Implement vector callback for PVHVM and unify event channel implementations

Re-structure Xen HVM support so that:
	- Xen is detected and hypercalls can be performed very
	  early in system startup.
	- Xen interrupt services are implemented using FreeBSD's native
	  interrupt delivery infrastructure.
	- the Xen interrupt service implementation is shared between PV
	  and HVM guests.
	- Xen interrupt handlers can optionally use a filter handler
	  in order to avoid the overhead of dispatch to an interrupt
	  thread.
	- interrupt load can be distributed among all available CPUs.
	- the overhead of accessing the emulated local and I/O apics
	  on HVM is removed for event channel port events.
	- a similar optimization can eventually, and fairly easily,
	  be used to optimize MSI.

Early Xen detection, HVM refactoring, PVHVM interrupt infrastructure,
and misc Xen cleanups:

Sponsored by: Spectra Logic Corporation

Unification of PV & HVM interrupt infrastructure, bug fixes,
and misc Xen cleanups:

Submitted by: Roger Pau Monné
Sponsored by: Citrix Systems R&D

sys/x86/x86/local_apic.c:
sys/amd64/include/apicvar.h:
sys/i386/include/apicvar.h:
sys/amd64/amd64/apic_vector.S:
sys/i386/i386/apic_vector.s:
sys/amd64/amd64/machdep.c:
sys/i386/i386/machdep.c:
sys/i386/xen/exception.s:
sys/x86/include/segments.h:
	Reserve IDT vector 0x93 for the Xen event channel upcall
	interrupt handler.  On Hypervisors that support the direct
	vector callback feature, we can request that this vector be
	called directly by an injected HVM interrupt event, instead
	of a simulated PCI interrupt on the Xen platform PCI device.
	This avoids all of the overhead of dealing with the emulated
	I/O APIC and local APIC.  It also means that the Hypervisor
	can inject these events on any CPU, allowing upcalls for
	different ports to be handled in parallel.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
	Map Xen per-vcpu area during AP startup.

sys/amd64/include/intr_machdep.h:
sys/i386/include/intr_machdep.h:
	Increase the FreeBSD IRQ vector table to include space
	for event channel interrupt sources.

sys/amd64/include/pcpu.h:
sys/i386/include/pcpu.h:
	Remove Xen HVM per-cpu variable data.  These fields are now
	allocated via the dynamic per-cpu scheme.  See xen_intr.c
	for details.

sys/amd64/include/xen/hypercall.h:
sys/dev/xen/blkback/blkback.c:
sys/i386/include/xen/xenvar.h:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/xen/gnttab.c:
	Prefer FreeBSD primatives to Linux ones in Xen support code.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
sys/dev/xen/balloon/balloon.c:
sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/console/xencons_ring.c:
sys/dev/xen/control/control.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/dev/xen/xenpci/xenpci.c:
sys/i386/i386/machdep.c:
sys/i386/include/pmap.h:
sys/i386/include/xen/xenfunc.h:
sys/i386/isa/npx.c:
sys/i386/xen/clock.c:
sys/i386/xen/mp_machdep.c:
sys/i386/xen/mptable.c:
sys/i386/xen/xen_clock_util.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/xen_rtc.c:
sys/xen/evtchn/evtchn_dev.c:
sys/xen/features.c:
sys/xen/gnttab.c:
sys/xen/gnttab.h:
sys/xen/hvm.h:
sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbus_if.m:
sys/xen/xenbus/xenbusb_front.c:
sys/xen/xenbus/xenbusvar.h:
sys/xen/xenstore/xenstore.c:
sys/xen/xenstore/xenstore_dev.c:
sys/xen/xenstore/xenstorevar.h:
	Pull common Xen OS support functions/settings into xen/xen-os.h.

sys/amd64/include/xen/xen-os.h:
sys/i386/include/xen/xen-os.h:
sys/xen/xen-os.h:
	Remove constants, macros, and functions unused in FreeBSD's Xen
	support.

