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2015-02-23x86/xen: Initialize cr4 shadow for 64-bit PV(H) guestsBoris Ostrovsky
Commit 1e02ce4cccdc ("x86: Store a per-cpu shadow copy of CR4") introduced CR4 shadows. These shadows are initialized in early boot code. The commit missed initialization for 64-bit PV(H) guests that this patch adds. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-02-23x86/xen: Make sure X2APIC_ENABLE bit of MSR_IA32_APICBASE is not setBoris Ostrovsky
Commit d524165cb8db ("x86/apic: Check x2apic early") tests X2APIC_ENABLE bit of MSR_IA32_APICBASE when CONFIG_X86_X2APIC is off and panics the kernel when this bit is set. Xen's PV guests will pass this MSR read to the hypervisor which will return its version of the MSR, where this bit might be set. Make sure we clear it before returning MSR value to the caller. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-02-21Merge branch 'locking-urgent-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull locking fixes from Ingo Molnar: "Two fixes: the paravirt spin_unlock() corruption/crash fix, and an rtmutex NULL dereference crash fix" * 'locking-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/spinlocks/paravirt: Fix memory corruption on unlock locking/rtmutex: Avoid a NULL pointer dereference on deadlock
2015-02-18x86/spinlocks/paravirt: Fix memory corruption on unlockRaghavendra K T
Paravirt spinlock clears slowpath flag after doing unlock. As explained by Linus currently it does: prev = *lock; add_smp(&lock->tickets.head, TICKET_LOCK_INC); /* add_smp() is a full mb() */ if (unlikely(lock->tickets.tail & TICKET_SLOWPATH_FLAG)) __ticket_unlock_slowpath(lock, prev); which is *exactly* the kind of things you cannot do with spinlocks, because after you've done the "add_smp()" and released the spinlock for the fast-path, you can't access the spinlock any more. Exactly because a fast-path lock might come in, and release the whole data structure. Linus suggested that we should not do any writes to lock after unlock(), and we can move slowpath clearing to fastpath lock. So this patch implements the fix with: 1. Moving slowpath flag to head (Oleg): Unlocked locks don't care about the slowpath flag; therefore we can keep it set after the last unlock, and clear it again on the first (try)lock. -- this removes the write after unlock. note that keeping slowpath flag would result in unnecessary kicks. By moving the slowpath flag from the tail to the head ticket we also avoid the need to access both the head and tail tickets on unlock. 2. use xadd to avoid read/write after unlock that checks the need for unlock_kick (Linus): We further avoid the need for a read-after-release by using xadd; the prev head value will include the slowpath flag and indicate if we need to do PV kicking of suspended spinners -- on modern chips xadd isn't (much) more expensive than an add + load. Result: setup: 16core (32 cpu +ht sandy bridge 8GB 16vcpu guest) benchmark overcommit %improve kernbench 1x -0.13 kernbench 2x 0.02 dbench 1x -1.77 dbench 2x -0.63 [Jeremy: Hinted missing TICKET_LOCK_INC for kick] [Oleg: Moved slowpath flag to head, ticket_equals idea] [PeterZ: Added detailed changelog] Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Reported-by: Sasha Levin <sasha.levin@oracle.com> Tested-by: Sasha Levin <sasha.levin@oracle.com> Signed-off-by: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Reviewed-by: Oleg Nesterov <oleg@redhat.com> Cc: Andrew Jones <drjones@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Christoph Lameter <cl@linux.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dave Jones <davej@redhat.com> Cc: David Vrabel <david.vrabel@citrix.com> Cc: Fernando Luis Vázquez Cao <fernando_b1@lab.ntt.co.jp> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ulrich Obergfell <uobergfe@redhat.com> Cc: Waiman Long <Waiman.Long@hp.com> Cc: a.ryabinin@samsung.com Cc: dave@stgolabs.net Cc: hpa@zytor.com Cc: jasowang@redhat.com Cc: jeremy@goop.org Cc: paul.gortmaker@windriver.com Cc: riel@redhat.com Cc: tglx@linutronix.de Cc: waiman.long@hp.com Cc: xen-devel@lists.xenproject.org Link: http://lkml.kernel.org/r/20150215173043.GA7471@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-02-16Merge branch 'perf-core-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 perf updates from Ingo Molnar: "This series tightens up RDPMC permissions: currently even highly sandboxed x86 execution environments (such as seccomp) have permission to execute RDPMC, which may leak various perf events / PMU state such as timing information and other CPU execution details. This 'all is allowed' RDPMC mode is still preserved as the (non-default) /sys/devices/cpu/rdpmc=2 