When the TIF_SINGLESTEP tracee dequeues a signal,
handle_signal() clears TIF_FORCED_TF and X86_EFLAGS_TF but
leaves TIF_SINGLESTEP set.
If the tracer does PTRACE_SINGLESTEP again, enable_single_step()
sets X86_EFLAGS_TF but not TIF_FORCED_TF. This means that the
subsequent PTRACE_CONT doesn't not clear X86_EFLAGS_TF, and the
tracee gets the wrong SIGTRAP.
Test-case (needs -O2 to avoid prologue insns in signal handler):
#include <unistd.h>
#include <stdio.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <sys/user.h>
#include <assert.h>
#include <stddef.h>
void handler(int n)
{
asm("nop");
}
int child(void)
{
assert(ptrace(PTRACE_TRACEME, 0,0,0) == 0);
signal(SIGALRM, handler);
kill(getpid(), SIGALRM);
return 0x23;
}
void *getip(int pid)
{
return (void*)ptrace(PTRACE_PEEKUSER, pid,
offsetof(struct user, regs.rip), 0);
}
int main(void)
{
int pid, status;
pid = fork();
if (!pid)
return child();
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGALRM);
assert(ptrace(PTRACE_SINGLESTEP, pid, 0, SIGALRM) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP);
assert((getip(pid) - (void*)handler) == 0);
assert(ptrace(PTRACE_SINGLESTEP, pid, 0, SIGALRM) == 0);
assert(wait(&status) == pid);
assert(WIFSTOPPED(status) && WSTOPSIG(status) == SIGTRAP);
assert((getip(pid) - (void*)handler) == 1);
assert(ptrace(PTRACE_CONT, pid, 0,0) == 0);
assert(wait(&status) == pid);
assert(WIFEXITED(status) && WEXITSTATUS(status) == 0x23);
return 0;
}
The last assert() fails because PTRACE_CONT wrongly triggers
another single-step and X86_EFLAGS_TF can't be cleared by
debugger until the tracee does sys_rt_sigreturn().
Change handle_signal() to do user_disable_single_step() if
stepping, we do not need to preserve TIF_SINGLESTEP because we
are going to do ptrace_notify(), and it is simply wrong to leak
this bit.
While at it, change the comment to explain why we also need to
clear TF unconditionally after setup_rt_frame().
Note: in the longer term we should probably change
setup_sigcontext() to use get_flags() and then just remove this
user_disable_single_step(). And, the state of TIF_FORCED_TF can
be wrong after restore_sigcontext() which can set/clear TF, this
needs another fix.
This fix fixes the 'single_step_syscall_32' testcase in
the x86 testsuite:
Before:
~/linux/tools/testing/selftests/x86> ./single_step_syscall_32
[RUN] Set TF and check nop
[OK] Survived with TF set and 9 traps
[RUN] Set TF and check int80
[OK] Survived with TF set and 9 traps
[RUN] Set TF and check a fast syscall
[WARN] Hit 10000 SIGTRAPs with si_addr 0xf7789cc0, ip 0xf7789cc0
Trace/breakpoint trap (core dumped)
After:
~/linux/linux/tools/testing/selftests/x86> ./single_step_syscall_32
[RUN] Set TF and check nop
[OK] Survived with TF set and 9 traps
[RUN] Set TF and check int80
[OK] Survived with TF set and 9 traps
[RUN] Set TF and check a fast syscall
[OK] Survived with TF set and 39 traps
[RUN] Fast syscall with TF cleared
[OK] Nothing unexpected happened
Reported-by: Evan Teran <eteran@alum.rit.edu>
Reported-by: Pedro Alves <palves@redhat.com>
Tested-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: 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: Thomas Gleixner <tglx@linutronix.de>
[ Added x86 self-test info. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Pull x86 vdso changes from Ingo Molnar:
"Misc vDSO updates"
* 'x86-vdso-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Remove x32 intermediates during 'make clean'
x86/vdso: Teach 'make clean' to remove generated vdso-image-*.c files
x86/vdso32/syscall.S: Do not load __USER32_DS to %ss
x86/vdso: Fix the x86 vdso2c tool includes
Pull x86 fix from Ingo Molnar:
"Leftover from 4.0
Fix a local stack variable corruption with certain kdump usage
patterns (Dave Young)"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm/numa: Fix kernel stack corruption in numa_init()->numa_clear_kernel_node_hotplug()
Pull x86 RAS changes from Ingo Molnar:
"The main changes in this cycle were:
- Simplify the CMCI storm logic on Intel CPUs after yet another
report about a race in the code (Borislav Petkov)
- Enable the MCE threshold irq on AMD CPUs by default (Aravind
