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* xen: implement Xen-specific spinlocksJeremy Fitzhardinge2008-07-161-0/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The standard ticket spinlocks are very expensive in a virtual environment, because their performance depends on Xen's scheduler giving vcpus time in the order that they're supposed to take the spinlock. This implements a Xen-specific spinlock, which should be much more efficient. The fast-path is essentially the old Linux-x86 locks, using a single lock byte. The locker decrements the byte; if the result is 0, then they have the lock. If the lock is negative, then locker must spin until the lock is positive again. When there's contention, the locker spin for 2^16[*] iterations waiting to get the lock. If it fails to get the lock in that time, it adds itself to the contention count in the lock and blocks on a per-cpu event channel. When unlocking the spinlock, the locker looks to see if there's anyone blocked waiting for the lock by checking for a non-zero waiter count. If there's a waiter, it traverses the per-cpu "lock_spinners" variable, which contains which lock each CPU is waiting on. It picks one CPU waiting on the lock and sends it an event to wake it up. This allows efficient fast-path spinlock operation, while allowing spinning vcpus to give up their processor time while waiting for a contended lock. [*] 2^16 iterations is threshold at which 98% locks have been taken according to Thomas Friebel's Xen Summit talk "Preventing Guests from Spinning Around". Therefore, we'd expect the lock and unlock slow paths will only be entered 2% of the time. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <clameter@linux-foundation.org> Cc: Petr Tesarik <ptesarik@suse.cz> Cc: Virtualization <virtualization@lists.linux-foundation.org> Cc: Xen devel <xen-devel@lists.xensource.com> Cc: Thomas Friebel <thomas.friebel@amd.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* xen64: fix !HVC_XEN build dependencyIngo Molnar2008-07-161-3/+4
| | | | | | | | | | | | | fix: arch/x86/xen/built-in.o: In function `set_page_prot': enlighten.c:(.text+0x111d): undefined reference to `xen_raw_printk' arch/x86/xen/built-in.o: In function `xen_start_kernel': : undefined reference to `xen_raw_console_write' arch/x86/xen/built-in.o: In function `xen_start_kernel': : undefined reference to `xen_raw_console_write' Signed-off-by: Ingo Molnar <mingo@elte.hu>
* xen64: define asm/xen/interface for 64-bitJeremy Fitzhardinge2008-07-161-3/+3
| | | | | | | | | | Copy 64-bit definitions of various interface structures into place. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* xen: add xen_arch_resume()/xen_timer_resume hook for ia64 supportIsaku Yamahata2008-07-161-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | add xen_timer_resume() hook. Timer resume should be done after event channel is resumed. add xen_arch_resume() hook when ipi becomes usable after resume. After resume, some cpu specific resource must be reinitialized on ia64 that can't be set by another cpu. However available hooks is run once on only one cpu so that ipi has to be used. During stop_machine_run() ipi can't be used because interrupt is masked. So add another hook after stop_machine_run(). Another approach might be use resume hook which is run by device_resume(). However device_resume() may be executed on suspend error recovery path. So it is necessary to determine whether it is executed on real resume path or error recovery path. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Cc: Stephen Tweedie <sct@redhat.com> Cc: Eduardo Habkost <ehabkost@redhat.com> Cc: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* xen: implement ptep_modify_prot_start/commitJeremy Fitzhardinge2008-06-252-2/+10
| | | | | | | | | | | | | | | | | | | | | | | | Xen has a pte update function which will update a pte while preserving its accessed and dirty bits. This means that ptep_modify_prot_start() can be implemented as a simple read of the pte value. The hardware may update the pte in the meantime, but ptep_modify_prot_commit() updates it while preserving any changes that may have happened in the meantime. The updates in ptep_modify_prot_commit() are batched if we're currently in lazy mmu mode. The mmu_update hypercall can take a batch of updates to perform, but this code doesn't make particular use of that feature, in favour of using generic multicall batching to get them all into the hypervisor. The net effect of this is that each mprotect pte update turns from two expensive trap-and-emulate faults into they hypervisor into a single hypercall whose cost is amortized in a batched multicall. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* Merge commit 'v2.6.26-rc8' into x86/xenIngo Molnar2008-06-251-4/+3
