299746 |
14-May-2016 |
jhb |
Add an EARLY_AP_STARTUP option to start APs earlier during boot.
Currently, Application Processors (non-boot CPUs) are started by MD code at SI_SUB_CPU, but they are kept waiting in a "pen" until SI_SUB_SMP at which point they are released to run kernel threads. SI_SUB_SMP is one of the last SYSINIT levels, so APs don't enter the scheduler and start running threads until fairly late in the boot.
This change moves SI_SUB_SMP up to just before software interrupt threads are created allowing the APs to start executing kernel threads much sooner (before any devices are probed). This allows several initialization routines that need to perform initialization on all CPUs to now perform that initialization in one step rather than having to defer the AP initialization to a second SYSINIT run at SI_SUB_SMP. It also permits all CPUs to be available for handling interrupts before any devices are probed.
This last feature fixes a problem on with interrupt vector exhaustion. Specifically, in the old model all device interrupts were routed onto the boot CPU during boot. Later after the APs were released at SI_SUB_SMP, interrupts were redistributed across all CPUs.
However, several drivers for multiqueue hardware allocate N interrupts per CPU in the system. In a system with many CPUs, just a few drivers doing this could exhaust the available pool of interrupt vectors on the boot CPU as each driver was allocating N * mp_ncpu vectors on the boot CPU. Now, drivers will allocate interrupts on their desired CPUs during boot meaning that only N interrupts are allocated from the boot CPU instead of N * mp_ncpu.
Some other bits of code can also be simplified as smp_started is now true much earlier and will now always be true for these bits of code. This removes the need to treat the single-CPU boot environment as a special case.
As a transition aid, the new behavior is available under a new kernel option (EARLY_AP_STARTUP). This will allow the option to be turned off if need be during initial testing. I plan to enable this on x86 by default in a followup commit in the next few days and to have all platforms moved over before 11.0. Once the transition is complete, the option will be removed along with the !EARLY_AP_STARTUP code.
These changes have only been tested on x86. Other platform maintainers are encouraged to port their architectures over as well. The main things to check for are any uses of smp_started in MD code that can be simplified and SI_SUB_SMP SYSINITs in MD code that can be removed in the EARLY_AP_STARTUP case (e.g. the interrupt shuffling).
PR: kern/199321 Reviewed by: markj, gnn, kib Sponsored by: Netflix
|
289686 |
21-Oct-2015 |
royger |
xen: Code cleanup and small bug fixes
xen/hypervisor.h: - Remove unused helpers: MULTI_update_va_mapping, is_initial_xendomain, is_running_on_xen - Remove unused define CONFIG_X86_PAE - Remove unused variable xen_start_info: note that it's used inpcifront which is not built at all - Remove forward declaration of HYPERVISOR_crash
xen/xen-os.h: - Remove unused define CONFIG_X86_PAE - Drop unused helpers: test_and_clear_bit, clear_bit, force_evtchn_callback - Implement a generic version (based on ofed/include/linux/bitops.h) of set_bit and test_bit and prefix them by xen_ to avoid any use by other code than Xen. Note that It would be worth to investigate a generic implementation in FreeBSD. - Replace barrier() by __compiler_membar() - Replace cpu_relax() by cpu_spinwait(): it's exactly the same as rep;nop = pause
xen/xen_intr.h: - Move the prototype of xen_intr_handle_upcall in it: Use by all the platform
x86/xen/xen_intr.c: - Use BITSET* for the enabledbits: Avoid to use custom helpers - test_bit/set_bit has been renamed to xen_test_bit/xen_set_bit - Don't export the variable xen_intr_pcpu
dev/xen/blkback/blkback.c: - Fix the string format when XBB_DEBUG is enabled: host_addr is typed uint64_t
dev/xen/balloon/balloon.c: - Remove set but not used variable - Use the correct type for frame_list: xen_pfn_t represents the frame number on any architecture
dev/xen/control/control.c: - Return BUS_PROBE_WILDCARD in xs_probe: Returning 0 in a probe callback means the driver can handle this device. If by any chance xenstore is the first driver, every new device with the driver is unset will use xenstore.