Gopalakrishnan)
- Add AMD-specific MCE-severity grading function. Further error
recovery actions will be based on its output (Aravind Gopalakrishnan)
- Documentation updates (Borislav Petkov)
- ... assorted fixes and cleanups"
* 'x86-ras-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce/severity: Fix warning about indented braces
x86/mce: Define mce_severity function pointer
x86/mce: Add an AMD severities-grading function
x86/mce: Reindent __mcheck_cpu_apply_quirks() properly
x86/mce: Use safe MSR accesses for AMD quirk
x86/MCE/AMD: Enable thresholding interrupts by default if supported
x86/MCE: Make mce_panic() fatal machine check msg in the same pattern
x86/MCE/intel: Cleanup CMCI storm logic
Documentation/acpi/einj: Correct and streamline text
x86/MCE/AMD: Drop bogus const modifier from AMD's bank4_names()
Pull x86 platform change from Ingo Molnar:
"An Intel Quark SoC fix"
* 'x86-platform-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/intel/quark: Run IMR self-test on IMR capble hw only
Pull x86 mm changes from Ingo Molnar:
"The main changes in this cycle were:
- reduce the x86/32 PAE per task PGD allocation overhead from 4K to
0.032k (Fenghua Yu)
- early_ioremap/memunmap() usage cleanups (Juergen Gross)
- gbpages support cleanups (Luis R Rodriguez)
- improve AMD Bulldozer (family 0x15) ASLR I$ aliasing workaround to
increase randomization by 3 bits (per bootup) (Hector
Marco-Gisbert)
- misc fixlets"
* 'x86-mm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mm: Improve AMD Bulldozer ASLR workaround
x86/mm/pat: Initialize __cachemode2pte_tbl[] and __pte2cachemode_tbl[] in a bit more readable fashion
init.h: Clean up the __setup()/early_param() macros
x86/mm: Simplify probe_page_size_mask()
x86/mm: Further simplify 1 GB kernel linear mappings handling
x86/mm: Use early_param_on_off() for direct_gbpages
init.h: Add early_param_on_off()
x86/mm: Simplify enabling direct_gbpages
x86/mm: Use IS_ENABLED() for direct_gbpages
x86/mm: Unexport set_memory_ro() and set_memory_rw()
x86/mm, efi: Use early_ioremap() in arch/x86/platform/efi/efi-bgrt.c
x86/mm: Use early_memunmap() instead of early_iounmap()
x86/mm/pat: Ensure different messages in STRICT_DEVMEM and PAT cases
x86/mm: Reduce PAE-mode per task pgd allocation overhead from 4K to 32 bytes
Pull x86 microcode changes from Ingo Molnar:
"Microcode driver updates: mostly cleanups but also some fixes
(Borislav Petkov)"
* 'x86-microcode-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/microcode/amd: Drop the pci_ids.h dependency
x86/microcode/intel: Fix printing of microcode blobs in show_saved_mc()
x86/microcode/intel: Check scan_microcode()'s retval
x86/microcode/intel: Sanitize microcode_pointer()
x86/microcode/intel: Move mc arg last in get_matching_{microcode|sig}
x86/microcode/intel: Simplify generic_load_microcode_early()
x86/microcode: Consolidate family,model, ... code
x86/microcode/intel: Rename update_match_revision()
x86/microcode/intel: Sanitize _save_mc()
x86/microcode/intel: Make _save_mc() return the updated saved count
x86/microcode/intel: Simplify load_ucode_intel_bsp()
x86/microcode/intel: Get rid of last arg to load_ucode_intel_bsp()
x86/microcode/intel: Do the mc_saved_src NULL check first
x86/microcode/intel: Check if microcode was found before applying
x86/microcode/intel: Fix out of bounds memory access to the extended header
Pull x86 fpu changes from Ingo Molnar:
"Various x86 FPU handling cleanups, refactorings and fixes (Borislav
Petkov, Oleg Nesterov, Rik van Riel)"
* 'x86-fpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (21 commits)
x86/fpu: Kill eager_fpu_init_bp()
x86/fpu: Don't allocate fpu->state for swapper/0
x86/fpu: Rename drop_init_fpu() to fpu_reset_state()
x86/fpu: Fold __drop_fpu() into its sole user
x86/fpu: Don't abuse drop_init_fpu() in flush_thread()
x86/fpu: Use restore_init_xstate() instead of math_state_restore() on kthread exec
x86/fpu: Introduce restore_init_xstate()
x86/fpu: Document user_fpu_begin()
x86/fpu: Factor out memset(xstate, 0) in fpu_finit() paths
x86/fpu: Change xstateregs_get()/set() to use ->xsave.i387 rather than ->fxsave
