Re: proposal to add "virtual instruction exception" to the hypervisor extension


Paolo Bonzini
 

On 05/05/20 23:15, John Hauser wrote:
- attempts to execute WFI, unless the instruction completes within an
implementation-specific, bounded time;
It would be great to have this controlled by a bit in the hstatus CSR.
For example a hypervisor that does not overcommit CPUs will probably
want to delegate WFI to the guest. Guest-delegated interrupts then
would not incur the overhead of world switching, while host-handled
interrupts would exit to the hypervisor anyway.

(It may even make sense to add this to mstatus, but I wouldn't care much
about it right now except perhaps when choosing which bit to use in
hstatus).

Paolo

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