setting. The new default is that RDPMC access is only allowed if a perf event is mmap-ed (which is needed to correctly interpret RDPMC counter values in any case). As a side effect of these changes CR4 handling is cleaned up in the x86 code and a shadow copy of the CR4 value is added. The extra CR4 manipulation adds ~ <50ns to the context switch cost between rdpmc-capable and rdpmc-non-capable mms" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/x86: Add /sys/devices/cpu/rdpmc=2 to allow rdpmc for all tasks perf/x86: Only allow rdpmc if a perf_event is mapped perf: Pass the event to arch_perf_update_userpage() perf: Add pmu callbacks to track event mapping and unmapping x86: Add a comment clarifying LDT context switching x86: Store a per-cpu shadow copy of CR4 x86: Clean up cr4 manipulation
2015-02-14Merge tag 'for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux Pull ACCESS_ONCE() rule tightening from Christian Borntraeger: "Tighten rules for ACCESS_ONCE This series tightens the rules for ACCESS_ONCE to only work on scalar types. It also contains the necessary fixups as indicated by build bots of linux-next. Now everything is in place to prevent new non-scalar users of ACCESS_ONCE and we can continue to convert code to READ_ONCE/WRITE_ONCE" * tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/borntraeger/linux: kernel: Fix sparse warning for ACCESS_ONCE next: sh: Fix compile error kernel: tighten rules for ACCESS ONCE mm/gup: Replace ACCESS_ONCE with READ_ONCE x86/spinlock: Leftover conversion ACCESS_ONCE->READ_ONCE x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCE ppc/hugetlbfs: Replace ACCESS_ONCE with READ_ONCE ppc/kvm: Replace ACCESS_ONCE with READ_ONCE
2015-02-04x86: Clean up cr4 manipulationAndy Lutomirski
CR4 manipulation was split, seemingly at random, between direct (write_cr4) and using a helper (set/clear_in_cr4). Unfortunately, the set_in_cr4 and clear_in_cr4 helpers also poke at the boot code, which only a small subset of users actually wanted. This patch replaces all cr4 access in functions that don't leave cr4 exactly the way they found it with new helpers cr4_set_bits, cr4_clear_bits, and cr4_set_bits_and_update_boot. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Vince Weaver <vince@deater.net> Cc: "hillf.zj" <hillf.zj@alibaba-inc.com> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/495a10bdc9e67016b8fd3945700d46cfd5c12c2f.1414190806.git.luto@amacapital.net Signed-off-by: Ingo Molnar <mingo@kernel.org>
2015-01-28xen: mark grant mapped pages as foreignJennifer Herbert
Use the "foreign" page flag to mark pages that have a grant map. Use page->private to store information of the grant (the granting domain and the grant reference). Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28x86/xen: require ballooned pages for grant mapsJennifer Herbert
Ballooned pages are always used for grant maps which means the original frame does not need to be saved in page->index nor restored after the grant unmap. This allows the workaround in netback for the conflicting use of the (unionized) page->index and page->pfmemalloc to be removed. Signed-off-by: Jennifer Herbert <jennifer.herbert@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28xen: remove scratch frames for ballooned pages and m2p overrideDavid Vrabel
The scratch frame mappings for ballooned pages and the m2p override are broken. Remove them in preparation for replacing them with simpler mechanisms that works. The scratch pages did not ensure that the page was not in use. In particular, the foreign page could still be in use by hardware. If the guest reused the frame the hardware could read or write that frame. The m2p override did not handle the same frame being granted by two different grant references. Trying an M2P override lookup in this case is impossible. With the m2p override removed, the grant map/unmap for the kernel mappings (for x86 PV) can be easily batched in set_foreign_p2m_mapping() and clear_foreign_p2m_mapping(). Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2015-01-28xen/grant-table: pre-populate kernel unmap ops for xen_gnttab_unmap_refs()David Vrabel
When unmapping grants, instead of converting the kernel map ops to unmap ops on the fly, pre-populate the set of unmap ops. This allows the grant unmap for the kernel mappings to be trivially batched in the future. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
2015-01-28x86/xen: cleanup arch/x86/xen/mmu.cJuergen Gross
Remove a nested ifdef. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28x86/xen: add some __init annotations in arch/x86/xen/mmu.cJuergen Gross
