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2009-06-10Merge branch 'x86-xen-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-xen-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (42 commits) xen: cache cr0 value to avoid trap'n'emulate for read_cr0 xen/x86-64: clean up warnings about IST-using traps xen/x86-64: fix breakpoints and hardware watchpoints xen: reserve Xen start_info rather than e820 reserving xen: add FIX_TEXT_POKE to fixmap lguest: update lazy mmu changes to match lguest's use of kvm hypercalls xen: honour VCPU availability on boot xen: add "capabilities" file xen: drop kexec bits from /sys/hypervisor since kexec isn't implemented yet xen/sys/hypervisor: change writable_pt to features xen: add /sys/hypervisor support xen/xenbus: export xenbus_dev_changed xen: use device model for suspending xenbus devices xen: remove suspend_cancel hook xen/dev-evtchn: clean up locking in evtchn xen: export ioctl headers to userspace xen: add /dev/xen/evtchn driver xen: add irq_from_evtchn xen: clean up gate trap/interrupt constants xen: set _PAGE_NX in __supported_pte_mask before pagetable construction ...
2009-05-13xen: use header for EXPORT_SYMBOL_GPLRandy Dunlap
mmu.c needs to #include module.h to prevent these warnings: arch/x86/xen/mmu.c:239: warning: data definition has no type or storage class arch/x86/xen/mmu.c:239: warning: type defaults to 'int' in declaration of 'EXPORT_SYMBOL_GPL' arch/x86/xen/mmu.c:239: warning: parameter names (without types) in function declaration [ Impact: cleanup ] Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-08Merge branch 'x86/urgent' into x86/xenIngo Molnar
Conflicts: arch/frv/include/asm/pgtable.h arch/x86/include/asm/required-features.h arch/x86/xen/mmu.c Merge reason: x86/xen was on a .29 base still, move it to a fresher branch and pick up Xen fixes as well, plus resolve conflicts Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-05-08x86: xen, i386: reserve Xen pagetablesJeremy Fitzhardinge
The Xen pagetables are no longer implicitly reserved as part of the other i386_start_kernel reservations, so make sure we explicitly reserve them. This prevents them from being released into the general kernel free page pool and reused. [ Impact: fix Xen guest crash ] Also-Bisected-by: Bryan Donlan <bdonlan@gmail.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Xen-devel <xen-devel@lists.xensource.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> LKML-Reference: <4A032EEC.30509@goop.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-13Merge branch 'for-rc1/xen/core' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen * 'for-rc1/xen/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen: xen: add FIX_TEXT_POKE to fixmap xen: honour VCPU availability on boot xen: clean up gate trap/interrupt constants xen: set _PAGE_NX in __supported_pte_mask before pagetable construction xen: resume interrupts before system devices. xen/mmu: weaken flush_tlb_other test xen/mmu: some early pagetable cleanups Xen: Add virt_to_pfn helper function x86-64: remove PGE from must-have feature list xen: mask XSAVE from cpuid NULL noise: arch/x86/xen/smp.c xen: remove xen_load_gdt debug xen: make xen_load_gdt simpler xen: clean up xen_load_gdt xen: split construction of p2m mfn tables from registration xen: separate p2m allocation from setting xen: disable preempt for leave_lazy_mmu
2009-04-09x86: fix set_fixmap to use phys_addr_tMasami Hiramatsu
Use phys_addr_t for receiving a physical address argument instead of unsigned long. This allows fixmap to handle pages higher than 4GB on x86-32. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2009-04-09xen: add FIX_TEXT_POKE to fixmapJeremy Fitzhardinge
FIX_TEXT_POKE[01] are used to map kernel addresses, so they're mapping pfns, not mfns. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen: add FIX_TEXT_POKE to fixmapJeremy Fitzhardinge
FIX_TEXT_POKE[01] are used to map kernel addresses, so they're mapping pfns, not mfns. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen/mmu: weaken flush_tlb_other testJeremy Fitzhardinge
