Doing an audit of trace events, I discovered two trace events in the xen
subsystem that use a hack to create zero data size trace events. This is not
what trace events are for. Trace events add memory footprint overhead, and
if all you need to do is see if a function is hit or not, simply make that
function noinline and use function tracer filtering.
Worse yet, the hack used was:
__array(char, x, 0)
Which creates a static string of zero in length. There's assumptions about
such constructs in ftrace that this is a dynamic string that is nul
terminated. This is not the case with these tracepoints and can cause
problems in various parts of ftrace.
Nuke the trace events!
Link: http://lkml.kernel.org/r/20180509144605.5a220327@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 95a7d76897 ("xen/mmu: Use Xen specific TLB flush instead of the generic one.")
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Juergen Gross noticed that commit f7f99100d8 ("mm: stop zeroing memory
during allocation in vmemmap") broke XEN PV domains when deferred struct
page initialization is enabled.
This is because the xen's PagePinned() flag is getting erased from
struct pages when they are initialized later in boot.
Juergen fixed this problem by disabling deferred pages on xen pv
domains. It is desirable, however, to have this feature available as it
reduces boot time. This fix re-enables the feature for pv-dmains, and
fixes the problem the following way:
The fix is to delay setting PagePinned flag until struct pages for all
allocated memory are initialized, i.e. until after free_all_bootmem().
A new x86_init.hyper op init_after_bootmem() is called to let xen know
that boot allocator is done, and hence struct pages for all the
allocated memory are now initialized. If deferred page initialization
is enabled, the rest of struct pages are going to be initialized later
in boot once page_alloc_init_late() is called.
xen_after_bootmem() walks page table's pages and marks them pinned.
Link: http://lkml.kernel.org/r/20180226160112.24724-2-pasha.tatashin@oracle.com
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Acked-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Tested-by: Juergen Gross <jgross@suse.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Laura Abbott <labbott@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Mathias Krause <minipli@googlemail.com>
Cc: Jinbum Park <jinb.park7@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Jia Zhang <zhang.jia@linux.alibaba.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With boot-time switching between paging modes, XEN_PV and XEN_PVH can be
boot into 4-level paging mode.
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20180216114948.68868-2-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
flush_tlb_single() and flush_tlb_one() sound almost identical, but
they really mean "flush one user translation" and "flush one kernel
translation". Rename them to flush_tlb_one_user() and
flush_tlb_one_kernel() to make the semantics more obvious.
[ I was looking at some PTI-related code, and the flush-one-address code
is unnecessarily hard to understand because the names of the helpers are
uninformative. This came up during PTI review, but no one got around to
doing it. ]
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Kees Cook <keescook@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux-MM <linux-mm@kvack.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Link: http://lkml.kernel.org/r/3303b02e3c3d049dc5235d5651e0ae6d29a34354.1517414378.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'for-linus-4.15-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"This contains two build fixes for clang and two fixes for rather
unlikely situations in the Xen gntdev driver"
* tag 'for-linus-4.15-rc8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/gntdev: Fix partial gntdev_mmap() cleanup
xen/gntdev: Fix off-by-one error when unmapping with holes
x86: xen: remove the use of VLAIS
x86/xen/time: fix section mismatch for xen_init_time_ops()
Variable Length Arrays In Structs (VLAIS) is not supported by Clang, and
frowned upon by others.
https://lkml.org/lkml/2013/9/23/500
Here, the VLAIS was used because the size of the bitmap returned from
xen_mc_entry() depended on possibly (based on kernel configuration)
runtime sized data. Rather than declaring args as a VLAIS then calling
sizeof on *args, we calculate the appropriate sizeof args manually.
Further, we can get rid of the #ifdef's and rely on num_possible_cpus()
(thanks to a helpful checkpatch warning from an earlier version of this
patch).
Suggested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Nick Desaulniers <nick.desaulniers@gmail.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Pull x86 PTI preparatory patches from Thomas Gleixner:
"Todays Advent calendar window contains twentyfour easy to digest
patches. The original plan was to have twenty three matching the date,
but a late fixup made that moot.
- Move the cpu_entry_area mapping out of the fixmap into a separate
address space. That's necessary because the fixmap becomes too big
with NRCPUS=8192 and this caused already subtle and hard to
diagnose failures.
