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>
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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>
