linux-toradex.git/arch/x86, branch v5.0 Linux kernel for Apalis and Colibri modules Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-03-02T19:47:29+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-03-02T19:47:29+00:00 e7c42a89e9f16039684418dfe3c43b068734ff8f Pull x86 fixes from Thomas Gleixner: "Two last minute fixes: - Prevent value evaluation via functions happening in the user access enabled region of __put_user() (put another way: make sure to evaluate the value to be stored in user space _before_ enabling user space accesses) - Correct the definition of a Hyper-V hypercall constant" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT x86/uaccess: Don't leak the AC flag into __put_user() value evaluation 
Pull x86 fixes from Thomas Gleixner:
 "Two last minute fixes:

   - Prevent value evaluation via functions happening in the user access
     enabled region of __put_user() (put another way: make sure to
     evaluate the value to be stored in user space _before_ enabling
     user space accesses)

   - Correct the definition of a Hyper-V hypercall constant"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT
  x86/uaccess: Don't leak the AC flag into __put_user() value evaluation
x86/hyper-v: Fix definition of HV_MAX_FLUSH_REP_COUNT 2019-02-28T10:58:29+00:00 Lan Tianyu Tianyu.Lan@microsoft.com 2019-02-25T14:31:14+00:00 9cd05ad2910b55238e3c720c99ad896dc538301b The max flush rep count of HvFlushGuestPhysicalAddressList hypercall is equal with how many entries of union hv_gpa_page_range can be populated into the input parameter page. The code lacks parenthesis around PAGE_SIZE - 2 * sizeof(u64) which results in bogus computations. Add them. Fixes: cc4edae4b924 ("x86/hyper-v: Add HvFlushGuestAddressList hypercall support") Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: kys@microsoft.com Cc: haiyangz@microsoft.com Cc: sthemmin@microsoft.com Cc: sashal@kernel.org Cc: bp@alien8.de Cc: hpa@zytor.com Cc: gregkh@linuxfoundation.org Cc: devel@linuxdriverproject.org Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/20190225143114.5149-1-Tianyu.Lan@microsoft.com 
The max flush rep count of HvFlushGuestPhysicalAddressList hypercall is
equal with how many entries of union hv_gpa_page_range can be populated
into the input parameter page.

The code lacks parenthesis around PAGE_SIZE - 2 * sizeof(u64) which results
in bogus computations. Add them.

Fixes: cc4edae4b924 ("x86/hyper-v: Add HvFlushGuestAddressList hypercall support")
Signed-off-by: Lan Tianyu <Tianyu.Lan@microsoft.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: kys@microsoft.com
Cc: haiyangz@microsoft.com
Cc: sthemmin@microsoft.com
Cc: sashal@kernel.org
Cc: bp@alien8.de
Cc: hpa@zytor.com
Cc: gregkh@linuxfoundation.org
Cc: devel@linuxdriverproject.org
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190225143114.5149-1-Tianyu.Lan@microsoft.com
x86/uaccess: Don't leak the AC flag into __put_user() value evaluation 2019-02-25T19:17:05+00:00 Andy Lutomirski luto@kernel.org 2019-02-23T01:17:04+00:00 2a418cf3f5f1caf911af288e978d61c9844b0695 When calling __put_user(foo(), ptr), the __put_user() macro would call foo() in between __uaccess_begin() and __uaccess_end(). If that code were buggy, then those bugs would be run without SMAP protection. Fortunately, there seem to be few instances of the problem in the kernel. Nevertheless, __put_user() should be fixed to avoid doing this. Therefore, evaluate __put_user()'s argument before setting AC. This issue was noticed when an objtool hack by Peter Zijlstra complained about genregs_get() and I compared the assembly output to the C source. [ bp: Massage commit message and fixed up whitespace. ] Fixes: 11f1a4b9755f ("x86: reorganize SMAP handling in user space accesses") Signed-off-by: Andy Lutomirski <luto@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Brian Gerst <brgerst@gmail.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: stable@vger.kernel.org Link: http://lkml.kernel.org/r/20190225125231.845656645@infradead.org 
When calling __put_user(foo(), ptr), the __put_user() macro would call
foo() in between __uaccess_begin() and __uaccess_end().  If that code
were buggy, then those bugs would be run without SMAP protection.

Fortunately, there seem to be few instances of the problem in the
kernel. Nevertheless, __put_user() should be fixed to avoid doing this.
Therefore, evaluate __put_user()'s argument before setting AC.