The top most patch is fresh from today and cures a brain slip of
that tall grumpy german greybeard, who ignored the intricacies of
32bit wraparounds.
- Limit the number of CPUs on 32bit to 64. That's insane big already,
but at least it's small enough to prevent address space issues with
the cpu_entry_area map, which have been observed and debugged with
the fixmap code
- A few TLB flush fixes in various places plus documentation which of
the TLB functions should be used for what.
- Rename the SYSENTER stack to CPU_ENTRY_AREA stack as it is used for
more than sysenter now and keeping the name makes backtraces
confusing.
- Prevent LDT inheritance on exec() by moving it to arch_dup_mmap(),
which is only invoked on fork().
- Make vysycall more robust.
- A few fixes and cleanups of the debug_pagetables code. Check
PAGE_PRESENT instead of checking the PTE for 0 and a cleanup of the
C89 initialization of the address hint array which already was out
of sync with the index enums.
- Move the ESPFIX init to a different place to prepare for PTI.
- Several code moves with no functional change to make PTI
integration simpler and header files less convoluted.
- Documentation fixes and clarifications"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (24 commits)
x86/cpu_entry_area: Prevent wraparound in setup_cpu_entry_area_ptes() on 32bit
init: Invoke init_espfix_bsp() from mm_init()
x86/cpu_entry_area: Move it out of the fixmap
x86/cpu_entry_area: Move it to a separate unit
x86/mm: Create asm/invpcid.h
x86/mm: Put MMU to hardware ASID translation in one place
x86/mm: Remove hard-coded ASID limit checks
x86/mm: Move the CR3 construction functions to tlbflush.h
x86/mm: Add comments to clarify which TLB-flush functions are supposed to flush what
x86/mm: Remove superfluous barriers
x86/mm: Use __flush_tlb_one() for kernel memory
x86/microcode: Dont abuse the TLB-flush interface
x86/uv: Use the right TLB-flush API
x86/entry: Rename SYSENTER_stack to CPU_ENTRY_AREA_entry_stack
x86/doc: Remove obvious weirdnesses from the x86 MM layout documentation
x86/mm/64: Improve the memory map documentation
x86/ldt: Prevent LDT inheritance on exec
x86/ldt: Rework locking
arch, mm: Allow arch_dup_mmap() to fail
x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode
...
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Merge tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"This contains two fixes for running under Xen:
- a fix avoiding resource conflicts between adding mmio areas and
memory hotplug
- a fix setting NX bits in page table entries copied from Xen when
running a PV guest"
* tag 'for-linus-4.15-rc5-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/balloon: Mark unallocated host memory as UNUSABLE
x86-64/Xen: eliminate W+X mappings
Put the cpu_entry_area into a separate P4D entry. The fixmap gets too big
and 0-day already hit a case where the fixmap PTEs were cleared by
cleanup_highmap().
Aside of that the fixmap API is a pain as it's all backwards.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
A few thousand such pages are usually left around due to the re-use of
L1 tables having been provided by the hypervisor (Dom0) or tool stack
(DomU). Set NX in the direct map variant, which needs to be done in L2
due to the dual use of the re-used L1s.
For x86_configure_nx() to actually do what it is supposed to do, call
get_cpu_cap() first. This was broken by commit 4763ed4d45 ("x86, mm:
Clean up and simplify NX enablement") when switching away from the
direct EFER read.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Pull x86 syscall entry code changes for PTI from Ingo Molnar:
"The main changes here are Andy Lutomirski's changes to switch the
x86-64 entry code to use the 'per CPU entry trampoline stack'. This,
besides helping fix KASLR leaks (the pending Page Table Isolation
(PTI) work), also robustifies the x86 entry code"
* 'WIP.x86-pti.entry-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (26 commits)
x86/cpufeatures: Make CPU bugs sticky
x86/paravirt: Provide a way to check for hypervisors
x86/paravirt: Dont patch flush_tlb_single
x86/entry/64: Make cpu_entry_area.tss read-only
x86/entry: Clean up the SYSENTER_stack code
x86/entry/64: Remove the SYSENTER stack canary
x86/entry/64: Move the IST stacks into struct cpu_entry_area
x86/entry/64: Create a per-CPU SYSCALL entry trampoline
x86/entry/64: Return to userspace from the trampoline stack
x86/entry/64: Use a per-CPU trampoline stack for IDT entries
x86/espfix/64: Stop assuming that pt_regs is on the entry stack
x86/entry/64: Separate cpu_current_top_of_stack from TSS.sp0
x86/entry: Remap the TSS into the CPU entry area
x86/entry: Move SYSENTER_stack to the beginning of struct tss_struct
x86/dumpstack: Handle stack overflow on all stacks
x86/entry: Fix assumptions that the HW TSS is at the beginning of cpu_tss
x86/kasan/64: Teach KASAN about the cpu_entry_area
x86/mm/fixmap: Generalize the GDT fixmap mechanism, introduce struct cpu_entry_area
x86/entry/gdt: Put per-CPU GDT remaps in ascending order
x86/dumpstack: Add get_stack_info() support for the SYSENTER stack
...
