| Commit message (Collapse) | Author | Age | Files | Lines |
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After the THP refcounting change, obtaining a compound pages from
get_user_pages() no longer allows us to assume the entire compound page
is immediately mappable from a secondary MMU.
A secondary MMU doesn't want to call get_user_pages() more than once for
each compound page, in order to know if it can map the whole compound
page. So a secondary MMU needs to know from a single get_user_pages()
invocation when it can map immediately the entire compound page to avoid
a flood of unnecessary secondary MMU faults and spurious
atomic_inc()/atomic_dec() (pages don't have to be pinned by MMU notifier
users).
Ideally instead of the page->_mapcount < 1 check, get_user_pages()
should return the granularity of the "page" mapping in the "mm" passed
to get_user_pages(). However it's non trivial change to pass the "pmd"
status belonging to the "mm" walked by get_user_pages up the stack (up
to the caller of get_user_pages). So the fix just checks if there is
not a single pte mapping on the page returned by get_user_pages, and in
turn if the caller can assume that the whole compound page is mapped in
the current "mm" (in a pmd_trans_huge()). In such case the entire
compound page is safe to map into the secondary MMU without additional
get_user_pages() calls on the surrounding tail/head pages. In addition
of being faster, not having to run other get_user_pages() calls also
reduces the memory footprint of the secondary MMU fault in case the pmd
split happened as result of memory pressure.
Without this fix after a MADV_DONTNEED (like invoked by QEMU during
postcopy live migration or balloning) or after generic swapping (with a
failure in split_huge_page() that would only result in pmd splitting and
not a physical page split), KVM would map the whole compound page into
the shadow pagetables, despite regular faults or userfaults (like
UFFDIO_COPY) may map regular pages into the primary MMU as result of the
pte faults, leading to the guest mode and userland mode going out of
sync and not working on the same memory at all times.
Any other secondary MMU notifier manager (KVM is just one of the many
MMU notifier users) will need the same information if it doesn't want to
run a flood of get_user_pages_fast and it can support multiple
granularity in the secondary MMU mappings, so I think it is justified to
be exposed not just to KVM.
The other option would be to move transparent_hugepage_adjust to
mm/huge_memory.c but that currently has all kind of KVM data structures
in it, so it's definitely not a cut-and-paste work, so I couldn't do a
fix as cleaner as this one for 4.6.
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: "Li, Liang Z" <liang.z.li@intel.com>
Cc: Amit Shah <amit.shah@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Some versions of Intel PT do not support tracing across VMXON, more
specifically, VMXON will clear TraceEn control bit and any attempt to
set it before VMXOFF will throw a #GP, which in the current state of
things will crash the kernel. Namely:
$ perf record -e intel_pt// kvm -nographic
on such a machine will kill it.
To avoid this, notify the intel_pt driver before VMXON and after
VMXOFF so that it knows when not to enable itself.
Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: hpa@zytor.com
Link: http://lkml.kernel.org/r/87oa9dwrfk.fsf@ashishki-desk.ger.corp.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This ensures that the guest doesn't see XSAVE extensions
(e.g. xgetbv1 or xsavec) that the host lacks.
Cc: stable@vger.kernel.org
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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An interrupt handler that uses the fpu can kill a KVM VM, if it runs
under the following conditions:
- the guest's xcr0 register is loaded on the cpu
- the guest's fpu context is not loaded
- the host is using eagerfpu
Note that the guest's xcr0 register and fpu context are not loaded as
part of the atomic world switch into "guest mode". They are loaded by
KVM while the cpu is still in "host mode".
Usage of the fpu in interrupt context is gated by irq_fpu_usable(). The
interrupt handler will look something like this:
if (irq_fpu_usable()) {
kernel_fpu_begin();
[... code that uses the fpu ...]
kernel_fpu_end();
}
As long as the guest's fpu is not loaded and the host is using eager
fpu, irq_fpu_usable() returns true (interrupted_kernel_fpu_idle()
returns true). The interrupt handler proceeds to use the fpu with
the guest's xcr0 live.
kernel_fpu_begin() saves the current fpu context. If this uses
XSAVE[OPT], it may leave the xsave area in an undesirable state.
