>>> On 17.10.13 at 11:27, Gleb Natapov <gleb@xxxxxxxxxx> wrote: > On Wed, Oct 16, 2013 at 05:13:40PM +0100, Jan Beulich wrote: >> > It preserves *less* state, because the upper 32 bits of rip are now >> > corrupted. Any 64-bit application that actually looks at the FP >> > rip/rdp fields now get the WRONG VALUES. >> >> But again - this isn't being done for ordinary 64-bit applications, >> this is only happening for KVM guests. And there not being a >> protocol for telling the caller whether a certain context hold >> 64-bit offsets or selector/offset pairs shouldn't be a reason to >> think of a solution to the problem. >> > KVM knows what mode guest vcpu is in. is_long_mode(vcpu) will tell you > if it is in long mode or not. No need to guess it. So what if that 64-bit guest OS is running a 32-bit app? You can only positively know the _current_ guest word size when the guest is not in long mode. Jan -- 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