This issue was noticed when an objtool hack by Peter Zijlstra complained
about genregs_get() and I compared the assembly output to the C source.

 [ bp: Massage commit message and fixed up whitespace. ]

Fixes: 11f1a4b9755f ("x86: reorganize SMAP handling in user space accesses")
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20190225125231.845656645@infradead.org
Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" 2019-02-25T17:10:51+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-02-25T17:10:51+00:00 53a41cb7ed381edee91029cdcabe9b3250f43f4d This reverts commit 9da3f2b74054406f87dff7101a569217ffceb29b. It was well-intentioned, but wrong. Overriding the exception tables for instructions for random reasons is just wrong, and that is what the new code did. It caused problems for tracing, and it caused problems for strncpy_from_user(), because the new checks made perfectly valid use cases break, rather than catch things that did bad things. Unchecked user space accesses are a problem, but that's not a reason to add invalid checks that then people have to work around with silly flags (in this case, that 'kernel_uaccess_faults_ok' flag, which is just an odd way to say "this commit was wrong" and was sprinked into random places to hide the wrongness). The real fix to unchecked user space accesses is to get rid of the special "let's not check __get_user() and __put_user() at all" logic. Make __{get|put}_user() be just aliases to the regular {get|put}_user() functions, and make it impossible to access user space without having the proper checks in places. The raison d'être of the special double-underscore versions used to be that the range check was expensive, and if you did multiple user accesses, you'd do the range check up front (like the signal frame handling code, for example). But SMAP (on x86) and PAN (on ARM) have made that optimization pointless, because the _real_ expense is the "set CPU flag to allow user space access". Do let's not break the valid cases to catch invalid cases that shouldn't even exist. Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kees Cook <keescook@chromium.org> Cc: Tobin C. Harding <tobin@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Andy Lutomirski <luto@kernel.org> Cc: Jann Horn <jannh@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> 
This reverts commit 9da3f2b74054406f87dff7101a569217ffceb29b.

It was well-intentioned, but wrong.  Overriding the exception tables for
instructions for random reasons is just wrong, and that is what the new
code did.

It caused problems for tracing, and it caused problems for strncpy_from_user(),
because the new checks made perfectly valid use cases break, rather than
catch things that did bad things.

Unchecked user space accesses are a problem, but that's not a reason to
add invalid checks that then people have to work around with silly flags
(in this case, that 'kernel_uaccess_faults_ok' flag, which is just an
odd way to say "this commit was wrong" and was sprinked into random
places to hide the wrongness).

The real fix to unchecked user space accesses is to get rid of the
special "let's not check __get_user() and __put_user() at all" logic.
Make __{get|put}_user() be just aliases to the regular {get|put}_user()
functions, and make it impossible to access user space without having
the proper checks in places.

The raison d'être of the special double-underscore versions used to be
that the range check was expensive, and if you did multiple user
accesses, you'd do the range check up front (like the signal frame
handling code, for example).  But SMAP (on x86) and PAN (on ARM) have
made that optimization pointless, because the _real_ expense is the "set
CPU flag to allow user space access".

Do let's not break the valid cases to catch invalid cases that shouldn't
even exist.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tobin C. Harding <tobin@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
KVM: MMU: record maximum physical address width in kvm_mmu_extended_role 2019-02-22T18:25:10+00:00 Yu Zhang yu.c.zhang@linux.intel.com 2019-01-31T16:09:23+00:00 de3ccd26fafc707b09792d9b633c8b5b48865315 Previously, commit 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow MMU reconfiguration is needed") offered some optimization to avoid the unnecessary reconfiguration. Yet one scenario is broken - when cpuid changes VM's maximum physical address width, reconfiguration is needed to reset the reserved bits. Also, the TDP may need to reset its shadow_root_level when this value is changed. To fix this, a new field, maxphyaddr, is introduced in the extended role structure to keep track of the configured guest physical address width. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Previously, commit 7dcd57552008 ("x86/kvm/mmu: check if tdp/shadow
MMU reconfiguration is needed") offered some optimization to avoid
the unnecessary reconfiguration. Yet one scenario is broken - when
cpuid changes VM's maximum physical address width, reconfiguration
is needed to reset the reserved bits.  Also, the TDP may need to
reset its shadow_root_level when this value is changed.