According to the SDM, during XSAVE bit i of XSTATE_BV is not modified
if bit i is 0 in xcr0. So it's possible that XSTATE_BV[i] == 1 and
xcr0[i] == 0 following an XSAVE.
kernel_fpu_end() restores the fpu context. Now if any bit i in
XSTATE_BV == 1 while xcr0[i] == 0, XRSTOR generates a #GP. The
fault is trapped and SIGSEGV is delivered to the current process.
Only pre-4.2 kernels appear to be vulnerable to this sequence of
events. Commit 653f52c ("kvm,x86: load guest FPU context more eagerly")
from 4.2 forces the guest's fpu to always be loaded on eagerfpu hosts.
This patch fixes the bug by keeping the host's xcr0 loaded outside
of the interrupts-disabled region where KVM switches into guest mode.
Cc: stable@vger.kernel.org
Suggested-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: David Matlack <dmatlack@google.com>
[Move load after goto cancel_injection. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm-unit-tests complained about the PFEC is not set properly, e.g,:
test pte.rw pte.d pte.nx pde.p pde.rw pde.pse user fetch: FAIL: error code 15
expected 5
Dump mapping: address: 0x123400000000
------L4: 3e95007
------L3: 3e96007
------L2: 2000083
It's caused by the reason that PFEC returned to guest is copied from the
PFEC triggered by shadow page table
This patch fixes it and makes the logic of updating errcode more clean
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
[Do not assume pfec.p=1. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When a vCPU runs on a nohz_full core, the hrtimer used by
the lapic emulation code can be migrated to another core.
When this happens, it's possible to observe milisecond
latency when delivering timer IRQs to KVM guests.
The huge latency is mainly due to the fact that
apic_timer_fn() expects to run during a kvm exit. It
sets KVM_REQ_PENDING_TIMER and let it be handled on kvm
entry. However, if the timer fires on a different core,
we have to wait until the next kvm exit for the guest
to see KVM_REQ_PENDING_TIMER set.
This problem became visible after commit 9642d18ee. This
commit changed the timer migration code to always attempt
to migrate timers away from nohz_full cores. While it's
discussable if this is correct/desirable (I don't think
it is), it's clear that the lapic emulation code has
a requirement on firing the hrtimer in the same core
where it was started. This is achieved by making the
hrtimer pinned.
Lastly, note that KVM has code to migrate timers when a
vCPU is scheduled to run in different core. However, this
forced migration may fail. When this happens, we can have
the same problem. If we want 100% correctness, we'll have
to modify apic_timer_fn() to cause a kvm exit when it runs
on a different core than the vCPU. Not sure if this is
possible.
Here's a reproducer for the issue being fixed:
1. Set all cores but core0 to be nohz_full cores
2. Start a guest with a single vCPU
3. Trace apic_timer_fn() and kvm_inject_apic_timer_irqs()
You'll see that apic_timer_fn() will run in core0 while
kvm_inject_apic_timer_irqs() runs in a different core. If
you get both on core0, try running a program that takes 100%
of the CPU and pin it to core0 to force the vCPU out.
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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In absence of shadow dirty mask, there is no need to set page dirty
if page has never been writable. This is a tiny optimization but
good to have for people who care much about dirty page tracking.
Signed-off-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If SynIC is disabled, there is nothing that userspace can do to
handle these exits; on the other hand, userspace probably will
not know about KVM_EXIT_HYPERV_HCALL and complain about it or
even exit. Just prevent anything bad from happening by handling
the hypercall in KVM and returning an "invalid hypercall" code.
Fixes: 83326e43f27e9a8a501427a0060f8af519a39bb2
Cc: Andrey Smetanin <irqlevel@gmail.com>
Reviewed-by: Roman Kagan <rkagan@virtuozzo.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Non maskable interrupts (NMI) are preferred to interrupts in current
implementation. If a NMI is pending and NMI is blocked by the result
of nmi_allowed(), pending interrupt is not injected and
enable_irq_window() is not executed, even if interrupts injection is
allowed.
