kvm, gpa >> PAGE_SHIFT); > + if (is_error_page(page)) > + goto emul_write; > > kaddr = kmap_atomic(page, KM_USER0); > kaddr += offset_in_page(gpa); > -- > 1.7.0.4 > > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- Gleb. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