Impact: fixes crashing bug There's no particular problem with getting an empty cpu mask, so just shortcut-return if we get one. Avoids crash reported by Christophe Saout <christophe@saout.de> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen/mmu: some early pagetable cleanupsJeremy Fitzhardinge
1. make sure early-allocated ptes are pinned, so they can be later unpinned 2. don't pin pmd+pud, just make them RO 3. scatter some __inits around Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen: split construction of p2m mfn tables from registrationJeremy Fitzhardinge
Build the p2m_mfn_list_list early with the rest of the p2m table, but register it later when the real shared_info structure is in place. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen: separate p2m allocation from settingJeremy Fitzhardinge
When doing very early p2m setting, we need to separate setting from allocation, so split things up accordingly. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-08xen: disable preempt for leave_lazy_mmuJeremy Fitzhardinge
xen_mc_flush() requires preemption to be disabled for its own sanity, so disable it while we're flushing. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-04-07Merge commit 'origin/master' into for-linus/xen/masterJeremy Fitzhardinge
* commit 'origin/master': (4825 commits) Fix build errors due to CONFIG_BRANCH_TRACER=y parport: Use the PCI IRQ if offered tty: jsm cleanups Adjust path to gpio headers KGDB_SERIAL_CONSOLE check for module Change KCONFIG name tty: Blackin CTS/RTS Change hardware flow control from poll to interrupt driven Add support for the MAX3100 SPI UART. lanana: assign a device name and numbering for MAX3100 serqt: initial clean up pass for tty side tty: Use the generic RS485 ioctl on CRIS tty: Correct inline types for tty_driver_kref_get() splice: fix deadlock in splicing to file nilfs2: support nanosecond timestamp nilfs2: introduce secondary super block nilfs2: simplify handling of active state of segments nilfs2: mark minor flag for checkpoint created by internal operation nilfs2: clean up sketch file nilfs2: super block operations fix endian bug ... Conflicts: arch/x86/include/asm/thread_info.h arch/x86/lguest/boot.c drivers/xen/manage.c
2009-03-30xen/mmu: weaken flush_tlb_other testJeremy Fitzhardinge
Impact: fixes crashing bug There's no particular problem with getting an empty cpu mask, so just shortcut-return if we get one. Avoids crash reported by Christophe Saout <christophe@saout.de> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-30xen/mmu: some early pagetable cleanupsJeremy Fitzhardinge
1. make sure early-allocated ptes are pinned, so they can be later unpinned 2. don't pin pmd+pud, just make them RO 3. scatter some __inits around Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-30xen: split construction of p2m mfn tables from registrationJeremy Fitzhardinge
Build the p2m_mfn_list_list early with the rest of the p2m table, but register it later when the real shared_info structure is in place. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-29xen: separate p2m allocation from settingJeremy Fitzhardinge
When doing very early p2m setting, we need to separate setting from allocation, so split things up accordingly. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-29xen: disable preempt for leave_lazy_mmuJeremy Fitzhardinge
xen_mc_flush() requires preemption to be disabled for its own sanity, so disable it while we're flushing. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
2009-03-29x86/paravirt: allow preemption with lazy mmu modeJeremy Fitzhardinge
Impact: remove obsolete checks, simplification Lift restrictions on preemption with lazy mmu mode, as it is now allowed. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2009-03-29x86/paravirt: flush pending mmu updates on context switchJeremy Fitzhardinge
Impact: allow preemption during lazy mmu updates If we're in lazy mmu mode when context switching, leave lazy mmu mode, but remember the task's state in TIF_LAZY_MMU_UPDATES. When we resume the task, check this flag and re-enter lazy mmu mode if its set. This sets things up for allowing lazy mmu mode while preemptible, though that won't actually be active until the next change. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2009-03-29x86/pvops: replace arch_enter_lazy_cpu_mode with arch_start_context_switchJeremy Fitzhardinge