In old kernel (e.g. 2.6.32), schedule() is often called in NMI context.
In this case, interrupts are needed to execute iret that intends end
of NMI. The flag of blocking new NMI is not cleared until the guest
execute the iret, and interrupts are blocked by pending NMI. Due to
this, iret can't be invoked in the guest, and the guest is starved
until block is cleared by some events (e.g. canceling injection).
This patch injects pending interrupts, when it's allowed, even if NMI
is blocked. And, If an interrupts is pending after executing
inject_pending_event(), enable_irq_window() is executed regardless of
NMI pending counter.
Cc: stable@vger.kernel.org
Signed-off-by: Yuki Shibuya <shibuya.yk@ncos.nec.co.jp>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
"Misc fixes:
- fix hotplug bugs
- fix irq live lock
- fix various topology handling bugs
- fix APIC ACK ordering
- fix PV iopl handling
- fix speling
- fix/tweak memcpy_mcsafe() return value
- fix fbcon bug
- remove stray prototypes"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/msr: Remove unused native_read_tscp()
x86/apic: Remove declaration of unused hw_nmi_is_cpu_stuck
x86/oprofile/nmi: Add missing hotplug FROZEN handling
x86/hpet: Use proper mask to modify hotplug action
x86/apic/uv: Fix the hotplug notifier
x86/apb/timer: Use proper mask to modify hotplug action
x86/topology: Use total_cpus not nr_cpu_ids for logical packages
x86/topology: Fix Intel HT disable
x86/topology: Fix logical package mapping
x86/irq: Cure live lock in fixup_irqs()
x86/tsc: Prevent NULL pointer deref in calibrate_delay_is_known()
x86/apic: Fix suspicious RCU usage in smp_trace_call_function_interrupt()
x86/iopl: Fix iopl capability check on Xen PV
x86/iopl/64: Properly context-switch IOPL on Xen PV
selftests/x86: Add an iopl test
x86/mm, x86/mce: Fix return type/value for memcpy_mcsafe()
x86/video: Don't assume all FB devices are PCI devices
arch/x86/irq: Purge useless handler declarations from hw_irq.h
x86: Fix misspellings in comments
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Pull in some merge window leftovers.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Signed-off-by: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: trivial@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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This happens when doing the reboot test from virt-tests:
[ 131.833653] BUG: unable to handle kernel NULL pointer dereference at (null)
[ 131.842461] IP: [<ffffffffa0950087>] kvm_page_track_is_active+0x17/0x60 [kvm]
[ 131.850500] PGD 0
[ 131.852763] Oops: 0000 [#1] SMP
[ 132.007188] task: ffff880075fbc500 ti: ffff880850a3c000 task.ti: ffff880850a3c000
[ 132.138891] Call Trace:
[ 132.141639] [<ffffffffa092bd11>] page_fault_handle_page_track+0x31/0x40 [kvm]
[ 132.149732] [<ffffffffa093380f>] paging64_page_fault+0xff/0x910 [kvm]
[ 132.172159] [<ffffffffa092c734>] kvm_mmu_page_fault+0x64/0x110 [kvm]
[ 132.179372] [<ffffffffa06743c2>] handle_exception+0x1b2/0x430 [kvm_intel]
[ 132.187072] [<ffffffffa067a301>] vmx_handle_exit+0x1e1/0xc50 [kvm_intel]
...
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Fixes: 3d0c27ad6ee465f174b09ee99fcaf189c57d567a
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The barrier also orders the write to mode from any reads
to the page tables done and so update the comment.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Update spte before increasing tlbs_dirty to make sure no tlb flush
in lost after spte is zapped. This pairs with the barrier in the
kvm_flush_remote_tlbs().