dev/xen/grant-table/grant_table.c: - Remove unused cmpxchg - Drop unused include opt_pmap.h: Doesn't exist on ARM64 and it doesn't contain anything required for the code on x86
dev/xen/netfront/netfront.c: - Use the correct type for rx_pfn_array: xen_pfn_t represents the frame number on any architecture
dev/xen/netback/netback.c: - Use the correct type for gmfn: xen_pfn_t represents the frame number on any architecture
dev/xen/xenstore/xenstore.c: - Return BUS_PROBE_WILDCARD in xctrl_probe: Returning 0 in a probe callback means the driver can handle this device. If by any chance xenstore is the first driver, every new device with the driver is unset will use xenstore.
Note that with the changes, x86/include/xen/xen-os.h doesn't contain anymore arch-specific code. Although, a new series will add some helpers that differ between x86 and ARM64, so I've kept the headers for now.
Submitted by: Julien Grall <julien.grall@citrix.com> Reviewed by: royger Differential Revision: https://reviews.freebsd.org/D3921 Sponsored by: Citrix Systems R&D
|
267534 |
16-Jun-2014 |
royger |
xen: unify gnttab initialization for PVHVM and PVH
Switch the initialization of gnttab to use an unused physical memory range for both PVHVM and PVH.
In the past PVHVM was using the xenpci BAR, but there's no reason to do that, and in fact FreeBSD was probably doing it because it was the way it was done in Windows, were drivers cannot probably request for unused physical memory ranges, but it was never enforced in the hypervisor.
Sponsored by: Citrix Systems R&D Approved by: gibbs
xen/gnttab.c: - Allocate contiguous physical memory for grant table frames for both PVHVM and PVH. - Since gnttab is not a device, use the xenpv device in order to request for this allocation.
dev/xen/xenpci/xenpcivar.h: dev/xen/xenpci/xenpci.c: - Remove the now unused xenpci_alloc_space and xenpci_alloc_space_int functions.
xen/gnttab.h: - Change the prototype of gnttab_init and gnttab_resume, that now takes a device_t parameter.
dev/xen/control/control.c: x86/xen/xenpv.c: - Changes to accomodate the new prototype of gnttab_init and gnttab_resume.
|
255726 |
20-Sep-2013 |
gibbs |
Add support for suspend/resume/migration operations when running as a Xen PVHVM guest.
Submitted by: Roger Pau Monné Sponsored by: Citrix Systems R&D Reviewed by: gibbs Approved by: re (blanket Xen) MFC after: 2 weeks
sys/amd64/amd64/mp_machdep.c: sys/i386/i386/mp_machdep.c: - Make sure that are no MMU related IPIs pending on migration. - Reset pending IPI_BITMAP on resume. - Init vcpu_info on resume.
sys/amd64/include/intr_machdep.h: sys/i386/include/intr_machdep.h: sys/x86/acpica/acpi_wakeup.c: sys/x86/x86/intr_machdep.c: sys/x86/isa/atpic.c: sys/x86/x86/io_apic.c: sys/x86/x86/local_apic.c: - Add a "suspend_cancelled" parameter to pic_resume(). For the Xen PIC, restoration of interrupt services differs between the aborted suspend and normal resume cases, so we must provide this information.
sys/dev/acpica/acpi_timer.c: sys/dev/xen/timer/timer.c: sys/timetc.h: - Don't swap out "suspend safe" timers across a suspend/resume cycle. This includes the Xen PV and ACPI timers.
sys/dev/xen/control/control.c: - Perform proper suspend/resume process for PVHVM: - Suspend all APs before going into suspension, this allows us to reset the vcpu_info on resume for each AP. - Reset shared info page and callback on resume.
sys/dev/xen/timer/timer.c: - Implement suspend/resume support for the PV timer. Since FreeBSD doesn't perform a per-cpu resume of the timer, we need to call smp_rendezvous in order to correctly resume the timer on each CPU.
