33845 Commits

Author SHA1 Message Date
Juergen Gross
7a94dfe5e2 x86/kvm: fix vcpu-id indexed array sizes
commit 76b4f357d0e7d8f6f0013c733e6cba1773c266d3 upstream.

KVM_MAX_VCPU_ID is the maximum vcpu-id of a guest, and not the number
of vcpu-ids. Fix array indexed by vcpu-id to have KVM_MAX_VCPU_ID+1
elements.

Note that this is currently no real problem, as KVM_MAX_VCPU_ID is
an odd number, resulting in always enough padding being available at
the end of those arrays.

Nevertheless this should be fixed in order to avoid rare problems in
case someone is using an even number for KVM_MAX_VCPU_ID.

Signed-off-by: Juergen Gross <jgross@suse.com>
Message-Id: <20210701154105.23215-2-jgross@suse.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-04 12:27:37 +02:00
Jan Kiszka
61f2cbc792 x86/asm: Ensure asm/proto.h can be included stand-alone
[ Upstream commit f7b21a0e41171d22296b897dac6e4c41d2a3643c ]

Fix:

  ../arch/x86/include/asm/proto.h:14:30: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
  long do_arch_prctl_64(struct task_struct *task, int option, unsigned long arg2);
                               ^~~~~~~~~~~

  .../arch/x86/include/asm/proto.h:40:34: warning: ‘struct task_struct’ declared \
    inside parameter list will not be visible outside of this definition or declaration
   long do_arch_prctl_common(struct task_struct *task, int option,
                                    ^~~~~~~~~~~

if linux/sched.h hasn't be included previously. This fixes a build error
when this header is used outside of the kernel tree.

 [ bp: Massage commit message. ]

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/b76b4be3-cf66-f6b2-9a6c-3e7ef54f9845@web.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-08-04 12:27:37 +02:00
Maxim Levitsky
af45f3527a KVM: x86: determine if an exception has an error code only when injecting it.
commit b97f074583736c42fb36f2da1164e28c73758912 upstream.

A page fault can be queued while vCPU is in real paged mode on AMD, and
AMD manual asks the user to always intercept it
(otherwise result is undefined).
The resulting VM exit, does have an error code.

Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20210225154135.405125-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Zubin Mithra <zsm@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-31 08:19:37 +02:00
Thomas Gleixner
aa51b6bc79 x86/fpu: Limit xstate copy size in xstateregs_set()
[ Upstream commit 07d6688b22e09be465652cf2da0da6bf86154df6 ]

If the count argument is larger than the xstate size, this will happily
copy beyond the end of xstate.

Fixes: 91c3dba7dbc1 ("x86/fpu/xstate: Fix PTRACE frames for XSAVES")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121452.120741557@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:10:50 +02:00
Chang S. Bae
00fcd8f33e x86/signal: Detect and prevent an alternate signal stack overflow
[ Upstream commit 2beb4a53fc3f1081cedc1c1a198c7f56cc4fc60c ]

The kernel pushes context on to the userspace stack to prepare for the
user's signal handler. When the user has supplied an alternate signal
stack, via sigaltstack(2), it is easy for the kernel to verify that the
stack size is sufficient for the current hardware context.

Check if writing the hardware context to the alternate stack will exceed
it's size. If yes, then instead of corrupting user-data and proceeding with
the original signal handler, an immediate SIGSEGV signal is delivered.

Refactor the stack pointer check code from on_sig_stack() and use the new
helper.

While the kernel allows new source code to discover and use a sufficient
alternate signal stack size, this check is still necessary to protect
binaries with insufficient alternate signal stack size from data
corruption.

Fixes: c2bc11f10a39 ("x86, AVX-512: Enable AVX-512 States Context Switch")
Reported-by: Florian Weimer <fweimer@redhat.com>
Suggested-by: Jann Horn <jannh@google.com>
Suggested-by: Andy Lutomirski <luto@kernel.org>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20210518200320.17239-6-chang.seok.bae@intel.com
Link: https://bugzilla.kernel.org/show_bug.cgi?id=153531
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:10:49 +02:00
Thomas Gleixner
12f8d6e7f2 x86/fpu: Return proper error codes from user access functions
[ Upstream commit aee8c67a4faa40a8df4e79316dbfc92d123989c1 ]

When *RSTOR from user memory raises an exception, there is no way to
differentiate them. That's bad because it forces the slow path even when
the failure was not a fault. If the operation raised eg. #GP then going
through the slow path is pointless.