The file arch/x86/xen/mmu.c has some functions that can be annotated with "__init". Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28x86/xen: add some __init and static annotations in arch/x86/xen/setup.cJuergen Gross
Some more functions in arch/x86/xen/setup.c can be made "__init". xen_ignore_unusable() can be made "static". Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28x86/xen: use correct types for addresses in arch/x86/xen/setup.cJuergen Gross
In many places in arch/x86/xen/setup.c wrong types are used for physical addresses (u64 or unsigned long long). Use phys_addr_t instead. Use macros already defined instead of open coding them. Correct some other type mismatches. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-28x86/xen: cleanup arch/x86/xen/setup.cJuergen Gross
Remove extern declarations in arch/x86/xen/setup.c which are either not used or redundant. Move needed other extern declarations to xen-ops.h Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-26x86,xen: use current->state helpersDavidlohr Bueso
Call __set_current_state() instead of assigning the new state directly. These interfaces also aid CONFIG_DEBUG_ATOMIC_SLEEP environments, keeping track of who changed the state. Signed-off-by: Davidlohr Bueso <dbueso@suse.de> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-20x86/xen: prefer TSC over xen clocksource for dom0Palik, Imre
In Dom0's the use of the TSC clocksource (whenever it is stable enough to be used) instead of the Xen clocksource should not cause any issues, as Dom0 VMs never live-migrated. The TSC clocksource is somewhat more efficient than the Xen paravirtualised clocksource, thus it should have higher rating. This patch decreases the rating of the Xen clocksource in Dom0s to 275. Which is half-way between the rating of the TSC clocksource (300) and the hpet clocksource (250). Cc: Anthony Liguori <aliguori@amazon.com> Signed-off-by: Imre Palik <imrep@amazon.de> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-19x86/xen/p2m: Replace ACCESS_ONCE with READ_ONCEChristian Borntraeger
ACCESS_ONCE does not work reliably on non-scalar types. For example gcc 4.6 and 4.7 might remove the volatile tag for such accesses during the SRA (scalar replacement of aggregates) step (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=58145) Change the p2m code to replace ACCESS_ONCE with READ_ONCE. Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com> Reviewed-by: Juergen Gross <jgross@suse.com> Acked-by: David Vrabel <david.vrabel@citrix.com>
2015-01-14Merge tag 'stable/for-linus-3.19-rc4-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull xen bug fixes from David Vrabel: "Several critical linear p2m fixes that prevented some hosts from booting" * tag 'stable/for-linus-3.19-rc4-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: x86/xen: properly retrieve NMI reason xen: check for zero sized area when invalidating memory xen: use correct type for physical addresses xen: correct race in alloc_p2m_pmd() xen: correct error for building p2m list on 32 bits x86/xen: avoid freeing static 'name' when kasprintf() fails x86/xen: add extra memory for remapped frames during setup x86/xen: don't count how many PFNs are identity mapped x86/xen: Free bootmem in free_p2m_page() during early boot x86/xen: Remove unnecessary BUG_ON(preemptible()) in xen_setup_timer()
2015-01-13x86/xen: properly retrieve NMI reasonJan Beulich
Using the native code here can't work properly, as the hypervisor would normally have cleared the two reason bits by the time Dom0 gets to see the NMI (if passed to it at all). There's a shared info field for this, and there's an existing hook to use - just fit the two together. This is particularly relevant so that NMIs intended to be handled by APEI / GHES actually make it to the respective handler. Note that the hook can (and should) be used irrespective of whether being in Dom0, as accessing port 0x61 in a DomU would be even worse, while the shared info field would just hold zero all the time. Note further that hardware NMI handling for PVH doesn't currently work anyway due to missing code in the hypervisor (but it is expected to work the native rather than the PV way). Signed-off-by: Jan Beulich <jbeulich@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-12xen: check for zero sized area when invalidating memoryJuergen Gross
With the introduction of the linear mapped p2m list setting memory areas to "invalid" had to be delayed. When doing the invalidation make sure no zero sized areas are processed. Signed-off-by: Juegren Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-12xen: use correct type for physical addressesJuergen Gross