sys/dev/xen/xenpci/xenpci.c: - Don't reset the PCI interrupt on each suspend/resume.
sys/kern/subr_smp.c: - When suspending a PVHVM domain make sure there are no MMU IPIs in-flight, or we will get a lockup on resume due to the fact that pending event channels are not carried over on migration. - Implement a generic version of restart_cpus that can be used by suspended and stopped cpus.
sys/x86/xen/hvm.c: - Implement resume support for the hypercall page and shared info. - Clear vcpu_info so it can be reset by APs when resuming from suspension.
sys/dev/xen/xenpci/xenpci.c: sys/x86/xen/hvm.c: sys/x86/xen/xen_intr.c: - Support UP kernel configurations.
sys/x86/xen/xen_intr.c: - Properly rebind per-cpus VIRQs and IPIs on resume.
|
255040 |
29-Aug-2013 |
gibbs |
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.
|
223758 |
04-Jul-2011 |
attilio |
With retirement of cpumask_t and usage of cpuset_t for representing a mask of CPUs, pc_other_cpus and pc_cpumask become highly inefficient.
Remove them and replace their usage with custom pc_cpuid magic (as, atm, pc_cpumask can be easilly represented by (1 << pc_cpuid) and pc_other_cpus by (all_cpus & ~(1 << pc_cpuid))).
This change is not targeted for MFC because of struct pcpu members removal and dependency by cpumask_t retirement.
MD review by: marcel, marius, alc Tested by: pluknet MD testing by: marcel, marius, gonzo, andreast
|
222813 |
07-Jun-2011 |
attilio |
etire the cpumask_t type and replace it with cpuset_t usage.
This is intended to fix the bug where cpu mask objects are capped to 32. MAXCPU, then, can now arbitrarely bumped to whatever value. Anyway, as long as several structures in the kernel are statically allocated and sized as MAXCPU, it is suggested to keep it as low as possible for the time being.
Technical notes on this commit itself: - More functions to handle with cpuset_t objects are introduced. The most notable are cpusetobj_ffs() (which calculates a ffs(3) for a cpuset_t object), cpusetobj_strprint() (which prepares a string representing a cpuset_t object) and cpusetobj_strscan() (which creates a valid cpuset_t starting from a string representation). - pc_cpumask and pc_other_cpus are target to be removed soon. With the moving from cpumask_t to cpuset_t they are now inefficient and not really useful. Anyway, for the time being, please note that access to pcpu datas is protected by sched_pin() in order to avoid migrating the CPU while reading more than one (possible) word - Please note that size of cpuset_t objects may differ between kernel and userland. While this is not directly related to the patch itself, it is good to understand that concept and possibly use the patch as a reference on how to deal with cpuset_t objects in userland, when accessing kernland members. - KTR_CPUMASK is changed and now is represented through a string, to be set as the example reported in NOTES.
Please additively note that no MAXCPU is bumped in this patch, but private testing has been done until to MAXCPU=128 on a real 8x8x2(htt) machine (amd64).
Please note that the FreeBSD version is not yet bumped because of the upcoming pcpu changes. However, note that this patch is not targeted for MFC.
People to thank for the time spent on this patch: - sbruno, pluknet and Nicholas Esborn (nick AT desert DOT net) tested several revision of the patches and really helped in improving stability of this work. - marius fixed several bugs in the sparc64 implementation and reviewed patches related to ktr. - jeff and jhb discussed the basic approach followed. - kib and marcel made targeted review on some specific part of the patch. - marius, art, nwhitehorn and andreast reviewed MD specific part of the patch. - marius, andreast, gonzo, nwhitehorn and jceel tested MD specific implementations of the patch. - Other people have made contributions on other patches that have been already committed and have been listed separately.
Companies that should be mentioned for having participated at several degrees: - Yahoo! for having offered the machines used for testing on big count of CPUs. - The FreeBSD Foundation for having sponsored my devsummit attendance, which has been instrumental. - Sandvine for having offered offices and infrastructure during development.