Use _ASM_EXTABLE_FAULT() which stores the trap number and let the exception
fixup return the negated trap number as error.

This allows to separate the fast path and let it handle faults directly and
avoid the slow path for all other exceptions.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210623121457.601480369@linutronix.de
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-20 16:10:47 +02:00
Lai Jiangshan
22257d3c68 KVM: X86: Disable hardware breakpoints unconditionally before kvm_x86->run()
commit f85d40160691881a17a397c448d799dfc90987ba upstream.

When the host is using debug registers but the guest is not using them
nor is the guest in guest-debug state, the kvm code does not reset
the host debug registers before kvm_x86->run().  Rather, it relies on
the hardware vmentry instruction to automatically reset the dr7 registers
which ensures that the host breakpoints do not affect the guest.

This however violates the non-instrumentable nature around VM entry
and exit; for example, when a host breakpoint is set on vcpu->arch.cr2,

Another issue is consistency.  When the guest debug registers are active,
the host breakpoints are reset before kvm_x86->run(). But when the
guest debug registers are inactive, the host breakpoints are delayed to
be disabled.  The host tracing tools may see different results depending
on what the guest is doing.

To fix the problems, we clear %db7 unconditionally before kvm_x86->run()
if the host has set any breakpoints, no matter if the guest is using
them or not.

Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20210628172632.81029-1-jiangshanlai@gmail.com>
Cc: stable@vger.kernel.org
[Only clear %db7 instead of reloading all debug registers. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20 16:10:40 +02:00
Sean Christopherson
dc91a480ac KVM: x86: Use guest MAXPHYADDR from CPUID.0x8000_0008 iff TDP is enabled
commit 4bf48e3c0aafd32b960d341c4925b48f416f14a5 upstream.

Ignore the guest MAXPHYADDR reported by CPUID.0x8000_0008 if TDP, i.e.
NPT, is disabled, and instead use the host's MAXPHYADDR.  Per AMD'S APM:

  Maximum guest physical address size in bits. This number applies only
  to guests using nested paging. When this field is zero, refer to the
  PhysAddrSize field for the maximum guest physical address size.

Fixes: 24c82e576b78 ("KVM: Sanitize cpuid")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210623230552.4027702-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-20 16:10:40 +02:00
Sean Christopherson
032fd28ed5 KVM: nVMX: Ensure 64-bit shift when checking VMFUNC bitmap
[ Upstream commit 0e75225dfa4c5d5d51291f54a3d2d5895bad38da ]

Use BIT_ULL() instead of an open-coded shift to check whether or not a
function is enabled in L1's VMFUNC bitmap.  This is a benign bug as KVM
supports only bit 0, and will fail VM-Enter if any other bits are set,
i.e. bits 63:32 are guaranteed to be zero.

Note, "function" is bounded by hardware as VMFUNC will #UD before taking
a VM-Exit if the function is greater than 63.

Before:
  if ((vmcs12->vm_function_control & (1 << function)) == 0)
   0x000000000001a916 <+118>:	mov    $0x1,%eax
   0x000000000001a91b <+123>:	shl    %cl,%eax
   0x000000000001a91d <+125>:	cltq
   0x000000000001a91f <+127>:	and    0x128(%rbx),%rax

After:
  if (!(vmcs12->vm_function_control & BIT_ULL(function & 63)))
   0x000000000001a955 <+117>:	mov    0x128(%rbx),%rdx
   0x000000000001a95c <+124>:	bt     %rax,%rdx

Fixes: 27c42a1bb867 ("KVM: nVMX: Enable VMFUNC for the L1 hypervisor")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609234235.1244004-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-07-14 16:53:23 +02:00
Alper Gun
a05499b29a KVM: SVM: Call SEV Guest Decommission if ASID binding fails
commit 934002cd660b035b926438244b4294e647507e13 upstream.

Send SEV_CMD_DECOMMISSION command to PSP firmware if ASID binding
fails. If a failure happens after  a successful LAUNCH_START command,
a decommission command should be executed. Otherwise, guest context
will be unfreed inside the AMD SP. After the firmware will not have
memory to allocate more SEV guest context, LAUNCH_START command will
begin to fail with SEV_RET_RESOURCE_LIMIT error.