To fix this, a new field, maxphyaddr, is introduced in the extended
role structure to keep track of the configured guest physical address
width.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
kvm: x86: Return LA57 feature based on hardware capability 2019-02-22T18:25:05+00:00 Yu Zhang yu.c.zhang@linux.intel.com 2019-01-31T16:09:43+00:00 511da98d207d5c0675a10351b01e37cbe50a79e5 Previously, 'commit 372fddf70904 ("x86/mm: Introduce the 'no5lvl' kernel parameter")' cleared X86_FEATURE_LA57 in boot_cpu_data, if Linux chooses to not run in 5-level paging mode. Yet boot_cpu_data is queried by do_cpuid_ent() as the host capability later when creating vcpus, and Qemu will not be able to detect this feature and create VMs with LA57 feature. As discussed earlier, VMs can still benefit from extended linear address width, e.g. to enhance features like ASLR. So we would like to fix this, by return the true hardware capability when Qemu queries. Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Previously, 'commit 372fddf70904 ("x86/mm: Introduce the 'no5lvl' kernel
parameter")' cleared X86_FEATURE_LA57 in boot_cpu_data, if Linux chooses
to not run in 5-level paging mode. Yet boot_cpu_data is queried by
do_cpuid_ent() as the host capability later when creating vcpus, and Qemu
will not be able to detect this feature and create VMs with LA57 feature.

As discussed earlier, VMs can still benefit from extended linear address
width, e.g. to enhance features like ASLR. So we would like to fix this,
by return the true hardware capability when Qemu queries.

Signed-off-by: Yu Zhang <yu.c.zhang@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
x86/kvm/mmu: fix switch between root and guest MMUs 2019-02-22T18:24:48+00:00 Vitaly Kuznetsov vkuznets@redhat.com 2019-02-22T16:45:01+00:00 ad7dc69aeb23138cc23c406cac25003b97e8ee17 Commit 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu") brought one subtle change: previously, when switching back from L2 to L1, we were resetting MMU hooks (like mmu->get_cr3()) in kvm_init_mmu() called from nested_vmx_load_cr3() and now we do that in nested_ept_uninit_mmu_context() when we re-target vcpu->arch.mmu pointer. The change itself looks logical: if nested_ept_init_mmu_context() changes something than nested_ept_uninit_mmu_context() restores it back. There is, however, one thing: the following call chain: nested_vmx_load_cr3() kvm_mmu_new_cr3() __kvm_mmu_new_cr3() fast_cr3_switch() cached_root_available() now happens with MMU hooks pointing to the new MMU (root MMU in our case) while previously it was happening with the old one. cached_root_available() tries to stash current root but it is incorrect to read current CR3 with mmu->get_cr3(), we need to use old_mmu->get_cr3() which in case we're switching from L2 to L1 is guest_mmu. (BTW, in shadow page tables case this is a non-issue because we don't switch MMU). While we could've tried to guess that we're switching between MMUs and call the right ->get_cr3() from cached_root_available() this seems to be overly complicated. Instead, just stash the corresponding CR3 when setting root_hpa and make cached_root_available() use the stashed value. Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu") Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Cc: stable@vger.kernel.org Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> 
Commit 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu") brought one subtle
change: previously, when switching back from L2 to L1, we were resetting
MMU hooks (like mmu->get_cr3()) in kvm_init_mmu() called from
nested_vmx_load_cr3() and now we do that in nested_ept_uninit_mmu_context()
when we re-target vcpu->arch.mmu pointer.
The change itself looks logical: if nested_ept_init_mmu_context() changes
something than nested_ept_uninit_mmu_context() restores it back. There is,
however, one thing: the following call chain:

 nested_vmx_load_cr3()
  kvm_mmu_new_cr3()
    __kvm_mmu_new_cr3()
      fast_cr3_switch()
        cached_root_available()

now happens with MMU hooks pointing to the new MMU (root MMU in our case)
while previously it was happening with the old one. cached_root_available()
tries to stash current root but it is incorrect to read current CR3 with
mmu->get_cr3(), we need to use old_mmu->get_cr3() which in case we're
switching from L2 to L1 is guest_mmu. (BTW, in shadow page tables case this
is a non-issue because we don't switch MMU).

While we could've tried to guess that we're switching between MMUs and call
the right ->get_cr3() from cached_root_available() this seems to be overly
complicated. Instead, just stash the corresponding CR3 when setting
root_hpa and make cached_root_available() use the stashed value.