Currently, the GDT is an ad-hoc array of pages, one per CPU, in the
fixmap. Generalize it to be an array of a new 'struct cpu_entry_area'
so that we can cleanly add new things to it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Borislav Petkov <bp@suse.de>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Laight <David.Laight@aculab.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Eduardo Valentin <eduval@amazon.com>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: aliguori@amazon.com
Cc: daniel.gruss@iaik.tugraz.at
Cc: hughd@google.com
Cc: keescook@google.com
Link: https://lkml.kernel.org/r/20171204150605.563271721@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
"Xen features and fixes for v4.15-rc1
Apart from several small fixes it contains the following features:
- a series by Joao Martins to add vdso support of the pv clock
interface
- a series by Juergen Gross to add support for Xen pv guests to be
able to run on 5 level paging hosts
- a series by Stefano Stabellini adding the Xen pvcalls frontend
driver using a paravirtualized socket interface"
* tag 'for-linus-4.15-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (34 commits)
xen/pvcalls: fix potential endless loop in pvcalls-front.c
xen/pvcalls: Add MODULE_LICENSE()
MAINTAINERS: xen, kvm: track pvclock-abi.h changes
x86/xen/time: setup vcpu 0 time info page
x86/xen/time: set pvclock flags on xen_time_init()
x86/pvclock: add setter for pvclock_pvti_cpu0_va
ptp_kvm: probe for kvm guest availability
xen/privcmd: remove unused variable pageidx
xen: select grant interface version
xen: update arch/x86/include/asm/xen/cpuid.h
xen: add grant interface version dependent constants to gnttab_ops
xen: limit grant v2 interface to the v1 functionality
xen: re-introduce support for grant v2 interface
xen: support priv-mapping in an HVM tools domain
xen/pvcalls: remove redundant check for irq >= 0
xen/pvcalls: fix unsigned less than zero error check
xen/time: Return -ENODEV from xen_get_wallclock()
xen/pvcalls-front: mark expected switch fall-through
xen: xenbus_probe_frontend: mark expected switch fall-throughs
xen/time: do not decrease steal time after live migration on xen
...
Physical addresses on processors supporting 5 level paging can be up to
52 bits wide. For a Xen pv guest running on such a machine those
physical addresses have to be supported in order to be able to use any
memory on the machine even if the guest itself does not support 5 level
paging.
So when reading/writing a MFN from/to a pte don't use the kernel's
PTE_PFN_MASK but a new XEN_PTE_MFN_MASK allowing full 40 bit wide MFNs.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
It was decided 5-level paging is not going to be supported in XEN_PV.
Let's drop the dead code from the XEN_PV code.
Tested-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@suse.de>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170929140821.37654-6-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'for-linus-4.14c-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
- avoid a warning when compiling with clang
- consider read-only bits in xen-pciback when writing to a BAR
- fix a boot crash of pv-domains
* tag 'for-linus-4.14c-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/mmu: Call xen_cleanhighmap() with 4MB aligned for page tables mapping
xen-pciback: relax BAR sizing write value check
x86/xen: clean up clang build warning
When bootup a PVM guest with large memory(Ex.240GB), XEN provided initial
mapping overlaps with kernel module virtual space. When mapping in this space
is cleared by xen_cleanhighmap(), in certain case there could be an 2MB mapping
left. This is due to XEN initialize 4MB aligned mapping but xen_cleanhighmap()
finish at 2MB boundary.