x86/fpu: Don't abuse FPU in kernel threads if use_eager_fpu()
x86/fpu: Always allow FPU in interrupt if use_eager_fpu()
x86/fpu: __kernel_fpu_begin() should clear fpu_owner_task even if use_eager_fpu()
x86/fpu: Also check fpu_lazy_restore() when use_eager_fpu()
x86/fpu: Use task_disable_lazy_fpu_restore() helper
x86/fpu: Use an explicit if/else in switch_fpu_prepare()
x86/fpu: Introduce task_disable_lazy_fpu_restore() helper
x86/fpu: Move lazy restore functions up a few lines
x86/fpu: Change math_error() to use unlazy_fpu(), kill (now) unused save_init_fpu()
x86/fpu: Don't do __thread_fpu_end() if use_eager_fpu()
...
Pull x86 debug changes from Ingo Molnar:
"Stack printing fixlets"
* 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/kernel: Use kstack_end() in dumpstack_64.c
x86/kernel: Fix output of show_stack_log_lvl()
Pull x86 cacheinfo sysfs changes from Ingo Molnar:
"This tree converts the x86 cacheinfo sysfs code to use the generic
code in drivers/base/cacheinfo.c.
It's not intended to change the sysfs ABI:
'This patch neither alters any existing sysfs entries nor their
formating, however since the generic cacheinfo has switched to
use the device attributes instead of the traditional raw
kobjects, a directory named 'power' along with its standard
attributes are added similar to any other device'"
* 'x86-cpu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu/cacheinfo: Fix cache_get_priv_group() for Intel processors
x86/cacheinfo: Move cacheinfo sysfs code to generic infrastructure
Pull x86 cleanups from Ingo Molnar:
"Various cleanups"
* 'x86-cleanups-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/iommu: Fix header comments regarding standard and _FINISH macros
x86/earlyprintk: Put CONFIG_PCI-only functions under the #ifdef
x86: Fix up obsolete __cpu_set() function usage
Pull x86 boot changes from Ingo Molnar:
"A number of cleanups"
* 'x86-boot-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/boot: Standardize strcmp()
x86/boot/64: Remove pointless early_printk() message
x86/boot/video: Move the 'video_segment' variable to video.c
Pull x86 asm changes from Ingo Molnar:
"There were lots of changes in this development cycle:
- over 100 separate cleanups, restructuring changes, speedups and
fixes in the x86 system call, irq, trap and other entry code, part
of a heroic effort to deobfuscate a decade old spaghetti asm code
and its C code dependencies (Denys Vlasenko, Andy Lutomirski)
- alternatives code fixes and enhancements (Borislav Petkov)
- simplifications and cleanups to the compat code (Brian Gerst)
- signal handling fixes and new x86 testcases (Andy Lutomirski)
- various other fixes and cleanups
By their nature many of these changes are risky - we tried to test
them well on many different x86 systems (there are no known
regressions), and they are split up finely to help bisection - but
there's still a fair bit of residual risk left so caveat emptor"
* 'x86-asm-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (148 commits)
perf/x86/64: Report regs_user->ax too in get_regs_user()
perf/x86/64: Simplify regs_user->abi setting code in get_regs_user()
perf/x86/64: Do report user_regs->cx while we are in syscall, in get_regs_user()
perf/x86/64: Do not guess user_regs->cs, ss, sp in get_regs_user()
x86/asm/entry/32: Tidy up JNZ instructions after TESTs
x86/asm/entry/64: Reduce padding in execve stubs
x86/asm/entry/64: Remove GET_THREAD_INFO() in ret_from_fork
x86/asm/entry/64: Simplify jumps in ret_from_fork
x86/asm/entry/64: Remove a redundant jump
x86/asm/entry/64: Optimize [v]fork/clone stubs
x86/asm/entry: Zero EXTRA_REGS for stub32_execve() too
x86/asm/entry/64: Move stub_x32_execvecloser() to stub_execveat()
x86/asm/entry/64: Use common code for rt_sigreturn() epilogue
x86/asm/entry/64: Add forgotten CFI annotation
x86/asm/entry/irq: Simplify interrupt dispatch table (IDT) layout
x86/asm/entry/64: Move opportunistic sysret code to syscall code path
x86, selftests: Add sigreturn selftest
x86/alternatives: Guard NOPs optimization
x86/asm/entry: Clear EXTRA_REGS for all executable formats
x86/signal: Remove pax argument from restore_sigcontext
...