The existing code calls decommission inside sev_unbind_asid, but it is
not called if a failure happens before guest activation succeeds. If
sev_bind_asid fails, decommission is never called. PSP firmware has a
limit for the number of guests. If sev_asid_binding fails many times,
PSP firmware will not have resources to create another guest context.

Cc: stable@vger.kernel.org
Fixes: 59414c989220 ("KVM: SVM: Add support for KVM_SEV_LAUNCH_START command")
Reported-by: Peter Gonda <pgonda@google.com>
Signed-off-by: Alper Gun <alpergun@google.com>
Reviewed-by: Marc Orr <marcorr@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-Id: <20210610174604.2554090-1-alpergun@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-11 12:52:07 +02:00
David Rientjes
abbd42939d KVM: SVM: Periodically schedule when unregistering regions on destroy
commit 7be74942f184fdfba34ddd19a0d995deb34d4a03 upstream.

There may be many encrypted regions that need to be unregistered when a
SEV VM is destroyed.  This can lead to soft lockups.  For example, on a
host running 4.15:

watchdog: BUG: soft lockup - CPU#206 stuck for 11s! [t_virtual_machi:194348]
CPU: 206 PID: 194348 Comm: t_virtual_machi
RIP: 0010:free_unref_page_list+0x105/0x170
...
Call Trace:
 [<0>] release_pages+0x159/0x3d0
 [<0>] sev_unpin_memory+0x2c/0x50 [kvm_amd]
 [<0>] __unregister_enc_region_locked+0x2f/0x70 [kvm_amd]
 [<0>] svm_vm_destroy+0xa9/0x200 [kvm_amd]
 [<0>] kvm_arch_destroy_vm+0x47/0x200
 [<0>] kvm_put_kvm+0x1a8/0x2f0
 [<0>] kvm_vm_release+0x25/0x30
 [<0>] do_exit+0x335/0xc10
 [<0>] do_group_exit+0x3f/0xa0
 [<0>] get_signal+0x1bc/0x670
 [<0>] do_signal+0x31/0x130

Although the CLFLUSH is no longer issued on every encrypted region to be
unregistered, there are no other changes that can prevent soft lockups for
very large SEV VMs in the latest kernel.

Periodically schedule if necessary.  This still holds kvm->lock across the
resched, but since this only happens when the VM is destroyed this is
assumed to be acceptable.

Signed-off-by: David Rientjes <rientjes@google.com>
Message-Id: <alpine.DEB.2.23.453.2008251255240.2987727@chino.kir.corp.google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[iwamatsu: adjust filename.]
Reference: CVE-2020-36311
Signed-off-by: Nobuhiro Iwamatsu (CIP) <nobuhiro1.iwamatsu@toshiba.co.jp>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-07-11 12:52:07 +02:00
Mikel Rychliski
d807b93f9b PCI: Add AMD RS690 quirk to enable 64-bit DMA
[ Upstream commit cacf994a91d3a55c0c2f853d6429cd7b86113915 ]

Although the AMD RS690 chipset has 64-bit DMA support, BIOS implementations
sometimes fail to configure the memory limit registers correctly.

The Acer F690GVM mainboard uses this chipset and a Marvell 88E8056 NIC. The
sky2 driver programs the NIC to use 64-bit DMA, which will not work:

  sky2 0000:02:00.0: error interrupt status=0x8
  sky2 0000:02:00.0 eth0: tx timeout
  sky2 0000:02:00.0 eth0: transmit ring 0 .. 22 report=0 done=0

Other drivers required by this mainboard either don't support 64-bit DMA,
or have it disabled using driver specific quirks. For example, the ahci
driver has quirks to enable or disable 64-bit DMA depending on the BIOS
version (see ahci_sb600_enable_64bit() in ahci.c). This ahci quirk matches
against the SB600 SATA controller, but the real issue is almost certainly
with the RS690 PCI host that it was commonly attached to.

To avoid this issue in all drivers with 64-bit DMA support, fix the
configuration of the PCI host. If the kernel is aware of physical memory
above 4GB, but the BIOS never configured the PCI host with this
information, update the registers with our values.