Impact: simplification, prepare for later changes Make lazy cpu mode more specific to context switching, so that it makes sense to do more context-switch specific things in the callbacks. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
2009-03-19x86: with the last user gone, remove set_pte_presentJeremy Fitzhardinge
Impact: cleanup set_pte_present() is no longer used, directly or indirectly, so remove it. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Xen-devel <xen-devel@lists.xensource.com> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Alok Kataria <akataria@vmware.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> Cc: Avi Kivity <avi@redhat.com> LKML-Reference: <1237406613-2929-2-git-send-email-jeremy@goop.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-03-14x86: add brk allocation for very, very early allocationsJeremy Fitzhardinge
Impact: new interface Add a brk()-like allocator which effectively extends the bss in order to allow very early code to do dynamic allocations. This is better than using statically allocated arrays for data in subsystems which may never get used. The space for brk allocations is in the bss ELF segment, so that the space is mapped properly by the code which maps the kernel, and so that bootloaders keep the space free rather than putting a ramdisk or something into it. The bss itself, delimited by __bss_stop, ends before the brk area (__brk_base to __brk_limit). The kernel text, data and bss is reserved up to __bss_stop. Any brk-allocated data is reserved separately just before the kernel pagetable is built, as that code allocates from unreserved spaces in the e820 map, potentially allocating from any unused brk memory. Ultimately any unused memory in the brk area is used in the general kernel memory pool. Initially the brk space is set to 1MB, which is probably much larger than any user needs (the largest current user is i386 head_32.S's code to build the pagetables to map the kernel, which can get fairly large with a big kernel image and no PSE support). So long as the system has sufficient memory for the bootloader to reserve the kernel+1MB brk, there are no bad effects resulting from an over-large brk. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-03-02xen: deal with virtually mapped percpu dataJeremy Fitzhardinge
The virtually mapped percpu space causes us two problems: - for hypercalls which take an mfn, we need to do a full pagetable walk to convert the percpu va into an mfn, and - when a hypercall requires a page to be mapped RO via all its aliases, we need to make sure its RO in both the percpu mapping and in the linear mapping This primarily affects the gdt and the vcpu info structure. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Xen-devel <xen-devel@lists.xensource.com> Cc: Gerd Hoffmann <kraxel@redhat.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Tejun Heo <htejun@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-13xen: fix xen_flush_tlb_othersIan Campbell
The commit commit 4595f9620cda8a1e973588e743cf5f8436dd20c6 Author: Rusty Russell <rusty@rustcorp.com.au> Date: Sat Jan 10 21:58:09 2009 -0800 x86: change flush_tlb_others to take a const struct cpumask causes xen_flush_tlb_others to allocate a multicall and then issue it without initializing it in the case where the cpumask is empty, leading to: [ 8.354898] 1 multicall(s) failed: cpu 1 [ 8.354921] Pid: 2213, comm: bootclean Not tainted 2.6.29-rc3-x86_32p-xenU-tip #135 [ 8.354937] Call Trace: [ 8.354955] [<c01036e3>] xen_mc_flush+0x133/0x1b0 [ 8.354971] [<c0105d2a>] ? xen_force_evtchn_callback+0x1a/0x30 [ 8.354988] [<c0105a60>] xen_flush_tlb_others+0xb0/0xd0 [ 8.355003] [<c0126643>] flush_tlb_page+0x53/0xa0 [ 8.355018] [<c0176a80>] do_wp_page+0x2a0/0x7c0 [ 8.355034] [<c0238f0a>] ? notify_remote_via_irq+0x3a/0x70 [ 8.355049] [<c0178950>] handle_mm_fault+0x7b0/0xa50 [ 8.355065] [<c0131a3e>] ? wake_up_new_task+0x8e/0xb0 [ 8.355079] [<c01337b5>] ? do_fork+0xe5/0x320 [ 8.355095] [<c0121919>] do_page_fault+0xe9/0x240 [ 8.355109] [<c0121830>] ? do_page_fault+0x0/0x240 [ 8.355125] [<c032457a>] error_code+0x72/0x78 [ 8.355139] call 1/1: op=2863311530 arg=[aaaaaaaa] result=-38 xen_flush_tlb_others+0x41/0xd0 Since empty cpumasks are rare and undoing an xen_mc_entry() is tricky just issue such requests normally. Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-02-04xen: fix 32-bit build resulting from mmu moveJeremy Fitzhardinge