Pull timer updates from Ingo Molnar:
"The main changes in this cycle were:
- clockevents state machine cleanups and enhancements (Viresh Kumar)
- clockevents broadcast notifier horror to state machine conversion
and related cleanups (Thomas Gleixner, Rafael J Wysocki)
- clocksource and timekeeping core updates (John Stultz)
- clocksource driver updates and fixes (Ben Dooks, Dmitry Osipenko,
Hans de Goede, Laurent Pinchart, Maxime Ripard, Xunlei Pang)
- y2038 fixes (Xunlei Pang, John Stultz)
- NMI-safe ktime_get_raw_fast() and general refactoring of the clock
code, in preparation to perf's per event clock ID support (Peter
Zijlstra)
- generic sched/clock fixes, optimizations and cleanups (Daniel
Thompson)
- clockevents cpu_down() race fix (Preeti U Murthy)"
* 'timers-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (94 commits)
timers/PM: Drop unnecessary braces from tick_freeze()
timers/PM: Fix up tick_unfreeze()
timekeeping: Get rid of stale comment
clockevents: Cleanup dead cpu explicitely
clockevents: Make tick handover explicit
clockevents: Remove broadcast oneshot control leftovers
sched/idle: Use explicit broadcast oneshot control function
ARM: Tegra: Use explicit broadcast oneshot control function
ARM: OMAP: Use explicit broadcast oneshot control function
intel_idle: Use explicit broadcast oneshot control function
ACPI/idle: Use explicit broadcast control function
ACPI/PAD: Use explicit broadcast oneshot control function
x86/amd/idle, clockevents: Use explicit broadcast oneshot control functions
clockevents: Provide explicit broadcast oneshot control functions
clockevents: Remove the broadcast control leftovers
ARM: OMAP: Use explicit broadcast control function
intel_idle: Use explicit broadcast control function
cpuidle: Use explicit broadcast control function
ACPI/processor: Use explicit broadcast control function
ACPI/PAD: Use explicit broadcast control function
...
Pull scheduler changes from Ingo Molnar:
"Major changes:
- Reworked CPU capacity code, for better SMP load balancing on
systems with assymetric CPUs. (Vincent Guittot, Morten Rasmussen)
- Reworked RT task SMP balancing to be push based instead of pull
based, to reduce latencies on large CPU count systems. (Steven
Rostedt)
- SCHED_DEADLINE support updates and fixes. (Juri Lelli)
- SCHED_DEADLINE task migration support during CPU hotplug. (Wanpeng Li)
- x86 mwait-idle optimizations and fixes. (Mike Galbraith, Len Brown)
- sched/numa improvements. (Rik van Riel)
- various cleanups"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (28 commits)
sched/core: Drop debugging leftover trace_printk call
sched/deadline: Support DL task migration during CPU hotplug
sched/core: Check for available DL bandwidth in cpuset_cpu_inactive()
sched/deadline: Always enqueue on previous rq when dl_task_timer() fires
sched/core: Remove unused argument from init_[rt|dl]_rq()
sched/deadline: Fix rt runtime corruption when dl fails its global constraints
sched/deadline: Avoid a superfluous check
sched: Improve load balancing in the presence of idle CPUs
sched: Optimize freq invariant accounting
sched: Move CFS tasks to CPUs with higher capacity
sched: Add SD_PREFER_SIBLING for SMT level
sched: Remove unused struct sched_group_capacity::capacity_orig
sched: Replace capacity_factor by usage
sched: Calculate CPU's usage statistic and put it into struct sg_lb_stats::group_usage
sched: Add struct rq::cpu_capacity_orig
sched: Make scale_rt invariant with frequency
sched: Make sched entity usage tracking scale-invariant
sched: Remove frequency scaling from cpu_capacity
sched: Track group sched_entity usage contributions
sched: Add sched_avg::utilization_avg_contrib
...