|\ | | | | | | | | | | | | | | | | Conflicts: arch/x86/xen/enlighten.c arch/x86/xen/mmu.c Signed-off-by: Ingo Molnar <mingo@elte.hu>
| * x86: Make xen use the paravirt clocksource structs and functionsGerd Hoffmann2008-06-241-4/+3
| | | | | | | | | | | | | | | | | | This patch updates the xen guest to use the pvclock structs and helper functions. Signed-off-by: Gerd Hoffmann <kraxel@redhat.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Avi Kivity <avi@qumranet.com>
* | xen: add new Xen elfnote types and use them appropriatelyJeremy Fitzhardinge2008-06-021-0/+20
| | | | | | | | | | | | | | | | Define recently added XEN_ELFNOTEs, and use them appropriately. Most significantly, this enables domain checkpointing (xm save -c). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | xen: fix "xen: implement save/restore"Ingo Molnar2008-05-291-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | -tip testing found the following build breakage: drivers/built-in.o: In function `xen_suspend': manage.c:(.text+0x4390f): undefined reference to `xen_console_resume' with this config: http://redhat.com/~mingo/misc/config-Thu_May_29_09_23_16_CEST_2008.bad i have bisected it down to: | commit 0e91398f2a5d4eb6b07df8115917d0d1cf3e9b58 | Author: Jeremy Fitzhardinge <jeremy@goop.org> | Date: Mon May 26 23:31:27 2008 +0100 | | xen: implement save/restore the problem is that drivers/xen/manage.c is built unconditionally if CONFIG_XEN is enabled and makes use of xen_suspend(), but drivers/char/hvc_xen.c, where the xen_suspend() method is implemented, is only build if CONFIG_HVC_XEN=y as well. i have solved this by providing a NOP implementation for xen_suspend() in the !CONFIG_HVC_XEN case. Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | xen: maintain clock offset over save/restoreJeremy Fitzhardinge2008-05-271-3/+0
| | | | | | | | | | | | | | | | | | | | Hook into the device model to make sure that timekeeping's resume handler is called. This deals with our clocksource's non-monotonicity over the save/restore. Explicitly call clock_has_changed() to make sure that all the timers get retriggered properly. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen: implement save/restoreJeremy Fitzhardinge2008-05-273-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements Xen save/restore and migration. Saving is triggered via xenbus, which is polled in drivers/xen/manage.c. When a suspend request comes in, the kernel prepares itself for saving by: 1 - Freeze all processes. This is primarily to prevent any partially-completed pagetable updates from confusing the suspend process. If CONFIG_PREEMPT isn't defined, then this isn't necessary. 2 - Suspend xenbus and other devices 3 - Stop_machine, to make sure all the other vcpus are quiescent. The Xen tools require the domain to run its save off vcpu0. 4 - Within the stop_machine state, it pins any unpinned pgds (under construction or destruction), performs canonicalizes various other pieces of state (mostly converting mfns to pfns), and finally 5 - Suspend the domain Restore reverses the steps used to save the domain, ending when all the frozen processes are thawed. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen-console: add save/restoreJeremy Fitzhardinge2008-05-271-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add code to: 1. Deal with the console page being canonicalized. During save, the console's mfn in the start_info structure is canonicalized to a pfn. In order to deal with that, we always use a copy of the pfn and indirect off that all the time. However, we fall back to using the mfn if the pfn hasn't been initialized yet. 2. Restore the console event channel, and rebind it to the existing irq. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen: add rebind_evtchn_irqJeremy Fitzhardinge2008-05-271-0/+1
