Pull tracing fix from Steven Rostedt:
"Some of the ftrace internal events use a zero for a data size of a
field event. This is increasingly important for the histogram trigger
work that is being extended.
While auditing trace events, I found that a couple of the xen events
were used as just marking that a function was called, by creating a
static array of size zero. This can play havoc with the tracing
features if these events are used, because a zero size of a static
array is denoted as a special nul terminated dynamic array (this is
what the trace_marker code uses). But since the xen events have no
size, they are not nul terminated, and unexpected results may occur.
As trace events were never intended on being a marker to denote that a
function was hit or not, especially since function tracing and kprobes
can trivially do the same, the best course of action is to simply
remove these events"
* tag 'trace-v4.17-rc4-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
tracing/x86/xen: Remove zero data size trace events trace_xen_mmu_flush_tlb{_all}
cleanup_trampoline() relocates the top-level page table out of
trampoline memory. We use 'top_pgtable' as our new top-level page table.
But if the 'top_pgtable' would be referenced from C in a usual way,
the address of the table will be calculated relative to RIP.
After kernel gets relocated, the address will be in the middle of
decompression buffer and the page table may get overwritten.
This leads to a crash.
We calculate the address of other page tables relative to the relocation
address. It makes them safe. We should do the same for 'top_pgtable'.
Calculate the address of 'top_pgtable' in assembly and pass down to
cleanup_trampoline().
Move the page table to .pgtable section where the rest of page tables
are. The section is @nobits so we save 4k in kernel image.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Fixes: e9d0e6330e ("x86/boot/compressed/64: Prepare new top-level page table for trampoline")
Link: http://lkml.kernel.org/r/20180516080131.27913-3-kirill.shutemov@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Variants of proc_create{,_data} that directly take a seq_file show
callback and drastically reduces the boilerplate code in the callers.
All trivial callers converted over.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Make the RETPOLINE_{RA,ED}X_BPF_JIT() a bit more readable by
cleaning up the macro, aligning comments and spacing.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Doing an audit of trace events, I discovered two trace events in the xen
subsystem that use a hack to create zero data size trace events. This is not
what trace events are for. Trace events add memory footprint overhead, and
if all you need to do is see if a function is hit or not, simply make that
function noinline and use function tracer filtering.
Worse yet, the hack used was:
__array(char, x, 0)
Which creates a static string of zero in length. There's assumptions about
such constructs in ftrace that this is a dynamic string that is nul
terminated. This is not the case with these tracepoints and can cause
problems in various parts of ftrace.
Nuke the trace events!
Link: http://lkml.kernel.org/r/20180509144605.5a220327@gandalf.local.home
Cc: stable@vger.kernel.org
Fixes: 95a7d76897 ("xen/mmu: Use Xen specific TLB flush instead of the generic one.")
Reviewed-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
These private pages have special purposes in the virtualization of L1,
but not in the virtualization of L2. In particular, L1's APIC access
page should never be entered into L2's page tables, because this
causes a great deal of confusion when the APIC virtualization hardware
is being used to accelerate L2's accesses to its own APIC.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
L1 and L2 need to have disjoint mappings, so that L1's APIC access
page (under VMX) can be omitted from L2's mappings.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
It is only possible to share the APIC access page between L1 and L2 if
they also share the virtual-APIC page. If L2 has its own virtual-APIC
page, then MMIO accesses to L1's TPR from L2 will access L2's TPR
instead. Moreover, L1's local APIC has to be in xAPIC mode, which is
another condition that hasn't been checked.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Previously, we toggled between SECONDARY_EXEC_VIRTUALIZE_X2APIC_MODE
and SECONDARY_EXEC_VIRTUALIZE_APIC_ACCESSES, depending on whether or
not the EXTD bit was set in MSR_IA32_APICBASE. However, if the local
APIC is disabled, we should not set either of these APIC
virtualization control bits.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The local APIC can be in one of three modes: disabled, xAPIC or
x2APIC. (A fourth mode, "invalid," is included for completeness.)
Using the new enumeration can make some of the APIC mode logic easier
to read. In kvm_set_apic_base, for instance, it is clear that one
cannot transition directly from x2APIC mode to xAPIC mode or directly
from APIC disabled to x2APIC mode.