Pull core locking changes from Ingo Molnar:
"Main changes:
- jump label asm preparatory work for PowerPC (Anton Blanchard)
- rwsem optimizations and cleanups (Davidlohr Bueso)
- mutex optimizations and cleanups (Jason Low)
- futex fix (Oleg Nesterov)
- remove broken atomicity checks from {READ,WRITE}_ONCE() (Peter
Zijlstra)"
* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
powerpc, jump_label: Include linux/jump_label.h to get HAVE_JUMP_LABEL define
jump_label: Allow jump labels to be used in assembly
jump_label: Allow asm/jump_label.h to be included in assembly
locking/mutex: Further simplify mutex_spin_on_owner()
locking: Remove atomicy checks from {READ,WRITE}_ONCE
locking/rtmutex: Rename argument in the rt_mutex_adjust_prio_chain() documentation as well
locking/rwsem: Fix lock optimistic spinning when owner is not running
locking: Remove ACCESS_ONCE() usage
locking/rwsem: Check for active lock before bailing on spinning
locking/rwsem: Avoid deceiving lock spinners
locking/rwsem: Set lock ownership ASAP
locking/rwsem: Document barrier need when waking tasks
locking/futex: Check PF_KTHREAD rather than !p->mm to filter out kthreads
locking/mutex: Refactor mutex_spin_on_owner()
locking/mutex: In mutex_spin_on_owner(), return true when owner changes
Pull EFI update from Ingo Molnar:
"This tree includes various fixes, cleanups, a new efi=debug boot
option and EFI boot stub memory allocation optimizations"
* 'core-efi-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
efi/libstub: Retrieve FDT size when loaded from UEFI config table
efi: Clean up the efi_call_phys_[prolog|epilog]() save/restore interaction
efi: Disable interrupts around EFI calls, not in the epilog/prolog calls
x86/efi: Add a "debug" option to the efi= cmdline
firmware: dmi_scan: Use direct access to static vars
firmware: dmi_scan: Use full dmi version for SMBIOS3
ARM/ARM64: fixes for live migration, irqfd and ioeventfd support (enabling
vhost, too), page aging
s390: interrupt handling rework, allowing to inject all local interrupts
via new ioctl and to get/set the full local irq state for migration
and introspection. New ioctls to access memory by virtual address,
and to get/set the guest storage keys. SIMD support.
MIPS: FPU and MIPS SIMD Architecture (MSA) support. Includes some patches
from Ralf Baechle's MIPS tree.
x86: bugfixes (notably for pvclock, the others are small) and cleanups.
Another small latency improvement for the TSC deadline timer.
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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm
Pull KVM updates from Paolo Bonzini:
"First batch of KVM changes for 4.1
The most interesting bit here is irqfd/ioeventfd support for ARM and
ARM64.
Summary:
ARM/ARM64:
fixes for live migration, irqfd and ioeventfd support (enabling
vhost, too), page aging
s390:
interrupt handling rework, allowing to inject all local interrupts
via new ioctl and to get/set the full local irq state for migration
and introspection. New ioctls to access memory by virtual address,
and to get/set the guest storage keys. SIMD support.
MIPS:
FPU and MIPS SIMD Architecture (MSA) support. Includes some
patches from Ralf Baechle's MIPS tree.
x86:
bugfixes (notably for pvclock, the others are small) and cleanups.
Another small latency improvement for the TSC deadline timer"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (146 commits)
KVM: use slowpath for cross page cached accesses
kvm: mmu: lazy collapse small sptes into large sptes
KVM: x86: Clear CR2 on VCPU reset
KVM: x86: DR0-DR3 are not clear on reset
KVM: x86: BSP in MSR_IA32_APICBASE is writable
KVM: x86: simplify kvm_apic_map
KVM: x86: avoid logical_map when it is invalid
KVM: x86: fix mixed APIC mode broadcast
KVM: x86: use MDA for interrupt matching
kvm/ppc/mpic: drop unused IRQ_testbit
KVM: nVMX: remove unnecessary double caching of MAXPHYADDR
KVM: nVMX: checks for address bits beyond MAXPHYADDR on VM-entry
KVM: x86: cache maxphyaddr CPUID leaf in struct kvm_vcpu
KVM: vmx: pass error code with internal error #2
x86: vdso: fix pvclock races with task migration
KVM: remove kvm_read_hva and kvm_read_hva_atomic
KVM: x86: optimize delivery of TSC deadline timer interrupt
KVM: x86: extract blocking logic from __vcpu_run
kvm: x86: fix x86 eflags fixed bit
KVM: s390: migrate vcpu interrupt state
...