When module loading is just on top of the 2MB space, got below warning:
WARNING: at mm/vmalloc.c:106 vmap_pte_range+0x14e/0x190()
Call Trace:
[<ffffffff81117083>] warn_alloc_failed+0xf3/0x160
[<ffffffff81146022>] __vmalloc_area_node+0x182/0x1c0
[<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
[<ffffffff81145df7>] __vmalloc_node_range+0xa7/0x110
[<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
[<ffffffff8103ca54>] module_alloc+0x64/0x70
[<ffffffff810ac91e>] ? module_alloc_update_bounds+0x1e/0x80
[<ffffffff810ac91e>] module_alloc_update_bounds+0x1e/0x80
[<ffffffff810ac9a7>] move_module+0x27/0x150
[<ffffffff810aefa0>] layout_and_allocate+0x120/0x1b0
[<ffffffff810af0a8>] load_module+0x78/0x640
[<ffffffff811ff90b>] ? security_file_permission+0x8b/0x90
[<ffffffff810af6d2>] sys_init_module+0x62/0x1e0
[<ffffffff815154c2>] system_call_fastpath+0x16/0x1b
Then the mapping of 2MB is cleared, finally oops when the page in that space is
accessed.
BUG: unable to handle kernel paging request at ffff880022600000
IP: [<ffffffff81260877>] clear_page_c_e+0x7/0x10
PGD 1788067 PUD 178c067 PMD 22434067 PTE 0
Oops: 0002 [#1] SMP
Call Trace:
[<ffffffff81116ef7>] ? prep_new_page+0x127/0x1c0
[<ffffffff81117d42>] get_page_from_freelist+0x1e2/0x550
[<ffffffff81133010>] ? ii_iovec_copy_to_user+0x90/0x140
[<ffffffff81119c9d>] __alloc_pages_nodemask+0x12d/0x230
[<ffffffff81155516>] alloc_pages_vma+0xc6/0x1a0
[<ffffffff81006ffd>] ? pte_mfn_to_pfn+0x7d/0x100
[<ffffffff81134cfb>] do_anonymous_page+0x16b/0x350
[<ffffffff81139c34>] handle_pte_fault+0x1e4/0x200
[<ffffffff8100712e>] ? xen_pmd_val+0xe/0x10
[<ffffffff810052c9>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e
[<ffffffff81139dab>] handle_mm_fault+0x15b/0x270
[<ffffffff81510c10>] do_page_fault+0x140/0x470
[<ffffffff8150d7d5>] page_fault+0x25/0x30
Call xen_cleanhighmap() with 4MB aligned for page tables mapping to fix it.
The unnecessory call of xen_cleanhighmap() in DEBUG mode is also removed.
-v2: add comment about XEN alignment from Juergen.
References: https://lists.xen.org/archives/html/xen-devel/2012-07/msg01562.html
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@oracle.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
[boris: added 'xen/mmu' tag to commit subject]
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Merge tag 'for-linus-4.14b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"A fix for a missing __init annotation and two cleanup patches"
* tag 'for-linus-4.14b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen, arm64: drop dummy lookup_address()
xen: don't compile pv-specific parts if XEN_PV isn't configured
xen: x86: mark xen_find_pt_base as __init
gcc-4.6 causes a harmless link-time warning:
WARNING: vmlinux.o(.text.unlikely+0x48e): Section mismatch in reference from the function xen_find_pt_base() to the function .init.text:m2p()
The function xen_find_pt_base() references
the function __init m2p().
This is often because xen_find_pt_base lacks a __init
annotation or the annotation of m2p is wrong.
Newer compilers inline this function, so it never shows up, but marking
it __init is the right way to avoid the warning.
Fixes: 70e6119955 ("xen: move p2m list if conflicting with e820 map")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
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Merge tag 'for-linus-4.14b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen updates from Juergen Gross:
- the new pvcalls backend for routing socket calls from a guest to dom0
- some cleanups of Xen code
- a fix for wrong usage of {get,put}_cpu()
* tag 'for-linus-4.14b-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip: (27 commits)
xen/mmu: set MMU_NORMAL_PT_UPDATE in remap_area_mfn_pte_fn
xen: Don't try to call xen_alloc_p2m_entry() on autotranslating guests
xen/events: events_fifo: Don't use {get,put}_cpu() in xen_evtchn_fifo_init()
xen/pvcalls: use WARN_ON(1) instead of __WARN()
xen: remove not used trace functions
xen: remove unused function xen_set_domain_pte()
xen: remove tests for pvh mode in pure pv paths
xen-platform: constify pci_device_id.
xen: cleanup xen.h
xen: introduce a Kconfig option to enable the pvcalls backend
xen/pvcalls: implement write
xen/pvcalls: implement read
xen/pvcalls: implement the ioworker functions
xen/pvcalls: disconnect and module_exit
xen/pvcalls: implement release command
xen/pvcalls: implement poll command
xen/pvcalls: implement accept command
xen/pvcalls: implement listen command
xen/pvcalls: implement bind command
xen/pvcalls: implement connect command
...
