On 20/08/14 11:19, Wei Hu wrote: > Hello, > > Sending to Xen, drivers and virtualization mailing lists since this might be > of interest to the folks on these aliases. > > I am working for Microsoft to improve the performance of FreeBSD running on > Hyper-V. Right now I am adding a feature in the vmbus driver which could > handle the host-guest channel communications on all vCPUs simultaneously. In > order to achieve this, the hypervisor will send same interrupt concurrently > on all the vCPUs. The traditional way on FreeBSD to set up interrupt handling > for devicse, such as calling bus_alloc_resource() to reserve an IRQ line, and > then calling bus_setup_intr() to create a vector, doesn't seem to work in > this case. It seems if the interrupt is routed via legacy IRQ, it can only be > active on one vCPU at a time. In order to allow the same interrupt to be > handled on all vCPUs concurrently, all I need is an IDT entry, not an IRQ > line. > > I checked current FreeBSD code. It looks to me Xen directly uses the vector > number IDT_EVTCHN (0x93) to achieve the same purpose. I am proposing both Xen > and Hyper-V share this same vector. Following is a little bit detail of my > proposal for the changes in the current kernel. > > > 1. In machdep.c: > > #ifdef XENHVM > > setidt(IDT_EVTCHN, &IDTVEC(xen_intr_upcall), SDT_SYSIGT, SEL_UPL, 0); > > #else > > setidt(IDT_EVTCHN, &IDTVEC(hv_vmbus_intr), SDT_SYSIGT, SEL_UPL, 0); > > #endif > > 2. Apic_vector.S > > Add IDTVEC(hv_vmbus_intr) to call Hyper-V vmbus interrupt service routine. > > Any thoughts, objections and feedbacks are all welcome.
Hello, I don't think using the same IDT vector is the right approach, I would just pick a different IDT vector and use that for Hyper-V. Using the same IDT vector (like your suggestion above) would prevent shipping a kernel with with both Hyper-V and Xen support (like it's done now in GENERIC). Roger. _______________________________________________ freebsd-virtualization@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization To unsubscribe, send any mail to "freebsd-virtualization-unsubscr...@freebsd.org"