[bhelgaas: drop PCI_DEVICE_ID_ATI_RS690 definition]
Link: https://lore.kernel.org/r/20210611214823.4898-1-mikel@mikelr.com
Signed-off-by: Mikel Rychliski <mikel@mikelr.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-30 08:47:49 -04:00
Thomas Gleixner
f3c629b164 x86/fpu: Reset state for all signal restore failures
commit efa165504943f2128d50f63de0c02faf6dcceb0d upstream.

If access_ok() or fpregs_soft_set() fails in __fpu__restore_sig() then the
function just returns but does not clear the FPU state as it does for all
other fatal failures.

Clear the FPU state for these failures as well.

Fixes: 72a671ced66d ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-23 14:41:29 +02:00
Thomas Gleixner
4f1e9bafa1 x86/pkru: Write hardware init value to PKRU when xstate is init
commit 510b80a6a0f1a0d114c6e33bcea64747d127973c upstream.

When user space brings PKRU into init state, then the kernel handling is
broken:

  T1 user space
     xsave(state)
     state.header.xfeatures &= ~XFEATURE_MASK_PKRU;
     xrstor(state)

  T1 -> kernel
     schedule()
       XSAVE(S) -> T1->xsave.header.xfeatures[PKRU] == 0
       T1->flags |= TIF_NEED_FPU_LOAD;

       wrpkru();

     schedule()
       ...
       pk = get_xsave_addr(&T1->fpu->state.xsave, XFEATURE_PKRU);
       if (pk)
	 wrpkru(pk->pkru);
       else
	 wrpkru(DEFAULT_PKRU);

Because the xfeatures bit is 0 and therefore the value in the xsave
storage is not valid, get_xsave_addr() returns NULL and switch_to()
writes the default PKRU. -> FAIL #1!

So that wrecks any copy_to/from_user() on the way back to user space
which hits memory which is protected by the default PKRU value.

Assumed that this does not fail (pure luck) then T1 goes back to user
space and because TIF_NEED_FPU_LOAD is set it ends up in

  switch_fpu_return()
      __fpregs_load_activate()
        if (!fpregs_state_valid()) {
  	 load_XSTATE_from_task();
        }

But if nothing touched the FPU between T1 scheduling out and back in,
then the fpregs_state is still valid which means switch_fpu_return()
does nothing and just clears TIF_NEED_FPU_LOAD. Back to user space with
DEFAULT_PKRU loaded. -> FAIL #2!

The fix is simple: if get_xsave_addr() returns NULL then set the
PKRU value to 0 instead of the restrictive default PKRU value in
init_pkru_value.

 [ bp: Massage in minor nitpicks from folks. ]

Fixes: 0cecca9d03c9 ("x86/fpu: Eager switch PKRU state")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Tested-by: Babu Moger <babu.moger@amd.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210608144346.045616965@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-23 14:41:29 +02:00
Thomas Gleixner
13c5f1f079 x86/process: Check PF_KTHREAD and not current->mm for kernel threads
commit 12f7764ac61200e32c916f038bdc08f884b0b604 upstream.

switch_fpu_finish() checks current->mm as indicator for kernel threads.
That's wrong because kernel threads can temporarily use a mm of a user
process via kthread_use_mm().

Check the task flags for PF_KTHREAD instead.

Fixes: 0cecca9d03c9 ("x86/fpu: Eager switch PKRU state")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rik van Riel <riel@surriel.com>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210608144345.912645927@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-23 14:41:29 +02:00
Sean Christopherson
cbb425f62d KVM: x86: Immediately reset the MMU context when the SMM flag is cleared
commit 78fcb2c91adfec8ce3a2ba6b4d0dda89f2f4a7c6 upstream.

Immediately reset the MMU context when the vCPU's SMM flag is cleared so
that the SMM flag in the MMU role is always synchronized with the vCPU's
flag.  If RSM fails (which isn't correctly emulated), KVM will bail
without calling post_leave_smm() and leave the MMU in a bad state.

