linux/arch/i386/xen/Makefile

obj-y		:= enlighten.o setup.o features.o multicalls.o mmu.o \
			events.o time.o
xen: event channels Xen implements interrupts in terms of event channels. Each guest domain gets 1024 event channels which can be used for a variety of purposes, such as Xen timer events, inter-domain events, inter-processor events (IPI) or for real hardware IRQs. Within the kernel, we map the event channels to IRQs, and implement the whole interrupt handling using a Xen irq_chip. Rather than setting NR_IRQ to 1024 under PARAVIRT in order to accomodate Xen, we create a dynamic mapping between event channels and IRQs. Ideally, Linux will eventually move towards dynamically allocating per-irq structures, and we can use a 1:1 mapping between event channels and irqs. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Eric W. Biederman <ebiederm@xmission.com> 2007-07-18 03:37:05 +02:00			`obj-y := enlighten.o setup.o features.o multicalls.o mmu.o \`
xen: time implementation Xen maintains a base clock which measures nanoseconds since system boot. This is provided to guests via a shared page which contains a base time in ns, a tsc timestamp at that point and tsc frequency parameters. Guests can compute the current time by reading the tsc and using it to extrapolate the current time from the basetime. The hypervisor makes sure that the frequency parameters are updated regularly, paricularly if the tsc changes rate or stops. This is implemented as a clocksource, so the interface to the rest of the kernel is a simple clocksource which simply returns the current time directly in nanoseconds. Xen also provides a simple timer mechanism, which allows a timeout to be set in the future. When that time arrives, a timer event is sent to the guest. There are two timer interfaces: - An old one which also delivers a stream of (unused) ticks at 100Hz, and on the same event, the actual timer events. The 100Hz ticks cause a lot of spurious wakeups, but are basically harmless. - The new timer interface doesn't have the 100Hz ticks, and can also fail if the specified time is in the past. This code presents the Xen timer as a clockevent driver, and uses the new interface by preference. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> 2007-07-18 03:37:05 +02:00			`events.o time.o`