| | | | | | | | | | | | | | | | | | | | Add rebind_evtchn_irq(), which will rebind an device driver's existing irq to a new event channel on restore. Since the new event channel will be masked and bound to vcpu0, we update the state accordingly and unmask the irq once everything is set up. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen: add missing definitions in include/xen/interface/memory.h which ↵Isaku Yamahata2008-05-271-4/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | ia64/xen needs Add xen handles realted definitions for xen memory which ia64/xen needs. Pointer argumsnts for ia64/xen hypercall are passed in pseudo physical address (guest physical address) so that it is required to convert guest kernel virtual address into pseudo physical address. The xen guest handle represents such arguments. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen pvfb: Dynamic mode support (screen resizing)Markus Armbruster2008-05-271-5/+24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The pvfb backend indicates dynamic mode support by creating node feature_resize with a non-zero value in its xenstore directory. xen-fbfront sends a resize notification event on mode change. Fully backwards compatible both ways. Framebuffer size and initial resolution can be controlled through kernel parameter xen_fbfront.video. The backend enforces a separate size limit, which it advertises in node videoram in its xenstore directory. xen-kbdfront gets the maximum screen resolution from nodes width and height in the backend's xenstore directory instead of hardcoding it. Additional goodie: support for larger framebuffers (512M on a 64-bit system with 4K pages). Changing the number of bits per pixels dynamically is not supported, yet. Ported from http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/92f7b3144f41 http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/bfc040135633 Signed-off-by: Pat Campbell <plc@novell.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen pvfb: Pointer z-axis (mouse wheel) supportMarkus Armbruster2008-05-271-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add z-axis motion to pointer events. Backward compatible, because there's space for the z-axis in union xenkbd_in_event, and old backends zero it. Derived from http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/57dfe0098000 http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/1edfea26a2a9 http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/c3ff0b26f664 Signed-off-by: Pat Campbell <plc@novell.com> Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* | xen: add raw console write functions for debugJeremy Fitzhardinge2008-05-271-0/+3
|/ | | | | | | | | Add a couple of functions which can write directly to the Xen console for debugging. This output ends up on the host's dom0 console (assuming it allows the domain to write there). Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: add balloon driverJeremy Fitzhardinge2008-04-242-8/+65
| | | | | | | | | | | | | | The balloon driver allows memory to be dynamically added or removed from the domain, in order to allow host memory to be balanced between multiple domains. This patch introduces the Xen balloon driver, though it currently only allows a domain to be shrunk from its initial size (and re-grown back to that size). A later patch will add the ability to grow a domain beyond its initial size. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen pvfb: Para-virtual framebuffer, keyboard and pointer driverMarkus Armbruster2008-04-242-0/+238
| | | | | | | | | | | | | | | | | | This is a pair of Xen para-virtual frontend device drivers: drivers/video/xen-fbfront.c provides a framebuffer, and drivers/input/xen-kbdfront provides keyboard and mouse. The backends run in dom0 user space. The two drivers are not in two separate patches, because the intermediate step (one driver, not the other) is somewhat problematic: the backend in dom0 needs both drivers, and will refuse to complete device initialization unless they're both present. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen blkfront: Delay wait for block devices until after the disk is addedChristian Limpach2008-04-241-0/+1
| | | | | | | | | | | | | | | | | | | | | When the xen block frontend driver is built as a module the module load is only synchronous up to the point where the frontend and the backend become connected rather than when the disk is added. This means that there can be a race on boot between loading the module and loading the dm-* modules and doing the scan for LVM physical volumes (all in the initrd). In the failure case the disk is not present until after the scan for physical volumes is complete. Taken from: http://xenbits.xensource.com/linux-2.6.18-xen.hg?rev/11483a00c017 Signed-off-by: Christian Limpach <Christian.Limpach@xensource.com> Signed-off-by: Mark McLoughlin <markmc@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: Make xen-blkfront write its protocol ABI to xenstoreMarkus Armbruster2008-04-241-0/+21
