SMEP 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, SMEP needs to be manually
disabled when guest switches to non-paging mode.
We met an issue that, SMP Linux guest with recent kernel (enable
SMEP support, for example, 3.5.3) would crash with triple fault if
setting unrestricted_guest=0. This is because KVM uses an identity
mapping page table to emulate the non-paging mode, where the page
table is set with USER flag. If SMEP is still enabled in this case,
guest will meet unhandlable page fault and then crash.
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Dongxiao Xu <dongxiao.xu@intel.com>
Signed-off-by: Xiantao Zhang <xiantao.zhang@intel.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
This reverts commit bd4c86eaa6.
There is not user for kvm_mmu_isolate_page() any more.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Pull full-dynticks (user-space execution is undisturbed and
receives no timer IRQs) preparation changes that convert the
cputime accounting code to be full-dynticks ready,
from Frederic Weisbecker:
"This implements the cputime accounting on full dynticks CPUs.
Typical cputime stats infrastructure relies on the timer tick and
its periodic polling on the CPU to account the amount of time
spent by the CPUs and the tasks per high level domains such as
userspace, kernelspace, guest, ...
Now we are preparing to implement full dynticks capability on
Linux for Real Time and HPC users who want full CPU isolation.
This feature requires a cputime accounting that doesn't depend
on the timer tick.
To implement it, this new cputime infrastructure plugs into
kernel/user/guest boundaries to take snapshots of cputime and
flush these to the stats when needed. This performs pretty
much like CONFIG_VIRT_CPU_ACCOUNTING except that context location
and cputime snaphots are synchronized between write and read
side such that the latter can safely retrieve the pending tickless
cputime of a task and add it to its latest cputime snapshot to
return the correct result to the user."
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Gust page walker puts only present ptes into ptes[] array. No need to
check it again.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Move base_role.nxe initialisation to where all other roles are initialized.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
spte_is_locklessly_modifiable() checks that both SPTE_HOST_WRITEABLE and
SPTE_MMU_WRITEABLE are present on spte. Make it more explicit.
Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Pull x86 fixes from Ingo Molnar:
"Three small fixlets"
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/intel/cacheinfo: Shut up annoying warning
x86, doc: Boot protocol 2.12 is in 3.8
x86-64: Replace left over sti/cli in ia32 audit exit code
Pull perf fixes from Ingo Molnar:
"Three fixlets and two small (and low risk) hw-enablement changes"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf: Fix event group context move
x86/perf: Add IvyBridge EP support
perf/x86: Fix P6 driver section warning
arch/x86/tools/insn_sanity.c: Identify source of messages
perf/x86: Enable Intel Lincroft/Penwell/Cloverview Atom support
I've been getting the following warning when doing randbuilds
since forever. Now it finally pissed me off just the perfect
amount so that I can fix it.
arch/x86/kernel/cpu/intel_cacheinfo.c:489:27: warning: ‘cache_disable_0’ defined but not used [-Wunused-variable]
arch/x86/kernel/cpu/intel_cacheinfo.c:491:27: warning: ‘cache_disable_1’ defined but not used [-Wunused-variable] arch/x86/kernel/cpu/intel_cacheinfo.c:524:27: warning: ‘subcaches’ defined but not used [-Wunused-variable]
It happens because in randconfigs where CONFIG_SYSFS is not set,
the whole sysfs-interface to L3 cache index disabling is
remaining unused and gcc correctly warns about it. Make it
optional, depending on CONFIG_SYSFS too, as is the case with
other sysfs-related machinery in this file.
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/r/1359969195-27362-1-git-send-email-bp@alien8.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Only alpha and sparc are unusual - they have ka_restorer in it.
And nobody needs that exposed to userland.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Switch from __ARCH_WANT_SYS_RT_SIGACTION to opposite
(!CONFIG_ODD_RT_SIGACTION); the only two architectures that
need it are alpha and sparc. The reason for use of CONFIG_...
instead of __ARCH_... is that it's needed only kernel-side
and doing it that way avoids a mess with include order on many
architectures.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Explicitly merging these two branches due to nontrivial conflicts and
to allow further work.
Resolved Conflicts:
arch/x86/kernel/head32.c
arch/x86/kernel/head64.c
arch/x86/mm/init_64.c
arch/x86/realmode/init.c
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
This code was an optimization for 32-bit NUMA systems.
It has probably been the cause of a number of subtle bugs over
the years, although the conditions to excite them would have
been hard to trigger. Essentially, we remap part of the kernel
linear mapping area, and then sometimes part of that area gets
freed back in to the bootmem allocator. If those pages get
used by kernel data structures (say mem_map[] or a dentry),
there's no big deal. But, if anyone ever tried to use the
linear mapping for these pages _and_ cared about their physical
address, bad things happen.
For instance, say you passed __GFP_ZERO to the page allocator
and then happened to get handed one of these pages, it zero the
remapped page, but it would make a pte to the _old_ page.
There are probably a hundred other ways that it could screw
with things.
We don't need to hang on to performance optimizations for
these old boxes any more. All my 32-bit NUMA systems are long
dead and buried, and I probably had access to more than most
people.
This code is causing real things to break today:
https://lkml.org/lkml/2013/1/9/376
I looked in to actually fixing this, but it requires surgery
to way too much brittle code, as well as stuff like
per_cpu_ptr_to_phys().
[ hpa: Cc: this for -stable, since it is a memory corruption issue.
However, an alternative is to simply mark NUMA as depends BROKEN
rather than EXPERIMENTAL in the X86_32 subclause... ]
Link: http://lkml.kernel.org/r/20130131005616.1C79F411@kernel.stglabs.ibm.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: <stable@vger.kernel.org>
Implementation of early update ucode on Intel's CPU.
load_ucode_intel_bsp() scans ucode in initrd image file which is a cpio format
ucode followed by ordinary initrd image file. The binary ucode file is stored
in kernel/x86/microcode/GenuineIntel.bin in the cpio data. All ucode
patches with the same model as BSP are saved in memory. A matching ucode patch
is updated on BSP.
load_ucode_intel_ap() reads saved ucoded patches and updates ucode on AP.
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/1356075872-3054-9-git-send-email-fenghua.yu@intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