When converting a pfn to a physical address be sure to use 64 bit wide types or convert the physical address to a pfn if possible. Signed-off-by: Juergen Gross <jgross@suse.com> Tested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-12xen: correct race in alloc_p2m_pmd()Juergen Gross
When allocating a new pmd for the linear mapped p2m list a check is done for not introducing another pmd when this just happened on another cpu. In this case the old pte pointer was returned which points to the p2m_missing or p2m_identity page. The correct value would be the pointer to the found new page. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-12xen: correct error for building p2m list on 32 bitsJuergen Gross
In xen_rebuild_p2m_list() for large areas of invalid or identity mapped memory the pmd entries on 32 bit systems are initialized wrong. Correct this error. Suggested-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-08x86/xen: avoid freeing static 'name' when kasprintf() failsVitaly Kuznetsov
In case kasprintf() fails in xen_setup_timer() we assign name to the static string "<timer kasprintf failed>". We, however, don't check that fact before issuing kfree() in xen_teardown_timer(), kernel is supposed to crash with 'kernel BUG at mm/slub.c:3341!' Solve the issue by making name a fixed length string inside struct xen_clock_event_device. 16 bytes should be enough. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2015-01-08x86/xen: add extra memory for remapped frames during setupDavid Vrabel
If the non-RAM regions in the e820 memory map are larger than the size of the initial balloon, a BUG was triggered as the frames are remaped beyond the limit of the linear p2m. The frames are remapped into the initial balloon area (xen_extra_mem) but not enough of this is available. Ensure enough extra memory regions are added for these remapped frames. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com>
2015-01-08x86/xen: don't count how many PFNs are identity mappedDavid Vrabel
This accounting is just used to print a diagnostic message that isn't very useful. Signed-off-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Juergen Gross <jgross@suse.com>
2015-01-08x86/xen: Free bootmem in free_p2m_page() during early bootBoris Ostrovsky
With recent changes in p2m we now have legitimate cases when p2m memory needs to be freed during early boot (i.e. before slab is initialized). Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-23x86/xen: Remove unnecessary BUG_ON(preemptible()) in xen_setup_timer()Boris Ostrovsky
There is no reason for having it and, with commit 250a1ac685f1 ("x86, smpboot: Remove pointless preempt_disable() in native_smp_prepare_cpus()"), it prevents HVM guests from booting. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-16Merge tag 'stable/for-linus-3.19-rc0b-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip Pull additional xen update from David Vrabel: "Xen: additional features for 3.19-rc0 - Linear p2m for x86 PV guests which simplifies the p2m code, improves performance and will allow for > 512 GB PV guests in the future. A last-minute, configuration specific issue was discovered with this change which is why it was not included in my previous pull request. This is now been fixed and tested" * tag 'stable/for-linus-3.19-rc0b-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: xen: switch to post-init routines in xen mmu.c earlier Revert "swiotlb-xen: pass dev_addr to swiotlb_tbl_unmap_single" xen: annotate xen_set_identity_and_remap_chunk() with __init xen: introduce helper functions to do safe read and write accesses xen: Speed up set_phys_to_machine() by using read-only mappings xen: switch to linear virtual mapped sparse p2m list xen: Hide get_phys_to_machine() to be able to tune common path x86: Introduce function to get pmd entry pointer xen: Delay invalidating extra memory xen: Delay m2p_override initialization xen: Delay remapping memory of pv-domain xen: use common page allocation function in p2m.c xen: Make functions static xen: fix some style issues in p2m.c
2014-12-11xen: switch to post-init routines in xen mmu.c earlierJuergen Gross