| | | | | | | | | | | | | | | | | | Frontends are expected to write their protocol ABI to xenstore. Since the protocol ABI defaults to the backend's native ABI, things work fine without that as long as the frontend's native ABI is identical to the backend's native ABI. This is not the case for xen-blkfront running 32-on-64, because its ABI differs between 32 and 64 bit, and thus needs this fix. Based on http://xenbits.xensource.com/xen-unstable.hg?rev/c545932a18f3 and http://xenbits.xensource.com/xen-unstable.hg?rev/ffe52263b430 by Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Jeremy Fitzhardinge <Jeremy.Fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: import arch generic part of xencommIsaku Yamahata2008-04-242-0/+118
| | | | | | | | | | | | | On xen/ia64 and xen/powerpc hypercall arguments are passed by pseudo physical address (guest physical address) so that it's necessary to convert from virtual address into pseudo physical address. The frame work is called xencomm. Import arch generic part of xencomm. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: make grant table arch portableIsaku Yamahata2008-04-241-0/+6
| | | | | | | | | | | | | split out x86 specific part from grant-table.c and allow ia64/xen specific initialization. ia64/xen grant table is based on pseudo physical address (guest physical address) unlike x86/xen. On ia64 init_mm doesn't map identity straight mapped area. ia64/xen specific grant table initialization is necessary. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: replace callers of alloc_vm_area()/free_vm_area() with xen_ prefixed oneIsaku Yamahata2008-04-241-0/+1
| | | | | | | | | | | | | | | | | | | | | | | Don't use alloc_vm_area()/free_vm_area() directly, instead define xen_alloc_vm_area()/xen_free_vm_area() and use them. alloc_vm_area()/free_vm_area() are used to allocate/free area which are for grant table mapping. Xen/x86 grant table is based on virtual address so that alloc_vm_area()/free_vm_area() are suitable. On the other hand Xen/ia64 (and Xen/powerpc) grant table is based on pseudo physical address (guest physical address) so that allocation should be done differently. The original version of xenified Linux/IA64 have its own allocate_vm_area()/free_vm_area() definitions which don't allocate vm area contradictory to those names. Now vanilla Linux already has its definitions so that it's impossible to have IA64 definitions of allocate_vm_area()/free_vm_area(). Instead introduce xen_allocate_vm_area()/xen_free_vm_area() and use them. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: make include/xen/page.h portable moving those definitions under asm dirIsaku Yamahata2008-04-241-168/+1
| | | | | | | | | | | The definitions in include/asm/xen/page.h are arch specific. ia64/xen wants to define its own version. So move them to arch specific directory and keep include/xen/page.h in order not to break compilation. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: add resend_irq_on_evtchn() definition into events.cIsaku Yamahata2008-04-241-0/+1
| | | | | | | | | | | Define resend_irq_on_evtchn() which ia64/xen uses. Although it isn't used by current x86/xen code, it's arch generic so that put it into common code. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* Xen: make events.c portable for ia64/xen supportIsaku Yamahata2008-04-241-7/+1
| | | | | | | | | | | | | | Remove x86 dependency in drivers/xen/events.c for ia64/xen support introducing include/asm/xen/events.h. Introduce xen_irqs_disabled() to hide regs->flags Introduce xen_do_IRQ() to hide regs->orig_ax. make enum ipi_vector definition arch specific. ia64/xen needs four vectors. Add one rmb() because on ia64 xchg() isn't barrier. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: move events.c to drivers/xen for IA64/Xen supportIsaku Yamahata2008-04-241-0/+8
| | | | | | | | | | | | move arch/x86/xen/events.c undedr drivers/xen to share codes with x86 and ia64. And minor adjustment to compile. ia64/xen also uses events.c Signed-off-by: Yaozu (Eddie) Dong <eddie.dong@intel.com> Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: add missing definitions in include/xen/interface/vcpu.h which ia64/xen ↵Isaku Yamahata2008-04-241-0/+5