I don't see why we report e.g. orix_ax, which is not always
meaningful, but don't report ax, which is meaningful.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1428671219-29341-4-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
user_64bit_mode(regs) basically checks regs->cs to point to a
64-bit segment. This check used to be unreliable here because
regs->cs was not always correct in syscalls.
Now regs->cs is always correct: in syscalls, in interrupts, in
exceptions. No need to emply heuristics here.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1428671219-29341-3-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Yes, it is true that cx contains return address.
It's not clear why we trash it.
Stop doing that.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1428671219-29341-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
After recent changes to syscall entry points,
user_regs->{cs,ss,sp} are always correct. (They used to be
undefined while in syscalls).
We can report them reliably, without guessing.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1428671219-29341-1-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Update the check for UV2000/3000. Note when the HUB is not recognized.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Hedi Berriche <hedi@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
Link: http://lkml.kernel.org/r/20150409182629.267239403@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Fix a bug in the OEM check function that determines if the
system is a UV system and the BIOS is compatible with the
kernel's UV apic driver. This prevents some possibly obscure
panics and guards the system against being started on SGI
hardware that does not have the required kernel support.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Hedi Berriche <hedi@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
Link: http://lkml.kernel.org/r/20150409182629.112998930@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Optimize the first "SGI" OEM check to return faster if the
system is not an SGI or UV system.
Signed-off-by: Mike Travis <travis@sgi.com>
Acked-by: Hedi Berriche <hedi@sgi.com>
Acked-by: Dimitri Sivanich <sivanich@sgi.com>
Link: http://lkml.kernel.org/r/20150409182628.952357922@asylum.americas.sgi.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The comment line regarding IOMMU_INIT and IOMMU_INIT_FINISH
macros is incorrect:
"The standard vs the _FINISH differs in that the _FINISH variant
will continue detecting other IOMMUs in the call list..."
It should be "..the *standard* variant will continue
detecting..."
Fix that. Also, make it readable while at it.
Signed-off-by: Aravind Gopalakrishnan <Aravind.Gopalakrishnan@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: konrad.wilk@oracle.com
Fixes: 6e96366933 ("x86, iommu: Update header comments with appropriate naming")
Link: http://lkml.kernel.org/r/1428508017-5316-1-git-send-email-Aravind.Gopalakrishnan@amd.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It used to be used to check for _TIF_IA32, but the check has
been removed.
Remove GET_THREAD_INFO() too.
Run-tested.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428439424-7258-7-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Jumping to the very next instruction is not very useful:
jmp label
label:
Removing the jump.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428439424-7258-5-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This is a preparatory patch for moving stub32_execve[at]() to this
file. It makes sense to have all execve stubs in one place, so
that they can reuse code.
Signed-off-by: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Alexei Starovoitov <ast@plumgrid.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Drewry <wad@chromium.org>
Link: http://lkml.kernel.org/r/1428439424-7258-2-git-send-email-dvlasenk@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The rule for 'copy_from_user()' is that it zeroes the remaining kernel
buffer even when the copy fails halfway, just to make sure that we don't
leave uninitialized kernel memory around. Because even if we check for
errors, some kernel buffers stay around after thge copy (think page
cache).
However, the x86-64 logic for user copies uses a copy_user_generic()
function for all the cases, that set the "zerorest" flag for any fault
on the source buffer. Which meant that it didn't just try to clear the
kernel buffer after a failure in copy_from_user(), it also tried to
clear the destination user buffer for the "copy_in_user()" case.
Not only is that pointless, it also means that the clearing code has to
worry about the tail clearing taking page faults for the user buffer
case. Which is just stupid, since that case shouldn't happen in the
first place.
Get rid of the whole "zerorest" thing entirely, and instead just check
if the destination is in kernel space or not. And then just use
memset() to clear the tail of the kernel buffer if necessary.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Dirty logging tracks sptes in 4k granularity, meaning that large sptes
have to be split. If live migration is successful, the guest in the
source machine will be destroyed and large sptes will be created in the
destination. However, the guest continues to run in the source machine
(for example if live migration fails), small sptes will remain around
and cause bad performance.