Moving the mmu code from enlighten.c to mmu.c inadvertently broke the 32-bit build. Fix it. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
2009-01-30x86/paravirt: use callee-saved convention for pte_val/make_pte/etcJeremy Fitzhardinge
Impact: Optimization In the native case, pte_val, make_pte, etc are all just identity functions, so there's no need to clobber a lot of registers over them. (This changes the 32-bit callee-save calling convention to return both EAX and EDX so functions can return 64-bit values.) Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-01-30xen: move remaining mmu-related stuff into mmu.cJeremy Fitzhardinge
Impact: Cleanup Move remaining mmu-related stuff into mmu.c. A general cleanup, and lay the groundwork for later patches. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2009-01-19x86-64: Move TLB state from PDA to per-cpu and consolidate with 32-bit.Brian Gerst
Signed-off-by: Brian Gerst <brgerst@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-01-16percpu: add optimized generic percpu accessorsIngo Molnar
It is an optimization and a cleanup, and adds the following new generic percpu methods: percpu_read() percpu_write() percpu_add() percpu_sub() percpu_and() percpu_or() percpu_xor() and implements support for them on x86. (other architectures will fall back to a default implementation) The advantage is that for example to read a local percpu variable, instead of this sequence: return __get_cpu_var(var); ffffffff8102ca2b: 48 8b 14 fd 80 09 74 mov -0x7e8bf680(,%rdi,8),%rdx ffffffff8102ca32: 81 ffffffff8102ca33: 48 c7 c0 d8 59 00 00 mov $0x59d8,%rax ffffffff8102ca3a: 48 8b 04 10 mov (%rax,%rdx,1),%rax We can get a single instruction by using the optimized variants: return percpu_read(var); ffffffff8102ca3f: 65 48 8b 05 91 8f fd mov %gs:0x7efd8f91(%rip),%rax I also cleaned up the x86-specific APIs and made the x86 code use these new generic percpu primitives. tj: * fixed generic percpu_sub() definition as Roel Kluin pointed out * added percpu_and() for completeness's sake * made generic percpu ops atomic against preemption Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Tejun Heo <tj@kernel.org>
2009-01-02Merge branch 'cpus4096-for-linus-2' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'cpus4096-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (66 commits) x86: export vector_used_by_percpu_irq x86: use logical apicid in x2apic_cluster's x2apic_cpu_mask_to_apicid_and() sched: nominate preferred wakeup cpu, fix x86: fix lguest used_vectors breakage, -v2 x86: fix warning in arch/x86/kernel/io_apic.c sched: fix warning in kernel/sched.c sched: move test_sd_parent() to an SMP section of sched.h sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0 sched: activate active load balancing in new idle cpus sched: bias task wakeups to preferred semi-idle packages sched: nominate preferred wakeup cpu sched: favour lower logical cpu number for sched_mc balance sched: framework for sched_mc/smt_power_savings=N sched: convert BALANCE_FOR_xx_POWER to inline functions x86: use possible_cpus=NUM to extend the possible cpus allowed x86: fix cpu_mask_to_apicid_and to include cpu_online_mask x86: update io_apic.c to the new cpumask code x86: Introduce topology_core_cpumask()/topology_thread_cpumask() x86: xen: use smp_call_function_many() x86: use work_on_cpu in x86/kernel/cpu/mcheck/mce_amd_64.c ... Fixed up trivial conflict in kernel/time/tick-sched.c manually
2008-12-16x86: xen: use smp_call_function_many()Mike Travis