| | | | | | | | | | | | | | | needs Add xen handles realted definitions for xen vcpu which ia64/xen needs. Pointer argumsnts for ia64/xen hypercall are passed in pseudo physical address (guest physical address) so that it is required to convert guest kernel virtual address into pseudo physical address. The xen guest handle represents such arguments. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: add missing definitions for xen grant table which ia64/xen needsIsaku Yamahata2008-04-241-3/+8
| | | | | | | | | | | | | | | | Add xen handles realted definitions for grant table which ia64/xen needs. Pointer argumsnts for ia64/xen hypercall are passed in pseudo physical address (guest physical address) so that it is required to convert guest kernel virtual address into pseudo physical address right before issuing hypercall. The xen guest handle represents such arguments. Define necessary handles and helper functions. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: definitions which ia64/xen needsIsaku Yamahata2008-04-241-1/+11
| | | | | | | | | | | | Add xen VIRQ numbers defined for arch specific use. ia64/xen domU uses VIRQ_ARCH_0 for virtual itc timer. Although all those constants aren't used yet by ia64 at this moment, add all arch specific VIRQ numbers. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: definisions which ia64 needsIsaku Yamahata2008-04-241-0/+10
| | | | | | | | | | | | Add xen hypercall numbers defined for arch specific use. ia64/xen domU uses __HYPERVISOR_arch_1 to manipulate paravirtualized IOSAPIC. Although all those constants aren't used yet by IA64 at this moment, add all arch specific hypercall numbers. Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: add support for callbackops hypercallJeremy Fitzhardinge2008-04-241-0/+102
| | | | | | | Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: unify pte operations on machine framesJeremy Fitzhardinge2008-04-241-15/+15
| | | | | | | | Xen's pte operations on mfns can be unified like the kernel's pfn operations. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: use phys_addr_t when referring to physical addressesJeremy Fitzhardinge2008-04-241-14/+2
| | | | | | Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* x86: page.h: make pte_t a union to always includeJeremy Fitzhardinge2008-01-301-3/+3
| | | | | | | | | | | | Make sure pte_t, whatever its definition, has a pte element with type pteval_t. This allows common code to access it without needing to be specifically parameterised on what pagetable mode we're compiling for. For 32-bit, this means that pte_t becomes a union with "pte" and "{ pte_low, pte_high }" (PAE) or just "pte_low" (non-PAE). Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
* xen: fix incorrect vcpu_register_vcpu_info hypercall argumentJeremy Fitzhardinge2007-10-161-2/+3
| | | | | | | | | | | | | | The kernel's copy of struct vcpu_register_vcpu_info was out of date, at best causing the hypercall to fail and the guest kernel to fall back to the old mechanism, or worse, causing random memory corruption. [ Stable folks: applies to 2.6.23 ] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Stable Kernel <stable@kernel.org> Cc: Morten =?utf-8?q?B=C3=B8geskov?= <xen-users@morten.bogeskov.dk> Cc: Mark Williamson <mark.williamson@cl.cam.ac.uk>
* xen: xen/page.h compile fixJeremy Fitzhardinge2007-07-261-0/+1
| | | | | | | | | | | | Fix: linux/include/xen/page.h: In function mfn_pte: linux/include/xen/page.h:149: error: __supported_pte_mask undeclared (first use in this function) linux/include/xen/page.h:149: error: (Each undeclared identifier is reported only once linux/include/xen/page.h:149: error: for each function it appears in.) Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xen: Place vcpu_info structure into per-cpu memoryJeremy Fitzhardinge2007-07-181-0/+13
| | | | | | | | | | | | | An experimental patch for Xen allows guests to place their vcpu_info structs anywhere. We try to use this to place the vcpu_info into the PDA, which allows direct access. If this works, then switch to using direct access operations for irq_enable, disable, save_fl and restore_fl. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Chris Wright <chrisw@sous-sol.org> Cc: Keir Fraser <keir@xensource.com>
* xen: add the Xenbus sysfs and virtual device hotplug driverJeremy Fitzhardinge2007-07-181-0/+234
