[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Re: sysenter/syscall support for 32-on-64 guests?
On 28/2/08 17:14, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote: >> Anyway, I wonder if you had a specific reason for allowing this, other >> than "because we can"? It seems to me that we should try to minimize >> the number of differences between 32-on-32 and 32-on-64 as much as possible. > > Since int80 cannot be directly passed to the guest (as in 32-on-32), it > seemed reasonable to cut on the overhead of syscalls by at least > allowing this (and syscall could also be made work now that the vdso > stuff is unified in 2.6.25) - for obvious reasons it still goes through the > hypervisor, but gets there faster Ah yes, I must admit I temporarily forgot you can only target 64-bit code segments in a long-mode IDT. -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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