Impact: use new API, remove cpumask from stack. Change smp_call_function_mask() callers to smp_call_function_many(). This removes a cpumask from the stack, and falls back should allocating the cpumask var fail (only possible with CONFIG_CPUMASKS_OFFSTACK). Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Mike Travis <travis@sgi.com> Cc: jeremy@xensource.com
2008-12-16xen: whitespace/checkpatch cleanupTej
Impact: cleanup Signed-off-by: Tej <bewith.tej@gmail.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-23xen: pin correct PGD on suspendIan Campbell
Impact: fix Xen guest boot failure commit eefb47f6a1e855653d275cb90592a3587ea93a09 ("xen: use spin_lock_nest_lock when pinning a pagetable") changed xen_pgd_walk to walk over mm->pgd rather than taking pgd as an argument. This breaks xen_mm_(un)pin_all() because it makes init_mm.pgd readonly instead of the pgd we are interested in and therefore the pin subsequently fails. (XEN) mm.c:2280:d15 Bad type (saw 00000000e8000001 != exp 0000000060000000) for mfn bc464 (pfn 21ca7) (XEN) mm.c:2665:d15 Error while pinning mfn bc464 [ 14.586913] 1 multicall(s) failed: cpu 0 [ 14.586926] Pid: 14, comm: kstop/0 Not tainted 2.6.28-rc5-x86_32p-xenU-00172-gee2f6cc #200 [ 14.586940] Call Trace: [ 14.586955] [<c030c17a>] ? printk+0x18/0x1e [ 14.586972] [<c0103df3>] xen_mc_flush+0x163/0x1d0 [ 14.586986] [<c0104bc1>] __xen_pgd_pin+0xa1/0x110 [ 14.587000] [<c015a330>] ? stop_cpu+0x0/0xf0 [ 14.587015] [<c0104d7b>] xen_mm_pin_all+0x4b/0x70 [ 14.587029] [<c022bcb9>] xen_suspend+0x39/0xe0 [ 14.587042] [<c015a330>] ? stop_cpu+0x0/0xf0 [ 14.587054] [<c015a3cd>] stop_cpu+0x9d/0xf0 [ 14.587067] [<c01417cd>] run_workqueue+0x8d/0x150 [ 14.587080] [<c030e4b3>] ? _spin_unlock_irqrestore+0x23/0x40 [ 14.587094] [<c014558a>] ? prepare_to_wait+0x3a/0x70 [ 14.587107] [<c0141918>] worker_thread+0x88/0xf0 [ 14.587120] [<c01453c0>] ? autoremove_wake_function+0x0/0x50 [ 14.587133] [<c0141890>] ? worker_thread+0x0/0xf0 [ 14.587146] [<c014509c>] kthread+0x3c/0x70 [ 14.587157] [<c0145060>] ? kthread+0x0/0x70 [ 14.587170] [<c0109d1b>] kernel_thread_helper+0x7/0x10 [ 14.587181] call 1/3: op=14 arg=[c0415000] result=0 [ 14.587192] call 2/3: op=14 arg=[e1ca2000] result=0 [ 14.587204] call 3/3: op=26 arg=[c1808860] result=-22 Signed-off-by: Ian Campbell <ian.campbell@citrix.com> Acked-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-07Merge branch 'x86-fixes-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, xen: fix use of pgd_page now that it really does return a page
2008-11-07xen: make sure stray alias mappings are gone before pinningJeremy Fitzhardinge
Xen requires that all mappings of pagetable pages are read-only, so that they can't be updated illegally. As a result, if a page is being turned into a pagetable page, we need to make sure all its mappings are RO. If the page had been used for ioremap or vmalloc, it may still have left over mappings as a result of not having been lazily unmapped. This change makes sure we explicitly mop them all up before pinning the page. Unlike aliases created by kmap, the there can be vmalloc aliases even for non-high pages, so we must do the flush unconditionally. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Linux Memory Management List <linux-mm@kvack.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-06x86, xen: fix use of pgd_page now that it really does return a pageJeremy Fitzhardinge
Impact: fix 32-bit Xen guest boot crash On 32-bit PAE, pud_page, for no good reason, didn't really return a struct page *. Since Jan Beulich's fix "i386/PAE: fix pud_page()", pud_page does return a struct page *. Because PAE has 3 pagetable levels, the pud level is folded into the pgd level, so pgd_page() is the same as pud_page(), and now returns a struct page *. Update the xen/mmu.c code which uses pgd_page() accordingly. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-27xen: fix Xen domU boot with batched mprotectChris Lalancette