The bad MMU role can lead to a NULL pointer dereference when grabbing a
shadow page's rmap for a page fault as the initial lookups for the gfn
will happen with the vCPU's SMM flag (=0), whereas the rmap lookup will
use the shadow page's SMM flag, which comes from the MMU (=1).  SMM has
an entirely different set of memslots, and so the initial lookup can find
a memslot (SMM=0) and then explode on the rmap memslot lookup (SMM=1).

  general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
  KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
  CPU: 1 PID: 8410 Comm: syz-executor382 Not tainted 5.13.0-rc5-syzkaller #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
  RIP: 0010:__gfn_to_rmap arch/x86/kvm/mmu/mmu.c:935 [inline]
  RIP: 0010:gfn_to_rmap+0x2b0/0x4d0 arch/x86/kvm/mmu/mmu.c:947
  Code: <42> 80 3c 20 00 74 08 4c 89 ff e8 f1 79 a9 00 4c 89 fb 4d 8b 37 44
  RSP: 0018:ffffc90000ffef98 EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffff888015b9f414 RCX: ffff888019669c40
  RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001
  RBP: 0000000000000001 R08: ffffffff811d9cdb R09: ffffed10065a6002
  R10: ffffed10065a6002 R11: 0000000000000000 R12: dffffc0000000000
  R13: 0000000000000003 R14: 0000000000000001 R15: 0000000000000000
  FS:  000000000124b300(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000000000000000 CR3: 0000000028e31000 CR4: 00000000001526e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
  Call Trace:
   rmap_add arch/x86/kvm/mmu/mmu.c:965 [inline]
   mmu_set_spte+0x862/0xe60 arch/x86/kvm/mmu/mmu.c:2604
   __direct_map arch/x86/kvm/mmu/mmu.c:2862 [inline]
   direct_page_fault+0x1f74/0x2b70 arch/x86/kvm/mmu/mmu.c:3769
   kvm_mmu_do_page_fault arch/x86/kvm/mmu.h:124 [inline]
   kvm_mmu_page_fault+0x199/0x1440 arch/x86/kvm/mmu/mmu.c:5065
   vmx_handle_exit+0x26/0x160 arch/x86/kvm/vmx/vmx.c:6122
   vcpu_enter_guest+0x3bdd/0x9630 arch/x86/kvm/x86.c:9428
   vcpu_run+0x416/0xc20 arch/x86/kvm/x86.c:9494
   kvm_arch_vcpu_ioctl_run+0x4e8/0xa40 arch/x86/kvm/x86.c:9722
   kvm_vcpu_ioctl+0x70f/0xbb0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3460
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:1069 [inline]
   __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:1055
   do_syscall_64+0x3f/0xb0 arch/x86/entry/common.c:47
   entry_SYSCALL_64_after_hwframe+0x44/0xae
  RIP: 0033:0x440ce9

Cc: stable@vger.kernel.org
Reported-by: syzbot+fb0b6a7e8713aeb0319c@syzkaller.appspotmail.com
Fixes: 9ec19493fb86 ("KVM: x86: clear SMM flags before loading state while leaving SMM")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210609185619.992058-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-23 14:41:29 +02:00
Jim Mattson
bf99ea5297 kvm: LAPIC: Restore guard to prevent illegal APIC register access
[ Upstream commit 218bf772bddd221489c38dde6ef8e917131161f6 ]

Per the SDM, "any access that touches bytes 4 through 15 of an APIC
register may cause undefined behavior and must not be executed."
Worse, such an access in kvm_lapic_reg_read can result in a leak of
kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC:
write down valid APIC registers"), such an access was explicitly
disallowed. Restore the guard that was removed in that commit.

Fixes: 01402cf81051 ("kvm: LAPIC: write down valid APIC registers")
Signed-off-by: Jim Mattson <jmattson@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Message-Id: <20210602205224.3189316-1-jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-06-23 14:41:23 +02:00
Sean Christopherson
796d3bd4ac KVM: x86: Ensure liveliness of nested VM-Enter fail tracepoint message
commit f31500b0d437a2464ca5972d8f5439e156b74960 upstream.

Use the __string() machinery provided by the tracing subystem to make a
copy of the string literals consumed by the "nested VM-Enter failed"
tracepoint.  A complete copy is necessary to ensure that the tracepoint
can't outlive the data/memory it consumes and deference stale memory.

Because the tracepoint itself is defined by kvm, if kvm-intel and/or
kvm-amd are built as modules, the memory holding the string literals
defined by the vendor modules will be freed when the module is unloaded,
whereas the tracepoint and its data in the ring buffer will live until
kvm is unloaded (or "indefinitely" if kvm is built-in).