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Krish Sadhukhan <krish.sadhukhan@oracle.com>
[Check invalid bits even if msr_info->host_initiated. Reported by
Wanpeng Li. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Enlightened MSR-Bitmap is a natural extension of Enlightened VMCS:
Hyper-V Top Level Functional Specification states:
"The L1 hypervisor may collaborate with the L0 hypervisor to make MSR
accesses more efficient. It can enable enlightened MSR bitmaps by setting
the corresponding field in the enlightened VMCS to 1. When enabled, the L0
hypervisor does not monitor the MSR bitmaps for changes. Instead, the L1
hypervisor must invalidate the corresponding clean field after making
changes to one of the MSR bitmaps."
I reached out to Hyper-V team for additional details and I got the
following information:
"Current Hyper-V implementation works as following:
If the enlightened MSR bitmap is not enabled:
- All MSR accesses of L2 guests cause physical VM-Exits
If the enlightened MSR bitmap is enabled:
- Physical VM-Exits for L2 accesses to certain MSRs (currently FS_BASE,
GS_BASE and KERNEL_GS_BASE) are avoided, thus making these MSR accesses
faster."
I tested my series with a tight rdmsrl loop in L2, for KERNEL_GS_BASE the
results are:
Without Enlightened MSR-Bitmap: 1300 cycles/read
With Enlightened MSR-Bitmap: 120 cycles/read
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Tested-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Extract the logic to free a root page in a separate function to avoid code
duplication in mmu_free_roots(). Also, change it to an exported function
i.e. kvm_mmu_free_roots().
Signed-off-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
MSB of CR3 is a reserved bit if the PCIDE bit is not set in CR4.
It should be checked when PCIDE bit is not set, however commit
'd1cd3ce900441 ("KVM: MMU: check guest CR3 reserved bits based on
its physical address width")' removes the bit 63 checking
unconditionally. This patch fixes it by checking bit 63 of CR3
when PCIDE bit is not set in CR4.
Fixes: d1cd3ce900 (KVM: MMU: check guest CR3 reserved bits based on its physical address width)
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Reviewed-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
My recent Xen patch series introduces a new HYPERVISOR_memory_op to
support direct priv-mapping of certain guest resources (such as ioreq
pages, used by emulators) by a tools domain, rather than having to access
such resources via the guest P2M.
This patch adds the necessary infrastructure to the privcmd driver and
Xen MMU code to support direct resource mapping.
NOTE: The adjustment in the MMU code is partially cosmetic. Xen will now
allow a PV tools domain to map guest pages either by GFN or MFN, thus
the term 'mfn' has been swapped for 'pfn' in the lower layers of the
remap code.
Signed-off-by: Paul Durrant <paul.durrant@citrix.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
mm_pkey_is_allocated() treats pkey 0 as unallocated. That is
inconsistent with the manpages, and also inconsistent with
mm->context.pkey_allocation_map. Stop special casing it and only
disallow values that are actually bad (< 0).
The end-user visible effect of this is that you can now use
mprotect_pkey() to set pkey=0.
This is a bit nicer than what Ram proposed[1] because it is simpler
and removes special-casing for pkey 0. On the other hand, it does
allow applications to pkey_free() pkey-0, but that's just a silly
thing to do, so we are not going to protect against it.
The scenario that could happen is similar to what happens if you free
any other pkey that is in use: it might get reallocated later and used
to protect some other data. The most likely scenario is that pkey-0
comes back from pkey_alloc(), an access-disable or write-disable bit
is set in PKRU for it, and the next stack access will SIGSEGV. It's
not horribly different from if you mprotect()'d your stack or heap to
be unreadable or unwritable, which is generally very foolish, but also
not explicitly prevented by the kernel.
1. http://lkml.kernel.org/r/1522112702-27853-1-git-send-email-linuxram@us.ibm.com
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>p
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 58ab9a088d ("x86/pkeys: Check against max pkey to avoid overflows")
Link: http://lkml.kernel.org/r/20180509171358.47FD785E@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
I got a bug report that the following code (roughly) was
causing a SIGSEGV:
mprotect(ptr, size, PROT_EXEC);
mprotect(ptr, size, PROT_NONE);
mprotect(ptr, size, PROT_READ);
*ptr = 100;
The problem is hit when the mprotect(PROT_EXEC)
is implicitly assigned a protection key to the VMA, and made
that key ACCESS_DENY|WRITE_DENY. The PROT_NONE mprotect()
failed to remove the protection key, and the PROT_NONE->
PROT_READ left the PTE usable, but the pkey still in place
and left the memory inaccessible.
To fix this, we ensure that we always "override" the pkee
at mprotect() if the VMA does not have execute-only
permissions, but the VMA has the execute-only pkey.