With the virtual mapped linear p2m list the post-init mmu operations must be used for setting up the p2m mappings, as in case of CONFIG_FLATMEM the init routines may trigger BUGs. paging_init() sets up all infrastructure needed to switch to the post-init mmu ops done by xen_post_allocator_init(). With the virtual mapped linear p2m list we need some mmu ops during setup of this list, so we have to switch to the correct mmu ops as soon as possible. The p2m list is usable from the beginning, just expansion requires to have established the new linear mapping. So the call of xen_remap_memory() had to be introduced, but this is not due to the mmu ops requiring this. Summing it up: calling xen_post_allocator_init() not directly after paging_init() was conceptually wrong in the beginning, it just didn't matter up to now as no functions used between the two calls needed some critical mmu ops (e.g. alloc_pte). This has changed now, so I corrected it. Reported-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-10Merge branch 'x86-vdso-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 vdso updates from Ingo Molnar: "Various vDSO updates from Andy Lutomirski, mostly cleanups and reorganization to improve maintainability, but also some micro-optimizations and robustization changes" * 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86_64/vsyscall: Restore orig_ax after vsyscall seccomp x86_64: Add a comment explaining the TASK_SIZE_MAX guard page x86_64,vsyscall: Make vsyscall emulation configurable x86_64, vsyscall: Rewrite comment and clean up headers in vsyscall code x86_64, vsyscall: Turn vsyscalls all the way off when vsyscall==none x86,vdso: Use LSL unconditionally for vgetcpu x86: vdso: Fix build with older gcc x86_64/vdso: Clean up vgetcpu init and merge the vdso initcalls x86_64/vdso: Remove jiffies from the vvar page x86/vdso: Make the PER_CPU segment 32 bits x86/vdso: Make the PER_CPU segment start out accessed x86/vdso: Change the PER_CPU segment to use struct desc_struct x86_64/vdso: Move getcpu code from vsyscall_64.c to vdso/vma.c x86_64/vsyscall: Move all of the gate_area code to vsyscall_64.c
2014-12-10Merge branch 'x86-mm-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip Pull x86 mm tree changes from Ingo Molnar: "The biggest change is full PAT support from Jürgen Gross: The x86 architecture offers via the PAT (Page Attribute Table) a way to specify different caching modes in page table entries. The PAT MSR contains 8 entries each specifying one of 6 possible cache modes. A pte references one of those entries via 3 bits: _PAGE_PAT, _PAGE_PWT and _PAGE_PCD. The Linux kernel currently supports only 4 different cache modes. The PAT MSR is set up in a way that the setting of _PAGE_PAT in a pte doesn't matter: the top 4 entries in the PAT MSR are the same as the 4 lower entries. This results in the kernel not supporting e.g. write-through mode. Especially this cache mode would speed up drivers of video cards which now have to use uncached accesses. OTOH some old processors (Pentium) don't support PAT correctly and the Xen hypervisor has been using a different PAT MSR configuration for some time now and can't change that as this setting is part of the ABI. This patch set abstracts the cache mode from the pte and introduces tables to translate between cache mode and pte bits (the default cache mode "write back" is hard-wired to PAT entry 0). The tables are statically initialized with values being compatible to old processors and current usage. As soon as the PAT MSR is changed (or - in case of Xen - is read at boot time) the tables are changed accordingly. Requests of mappings with special cache modes are always possible now, in case they are not supported there will be a fallback to a compatible but slower mode. Summing it up, this patch set adds the following features: - capability to support WT and WP cache modes on processors with full PAT support - processors with no or uncorrect PAT support are still working as today, even if WT or WP cache mode are selected by drivers for some pages - reduction of Xen special handling regarding cache mode Another change is a boot speedup on ridiculously large RAM systems, plus other smaller fixes" * 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (22 commits) x86: mm: Move PAT only functions to mm/pat.c xen: Support Xen pv-domains using PAT x86: Enable PAT to use cache mode translation tables x86: Respect PAT bit when copying pte values between large and normal pages x86: Support PAT bit in pagetable dump for lower levels x86: Clean up pgtable_types.h x86: Use new cache mode type in memtype related functions x86: Use new cache mode type in mm/ioremap.c x86: Use new cache mode type in setting page attributes x86: Remove looking for setting of _PAGE_PAT_LARGE in pageattr.c x86: Use new cache mode type in track_pfn_remap() and track_pfn_insert() x86: Use new cache mode type in mm/iomap_32.c x86: Use new cache mode type in asm/pgtable.h x86: Use new cache mode type in arch/x86/mm/init_64.c x86: Use new cache mode type in arch/x86/pci x86: Use new cache mode type in drivers/video/fbdev/vermilion x86: Use new cache mode type in drivers/video/fbdev/gbefb.c x86: Use new cache mode type in include/asm/fb.h x86: Make page cache mode a real type x86: mm: Use 2GB memory block size on large-memory x86-64 systems ...