This bug has existed since the tracepoint was added, but was recently
exposed by a new check in tracing to detect exactly this type of bug.

  fmt: '%s%s
  ' current_buffer: ' vmx_dirty_log_t-140127  [003] ....  kvm_nested_vmenter_failed: '
  WARNING: CPU: 3 PID: 140134 at kernel/trace/trace.c:3759 trace_check_vprintf+0x3be/0x3e0
  CPU: 3 PID: 140134 Comm: less Not tainted 5.13.0-rc1-ce2e73ce600a-req #184
  Hardware name: ASUS Q87M-E/Q87M-E, BIOS 1102 03/03/2014
  RIP: 0010:trace_check_vprintf+0x3be/0x3e0
  Code: <0f> 0b 44 8b 4c 24 1c e9 a9 fe ff ff c6 44 02 ff 00 49 8b 97 b0 20
  RSP: 0018:ffffa895cc37bcb0 EFLAGS: 00010282
  RAX: 0000000000000000 RBX: ffffa895cc37bd08 RCX: 0000000000000027
  RDX: 0000000000000027 RSI: 00000000ffffdfff RDI: ffff9766cfad74f8
  RBP: ffffffffc0a041d4 R08: ffff9766cfad74f0 R09: ffffa895cc37bad8
  R10: 0000000000000001 R11: 0000000000000001 R12: ffffffffc0a041d4
  R13: ffffffffc0f4dba8 R14: 0000000000000000 R15: ffff976409f2c000
  FS:  00007f92fa200740(0000) GS:ffff9766cfac0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 0000559bd11b0000 CR3: 000000019fbaa002 CR4: 00000000001726e0
  Call Trace:
   trace_event_printf+0x5e/0x80
   trace_raw_output_kvm_nested_vmenter_failed+0x3a/0x60 [kvm]
   print_trace_line+0x1dd/0x4e0
   s_show+0x45/0x150
   seq_read_iter+0x2d5/0x4c0
   seq_read+0x106/0x150
   vfs_read+0x98/0x180
   ksys_read+0x5f/0xe0
   do_syscall_64+0x40/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xae

Cc: Steven Rostedt <rostedt@goodmis.org>
Fixes: 380e0055bc7e ("KVM: nVMX: trace nested VM-Enter failures detected by H/W")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Message-Id: <20210607175748.674002-1-seanjc@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16 11:59:44 +02:00
Arvind Sankar
a225ee1fe4 x86/boot: Add .text.* to setup.ld
commit 2e7a858ba843d2e6ceab1ba996805411de51b340 upstream.

GCC puts the main function into .text.startup when compiled with -Os (or
-O2). This results in arch/x86/boot/main.c having a .text.startup
section which is currently not included explicitly in the linker script
setup.ld in the same directory.

The BFD linker places this orphan section immediately after .text, so
this still works. However, LLD git, since [1], is choosing to place it
immediately after the .bstext section instead (this is the first code
section). This plays havoc with the section layout that setup.elf
requires to create the setup header, for eg on 64-bit:

    LD      arch/x86/boot/setup.elf
  ld.lld: error: section .text.startup file range overlaps with .header
  >>> .text.startup range is [0x200040, 0x2001FE]
  >>> .header range is [0x2001EF, 0x20026B]

  ld.lld: error: section .header file range overlaps with .bsdata
  >>> .header range is [0x2001EF, 0x20026B]
  >>> .bsdata range is [0x2001FF, 0x200398]

  ld.lld: error: section .bsdata file range overlaps with .entrytext
  >>> .bsdata range is [0x2001FF, 0x200398]
  >>> .entrytext range is [0x20026C, 0x2002D3]

  ld.lld: error: section .text.startup virtual address range overlaps
  with .header
  >>> .text.startup range is [0x40, 0x1FE]
  >>> .header range is [0x1EF, 0x26B]

  ld.lld: error: section .header virtual address range overlaps with
  .bsdata
  >>> .header range is [0x1EF, 0x26B]
  >>> .bsdata range is [0x1FF, 0x398]

  ld.lld: error: section .bsdata virtual address range overlaps with
  .entrytext
  >>> .bsdata range is [0x1FF, 0x398]
  >>> .entrytext range is [0x26C, 0x2D3]

  ld.lld: error: section .text.startup load address range overlaps with
  .header
  >>> .text.startup range is [0x40, 0x1FE]
  >>> .header range is [0x1EF, 0x26B]

  ld.lld: error: section .header load address range overlaps with
  .bsdata
  >>> .header range is [0x1EF, 0x26B]
  >>> .bsdata range is [0x1FF, 0x398]

  ld.lld: error: section .bsdata load address range overlaps with
  .entrytext
  >>> .bsdata range is [0x1FF, 0x398]
  >>> .entrytext range is [0x26C, 0x2D3]

Add .text.* to the .text output section to fix this, and also prevent
any future surprises if the compiler decides to create other such
sections.