Impact: fix guest kernel boot crash on certain configs Recent i686 2.6.27 kernels with a certain amount of memory (between 736 and 855MB) have a problem booting under a hypervisor that supports batched mprotect (this includes the RHEL-5 Xen hypervisor as well as any 3.3 or later Xen hypervisor). The problem ends up being that xen_ptep_modify_prot_commit() is using virt_to_machine to calculate which pfn to update. However, this only works for pages that are in the p2m list, and the pages coming from change_pte_range() in mm/mprotect.c are kmap_atomic pages. Because of this, we can run into the situation where the lookup in the p2m table returns an INVALID_MFN, which we then try to pass to the hypervisor, which then (correctly) denies the request to a totally bogus pfn. The right thing to do is to use arbitrary_virt_to_machine, so that we can be sure we are modifying the right pfn. This unfortunately introduces a performance penalty because of a full page-table-walk, but we can avoid that penalty for pages in the p2m list by checking if virt_addr_valid is true, and if so, just doing the lookup in the p2m table. The attached patch implements this, and allows my 2.6.27 i686 based guest with 768MB of memory to boot on a RHEL-5 hypervisor again. Thanks to Jeremy for the suggestions about how to fix this particular issue. Signed-off-by: Chris Lalancette <clalance@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Chris Lalancette <clalance@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-20mm: rewrite vmap layerNick Piggin
Rewrite the vmap allocator to use rbtrees and lazy tlb flushing, and provide a fast, scalable percpu frontend for small vmaps (requires a slightly different API, though). The biggest problem with vmap is actually vunmap. Presently this requires a global kernel TLB flush, which on most architectures is a broadcast IPI to all CPUs to flush the cache. This is all done under a global lock. As the number of CPUs increases, so will the number of vunmaps a scaled workload will want to perform, and so will the cost of a global TLB flush. This gives terrible quadratic scalability characteristics. Another problem is that the entire vmap subsystem works under a single lock. It is a rwlock, but it is actually taken for write in all the fast paths, and the read locking would likely never be run concurrently anyway, so it's just pointless. This is a rewrite of vmap subsystem to solve those problems. The existing vmalloc API is implemented on top of the rewritten subsystem. The TLB flushing problem is solved by using lazy TLB unmapping. vmap addresses do not have to be flushed immediately when they are vunmapped, because the kernel will not reuse them again (would be a use-after-free) until they are reallocated. So the addresses aren't allocated again until a subsequent TLB flush. A single TLB flush then can flush multiple vunmaps from each CPU. XEN and PAT and such do not like deferred TLB flushing because they can't always handle multiple aliasing virtual addresses to a physical address. They now call vm_unmap_aliases() in order to flush any deferred mappings. That call is very expensive (well, actually not a lot more expensive than a single vunmap under the old scheme), however it should be OK if not called too often. The virtual memory extent information is stored in an rbtree rather than a linked list to improve the algorithmic scalability. There is a per-CPU allocator for small vmaps, which amortizes or avoids global locking. To use the per-CPU interface, the vm_map_ram / vm_unmap_ram interfaces must be used in place of vmap and vunmap. Vmalloc does not use these interfaces at the moment, so it will not be quite so scalable (although it will use lazy TLB flushing). As a quick test of performance, I ran a test that loops in the kernel, linearly mapping then touching then unmapping 4 pages. Different numbers of tests were run in parallel on an 4 core, 2 socket opteron. Results are in nanoseconds per map+touch+unmap. threads vanilla vmap rewrite 1 14700 2900 2 33600 3000 4 49500 2800 8 70631 2900 So with a 8 cores, the rewritten version is already 25x faster. In a slightly more realistic test (although with an older and less scalable version of the patch), I ripped the not-very-good vunmap batching code out of