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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walk_shadow_page_lockless_begin/end()
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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There is already a barrier inside of kvm_flush_remote_tlbs() which can
help to make sure everyone sees our modifications to the page tables and
see changes to vcpu->mode here. So remove the smp_mb in the
kvm_mmu_commit_zap_page() and update the comment.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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X86_FEATURE_PKU is referred to as "PKU" in the hardware documentation:
CPUID.7.0.ECX[3]:PKU. X86_FEATURE_OSPKE is software support for pkeys,
enumerated with CPUID.7.0.ECX[4]:OSPKE, and it reflects the setting of
CR4.PKE(bit 22).
This patch disables CPUID:PKU without ept, because pkeys is not yet
implemented for shadow paging.
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Protection keys define a new 4-bit protection key field (PKEY) in bits
62:59 of leaf entries of the page tables, the PKEY is an index to PKRU
register(16 domains), every domain has 2 bits(write disable bit, access
disable bit).
Static logic has been produced in update_pkru_bitmask, dynamic logic need
read pkey from page table entries, get pkru value, and deduce the correct
result.
[ Huaitong: Xiao helps to modify many sections. ]
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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PKEYS defines a new status bit in the PFEC. PFEC.PK (bit 5), if some
conditions is true, the fault is considered as a PKU violation.
pkru_mask indicates if we need to check PKRU.ADi and PKRU.WDi, and
does cache some conditions for permission_fault.
[ Huaitong: Xiao helps to modify many sections. ]
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Currently XSAVE state of host is not restored after VM-exit and PKRU
is managed by XSAVE so the PKRU from guest is still controlling the
memory access even if the CPU is running the code of host. This is
not safe as KVM needs to access the memory of userspace (e,g QEMU) to
do some emulation.
So we save/restore PKRU when guest/host switches.
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This patch adds pkeys support for xsave state.
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Pkeys is disabled if CPU is in non-paging mode in hardware. However KVM
always uses paging mode to emulate guest non-paging, mode with TDP. To
emulate this behavior, pkeys needs to be manually disabled when guest
switches to non-paging mode.
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This patch removes magic number with enum cpuid_leafs.
Signed-off-by: Huaitong Han <huaitong.han@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This will help in the implementation of PKRU, where the PK bit of the page
fault error code cannot be computed in advance (unlike I/D, R/W and U/S).
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Old KVM guests invoke single-context invvpid without actually checking
whether it is supported. This was fixed by commit 518c8ae ("KVM: VMX:
Make sure single type invvpid is supported before issuing invvpid
instruction", 2010-08-01) and the patch after, but pre-2.6.36
kernels lack it including RHEL 6.
Reported-by: jmontleo@redhat.com
Tested-by: jmontleo@redhat.com
Cc: stable@vger.kernel.org
Fixes: 99b83ac893b84ed1a62ad6d1f2b6cc32026b9e85
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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A guest executing an invalid invvpid instruction would hang
because the instruction pointer was not updated.
Reported-by: jmontleo@redhat.com
Tested-by: jmontleo@redhat.com
Cc: stable@vger.kernel.org
Fixes: 99b83ac893b84ed1a62ad6d1f2b6cc32026b9e85
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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A guest executing an invalid invept instruction would hang
because the instruction pointer was not updated.
Cc: stable@vger.kernel.org
Fixes: bfd0a56b90005f8c8a004baf407ad90045c2b11e
Reviewed-by: David Matlack <dmatlack@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull 'objtool' stack frame validation from Ingo Molnar:
"This tree adds a new kernel build-time object file validation feature
(ONFIG_STACK_VALIDATION=y): kernel stack frame correctness validation.
It was written by and is maintained by Josh Poimboeuf.
The motivation: there's a category of hard to find kernel bugs, most
of them in assembly code (but also occasionally in C code), that
degrades the quality of kernel stack dumps/backtraces. These bugs are
hard to detect at the source code level. Such bugs result in
incorrect/incomplete backtraces most of time - but can also in some
rare cases result in crashes or other undefined behavior.
The build time correctness checking is done via the new 'objtool'
user-space utility that was written for this purpose and which is
hosted in the kernel repository in tools/objtool/. The tool's (very
simple) UI and source code design is shaped after Git and perf and
shares quite a bit of infrastructure with tools/perf (which tooling
infrastructure sharing effort got merged via perf and is already
upstream). Objtool follows the well-known kernel coding style.