sys/xen/xen-os.h:
sys/i386/xen/xen_machdep.c:
sys/x86/xen/hvm.c:
	Introduce new functions xen_domain(), xen_pv_domain(), and
	xen_hvm_domain().  These are used in favor of #ifdefs so that
	FreeBSD can dynamically detect and adapt to the presence of
	a hypervisor.  The goal is to have an HVM optimized GENERIC,
	but more is necessary before this is possible.

sys/amd64/amd64/machdep.c:
sys/dev/xen/xenpci/xenpcivar.h:
sys/dev/xen/xenpci/xenpci.c:
sys/x86/xen/hvm.c:
sys/sys/kernel.h:
	Refactor magic ioport, Hypercall table and Hypervisor shared
	information page setup, and move it to a dedicated HVM support
	module.

	HVM mode initialization is now triggered during the
	SI_SUB_HYPERVISOR phase of system startup.  This currently
	occurs just after the kernel VM is fully setup which is
	just enough infrastructure to allow the hypercall table
	and shared info page to be properly mapped.

sys/xen/hvm.h:
sys/x86/xen/hvm.c:
	Add definitions and a method for configuring Hypervisor event
	delievery via a direct vector callback.

sys/amd64/include/xen/xen-os.h:
sys/x86/xen/hvm.c:

sys/conf/files:
sys/conf/files.amd64:
sys/conf/files.i386:
	Adjust kernel build to reflect the refactoring of early
	Xen startup code and Xen interrupt services.

sys/dev/xen/blkback/blkback.c:
sys/dev/xen/blkfront/blkfront.c:
sys/dev/xen/blkfront/block.h:
sys/dev/xen/control/control.c:
sys/dev/xen/evtchn/evtchn_dev.c:
sys/dev/xen/netback/netback.c:
sys/dev/xen/netfront/netfront.c:
sys/xen/xenstore/xenstore.c:
sys/xen/evtchn/evtchn_dev.c:
sys/dev/xen/console/console.c:
sys/dev/xen/console/xencons_ring.c
	Adjust drivers to use new xen_intr_*() API.

sys/dev/xen/blkback/blkback.c:
	Since blkback defers all event handling to a taskqueue,
	convert this task queue to a "fast" taskqueue, and schedule
	it via an interrupt filter.  This avoids an unnecessary
	ithread context switch.

sys/xen/xenstore/xenstore.c:
	The xenstore driver is MPSAFE.  Indicate as much when
	registering its interrupt handler.

sys/xen/xenbus/xenbus.c:
sys/xen/xenbus/xenbusvar.h:
	Remove unused event channel APIs.

sys/xen/evtchn.h:
	Remove all kernel Xen interrupt service API definitions
	from this file.  It is now only used for structure and
	ioctl definitions related to the event channel userland
	device driver.

	Update the definitions in this file to match those from
	NetBSD.  Implementing this interface will be necessary for
	Dom0 support.

sys/xen/evtchn/evtchnvar.h:
	Add a header file for implemenation internal APIs related
	to managing event channels event delivery.  This is used
	to allow, for example, the event channel userland device
	driver to access low-level routines that typical kernel
	consumers of event channel services should never access.

sys/xen/interface/event_channel.h:
sys/xen/xen_intr.h:
	Standardize on the evtchn_port_t type for referring to
	an event channel port id.  In order to prevent low-level
	event channel APIs from leaking to kernel consumers who
	should not have access to this data, the type is defined
	twice: Once in the Xen provided event_channel.h, and again
	in xen/xen_intr.h.  The double declaration is protected by
	__XEN_EVTCHN_PORT_DEFINED__ to ensure it is never declared
	twice within a given compilation unit.

sys/xen/xen_intr.h:
sys/xen/evtchn/evtchn.c:
sys/x86/xen/xen_intr.c:
sys/dev/xen/xenpci/evtchn.c:
sys/dev/xen/xenpci/xenpcivar.h:
	New implementation of Xen interrupt services.  This is
	similar in many respects to the i386 PV implementation with
	the exception that events for bound to event channel ports
	(i.e. not IPI, virtual IRQ, or physical IRQ) are further
	optimized to avoid mask/unmask operations that aren't
	necessary for these edge triggered events.