| | | | | | | | | | | | | | | | This communicates with the machine control software via a registry residing in a controlling virtual machine. This allows dynamic creation, destruction and modification of virtual device configurations (network devices, block devices and CPUS, to name some examples). [ Greg, would you mind giving this a review? Thanks -J ] Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Greg KH <greg@kroah.com>
* xen: Add grant table supportJeremy Fitzhardinge2007-07-182-10/+191
| | | | | | | | | | | | | | | | | Add Xen 'grant table' driver which allows granting of access to selected local memory pages by other virtual machines and, symmetrically, the mapping of remote memory pages which other virtual machines have granted access to. This driver is a prerequisite for many of the Xen virtual device drivers, which grant the 'device driver domain' restricted and temporary access to only those memory pages that are currently involved in I/O operations. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
* xen: use the hvc console infrastructure for Xen consoleJeremy Fitzhardinge2007-07-182-0/+7
| | | | | | | | | | | | | | Implement a Xen back-end for hvc console. * * * Add early printk support via hvc console, enable using "earlyprintk=xen" on the kernel command line. From: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Olof Johansson <olof@lixom.net>
* xen: SMP guest supportJeremy Fitzhardinge2007-07-181-4/+23
| | | | | | | | | | | | | | | | | | | | | This is a fairly straightforward Xen implementation of smp_ops. Xen has its own IPI mechanisms, and has no dependency on any APIC-based IPI. The smp_ops hooks and the flush_tlb_others pv_op allow a Xen guest to avoid all APIC code in arch/i386 (the only apic operation is a single apic_read for the apic version number). One subtle point which needs to be addressed is unpinning pagetables when another cpu may have a lazy tlb reference to the pagetable. Xen will not allow an in-use pagetable to be unpinned, so we must find any other cpus with a reference to the pagetable and get them to shoot down their references. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Benjamin LaHaise <bcrl@kvack.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Andi Kleen <ak@suse.de>
* xen: event channelsJeremy Fitzhardinge2007-07-181-0/+28
| | | | | | | | | | | | | | | | | | | | | 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>
* xen: Core Xen implementationJeremy Fitzhardinge2007-07-182-0/+202
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a rollup of all the core pieces of the Xen implementation, including: - booting and setup - pagetable setup - privileged instructions - segmentation - interrupt flags - upcalls - multicall batching BOOTING AND SETUP The vmlinux image is decorated with ELF notes which tell the Xen domain builder what the kernel's requirements are; the domain builder then constructs the address space accordingly and starts the kernel. Xen has its own entrypoint for the kernel (contained in an ELF note). The ELF notes are set up by xen-head.S, which is included into head.S. In principle it could be linked separately, but it seems to provoke lots of binutils bugs. Because the domain builder starts the kernel in a fairly sane state (32-bit protected mode, paging enabled, flat segments set up), there's not a lot of setup needed before starting the kernel proper. The main steps are: 1. Install the Xen paravirt_ops, which is simply a matter of a structure assignment. 2. Set init_mm to use the Xen-supplied pagetables (analogous to the head.S generated pagetables in a native boot). 3. Reserve address space for Xen, since it takes a chunk at the top of the address space for its own use. 4. Call start_kernel() PAGETABLE SETUP Once we hit the main kernel boot sequence, it will end up calling back via paravirt_ops to set up various pieces of Xen specific state. One of the critical things which requires a bit of extra care is the construction of the initial init_mm pagetable. Because Xen places tight constraints on pagetables (an active pagetable must always be valid, and must always be mapped read-only to the guest domain), we need to be careful when constructing the new pagetable to keep these constraints in mind. It turns out that the easiest way to do this is use the initial Xen-provided pagetable as a template, and then just insert new mappings for memory where a mapping doesn't already exist. This means that during pagetable