Objtool does not try to check .c or .S files, it instead analyzes the
resulting .o generated machine code from first principles: it decodes
the instruction stream and interprets it. (Right now objtool supports
the x86-64 architecture.)
From tools/objtool/Documentation/stack-validation.txt:
"The kernel CONFIG_STACK_VALIDATION option enables a host tool named
objtool which runs at compile time. It has a "check" subcommand
which analyzes every .o file and ensures the validity of its stack
metadata. It enforces a set of rules on asm code and C inline
assembly code so that stack traces can be reliable.
Currently it only checks frame pointer usage, but there are plans to
add CFI validation for C files and CFI generation for asm files.
For each function, it recursively follows all possible code paths
and validates the correct frame pointer state at each instruction.
It also follows code paths involving special sections, like
.altinstructions, __jump_table, and __ex_table, which can add
alternative execution paths to a given instruction (or set of
instructions). Similarly, it knows how to follow switch statements,
for which gcc sometimes uses jump tables."
When this new kernel option is enabled (it's disabled by default), the
tool, if it finds any suspicious assembly code pattern, outputs
warnings in compiler warning format:
warning: objtool: rtlwifi_rate_mapping()+0x2e7: frame pointer state mismatch
warning: objtool: cik_tiling_mode_table_init()+0x6ce: call without frame pointer save/setup
warning: objtool:__schedule()+0x3c0: duplicate frame pointer save
warning: objtool:__schedule()+0x3fd: sibling call from callable instruction with changed frame pointer
... so that scripts that pick up compiler warnings will notice them.
All known warnings triggered by the tool are fixed by the tree, most
of the commits in fact prepare the kernel to be warning-free. Most of
them are bugfixes or cleanups that stand on their own, but there are
also some annotations of 'special' stack frames for justified cases
such entries to JIT-ed code (BPF) or really special boot time code.
There are two other long-term motivations behind this tool as well:
- To improve the quality and reliability of kernel stack frames, so
that they can be used for optimized live patching.
- To create independent infrastructure to check the correctness of
CFI stack frames at build time. CFI debuginfo is notoriously
unreliable and we cannot use it in the kernel as-is without extra
checking done both on the kernel side and on the build side.
The quality of kernel stack frames matters to debuggability as well,
so IMO we can merge this without having to consider the live patching
or CFI debuginfo angle"
* 'core-objtool-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (52 commits)
objtool: Only print one warning per function
objtool: Add several performance improvements
tools: Copy hashtable.h into tools directory
objtool: Fix false positive warnings for functions with multiple switch statements
objtool: Rename some variables and functions
objtool: Remove superflous INIT_LIST_HEAD
objtool: Add helper macros for traversing instructions
objtool: Fix false positive warnings related to sibling calls
objtool: Compile with debugging symbols
objtool: Detect infinite recursion
objtool: Prevent infinite recursion in noreturn detection
objtool: Detect and warn if libelf is missing and don't break the build
tools: Support relative directory path for 'O='
objtool: Support CROSS_COMPILE
x86/asm/decoder: Use explicitly signed chars
objtool: Enable stack metadata validation on 64-bit x86
objtool: Add CONFIG_STACK_VALIDATION option
objtool: Add tool to perform compile-time stack metadata validation
x86/kprobes: Mark kretprobe_trampoline() stack frame as non-standard
sched: Always inline context_switch()
...
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Stacktool generates the following warning:
stacktool: arch/x86/kvm/vmx.o: vmx_handle_external_intr()+0x67: call without frame pointer save/setup
By adding the stackpointer as an output operand, this patch ensures that a
stack frame is created when CONFIG_FRAME_POINTER is enabled for the inline
assmebly statement.