XFS, and implemented the large buffer mapping with vm_map_ram and vm_unmap_ram... along with a couple of other tricks, I was able to speed up a large directory workload by 20x on a 64 CPU system. I believe vmap/vunmap is actually sped up a lot more than 20x on such a system, but I'm running into other locks now. vmap is pretty well blown off the profiles. Before: 1352059 total 0.1401 798784 _write_lock 8320.6667 <- vmlist_lock 529313 default_idle 1181.5022 15242 smp_call_function 15.8771 <- vmap tlb flushing 2472 __get_vm_area_node 1.9312 <- vmap 1762 remove_vm_area 4.5885 <- vunmap 316 map_vm_area 0.2297 <- vmap 312 kfree 0.1950 300 _spin_lock 3.1250 252 sn_send_IPI_phys 0.4375 <- tlb flushing 238 vmap 0.8264 <- vmap 216 find_lock_page 0.5192 196 find_next_bit 0.3603 136 sn2_send_IPI 0.2024 130 pio_phys_write_mmr 2.0312 118 unmap_kernel_range 0.1229 After: 78406 total 0.0081 40053 default_idle 89.4040 33576 ia64_spinlock_contention 349.7500 1650 _spin_lock 17.1875 319 __reg_op 0.5538 281 _atomic_dec_and_lock 1.0977 153 mutex_unlock 1.5938 123 iget_locked 0.1671 117 xfs_dir_lookup 0.1662 117 dput 0.1406 114 xfs_iget_core 0.0268 92 xfs_da_hashname 0.1917 75 d_alloc 0.0670 68 vmap_page_range 0.0462 <- vmap 58 kmem_cache_alloc 0.0604 57 memset 0.0540 52 rb_next 0.1625 50 __copy_user 0.0208 49 bitmap_find_free_region 0.2188 <- vmap 46 ia64_sn_udelay 0.1106 45 find_inode_fast 0.1406 42 memcmp 0.2188 42 finish_task_switch 0.1094 42 __d_lookup 0.0410 40 radix_tree_lookup_slot 0.1250 37 _spin_unlock_irqrestore 0.3854 36 xfs_bmapi 0.0050 36 kmem_cache_free 0.0256 35 xfs_vn_getattr 0.0322 34 radix_tree_lookup 0.1062 33 __link_path_walk 0.0035 31 xfs_da_do_buf 0.0091 30 _xfs_buf_find 0.0204 28 find_get_page 0.0875 27 xfs_iread 0.0241 27 __strncpy_from_user 0.2812 26 _xfs_buf_initialize 0.0406 24 _xfs_buf_lookup_pages 0.0179 24 vunmap_page_range 0.0250 <- vunmap 23 find_lock_page 0.0799 22 vm_map_ram 0.0087 <- vmap 20 kfree 0.0125 19 put_page 0.0330 18 __kmalloc 0.0176 17 xfs_da_node_lookup_int 0.0086 17 _read_lock 0.0885 17 page_waitqueue 0.0664 vmap has gone from being the top 5 on the profiles and flushing the crap out of all TLBs, to using less than 1% of kernel time. [akpm@linux-foundation.org: cleanups, section fix] [akpm@linux-foundation.org: fix build on alpha] Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Krzysztof Helt <krzysztof.h1@poczta.fm> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-09xen: use spin_lock_nest_lock when pinning a pagetableJeremy Fitzhardinge
When pinning/unpinning a pagetable with split pte locks, we can end up holding multiple pte locks at once (we need to hold the locks while there's a pending batched hypercall affecting the pte page). Because all the pte locks are in the same lock class, lockdep thinks that we're potentially taking a lock recursively. This warning is spurious because we always take the pte locks while holding mm->page_table_lock. lockdep now has spin_lock_nest_lock to express this kind of dominant lock use, so use it here so that lockdep knows what's going on. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-10Merge branch 'core/xen' into x86/xenIngo Molnar
2008-09-10mm: define USE_SPLIT_PTLOCKS rather than repeating expressionJeremy Fitzhardinge
Define USE_SPLIT_PTLOCKS as a constant expression rather than repeating "NR_CPUS >= CONFIG_SPLIT_PTLOCK_CPUS" all over the place. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-21xen: add debugfs supportJeremy Fitzhardinge
Add support for exporting statistics on mmu updates, multicall batching and pv spinlocks into debugfs. The base path is xen/ and each subsystem adds its own directory: mmu, multicalls, spinlocks. In each directory, writing 1 to "zero_stats" will cause the corresponding stats to be zeroed the next time they're updated. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Acked-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20xen: add xen_ prefixes to make tracing with ftrace easierJeremy Fitzhardinge
It's easier to pattern match on Xen function if they all start with xen_. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-08-20xen: clarify locking used when pinning a pagetable.Jeremy Fitzhardinge