	Stubs exist for supporting physical IRQ binding, but will
	need additional work before this implementation can be
	fully shared between PV and HVM.

sys/amd64/amd64/mp_machdep.c:
sys/i386/i386/mp_machdep.c:
sys/i386/xen/mp_machdep.c
sys/x86/xen/hvm.c:
	Add support for placing vcpu_info into an arbritary memory
	page instead of using HYPERVISOR_shared_info->vcpu_info.
	This allows the creation of domains with more than 32 vcpus.

sys/i386/i386/machdep.c:
sys/i386/xen/clock.c:
sys/i386/xen/xen_machdep.c:
sys/i386/xen/exception.s:
	Add support for new event channle implementation.

1 files changed, 65 insertions, 161 deletions

diff --git a/sys/dev/xen/xenpci/xenpci.c b/sys/dev/xen/xenpci/xenpci.c
index 2d74676..0b1762d 100644
--- a/sys/dev/xen/xenpci/xenpci.c
+++ b/sys/dev/xen/xenpci/xenpci.c
@@ -32,40 +32,25 @@ __FBSDID("$FreeBSD$");
 #include <sys/kernel.h>
 #include <sys/malloc.h>
 #include <sys/module.h>
-#include <sys/proc.h>
-#include <sys/systm.h>
-#include <sys/time.h>
 
 #include <machine/bus.h>
 #include <machine/resource.h>
 #include <sys/rman.h>
 
 #include <machine/stdarg.h>
-#include <machine/xen/xen-os.h>
+
+#include <xen/xen-os.h>
 #include <xen/features.h>
 #include <xen/hypervisor.h>
-#include <xen/gnttab.h>
-#include <xen/xen_intr.h>
-#include <xen/interface/memory.h>
-#include <xen/interface/hvm/params.h>
+#include <xen/hvm.h>
 
 #include <dev/pci/pcireg.h>
 #include <dev/pci/pcivar.h>
 
-#include <vm/vm.h>
-#include <vm/vm_extern.h>
-#include <vm/vm_kern.h>
-#include <vm/pmap.h>
-
 #include <dev/xen/xenpci/xenpcivar.h>
 
-/*
- * These variables are used by the rest of the kernel to access the
- * hypervisor.
- */
-char *hypercall_stubs;
-shared_info_t *HYPERVISOR_shared_info;
-static vm_paddr_t shared_info_pa;
+extern void xen_intr_handle_upcall(struct trapframe *trap_frame);
+
 static device_t nexus;
 
 /*
@@ -73,103 +58,42 @@ static device_t nexus;
  */
 static devclass_t xenpci_devclass;
 
-/*
- * Return the CPUID base address for Xen functions.
- */
-static uint32_t
-xenpci_cpuid_base(void)
+static int
+xenpci_intr_filter(void *trap_frame)
 {
-	uint32_t base, regs[4];
-
-	for (base = 0x40000000; base < 0x40010000; base += 0x100) {
-		do_cpuid(base, regs);
-		if (!memcmp("XenVMMXenVMM", &regs[1], 12)
-		    && (regs[0] - base) >= 2)
-			return (base);
-	}
-	return (0);
+	xen_intr_handle_upcall(trap_frame);
+	return (FILTER_HANDLED);
 }
 
-/*
- * Allocate and fill in the hypcall page.
- */
 static int
-xenpci_init_hypercall_stubs(device_t dev, struct xenpci_softc * scp)
+xenpci_irq_init(device_t device, struct xenpci_softc *scp)
 {
-	uint32_t base, regs[4];
-	int i;
-
-	base = xenpci_cpuid_base();
-	if (!base) {
-		device_printf(dev, "Xen platform device but not Xen VMM\n");
-		return (EINVAL);
-	}
+	int error;
 