Signed-off-by: Chris J Arges <chris.j.arges@canonical.com>
Reviewed-by: 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: gleb@kernel.org
Cc: kvm@vger.kernel.org
Cc: live-patching@vger.kernel.org
Cc: pbonzini@redhat.com
Link: http://lkml.kernel.org/r/1453499078-9330-3-git-send-email-chris.j.arges@canonical.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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With some configs (including allyesconfig), gcc doesn't inline
test_cc(). When that happens, test_cc() doesn't create a stack frame
before inserting the inline asm call instruction. This breaks frame
pointer convention if CONFIG_FRAME_POINTER is enabled and can result in
a bad stack trace.
Force it to always be inlined so that its containing function's stack
frame can be used.
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/20160122161612.GE20502@treble.redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The callable functions created with the FOP* and FASTOP* macros are
missing ELF function annotations, which confuses tools like stacktool.
Properly annotate them.
This adds some additional labels to the assembly, but the generated
binary code is unchanged (with the exception of instructions which have
embedded references to __LINE__).
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Gleb Natapov <gleb@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm@vger.kernel.org
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/e399651c89ace54906c203c0557f66ed6ea3ce8d.1453405861.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Pull KVM updates from Paolo Bonzini:
"One of the largest releases for KVM... Hardly any generic
changes, but lots of architecture-specific updates.
ARM:
- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- various optimizations to the vgic save/restore code.
PPC:
- enabled KVM-VFIO integration ("VFIO device")
- optimizations to speed up IPIs between vcpus
- in-kernel handling of IOMMU hypercalls
- support for dynamic DMA windows (DDW).
s390:
- provide the floating point registers via sync regs;
- separated instruction vs. data accesses
- dirty log improvements for huge guests
- bugfixes and documentation improvements.
x86:
- Hyper-V VMBus hypercall userspace exit
- alternative implementation of lowest-priority interrupts using
vector hashing (for better VT-d posted interrupt support)
- fixed guest debugging with nested virtualizations
- improved interrupt tracking in the in-kernel IOAPIC
- generic infrastructure for tracking writes to guest
memory - currently its only use is to speedup the legacy shadow
paging (pre-EPT) case, but in the future it will be used for
virtual GPUs as well
- much cleanup (LAPIC, kvmclock, MMU, PIT), including ubsan fixes"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (217 commits)
KVM: x86: remove eager_fpu field of struct kvm_vcpu_arch
KVM: x86: disable MPX if host did not enable MPX XSAVE features
arm64: KVM: vgic-v3: Only wipe LRs on vcpu exit
arm64: KVM: vgic-v3: Reset LRs at boot time
arm64: KVM: vgic-v3: Do not save an LR known to be empty
arm64: KVM: vgic-v3: Save maintenance interrupt state only if required
arm64: KVM: vgic-v3: Avoid accessing ICH registers
KVM: arm/arm64: vgic-v2: Make GICD_SGIR quicker to hit
KVM: arm/arm64: vgic-v2: Only wipe LRs on vcpu exit
KVM: arm/arm64: vgic-v2: Reset LRs at boot time
KVM: arm/arm64: vgic-v2: Do not save an LR known to be empty
KVM: arm/arm64: vgic-v2: Move GICH_ELRSR saving to its own function
KVM: arm/arm64: vgic-v2: Save maintenance interrupt state only if required
KVM: arm/arm64: vgic-v2: Avoid accessing GICH registers
KVM: s390: allocate only one DMA page per VM
KVM: s390: enable STFLE interpretation only if enabled for the guest
KVM: s390: wake up when the VCPU cpu timer expires
KVM: s390: step the VCPU timer while in enabled wait
KVM: s390: protect VCPU cpu timer with a seqcount
KVM: s390: step VCPU cpu timer during kvm_run ioctl
...
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It is now equal to use_eager_fpu(), which simply tests a cpufeature bit.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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When eager FPU is disabled, KVM will still see the MPX bit in CPUID and
presumably the MPX vmentry and vmexit controls. However, it will not
be able to expose the MPX XSAVE features to the guest, because the guest's
accessible XSAVE features are always a subset of host_xcr0.
In this case, we should disable the MPX CPUID bit, the BNDCFGS MSR,
and the MPX vmentry and vmexit controls for nested virtualization.