(I really hope I didn't forget anyone, if it happened I apologize in advance).
|
214077 |
19-Oct-2010 |
gibbs |
Improve the Xen para-virtualized device infrastructure of FreeBSD:
o Add support for backend devices (e.g. blkback) o Implement extensions to the Xen para-virtualized block API to allow for larger and more outstanding I/Os. o Import a completely rewritten block back driver with support for fronting I/O to both raw devices and files. o General cleanup and documentation of the XenBus and XenStore support code. o Robustness and performance updates for the block front driver. o Fixes to the netfront driver.
Sponsored by: Spectra Logic Corporation
sys/xen/xenbus/init.txt: Deleted: This file explains the Linux method for XenBus device enumeration and thus does not apply to FreeBSD's NewBus approach.
sys/xen/xenbus/xenbus_probe_backend.c: Deleted: Linux version of backend XenBus service routines. It was never ported to FreeBSD. See xenbusb.c, xenbusb_if.m, xenbusb_front.c xenbusb_back.c for details of FreeBSD's XenBus support.
sys/xen/xenbus/xenbusvar.h: sys/xen/xenbus/xenbus_xs.c: sys/xen/xenbus/xenbus_comms.c: sys/xen/xenbus/xenbus_comms.h: sys/xen/xenstore/xenstorevar.h: sys/xen/xenstore/xenstore.c: Split XenStore into its own tree. XenBus is a software layer built on top of XenStore. The old arrangement and the naming of some structures and functions blurred these lines making it difficult to discern what services are provided by which layer and at what times these services are available (e.g. during system startup and shutdown).
sys/xen/xenbus/xenbus_client.c: sys/xen/xenbus/xenbus.c: sys/xen/xenbus/xenbus_probe.c: sys/xen/xenbus/xenbusb.c: sys/xen/xenbus/xenbusb.h: Split up XenBus code into methods available for use by client drivers (xenbus.c) and code used by the XenBus "bus code" to enumerate, attach, detach, and service bus drivers.
sys/xen/reboot.c: sys/dev/xen/control/control.c: Add a XenBus front driver for handling shutdown, reboot, suspend, and resume events published in the XenStore. Move all PV suspend/reboot support from reboot.c into this driver.
sys/xen/blkif.h: New file from Xen vendor with macros and structures used by a block back driver to service requests from a VM running a different ABI (e.g. amd64 back with i386 front).
sys/conf/files: Adjust kernel build spec for new XenBus/XenStore layout and added Xen functionality.
sys/dev/xen/balloon/balloon.c: sys/dev/xen/netfront/netfront.c: sys/dev/xen/blkfront/blkfront.c: sys/xen/xenbus/... sys/xen/xenstore/... o Rename XenStore APIs and structures from xenbus_* to xs_*. o Adjust to use of M_XENBUS and M_XENSTORE malloc types for allocation of objects returned by these APIs. o Adjust for changes in the bus interface for Xen drivers.
sys/xen/xenbus/... sys/xen/xenstore/... Add Doxygen comments for these interfaces and the code that implements them.
sys/dev/xen/blkback/blkback.c: o Rewrite the Block Back driver to attach properly via newbus, operate correctly in both PV and HVM mode regardless of domain (e.g. can be in a DOM other than 0), and to deal with the latest metadata available in XenStore for block devices.
o Allow users to specify a file as a backend to blkback, in addition to character devices. Use the namei lookup of the backend path to automatically configure, based on file type, the appropriate backend method.
The current implementation is limited to a single outstanding I/O at a time to file backed storage.
sys/dev/xen/blkback/blkback.c: sys/xen/interface/io/blkif.h: sys/xen/blkif.h: sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: Extend the Xen blkif API: Negotiable request size and number of requests.