We had a check for PROT_READ/WRITE, but it did not work
for PROT_NONE. This entirely removes the PROT_* checks,
which ensures that PROT_NONE now works.
Reported-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michael Ellermen <mpe@ellerman.id.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Cc: stable@vger.kernel.org
Fixes: 62b5f7d013 ("mm/core, x86/mm/pkeys: Add execute-only protection keys support")
Link: http://lkml.kernel.org/r/20180509171351.084C5A71@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cast val and (val >> 32) to (u32), so that they fit in a
general-purpose register in both 32-bit and 64-bit code.
[ tglx: Made it u32 instead of uintptr_t ]
Fixes: c65732e4f7 ("x86/cpu: Restore CPUID_8000_0008_EBX reload")
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
setup_efi_pci() tries to save a copy of each PCI option ROM as this may
be necessary for the device driver for the PCI device to have access too.
On some systems the efi_pci_io_protocol's romimage and romsize fields
contain invalid data, which looks a bit like pointers pointing back into
other EFI code or data. Interpreting these pointers as romsize leads to
a very large value and if we then try to alloc this amount of memory to
save a copy the alloc call fails.
This leads to a "Failed to alloc mem for rom" error being printed on the
EFI console for each PCI device.
This commit avoids the printing of these errors, by checking romsize before
doing the alloc and if it is larger then the EFI spec limit of 16 MiB
silently ignore the ROM fields instead of trying to alloc mem and fail.
Tested-by: Hans de Goede <hdegoede@redhat.com>
[ardb: deduplicate 32/64 bit changes, use SZ_16M symbolic constant]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180504060003.19618-16-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Initialize UEFI secure boot state during dom0 boot. Otherwise the kernel
may not even know that it runs on secure boot enabled platform.
Note that part of drivers/firmware/efi/libstub/secureboot.c is duplicated
by this patch, only in this case, it runs in the context of the kernel
proper rather than UEFI boot context. The reason for the duplication is
that maintaining the original code to run correctly on ARM/arm64 as well
as on all the quirky x86 firmware we support is enough of a burden as it
is, and adding the x86/Xen execution context to that mix just so we can
reuse a single routine just isn't worth it.
[ardb: explain rationale for code duplication]
Signed-off-by: Daniel Kiper <daniel.kiper@oracle.com>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20180504060003.19618-2-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
dev_err is becoming a macro calling _dev_err to allow prefixing of
dev_fmt to any dev_<level> use that has a #define dev_fmt(fmt) similar
to the existing #define pr_fmt(fmt) uses.
Remove this dev_err macro and convert the existing two uses to pr_err.
This allows clean compilation in the patch that introduces dev_fmt which
can prefix dev_<level> logging macros with arbitrary content similar to
the #define pr_fmt macro.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lkml.kernel.org/r/8fb4b2a77d50e21ae1f7e4e267e68691efe2c270.1525878372.git.joe@perches.com
Pull x86/pti updates from Thomas Gleixner:
"A mixed bag of fixes and updates for the ghosts which are hunting us.
The scheduler fixes have been pulled into that branch to avoid
conflicts.
- A set of fixes to address a khread_parkme() race which caused lost
wakeups and loss of state.
- A deadlock fix for stop_machine() solved by moving the wakeups
outside of the stopper_lock held region.
- A set of Spectre V1 array access restrictions. The possible
problematic spots were discuvered by Dan Carpenters new checks in
smatch.
- Removal of an unused file which was forgotten when the rest of that
functionality was removed"
* 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vdso: Remove unused file
perf/x86/cstate: Fix possible Spectre-v1 indexing for pkg_msr
perf/x86/msr: Fix possible Spectre-v1 indexing in the MSR driver
perf/x86: Fix possible Spectre-v1 indexing for x86_pmu::event_map()
perf/x86: Fix possible Spectre-v1 indexing for hw_perf_event cache_*
perf/core: Fix possible Spectre-v1 indexing for ->aux_pages[]
sched/autogroup: Fix possible Spectre-v1 indexing for sched_prio_to_weight[]
sched/core: Fix possible Spectre-v1 indexing for sched_prio_to_weight[]
sched/core: Introduce set_special_state()
kthread, sched/wait: Fix kthread_parkme() completion issue
kthread, sched/wait: Fix kthread_parkme() wait-loop
sched/fair: Fix the update of blocked load when newly idle
stop_machine, sched: Fix migrate_swap() vs. active_balance() deadlock