It is then unnecessary to enable guest eager FPU if the guest has the
MPX CPUID bit set.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD
KVM/ARM updates for 4.6
- VHE support so that we can run the kernel at EL2 on ARMv8.1 systems
- PMU support for guests
- 32bit world switch rewritten in C
- Various optimizations to the vgic save/restore code
Conflicts:
include/uapi/linux/kvm.h
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Avoid AND-NOT, most x86 processor lack an instruction for it.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Branch-free code is fun and everybody knows how much Avi loves it,
but last_pte_bitmap takes it a bit to the extreme. Since the code
is simply doing a range check, like
(level == 1 ||
((gpte & PT_PAGE_SIZE_MASK) && level < N)
we can make it branch-free without storing the entire truth table;
it is enough to cache N.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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mmu_sync_children can only process up to 16 pages at a time. Check
if we need to reschedule, and do not bother zapping the pages until
that happens.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_mmu_get_page is the only caller of kvm_sync_page_transient
and kvm_sync_pages. Moving the handling of the invalid_list there
removes the need for the underdocumented kvm_sync_page_transient
function.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Return true if the page was synced (and the TLB must be flushed)
and false if the page was zapped.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Calling kvm_unlink_unsync_page in the middle of __kvm_sync_page makes
things unnecessarily tricky. If kvm_mmu_prepare_zap_page is called,
it will call kvm_unlink_unsync_page too. So kvm_unlink_unsync_page can
be called just as well at the beginning or the end of __kvm_sync_page...
which means that we might do it in kvm_sync_page too and remove the
parameter.
kvm_sync_page ends up being the same code that kvm_sync_pages used
to have before the previous patch.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If the last argument is true, kvm_unlink_unsync_page is called anyway in
__kvm_sync_page (either by kvm_mmu_prepare_zap_page or by __kvm_sync_page
itself). Therefore, kvm_sync_pages can just call kvm_sync_page, instead
of going through kvm_unlink_unsync_page+__kvm_sync_page.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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By doing this, kvm_sync_pages can use __kvm_sync_page instead of
reinventing it. Because of kvm_mmu_flush_or_zap, the code does not
end up being more complex than before, and more cleanups to kvm_sync_pages
will come in the next patches.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This is a generalization of mmu_pte_write_flush_tlb, that also
takes care of calling kvm_mmu_commit_zap_page. The next
patches will introduce more uses.
Reviewed-by: Takuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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A function that does the same as i8254.c's muldiv64 has been added
(for KVM's own use, in fact!) in include/linux/math64.h. Use it
instead of muldiv64.
Reviewed-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Give a special invalid index to the root of the walk, so that we
can check the consistency of kvm_mmu_pages and mmu_page_path.
Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
[Extracted from a bigger patch proposed by Guangrong. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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kvm_mmu_pages_init is doing some really yucky stuff. It is setting
up a sentinel for mmu_page_clear_parents; however, because of a) the
way levels are numbered starting from 1 and b) the way mmu_page_path
sizes its arrays with PT64_ROOT_LEVEL-1 elements, the access can be
out of bounds. This is harmless because the code overwrites up to the
first two elements of parents->idx and these are initialized, and
because the sentinel is not needed in this case---mmu_page_clear_parents
exits anyway when it gets to the end of the array. However ubsan
complains, and everyone else should too.
This fix does three things. First it makes the mmu_page_path arrays
PT64_ROOT_LEVEL elements in size, so that we can write to them without
checking the level in advance. Second it disintegrates kvm_mmu_pages_init
between mmu_unsync_walk (to reset the struct kvm_mmu_pages) and
for_each_sp (to place the NULL sentinel at the end of the current path).
This is okay because the mmu_page_path is only used in
mmu_pages_clear_parents; mmu_pages_clear_parents itself is called within
a for_each_sp iterator, and hence always after a call to mmu_pages_next.
Third it changes mmu_pages_clear_parents to just use the sentinel to
stop iteration, without checking the bounds on level.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Reported-by: Mike Krinkin <krinkin.m.u@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The goto and temporary variable are unnecessary, just use return
statements.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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