This change extends the information recorded in the XenStore allowing block front/back devices to negotiate for optimal I/O parameters. This has been achieved without sacrificing backward compatibility with drivers that are unaware of these protocol enhancements. The extensions center around the connection protocol which now includes these additions:
o The back-end device publishes its maximum supported values for, request I/O size, the number of page segments that can be associated with a request, the maximum number of requests that can be concurrently active, and the maximum number of pages that can be in the shared request ring. These values are published before the back-end enters the XenbusStateInitWait state.
o The front-end waits for the back-end to enter either the InitWait or Initialize state. At this point, the front end limits it's own capabilities to the lesser of the values it finds published by the backend, it's own maximums, or, should any back-end data be missing in the store, the values supported by the original protocol. It then initializes it's internal data structures including allocation of the shared ring, publishes its maximum capabilities to the XenStore and transitions to the Initialized state.
o The back-end waits for the front-end to enter the Initalized state. At this point, the back end limits it's own capabilities to the lesser of the values it finds published by the frontend, it's own maximums, or, should any front-end data be missing in the store, the values supported by the original protocol. It then initializes it's internal data structures, attaches to the shared ring and transitions to the Connected state.
o The front-end waits for the back-end to enter the Connnected state, transitions itself to the connected state, and can commence I/O.
Although an updated front-end driver must be aware of the back-end's InitWait state, the back-end has been coded such that it can tolerate a front-end that skips this step and transitions directly to the Initialized state without waiting for the back-end.
sys/xen/interface/io/blkif.h: o Increase BLKIF_MAX_SEGMENTS_PER_REQUEST to 255. This is the maximum number possible without changing the blkif request header structure (nr_segs is a uint8_t).
o Add two new constants: BLKIF_MAX_SEGMENTS_PER_HEADER_BLOCK, and BLKIF_MAX_SEGMENTS_PER_SEGMENT_BLOCK. These respectively indicate the number of segments that can fit in the first ring-buffer entry of a request, and for each subsequent (sg element only) ring-buffer entry associated with the "header" ring-buffer entry of the request.
o Add the blkif_request_segment_t typedef for segment elements.
o Add the BLKRING_GET_SG_REQUEST() macro which wraps the RING_GET_REQUEST() macro and returns a properly cast pointer to an array of blkif_request_segment_ts.
o Add the BLKIF_SEGS_TO_BLOCKS() macro which calculates the number of ring entries that will be consumed by a blkif request with the given number of segments.
sys/xen/blkif.h: o Update for changes in interface/io/blkif.h macros.
o Update the BLKIF_MAX_RING_REQUESTS() macro to take the ring size as an argument to allow this calculation on multi-page rings.
o Add a companion macro to BLKIF_MAX_RING_REQUESTS(), BLKIF_RING_PAGES(). This macro determines the number of ring pages required in order to support a ring with the supplied number of request blocks.
sys/dev/xen/blkback/blkback.c: sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: o Negotiate with the other-end with the following limits: Reqeust Size: MAXPHYS Max Segments: (MAXPHYS/PAGE_SIZE) + 1 Max Requests: 256 Max Ring Pages: Sufficient to support Max Requests with Max Segments.
o Dynamically allocate request pools and segemnts-per-request.
o Update ring allocation/attachment code to support a multi-page shared ring.
o Update routines that access the shared ring to handle multi-block requests.
sys/dev/xen/blkfront/blkfront.c: o Track blkfront allocations in a blkfront driver specific malloc pool.
o Strip out XenStore transaction retry logic in the connection code. Transactions only need to be used when the update to multiple XenStore nodes must be atomic. That is not the case here.
o Fully disable blkif_resume() until it can be fixed properly (it didn't work before this change).
o Destroy bus-dma objects during device instance tear-down.
o Properly handle backend devices with powef-of-2 sector sizes larger than 512b.
sys/dev/xen/blkback/blkback.c: Advertise support for and implement the BLKIF_OP_WRITE_BARRIER and BLKIF_OP_FLUSH_DISKCACHE blkif opcodes using BIO_FLUSH and the BIO_ORDERED attribute of bios.
sys/dev/xen/blkfront/blkfront.c: sys/dev/xen/blkfront/block.h: Fix various bugs in blkfront.