This patch introduce lazy collapsing of small sptes into large sptes.
The rmap will be scanned in ioctl context when dirty logging is stopped,
dropping those sptes which can be collapsed into a single large-page spte.
Later page faults will create the large-page sptes.
Reviewed-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Signed-off-by: Wanpeng Li <wanpeng.li@linux.intel.com>
Message-Id: <1428046825-6905-1-git-send-email-wanpeng.li@linux.intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
CR2 is not cleared as it should after reset. See Intel SDM table named "IA-32
Processor States Following Power-up, Reset, or INIT".
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-5-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
DR0-DR3 are not cleared as they should during reset and when they are set from
userspace. It appears to be caused by c77fb5fe6f ("KVM: x86: Allow the guest
to run with dirty debug registers").
Force their reload on these situations.
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-4-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After reset, the CPU can change the BSP, which will be used upon INIT. Reset
should return the BSP which QEMU asked for, and therefore handled accordingly.
To quote: "If the MP protocol has completed and a BSP is chosen, subsequent
INITs (either to a specific processor or system wide) do not cause the MP
protocol to be repeated."
[Intel SDM 8.4.2: MP Initialization Protocol Requirements and Restrictions]
Signed-off-by: Nadav Amit <namit@cs.technion.ac.il>
Message-Id: <1427933438-12782-3-git-send-email-namit@cs.technion.ac.il>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
recalculate_apic_map() uses two passes over all VCPUs. This is a relic
from time when we selected a global mode in the first pass and set up
the optimized table in the second pass (to have a consistent mode).
Recent changes made mixed mode unoptimized and we can do it in one pass.
Format of logical MDA is a function of the mode, so we encode it in
apic_logical_id() and drop obsoleted variables from the struct.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-5-git-send-email-rkrcmar@redhat.com>
[Add lid_bits temporary in apic_logical_id. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
We want to support mixed modes and the easiest solution is to avoid
optimizing those weird and unlikely scenarios.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-4-git-send-email-rkrcmar@redhat.com>
[Add comment above KVM_APIC_MODE_* defines. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Broadcast allowed only one global APIC mode, but mixed modes are
theoretically possible. x2APIC IPI doesn't mean 0xff as broadcast,
the rest does.
x2APIC broadcasts are accepted by xAPIC. If we take SDM to be logical,
even addreses beginning with 0xff should be accepted, but real hardware
disagrees. This patch aims for simple code by considering most of real
behavior as undefined.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-3-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
In mixed modes, we musn't deliver xAPIC IPIs like x2APIC and vice versa.
Instead of preserving the information in apic_send_ipi(), we regain it
by converting all destinations into correct MDA in the slow path.
This allows easier reasoning about subsequent matching.
Our kvm_apic_broadcast() had an interesting design decision: it didn't
consider IOxAPIC 0xff as broadcast in x2APIC mode ...
everything worked because IOxAPIC can't set that in physical mode and
logical mode considered it as a message for first 8 VCPUs.
This patch interprets IOxAPIC 0xff as x2APIC broadcast.
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Message-Id: <1423766494-26150-2-git-send-email-rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
After speed-up of cpuid_maxphyaddr() it can be called frequently:
instead of heavyweight enumeration of CPUID entries it returns a cached
pre-computed value. It is also inlined now. So caching its result became
unnecessary and can be removed.
Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Message-Id: <20150329205644.GA1258@gnote>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
On each VM-entry CPU should check the following VMCS fields for zero bits
beyond physical address width:
- APIC-access address
- virtual-APIC address
- posted-interrupt descriptor address
This patch adds these checks required by Intel SDM.
Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Message-Id: <20150329205627.GA1244@gnote>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
cpuid_maxphyaddr(), which performs lot of memory accesses is called
extensively across KVM, especially in nVMX code.
This patch adds a cached value of maxphyaddr to vcpu.arch to reduce the
pressure onto CPU cache and simplify the code of cpuid_maxphyaddr()
callers. The cached value is initialized in kvm_arch_vcpu_init() and
reloaded every time CPUID is updated by usermode. It is obvious that
these reloads occur infrequently.
Signed-off-by: Eugene Korenevsky <ekorenevsky@gmail.com>
Message-Id: <20150329205612.GA1223@gnote>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Oleg Nesterov