[1] https://reviews.llvm.org/D75225

Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Link: https://lore.kernel.org/r/20200731230820.1742553-5-keescook@chromium.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-16 11:59:38 +02:00
Vitaly Kuznetsov
97e814e6b5 x86/kvm: Disable all PV features on crash
commit 3d6b84132d2a57b5a74100f6923a8feb679ac2ce upstream.

Crash shutdown handler only disables kvmclock and steal time, other PV
features remain active so we risk corrupting memory or getting some
side-effects in kdump kernel. Move crash handler to kvm.c and unify
with CPU offline.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210414123544.1060604-5-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10 13:37:16 +02:00
Vitaly Kuznetsov
9084fe1b35 x86/kvm: Disable kvmclock on all CPUs on shutdown
commit c02027b5742b5aa804ef08a4a9db433295533046 upstream.

Currenly, we disable kvmclock from machine_shutdown() hook and this
only happens for boot CPU. We need to disable it for all CPUs to
guard against memory corruption e.g. on restore from hibernate.

Note, writing '0' to kvmclock MSR doesn't clear memory location, it
just prevents hypervisor from updating the location so for the short
while after write and while CPU is still alive, the clock remains usable
and correct so we don't need to switch to some other clocksource.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210414123544.1060604-4-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10 13:37:16 +02:00
Vitaly Kuznetsov
7620a66911 x86/kvm: Teardown PV features on boot CPU as well
commit 8b79feffeca28c5459458fe78676b081e87c93a4 upstream.

Various PV features (Async PF, PV EOI, steal time) work through memory
shared with hypervisor and when we restore from hibernation we must
properly teardown all these features to make sure hypervisor doesn't
write to stale locations after we jump to the previously hibernated kernel
(which can try to place anything there). For secondary CPUs the job is
already done by kvm_cpu_down_prepare(), register syscore ops to do
the same for boot CPU.

Krzysztof:
This fixes memory corruption visible after second resume from
hibernation:

  BUG: Bad page state in process dbus-daemon  pfn:18b01
  page:ffffea000062c040 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 compound_mapcount: -30591
  flags: 0xfffffc0078141(locked|error|workingset|writeback|head|mappedtodisk|reclaim)
  raw: 000fffffc0078141 dead0000000002d0 dead000000000100 0000000000000000
  raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
  page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
  bad because of flags: 0x78141(locked|error|workingset|writeback|head|mappedtodisk|reclaim)

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20210414123544.1060604-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Andrea Righi <andrea.righi@canonical.com>
[krzysztof: Extend the commit message]
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10 13:37:15 +02:00
Sean Christopherson
2295e87a5e KVM: SVM: Truncate GPR value for DR and CR accesses in !64-bit mode
commit 0884335a2e653b8a045083aa1d57ce74269ac81d upstream.

Drop bits 63:32 on loads/stores to/from DRs and CRs when the vCPU is not
in 64-bit mode.  The APM states bits 63:32 are dropped for both DRs and
CRs:

  In 64-bit mode, the operand size is fixed at 64 bits without the need
  for a REX prefix. In non-64-bit mode, the operand size is fixed at 32
  bits and the upper 32 bits of the destination are forced to 0.

Fixes: 7ff76d58a9dc ("KVM: SVM: enhance MOV CR intercept handler")
Fixes: cae3797a4639 ("KVM: SVM: enhance mov DR intercept handler")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422022128.3464144-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[sudip: manual backport to old file]
Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10 13:37:15 +02:00
Thomas Gleixner
12ca65539b x86/apic: Mark _all_ legacy interrupts when IO/APIC is missing
commit 7d65f9e80646c595e8c853640a9d0768a33e204c upstream.

PIC interrupts do not support affinity setting and they can end up on
any online CPU. Therefore, it's required to mark the associated vectors
as system-wide reserved. Otherwise, the corresponding irq descriptors
are copied to the secondary CPUs but the vectors are not marked as
assigned or reserved. This works correctly for the IO/APIC case.

