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A bugfix commit:
45dbea5f55c0 ("x86/paravirt: Fix native_patch()")
... introduced a harmless warning:
arch/x86/kernel/paravirt_patch_32.c: In function 'native_patch':
arch/x86/kernel/paravirt_patch_32.c:71:1: error: label 'patch_default' defined but not used [-Werror=unused-label]
Fix it by annotating the label as __maybe_unused.
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: Piotr Gregor <piotrgregor@rsyncme.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 45dbea5f55c0 ("x86/paravirt: Fix native_patch()")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 FPU updates from Ingo Molnar:
"The main changes in this cycle were:
- do a large round of simplifications after all CPUs do 'eager' FPU
context switching in v4.9: remove CR0 twiddling, remove leftover
eager/lazy bts, etc (Andy Lutomirski)
- more FPU code simplifications: remove struct fpu::counter, clarify
nomenclature, remove unnecessary arguments/functions and better
structure the code (Rik van Riel)"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu: Remove clts()
x86/fpu: Remove stts()
x86/fpu: Handle #NM without FPU emulation as an error
x86/fpu, lguest: Remove CR0.TS support
x86/fpu, kvm: Remove host CR0.TS manipulation
x86/fpu: Remove irq_ts_save() and irq_ts_restore()
x86/fpu: Stop saving and restoring CR0.TS in fpu__init_check_bugs()
x86/fpu: Get rid of two redundant clts() calls
x86/fpu: Finish excising 'eagerfpu'
x86/fpu: Split old_fpu & new_fpu handling into separate functions
x86/fpu: Remove 'cpu' argument from __cpu_invalidate_fpregs_state()
x86/fpu: Split old & new FPU code paths
x86/fpu: Remove __fpregs_(de)activate()
x86/fpu: Rename lazy restore functions to "register state valid"
x86/fpu, kvm: Remove KVM vcpu->fpu_counter
x86/fpu: Remove struct fpu::counter
x86/fpu: Remove use_eager_fpu()
x86/fpu: Remove the XFEATURE_MASK_EAGER/LAZY distinction
x86/fpu: Hard-disable lazy FPU mode
x86/crypto, x86/fpu: Remove X86_FEATURE_EAGER_FPU #ifdef from the crc32c code
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While chasing a regression I noticed we potentially patch the wrong
code in native_patch().
If we do not select the native code sequence, we must use the default
patcher, not fall-through the switch case.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alok Kataria <akataria@vmware.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Anvin <hpa@zytor.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel test robot <xiaolong.ye@intel.com>
Fixes: 3cded4179481 ("x86/paravirt: Optimize native pv_lock_ops.vcpu_is_preempted()")
Link: http://lkml.kernel.org/r/20161208154349.270616999@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Avoid the pointless function call to pv_lock_ops.vcpu_is_preempted()
when a paravirt spinlock enabled kernel is ran on native hardware.
Do this by patching out the CALL instruction with "XOR %RAX,%RAX"
which has the same effect (0 return value).
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David.Laight@ACULAB.COM
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Pan Xinhui <xinhui.pan@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: benh@kernel.crashing.org
Cc: boqun.feng@gmail.com
Cc: borntraeger@de.ibm.com
Cc: bsingharora@gmail.com
Cc: dave@stgolabs.net
Cc: jgross@suse.com
Cc: kernellwp@gmail.com
Cc: konrad.wilk@oracle.com
Cc: mpe@ellerman.id.au
Cc: paulmck@linux.vnet.ibm.com
Cc: paulus@samba.org
Cc: pbonzini@redhat.com
Cc: rkrcmar@redhat.com
Cc: will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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The kernel doesn't use clts() any more. Remove it and all of its
paravirt infrastructure.
A careful reader may notice that xen_clts() appears to have been
buggy -- it didn't update xen_cr0_value.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Casasnovas <quentin.casasnovas@oracle.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm list <kvm@vger.kernel.org>
Link: http://lkml.kernel.org/r/3d3c8ca62f17579b9849a013d71e59a4d5d1b079.1477951965.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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We've unconditionally used the queued spinlock for many releases now.
Its time to remove the old ticket lock code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Waiman Long <waiman.long@hpe.com>
Cc: Waiman.Long@hpe.com
Cc: david.vrabel@citrix.com
Cc: dhowells@redhat.com
Cc: pbonzini@redhat.com
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/20160518184302.GO3193@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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As result of commit "x86/xen: Avoid fast syscall path for Xen PV
guests", the irq_enable_sysexit pv op is not called by Xen PV guests
anymore and since they were the only ones who used it we can
safely remove it.