The function xen_set_domain_pte() is used nowhere in the kernel.
Remove it.
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
The SME patches we are about to apply add some E820 logic, so merge in
pending E820 code changes first, to have a single code base.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
As Eric said,
"what we need to do is move the variable vmcoreinfo_note out of the
kernel's .bss section. And modify the code to regenerate and keep this
information in something like the control page.
Definitely something like this needs a page all to itself, and ideally
far away from any other kernel data structures. I clearly was not
watching closely the data someone decided to keep this silly thing in
the kernel's .bss section."
This patch allocates extra pages for these vmcoreinfo_XXX variables, one
advantage is that it enhances some safety of vmcoreinfo, because
vmcoreinfo now is kept far away from other kernel data structures.
Link: http://lkml.kernel.org/r/1493281021-20737-1-git-send-email-xlpang@redhat.com
Signed-off-by: Xunlei Pang <xlpang@redhat.com>
Tested-by: Michael Holzheu <holzheu@linux.vnet.ibm.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Suggested-by: Eric Biederman <ebiederm@xmission.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dave Young <dyoung@redhat.com>
Cc: Hari Bathini <hbathini@linux.vnet.ibm.com>
Cc: Mahesh Salgaonkar <mahesh@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
x86's lazy TLB mode used to be fairly weak -- it would switch to
init_mm the first time it tried to flush a lazy TLB. This meant an
unnecessary CR3 write and, if the flush was remote, an unnecessary
IPI.
Rewrite it entirely. When we enter lazy mode, we simply remove the
CPU from mm_cpumask. This means that we need a way to figure out
whether we've missed a flush when we switch back out of lazy mode.
I use the tlb_gen machinery to track whether a context is up to
date.
Note to reviewers: this patch, my itself, looks a bit odd. I'm
using an array of length 1 containing (ctx_id, tlb_gen) rather than
just storing tlb_gen, and making it at array isn't necessary yet.
I'm doing this because the next few patches add PCID support, and,
with PCID, we need ctx_id, and the array will end up with a length
greater than 1. Making it an array now means that there will be
less churn and therefore less stress on your eyeballs.
NB: This is dubious but, AFAICT, still correct on Xen and UV.
xen_exit_mmap() uses mm_cpumask() for nefarious purposes and this
patch changes the way that mm_cpumask() works. This should be okay,
since Xen *also* iterates all online CPUs to find all the CPUs it
needs to twiddle.
The UV tlbflush code is rather dated and should be changed.
Here are some benchmark results, done on a Skylake laptop at 2.3 GHz
(turbo off, intel_pstate requesting max performance) under KVM with
the guest using idle=poll (to avoid artifacts when bouncing between
CPUs). I haven't done any real statistics here -- I just ran them
in a loop and picked the fastest results that didn't look like
outliers. Unpatched means commit a4eb8b9935, so all the
bookkeeping overhead is gone.
MADV_DONTNEED; touch the page; switch CPUs using sched_setaffinity. In
an unpatched kernel, MADV_DONTNEED will send an IPI to the previous CPU.
This is intended to be a nearly worst-case test.
patched: 13.4µs
unpatched: 21.6µs
Vitaly's pthread_mmap microbenchmark with 8 threads (on four cores),
nrounds = 100, 256M data
patched: 1.1 seconds or so
unpatched: 1.9 seconds or so
The sleepup on Vitaly's test appearss to be because it spends a lot
of time blocked on mmap_sem, and this patch avoids sending IPIs to
blocked CPUs.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Nadav Amit <nadav.amit@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Andrew Banman <abanman@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Dimitri Sivanich <sivanich@sgi.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Travis <travis@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/ddf2c92962339f4ba39d8fc41b853936ec0b44f1.1498751203.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With CONFIG_X86_5LEVEL=y, level 4 is no longer top level of page tables.