o gnttab_alloc_grant_references() returns 0 for success and non-zero for failure. The check for < 0 is a leftover Linuxism.
o When we negotiate with blkback and have to reduce some of our capabilities, print out the original and reduced capability before changing the local capability. So the user now gets the correct information.
o Fix blkif_restart_queue_callback() formatting. Make sure we hold the mutex in that function before calling xb_startio().
o Fix a couple of KASSERT()s.
o Fix a check in the xb_remove_* macro to be a little more specific.
sys/xen/gnttab.h: sys/xen/gnttab.c: Define GNTTAB_LIST_END publicly as GRANT_REF_INVALID.
sys/dev/xen/netfront/netfront.c: Use GRANT_REF_INVALID instead of driver private definitions of the same constant.
sys/xen/gnttab.h: sys/xen/gnttab.c: Add the gnttab_end_foreign_access_references() API.
This API allows a client to batch the release of an array of grant references, instead of coding a private for loop. The implementation takes advantage of this batching to reduce lock overhead to one acquisition and release per-batch instead of per-freed grant reference.
While here, reduce the duration the gnttab_list_lock is held during gnttab_free_grant_references() operations. The search to find the tail of the incoming free list does not rely on global state and so can be performed without holding the lock.
sys/dev/xen/xenpci/evtchn.c: sys/dev/xen/evtchn/evtchn.c: sys/xen/xen_intr.h: o Implement the bind_interdomain_evtchn_to_irqhandler API for HVM mode. This allows an HVM domain to serve back end devices to other domains. This API is already implemented for PV mode.
o Synchronize the API between HVM and PV.
sys/dev/xen/xenpci/xenpci.c: o Scan the full region of CPUID space in which the Xen VMM interface may be implemented. On systems using SuSE as a Dom0 where the Viridian API is also exported, the VMM interface is above the region we used to search.
o Pass through bus_alloc_resource() calls so that XenBus drivers attaching on an HVM system can allocate unused physical address space from the nexus. The block back driver makes use of this facility.
sys/i386/xen/xen_machdep.c: Use the correct type for accessing the statically mapped xenstore metadata.
sys/xen/interface/hvm/params.h: sys/xen/xenstore/xenstore.c: Move hvm_get_parameter() to the correct global header file instead of as a private method to the XenStore.
sys/xen/interface/io/protocols.h: Sync with vendor.
sys/xeninterface/io/ring.h: Add macro for calculating the number of ring pages needed for an N deep ring.
To avoid duplication within the macros, create and use the new __RING_HEADER_SIZE() macro. This macro calculates the size of the ring book keeping struct (producer/consumer indexes, etc.) that resides at the head of the ring.
Add the __RING_PAGES() macro which calculates the number of shared ring pages required to support a ring with the given number of requests.
These APIs are used to support the multi-page ring version of the Xen block API.
sys/xeninterface/io/xenbus.h: Add Comments.
sys/xen/xenbus/... o Refactor the FreeBSD XenBus support code to allow for both front and backend device attachments.
o Make use of new config_intr_hook capabilities to allow front and back devices to be probed/attached in parallel.
o Fix bugs in probe/attach state machine that could cause the system to hang when confronted with a failure either in the local domain or in a remote domain to which one of our driver instances is attaching.
o Publish all required state to the XenStore on device detach and failure. The majority of the missing functionality was for serving as a back end since the typical "hot-plug" scripts in Dom0 don't handle the case of cleaning up for a "service domain" that is not itself.
o Add dynamic sysctl nodes exposing the generic ivars of XenBus devices.
o Add doxygen style comments to the majority of the code.
o Cleanup types, formatting, etc.
sys/xen/xenbus/xenbusb.c: Common code used by both front and back XenBus busses.
sys/xen/xenbus/xenbusb_if.m: Method definitions for a XenBus bus.
sys/xen/xenbus/xenbusb_front.c: sys/xen/xenbus/xenbusb_back.c: XenBus bus specialization for front and back devices.
MFC after: 1 month
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