Add some comments explaining the locking and pinning algorithm when using split pte locks. Also implement a minor optimisation of not pinning the PTE when not using split pte locks. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Cc: Xen-devel <xen-devel@lists.xensource.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-22x86: add PTE_FLAGS_MASKJeremy Fitzhardinge
PTE_PFN_MASK was getting lonely, so I made it a friend. Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-22x86: rename PTE_MASK to PTE_PFN_MASKJeremy Fitzhardinge
Rusty, in his peevish way, complained that macros defining constants should have a name which somewhat accurately reflects the actual purpose of the constant. Aside from the fact that PTE_MASK gives no clue as to what's actually being masked, and is misleadingly similar to the functionally entirely different PMD_MASK, PUD_MASK and PGD_MASK, I don't really see what the problem is. But if this patch silences the incessent noise, then it will have achieved its goal (TODO: write test-case). Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-07-16xen64: allocate and manage user pagetablesJeremy Fitzhardinge
Because the x86_64 architecture does not enforce segment limits, Xen cannot protect itself with them as it does in 32-bit mode. Therefore, to protect itself, it runs the guest kernel in ring 3. Since it also runs the guest userspace in ring3, the guest kernel must maintain a second pagetable for its userspace, which does not map kernel space. Naturally, the guest kernel pagetables map both kernel and userspace. The userspace pagetable is attached to the corresponding kernel pagetable via the pgd's page->private field. It is allocated and freed at the same time as the kernel pgd via the paravirt_pgd_alloc/free hooks. Fortunately, the user pagetable is almost entirely shared with the kernel pagetable; the only difference is the pgd page itself. set_pgd will populate all entries in the kernel pagetable, and also set the corresponding user pgd entry if the address is less than STACK_TOP_MAX. The user pagetable must be pinned and unpinned with the kernel one, but because the pagetables are aliased, pgd_walk() only needs to be called on the kernel pagetable. The user pgd page is then pinned/unpinned along with the kernel pgd page. xen_write_cr3 must write both the kernel and user cr3s. The init_mm.pgd pagetable never has a user pagetable allocated for it, because it can never be used while running usermode. One awkward area is that early in boot the page structures are not available. No user pagetable can exist at that point, but it complicates the logic to avoid looking at the page structure. 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>
2008-07-16xen: rework pgd_walk to deal with 32/64 bitJeremy Fitzhardinge
Rewrite pgd_walk to deal with 64-bit address spaces. There are two notible features of 64-bit workspaces: 1. The physical address is only 48 bits wide, with the upper 16 bits being sign extension; kernel addresses are negative, and userspace is positive. 2. The Xen hypervisor mapping is at the negative-most address, just above the sign-extension hole. 1. means that we can't easily use addresses when traversing the space, since we must deal with sign extension. This rewrite expresses everything in terms of pgd/pud/pmd indices, which means we don't need to worry about the exact configuration of the virtual memory space. This approach works equally well in 32-bit. To deal with 2, assume the hole is between the uppermost userspace address and PAGE_OFFSET. For 64-bit this skips the Xen mapping hole. For 32-bit, the hole is zero-sized. In all cases, the uppermost kernel address is FIXADDR_TOP. A side-effect of this patch is that the upper boundary is actually handled properly, exposing a long-standing bug in 32-bit, which failed to pin kernel pmd page. The kernel pmd is not shared, and so must be explicitly pinned, even though the kernel ptes are shared and don't need pinning. 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>