-	if (bootverbose) {
-		do_cpuid(base + 1, regs);
-		device_printf(dev, "Xen version %d.%d.\n",
-		    regs[0] >> 16, regs[0] & 0xffff);
-	}
+	error = BUS_SETUP_INTR(device_get_parent(device), device,
+			       scp->res_irq, INTR_MPSAFE|INTR_TYPE_MISC,
+			       xenpci_intr_filter, NULL, /*trap_frame*/NULL,
+			       &scp->intr_cookie);
+	if (error)
+		return error;
 
 	/*
-	 * Find the hypercall pages.
+	 * When using the PCI event delivery callback we cannot assign
+	 * events to specific vCPUs, so all events are delivered to vCPU#0 by
+	 * Xen. Since the PCI interrupt can fire on any CPU by default, we
+	 * need to bind it to vCPU#0 in order to ensure that
+	 * xen_intr_handle_upcall always gets called on vCPU#0.
 	 */
-	do_cpuid(base + 2, regs);
-	
-	hypercall_stubs = malloc(regs[0] * PAGE_SIZE, M_TEMP, M_WAITOK);
-
-	for (i = 0; i < regs[0]; i++) {
-		wrmsr(regs[1], vtophys(hypercall_stubs + i * PAGE_SIZE) + i);
-	}
+	error = BUS_BIND_INTR(device_get_parent(device), device,
+	                      scp->res_irq, 0);
+	if (error)
+		return error;
 
+	xen_hvm_set_callback(device);
 	return (0);
 }
 
 /*
- * After a resume, re-initialise the hypercall page.
- */
-static void
-xenpci_resume_hypercall_stubs(device_t dev, struct xenpci_softc * scp)
-{
-	uint32_t base, regs[4];
-	int i;
-
-	base = xenpci_cpuid_base();
-
-	do_cpuid(base + 2, regs);
-	for (i = 0; i < regs[0]; i++) {
-		wrmsr(regs[1], vtophys(hypercall_stubs + i * PAGE_SIZE) + i);
-	}
-}
-
-/*
- * Tell the hypervisor how to contact us for event channel callbacks.
- */
-static void
-xenpci_set_callback(device_t dev)
-{
-	int irq;
-	uint64_t callback;
-	struct xen_hvm_param xhp;
-
-	irq = pci_get_irq(dev);
-	if (irq < 16) {
-		callback = irq;
-	} else {
-		callback = (pci_get_intpin(dev) - 1) & 3;
-		callback |= pci_get_slot(dev) << 11;
-		callback |= 1ull << 56;
-	}
-
-	xhp.domid = DOMID_SELF;
-	xhp.index = HVM_PARAM_CALLBACK_IRQ;
-	xhp.value = callback;
-	if (HYPERVISOR_hvm_op(HVMOP_set_param, &xhp))
-		panic("Can't set evtchn callback");
-}
-
-
-/*
  * Deallocate anything allocated by xenpci_allocate_resources.
  */
 static int
@@ -293,35 +217,6 @@ xenpci_deactivate_resource(device_t dev, device_t child, int type,
 }
 
 /*
- * Called very early in the resume sequence - reinitialise the various
- * bits of Xen machinery including the hypercall page and the shared
- * info page.
- */
-void
-xenpci_resume()
-{
-	device_t dev = devclass_get_device(xenpci_devclass, 0);
-	struct xenpci_softc *scp = device_get_softc(dev);
-	struct xen_add_to_physmap xatp;
-
-	xenpci_resume_hypercall_stubs(dev, scp);
-
-	xatp.domid = DOMID_SELF;
-	xatp.idx = 0;
-	xatp.space = XENMAPSPACE_shared_info;
-	xatp.gpfn = shared_info_pa >> PAGE_SHIFT;
-	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
-		panic("HYPERVISOR_memory_op failed");
-
-	pmap_kenter((vm_offset_t) HYPERVISOR_shared_info, shared_info_pa);
-
-	xenpci_set_callback(dev);
-
-	gnttab_resume();
-	irq_resume();
-}
-
-/*
  * Probe - just check device ID.
  */
 static int
@@ -341,11 +236,9 @@ xenpci_probe(device_t dev)
 static int
 xenpci_attach(device_t dev)
 {
-	int error;
 	struct xenpci_softc *scp = device_get_softc(dev);
-	struct xen_add_to_physmap xatp;
-	vm_offset_t shared_va;
 	devclass_t dc;
+	int error;
 