2014-12-08xen: annotate xen_set_identity_and_remap_chunk() with __initJuergen Gross
Commit 5b8e7d80542487ff1bf17b4cf2922a01dee13d3a removed the __init annotation from xen_set_identity_and_remap_chunk(). Add it again. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-08xen: introduce helper functions to do safe read and write accessesJuergen Gross
Introduce two helper functions to safely read and write unsigned long values from or to memory when the access may fault because the mapping is non-present or read-only. These helpers can be used instead of open coded uses of __get_user() and __put_user() avoiding the need to do casts to fix sparse warnings. Use the helpers in page.h and p2m.c. This will fix the sparse warnings when doing "make C=1". Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Speed up set_phys_to_machine() by using read-only mappingsJuergen Gross
Instead of checking at each call of set_phys_to_machine() whether a new p2m page has to be allocated due to writing an entry in a large invalid or identity area, just map those areas read only and react to a page fault on write by allocating the new page. This change will make the common path with no allocation much faster as it only requires a single write of the new mfn instead of walking the address translation tables and checking for the special cases. Suggested-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: switch to linear virtual mapped sparse p2m listJuergen Gross
At start of the day the Xen hypervisor presents a contiguous mfn list to a pv-domain. In order to support sparse memory this mfn list is accessed via a three level p2m tree built early in the boot process. Whenever the system needs the mfn associated with a pfn this tree is used to find the mfn. Instead of using a software walked tree for accessing a specific mfn list entry this patch is creating a virtual address area for the entire possible mfn list including memory holes. The holes are covered by mapping a pre-defined page consisting only of "invalid mfn" entries. Access to a mfn entry is possible by just using the virtual base address of the mfn list and the pfn as index into that list. This speeds up the (hot) path of determining the mfn of a pfn. Kernel build on a Dell Latitude E6440 (2 cores, HT) in 64 bit Dom0 showed following improvements: Elapsed time: 32:50 -> 32:35 System: 18:07 -> 17:47 User: 104:00 -> 103:30 Tested with following configurations: - 64 bit dom0, 8GB RAM - 64 bit dom0, 128 GB RAM, PCI-area above 4 GB - 32 bit domU, 512 MB, 8 GB, 43 GB (more wouldn't work even without the patch) - 32 bit domU, ballooning up and down - 32 bit domU, save and restore - 32 bit domU with PCI passthrough - 64 bit domU, 8 GB, 2049 MB, 5000 MB - 64 bit domU, ballooning up and down - 64 bit domU, save and restore - 64 bit domU with PCI passthrough Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Hide get_phys_to_machine() to be able to tune common pathJuergen Gross
Today get_phys_to_machine() is always called when the mfn for a pfn is to be obtained. Add a wrapper __pfn_to_mfn() as inline function to be able to avoid calling get_phys_to_machine() when possible as soon as the switch to a linear mapped p2m list has been done. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Delay invalidating extra memoryJuergen Gross
When the physical memory configuration is initialized the p2m entries for not pouplated memory pages are set to "invalid". As those pages are beyond the hypervisor built p2m list the p2m tree has to be extended. This patch delays processing the extra memory related p2m entries during the boot process until some more basic memory management functions are callable. This removes the need to create new p2m entries until virtual memory management is available. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Delay m2p_override initializationJuergen Gross
The m2p overrides are used to be able to find the local pfn for a foreign mfn mapped into the domain. They are used by driver backends having to access frontend data. As this functionality isn't used in early boot it makes no sense to initialize the m2p override functions very early. It can be done later without doing any harm, removing the need for allocating memory via extend_brk(). While at it make some m2p override functions static as they are only used internally. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Delay remapping memory of pv-domainJuergen Gross