Let's give these variable more generic names: init_top_pgt and
early_top_pgt.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/20170606113133.22974-9-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The kernel has several code paths that read CR3. Most of them assume that
CR3 contains the PGD's physical address, whereas some of them awkwardly
use PHYSICAL_PAGE_MASK to mask off low bits.
Add explicit mask macros for CR3 and convert all of the CR3 readers.
This will keep them from breaking when PCID is enabled.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/883f8fb121f4616c1c1427ad87350bb2f5ffeca1.1497288170.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Lazy TLB state is currently managed in a rather baroque manner.
AFAICT, there are three possible states:
- Non-lazy. This means that we're running a user thread or a
kernel thread that has called use_mm(). current->mm ==
current->active_mm == cpu_tlbstate.active_mm and
cpu_tlbstate.state == TLBSTATE_OK.
- Lazy with user mm. We're running a kernel thread without an mm
and we're borrowing an mm_struct. We have current->mm == NULL,
current->active_mm == cpu_tlbstate.active_mm, cpu_tlbstate.state
!= TLBSTATE_OK (i.e. TLBSTATE_LAZY or 0). The current cpu is set
in mm_cpumask(current->active_mm). CR3 points to
current->active_mm->pgd. The TLB is up to date.
- Lazy with init_mm. This happens when we call leave_mm(). We
have current->mm == NULL, current->active_mm ==
cpu_tlbstate.active_mm, but that mm is only relelvant insofar as
the scheduler is tracking it for refcounting. cpu_tlbstate.state
!= TLBSTATE_OK. The current cpu is clear in
mm_cpumask(current->active_mm). CR3 points to swapper_pg_dir,
i.e. init_mm->pgd.
This patch simplifies the situation. Other than perf, x86 stops
caring about current->active_mm at all. We have
cpu_tlbstate.loaded_mm pointing to the mm that CR3 references. The
TLB is always up to date for that mm. leave_mm() just switches us
to init_mm. There are no longer any special cases for mm_cpumask,
and switch_mm() switches mms without worrying about laziness.
After this patch, cpu_tlbstate.state serves only to tell the TLB
flush code whether it may switch to init_mm instead of doing a
normal flush.
This makes fairly extensive changes to xen_exit_mmap(), which used
to look a bit like black magic.
Perf is unchanged. With or without this change, perf may behave a bit
erratically if it tries to read user memory in kernel thread context.
We should build on this patch to teach perf to never look at user
memory when cpu_tlbstate.loaded_mm != current->mm.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Rather than passing all the contents of flush_tlb_info to
flush_tlb_others(), pass a pointer to the structure directly. For
consistency, this also removes the unnecessary cpu parameter from
uv_flush_tlb_others() to make its signature match the other
*flush_tlb_others() functions.
This serves two purposes:
- It will dramatically simplify future patches that change struct
flush_tlb_info, which I'm planning to do.
- struct flush_tlb_info is an adequate description of what to do
for a local flush, too, so by reusing it we can remove duplicated
code between local and remove flushes in a future patch.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Borislav Petkov <bpetkov@suse.de>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Nadav Amit <namit@vmware.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
[ Fix build warning. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
There are some leftovers testing for pvh guest mode in pv-only source
files. Remove them.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
When booted as pv-guest the p2m list presented by the Xen is already
mapped to virtual addresses. In dom0 case the hypervisor might make use
of 2M- or 1G-pages for this mapping. Unfortunately while being properly
aligned in virtual and machine address space, those pages might not be
aligned properly in guest physical address space.
So when trying to obtain the guest physical address of such a page
pud_pfn() and pmd_pfn() must be avoided as those will mask away guest
physical address bits not being zero in this special case.
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
For kdump to work correctly it needs the physical address of
vmcoreinfo_note. When running as dom0 this means the virtual address
has to be translated to the related machine address.
paddr_vmcoreinfo_note() is meant to do the translation via
__pa_symbol() only, but being attributed "weak" it can be replaced
easily in Xen case.
Signed-off-by: Juergen Gross <jgross@suse.com>
Tested-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Basically, mmu.c is renamed to mmu_pv.c and some code moved out to common
mmu.c.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Steven Rostedt (VMware)