setup, it uses a special version of xen_set_pte which ignores any attempt to remap a read-only page as read-write (since Xen will map its own initial pagetable as RO), but lets other changes to the ptes happen, so that things like NX are set properly. PRIVILEGED INSTRUCTIONS AND SEGMENTATION When the kernel runs under Xen, it runs in ring 1 rather than ring 0. This means that it is more privileged than user-mode in ring 3, but it still can't run privileged instructions directly. Non-performance critical instructions are dealt with by taking a privilege exception and trapping into the hypervisor and emulating the instruction, but more performance-critical instructions have their own specific paravirt_ops. In many cases we can avoid having to do any hypercalls for these instructions, or the Xen implementation is quite different from the normal native version. The privileged instructions fall into the broad classes of: Segmentation: setting up the GDT and the GDT entries, LDT, TLS and so on. Xen doesn't allow the GDT to be directly modified; all GDT updates are done via hypercalls where the new entries can be validated. This is important because Xen uses segment limits to prevent the guest kernel from damaging the hypervisor itself. Traps and exceptions: Xen uses a special format for trap entrypoints, so when the kernel wants to set an IDT entry, it needs to be converted to the form Xen expects. Xen sets int 0x80 up specially so that the trap goes straight from userspace into the guest kernel without going via the hypervisor. sysenter isn't supported. Kernel stack: The esp0 entry is extracted from the tss and provided to Xen. TLB operations: the various TLB calls are mapped into corresponding Xen hypercalls. Control registers: all the control registers are privileged. The most important is cr3, which points to the base of the current pagetable, and we handle it specially. Another instruction we treat specially is CPUID, even though its not privileged. We want to control what CPU features are visible to the rest of the kernel, and so CPUID ends up going into a paravirt_op. Xen implements this mainly to disable the ACPI and APIC subsystems. INTERRUPT FLAGS Xen maintains its own separate flag for masking events, which is contained within the per-cpu vcpu_info structure. Because the guest kernel runs in ring 1 and not 0, the IF flag in EFLAGS is completely ignored (and must be, because even if a guest domain disables interrupts for itself, it can't disable them overall). (A note on terminology: "events" and interrupts are effectively synonymous. However, rather than using an "enable flag", Xen uses a "mask flag", which blocks event delivery when it is non-zero.) There are paravirt_ops for each of cli/sti/save_fl/restore_fl, which are implemented to manage the Xen event mask state. The only thing worth noting is that when events are unmasked, we need to explicitly see if there's a pending event and call into the hypervisor to make sure it gets delivered. UPCALLS Xen needs a couple of upcall (or callback) functions to be implemented by each guest. One is the event upcalls, which is how events (interrupts, effectively) are delivered to the guests. The other is the failsafe callback, which is used to report errors in either reloading a segment register, or caused by iret. These are implemented in i386/kernel/entry.S so they can jump into the normal iret_exc path when necessary. MULTICALL BATCHING Xen provides a multicall mechanism, which allows multiple hypercalls to be issued at once in order to mitigate the cost of trapping into the hypervisor. This is particularly useful for context switches, since the 4-5 hypercalls they would normally need (reload cr3, update TLS, maybe update LDT) can be reduced to one. This patch implements a generic batching mechanism for hypercalls, which gets used in many places in the Xen code. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Ian Pratt <ian.pratt@xensource.com> Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Cc: Adrian Bunk <bunk@stusta.de>
* xen: Add Xen interface header filesJeremy Fitzhardinge2007-07-1816-0/+2366
Add Xen interface header files. These are taken fairly directly from the Xen tree, but somewhat rearranged to suit the kernel's conventions. Define macros and inline functions for doing hypercalls into the hypervisor. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org>
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