Early in the boot process the memory layout of a pv-domain is changed to match the E820 map (either the host one for Dom0 or the Xen one) regarding placement of RAM and PCI holes. This requires removing memory pages initially located at positions not suitable for RAM and adding them later at higher addresses where no restrictions apply. To be able to operate on the hypervisor supported p2m list until a virtual mapped linear p2m list can be constructed, remapping must be delayed until virtual memory management is initialized, as the initial p2m list can't be extended unlimited at physical memory initialization time due to it's fixed structure. A further advantage is the reduction in complexity and code volume as we don't have to be careful regarding memory restrictions during p2m updates. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: use common page allocation function in p2m.cJuergen Gross
In arch/x86/xen/p2m.c three different allocation functions for obtaining a memory page are used: extend_brk(), alloc_bootmem_align() or __get_free_page(). Which of those functions is used depends on the progress of the boot process of the system. Introduce a common allocation routine selecting the to be called allocation routine dynamically based on the boot progress. This allows moving initialization steps without having to care about changing allocation calls. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: Make functions staticJuergen Gross
Some functions in arch/x86/xen/p2m.c are used locally only. Make them static. Rearrange the functions in p2m.c to avoid forward declarations. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-12-04xen: fix some style issues in p2m.cJuergen Gross
The source arch/x86/xen/p2m.c has some coding style issues. Fix them. Signed-off-by: Juergen Gross <jgross@suse.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-11-16xen: Support Xen pv-domains using PATJuergen Gross
With the dynamical mapping between cache modes and pgprot values it is now possible to use all cache modes via the Xen hypervisor PAT settings in a pv domain. All to be done is to read the PAT configuration MSR and set up the translation tables accordingly. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Cc: stefan.bader@canonical.com Cc: xen-devel@lists.xensource.com Cc: ville.syrjala@linux.intel.com Cc: jbeulich@suse.com Cc: toshi.kani@hp.com Cc: plagnioj@jcrosoft.com Cc: tomi.valkeinen@ti.com Cc: bhelgaas@google.com Link: http://lkml.kernel.org/r/1415019724-4317-19-git-send-email-jgross@suse.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-11-10x86/core, x86/xen/smp: Use 'die_complete' completion when taking CPU downBoris Ostrovsky
Commit 2ed53c0d6cc9 ("x86/smpboot: Speed up suspend/resume by avoiding 100ms sleep for CPU offline during S3") introduced completions to CPU offlining process. These completions are not initialized on Xen kernels causing a panic in play_dead_common(). Move handling of die_complete into common routines to make them available to Xen guests. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> Cc: tianyu.lan@intel.com Cc: konrad.wilk@oracle.com Cc: xen-devel@lists.xenproject.org Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/1414770572-7950-1-git-send-email-boris.ostrovsky@oracle.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-11-03x86_64,vsyscall: Make vsyscall emulation configurableAndy Lutomirski
This adds CONFIG_X86_VSYSCALL_EMULATION, guarded by CONFIG_EXPERT. Turning it off completely disables vsyscall emulation, saving ~3.5k for vsyscall_64.c, 4k for vsyscall_emu_64.S (the fake vsyscall page), some tiny amount of core mm code that supports a gate area, and possibly 4k for a wasted pagetable. The latter is because the vsyscall addresses are misaligned and fit poorly in the fixmap. Signed-off-by: Andy Lutomirski <luto@amacapital.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/406db88b8dd5f0cbbf38216d11be34bbb43c7eae.1414618407.git.luto@amacapital.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2014-10-23x86/xen: panic on bad Xen-provided memory mapMartin Kelly
Panic if Xen provides a memory map with 0 entries. Although this is unlikely, it is better to catch the error at the point of seeing the map than later on as a symptom of some other crash. Signed-off-by: Martin Kelly <martkell@amazon.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
2014-10-23x86/xen: Fix incorrect per_cpu accessor in xen_clocksource_read()Boris Ostrovsky
Commit 89cbc76768c2 ("x86: Replace __get_cpu_var uses") replaced __get_cpu_var() with this_cpu_ptr() in xen_clocksource_read() in such a way that instead of accessing a structure pointed to by a per-cpu pointer we are trying to get to a per-cpu structure. __this_cpu_read() of the pointer is the more appropriate accessor. Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>