 	/*
 	 * Find and record nexus0.  Since we are not really on the
@@ -365,33 +258,15 @@ xenpci_attach(device_t dev)
 		goto errexit;
 	}
 
-	error = xenpci_init_hypercall_stubs(dev, scp);
-	if (error) {
-		device_printf(dev, "xenpci_init_hypercall_stubs failed(%d).\n",
-		    error);
-		goto errexit;
-	}
-
-	setup_xen_features();
-
-	xenpci_alloc_space_int(scp, PAGE_SIZE, &shared_info_pa); 
-
-	xatp.domid = DOMID_SELF;
-	xatp.idx = 0;
-	xatp.space = XENMAPSPACE_shared_info;
-	xatp.gpfn = shared_info_pa >> PAGE_SHIFT;
-	if (HYPERVISOR_memory_op(XENMEM_add_to_physmap, &xatp))
-		panic("HYPERVISOR_memory_op failed");
-
-	shared_va = kva_alloc(PAGE_SIZE);
-	pmap_kenter(shared_va, shared_info_pa);
-	HYPERVISOR_shared_info = (void *) shared_va;
-
 	/*
 	 * Hook the irq up to evtchn
 	 */
-	xenpci_irq_init(dev, scp);
-	xenpci_set_callback(dev);
+	error = xenpci_irq_init(dev, scp);
+	if (error) {
+		device_printf(dev, "xenpci_irq_init failed(%d).\n",
+			error);
+		goto errexit;
+	}
 
 	return (bus_generic_attach(dev));
 
@@ -431,13 +306,42 @@ xenpci_detach(device_t dev)
 	return (xenpci_deallocate_resources(dev));
 }
 
+static int
+xenpci_suspend(device_t dev)
+{
+	struct xenpci_softc *scp = device_get_softc(dev);
+	device_t parent = device_get_parent(dev);
+
+	if (scp->intr_cookie != NULL) {
+		if (BUS_TEARDOWN_INTR(parent, dev, scp->res_irq,
+		    scp->intr_cookie) != 0)
+			printf("intr teardown failed.. continuing\n");
+		scp->intr_cookie = NULL;
+	}
+
+	return (bus_generic_suspend(dev));
+}
+
+static int
+xenpci_resume(device_t dev)
+{
+	struct xenpci_softc *scp = device_get_softc(dev);
+	device_t parent = device_get_parent(dev);
+
+	BUS_SETUP_INTR(parent, dev, scp->res_irq,
+	    INTR_MPSAFE|INTR_TYPE_MISC, xenpci_intr_filter, NULL,
+	    /*trap_frame*/NULL, &scp->intr_cookie);
+	xen_hvm_set_callback(dev);
+	return (bus_generic_resume(dev));
+}
+
 static device_method_t xenpci_methods[] = {
 	/* Device interface */
 	DEVMETHOD(device_probe,		xenpci_probe),
 	DEVMETHOD(device_attach,	xenpci_attach),
 	DEVMETHOD(device_detach,	xenpci_detach),
-	DEVMETHOD(device_suspend,	bus_generic_suspend),
-	DEVMETHOD(device_resume,	bus_generic_resume),
+	DEVMETHOD(device_suspend,	xenpci_suspend),
+	DEVMETHOD(device_resume,	xenpci_resume),
 
 	/* Bus interface */
 	DEVMETHOD(bus_add_child,	bus_generic_add_child),