Fixes: 14c07ad89f4d ("x86/kvm/mmu: introduce guest_mmu")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-02-17T16:44:38+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-02-17T16:44:38+00:00 8d33316d520501f24fef180ea5b860ecb9e64506 Pull x86 fixes from Ingo Molnar: "Three changes: - An UV fix/quirk to pull UV BIOS calls into the efi_runtime_lock locking regime. (This done by aliasing __efi_uv_runtime_lock to efi_runtime_lock, which should make the quirk nature obvious and maintain the general policy that the EFI lock (name...) isn't exposed to drivers.) - Our version of MAGA: Make a.out Great Again. - Add a new Intel model name enumerator to an upstream header to help reduce dependencies going forward" * 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls x86/CPU: Add Icelake model number x86/a.out: Clear the dump structure initially 
Pull x86 fixes from Ingo Molnar:
 "Three changes:

   - An UV fix/quirk to pull UV BIOS calls into the efi_runtime_lock
     locking regime. (This done by aliasing __efi_uv_runtime_lock to
     efi_runtime_lock, which should make the quirk nature obvious and
     maintain the general policy that the EFI lock (name...) isn't
     exposed to drivers.)

   - Our version of MAGA: Make a.out Great Again.

   - Add a new Intel model name enumerator to an upstream header to help
     reduce dependencies going forward"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls
  x86/CPU: Add Icelake model number
  x86/a.out: Clear the dump structure initially
Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 2019-02-17T16:38:13+00:00 Linus Torvalds torvalds@linux-foundation.org 2019-02-17T16:38:13+00:00 dd6f29da695dbfe5a8ff84ebfdd2110d68e8f511 Pull perf fixes from Ingo Molnar: "Two fixes on the kernel side: fix an over-eager condition that failed larger perf ring-buffer sizes, plus fix crashes in the Intel BTS code for a corner case, found by fuzzing" * 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: perf/core: Fix impossible ring-buffer sizes warning perf/x86: Add check_period PMU callback 
Pull perf fixes from Ingo Molnar:
 "Two fixes on the kernel side: fix an over-eager condition that failed
  larger perf ring-buffer sizes, plus fix crashes in the Intel BTS code
  for a corner case, found by fuzzing"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/core: Fix impossible ring-buffer sizes warning
  perf/x86: Add check_period PMU callback
x86/platform/UV: Use efi_runtime_lock to serialise BIOS calls 2019-02-15T14:19:56+00:00 Hedi Berriche hedi.berriche@hpe.com 2019-02-13T19:34:13+00:00 f331e766c4be33f4338574f3c9f7f77e98ab4571 Calls into UV firmware must be protected against concurrency, expose the efi_runtime_lock to the UV platform, and use it to serialise UV BIOS calls. Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Reviewed-by: Russ Anderson <rja@hpe.com> Reviewed-by: Dimitri Sivanich <sivanich@hpe.com> Reviewed-by: Mike Travis <mike.travis@hpe.com> Cc: Andy Shevchenko <andy@infradead.org> Cc: Bhupesh Sharma <bhsharma@redhat.com> Cc: Darren Hart <dvhart@infradead.org> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: linux-efi <linux-efi@vger.kernel.org> Cc: platform-driver-x86@vger.kernel.org Cc: stable@vger.kernel.org # v4.9+ Cc: Steve Wahl <steve.wahl@hpe.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: x86-ml <x86@kernel.org> Link: https://lkml.kernel.org/r/20190213193413.25560-5-hedi.berriche@hpe.com 
Calls into UV firmware must be protected against concurrency, expose the
efi_runtime_lock to the UV platform, and use it to serialise UV BIOS
calls.

Signed-off-by: Hedi Berriche <hedi.berriche@hpe.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Russ Anderson <rja@hpe.com>
Reviewed-by: Dimitri Sivanich <sivanich@hpe.com>
Reviewed-by: Mike Travis <mike.travis@hpe.com>
Cc: Andy Shevchenko <andy@infradead.org>
Cc: Bhupesh Sharma <bhsharma@redhat.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: linux-efi <linux-efi@vger.kernel.org>
Cc: platform-driver-x86@vger.kernel.org
Cc: stable@vger.kernel.org # v4.9+
Cc: Steve Wahl <steve.wahl@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: x86-ml <x86@kernel.org>
Link: https://lkml.kernel.org/r/20190213193413.25560-5-hedi.berriche@hpe.com