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Borislav Petkov <bp@suse.de>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: david.vrabel@citrix.com
Cc: konrad.wilk@oracle.com
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1447970147-1733-3-git-send-email-boris.ostrovsky@oracle.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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We've had ->read_tsc() and ->read_tscp() paravirt hooks since
the very beginning of paravirt, i.e.,
d3561b7fa0fb ("[PATCH] paravirt: header and stubs for paravirtualisation").
AFAICT, the only paravirt guest implementation that ever
replaced these calls was vmware, and it's gone. Arguably even
vmware shouldn't have hooked RDTSC -- we fully support systems
that don't have a TSC at all, so there's no point for a paravirt
implementation to pretend that we have a TSC but to replace it.
I also doubt that these hooks actually worked. Calls to rdtscl()
and rdtscll(), which respected the hooks, were used seemingly
interchangeably with native_read_tsc(), which did not.
Just remove them. If anyone ever needs them again, they can try
to make a case for why they need them.
Before, on a paravirt config:
text data bss dec hex filename
12618257 1816384 1093632 15528273 ecf151 vmlinux
After:
text data bss dec hex filename
12617207 1816384 1093632 15527223 eced37 vmlinux
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andy Lutomirski <luto@amacapital.net>
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: Huang Rui <ray.huang@amd.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kvm ML <kvm@vger.kernel.org>
Cc: virtualization@lists.linux-foundation.org
Link: http://lkml.kernel.org/r/d08a2600fb298af163681e5efd8e599d889a5b97.1434501121.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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We use the regular paravirt call patching to switch between:
native_queued_spin_lock_slowpath() __pv_queued_spin_lock_slowpath()
native_queued_spin_unlock() __pv_queued_spin_unlock()
We use a callee saved call for the unlock function which reduces the
i-cache footprint and allows 'inlining' of SPIN_UNLOCK functions
again.
We further optimize the unlock path by patching the direct call with a
"movb $0,%arg1" if we are indeed using the native unlock code. This
makes the unlock code almost as fast as the !PARAVIRT case.
This significantly lowers the overhead of having
CONFIG_PARAVIRT_SPINLOCKS enabled, even for native code.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Waiman Long <Waiman.Long@hp.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Daniel J Blueman <daniel@numascale.com>
Cc: David Vrabel <david.vrabel@citrix.com>
Cc: Douglas Hatch <doug.hatch@hp.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paolo Bonzini <paolo.bonzini@gmail.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Scott J Norton <scott.norton@hp.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: virtualization@lists.linux-foundation.org
Cc: xen-devel@lists.xenproject.org
Link: http://lkml.kernel.org/r/1429901803-29771-10-git-send-email-Waiman.Long@hp.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Impact: Optimization
Several paravirt ops implementations simply return their arguments,
the most obvious being the make_pte/pte_val class of operations on
native.
On 32-bit, the identity function is literally a no-op, as the calling
convention uses the same registers for the first argument and return.
On 64-bit, it can be implemented with a single "mov".
This patch adds special identity functions for 32 and 64 bit argument,
and machinery to recognize them and replace them with either nops or a
mov as appropriate.
At the moment, the only users for the identity functions are the
pagetable entry conversion functions.
The result is a measureable improvement on pagetable-heavy benchmarks
(2-3%, reducing the pvops overhead from 5 to 2%).
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
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Before:
total: 3 errors, 1 warnings, 49 lines checked
After:
total: 2 errors, 1 warnings, 49 lines checked
paolo@paolo-desktop:~/linux.trees.git$ md5sum /tmp/paravirt_patch_32.o.*
a78eea4264723e18c49dcfbe0ee0aae7 /tmp/paravirt_patch_32.o.after
a78eea4264723e18c49dcfbe0ee0aae7 /tmp/paravirt_patch_32.o.before
Signed-off-by: Paolo Ciarrocchi <paolo.ciarrocchi@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Don't conflate sysret and sysexit; they're different instructions with
different semantics, and may be in use at the same time (at least
within the same kernel, depending on whether its an Intel or AMD
system).
sysexit - just return to userspace, does no register restoration of
any kind; must explicitly atomically enable interrupts.
sysret - reloads flags from r11, so no need to explicitly enable
interrupts on 64-bit, responsible for restoring usermode %gs
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citirx.com>
Cc: xen-devel <xen-devel@lists.xensource.com>
Cc: Stephen Tweedie <sct@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>
Cc: Mark McLoughlin <markmc@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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The core patching code for paravirt is sufficiently different
among i386 and x86_64, and we move them to specific files.
Signed-off-by: Glauber de Oliveira Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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