On 06/24/2015 05:47 AM, Andrew Cooper wrote: >> + case EXIT_REASON_VMFUNC: >> + if ( vmx_vmfunc_intercept(regs) == X86EMUL_OKAY ) > > This is currently an unconditional failure, and I don't see subsequent > patches which alter vmx_vmfunc_intercept(). Shouldn't > vmx_vmfunc_intercept() switch on eax and optionally call > p2m_switch_vcpu_altp2m_by_id()?
If the VMFUNC instruction was valid, the hardware would have executed it. The only time a VMFUNC exit occurs is if the hardware supports VMFUNC and the hypervisor has enabled it, but the VMFUNC instruction is invalid in some way and can't be executed (because EAX != 0, for example). There are only two choices: crash the domain or inject #UD (which is the closest analogue to what happens in the absence of a hypervisor and will probably crash the OS in the domain). I chose the latter in the code I originally wrote; Ravi chose the former in his patch. I don't have a strong opinion either way, but I think these are the only two choices. I hope this answers Jan's question in another email on the same subject. Ed _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