When the IO/APIC is disabled via config, kernel command line or lack of
enumeration then all legacy interrupts are routed through the PIC, but
nothing marks them as system-wide reserved vectors.

As a consequence, a subsequent allocation on a secondary CPU can result in
allocating one of these vectors, which triggers the BUG() in
apic_update_vector() because the interrupt descriptor slot is not empty.

Imran tried to work around that by marking those interrupts as allocated
when a CPU comes online. But that's wrong in case that the IO/APIC is
available and one of the legacy interrupts, e.g. IRQ0, has been switched to
PIC mode because then marking them as allocated will fail as they are
already marked as system vectors.

Stay consistent and update the legacy vectors after attempting IO/APIC
initialization and mark them as system vectors in case that no IO/APIC is
available.

Fixes: 69cde0004a4b ("x86/vector: Use matrix allocator for vector assignment")
Reported-by: Imran Khan <imran.f.khan@oracle.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20210519233928.2157496-1-imran.f.khan@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-06-10 13:37:12 +02:00
Arnd Bergmann
b806b41bf5 x86/msr: Fix wr/rdmsr_safe_regs_on_cpu() prototypes
commit 396a66aa1172ef2b78c21651f59b40b87b2e5e1e upstream.

gcc-11 warns about mismatched prototypes here:

  arch/x86/lib/msr-smp.c:255:51: error: argument 2 of type ‘u32 *’ {aka ‘unsigned int *’} declared as a pointer [-Werror=array-parameter=]
    255 | int rdmsr_safe_regs_on_cpu(unsigned int cpu, u32 *regs)
        |                                              ~~~~~^~~~
  arch/x86/include/asm/msr.h:347:50: note: previously declared as an array ‘u32[8]’ {aka ‘unsigned int[8]’}

GCC is right here - fix up the types.

[ mingo: Twiddled the changelog. ]

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210322164541.912261-1-arnd@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-22 11:38:27 +02:00
Thomas Gleixner
187598fd82 KVM: x86: Cancel pvclock_gtod_work on module removal
commit 594b27e677b35f9734b1969d175ebc6146741109 upstream.

Nothing prevents the following:

  pvclock_gtod_notify()
    queue_work(system_long_wq, &pvclock_gtod_work);
  ...
  remove_module(kvm);
  ...
  work_queue_run()
    pvclock_gtod_work()	<- UAF

Ditto for any other operation on that workqueue list head which touches
pvclock_gtod_work after module removal.

Cancel the work in kvm_arch_exit() to prevent that.

Fixes: 16e8d74d2da9 ("KVM: x86: notifier for clocksource changes")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Message-Id: <87czu4onry.ffs@nanos.tec.linutronix.de>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-19 10:08:31 +02:00
Sean Christopherson
18cb19eab7 KVM: x86/mmu: Remove the defunct update_pte() paging hook
commit c5e2184d1544f9e56140791eff1a351bea2e63b9 upstream.

Remove the update_pte() shadow paging logic, which was obsoleted by
commit 4731d4c7a077 ("KVM: MMU: out of sync shadow core"), but never
removed.  As pointed out by Yu, KVM never write protects leaf page
tables for the purposes of shadow paging, and instead marks their
associated shadow page as unsync so that the guest can write PTEs at
will.

The update_pte() path, which predates the unsync logic, optimizes COW
scenarios by refreshing leaf SPTEs when they are written, as opposed to
zapping the SPTE, restarting the guest, and installing the new SPTE on
the subsequent fault.  Since KVM no longer write-protects leaf page
tables, update_pte() is unreachable and can be dropped.

Reported-by: Yu Zhang <yu.c.zhang@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210115004051.4099250-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
(jwang: backport to 5.4 to fix a warning on AMD nested Virtualization)
Signed-off-by: Jack Wang <jinpu.wang@ionos.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-19 10:08:20 +02:00
Nathan Chancellor
c01fc0adba x86/events/amd/iommu: Fix sysfs type mismatch
[ Upstream commit de5bc7b425d4c27ae5faa00ea7eb6b9780b9a355 ]

dev_attr_show() calls _iommu_event_show() via an indirect call but
_iommu_event_show()'s type does not currently match the type of the
show() member in 'struct device_attribute', resulting in a Control Flow
Integrity violation.

$ cat /sys/devices/amd_iommu_1/events/mem_dte_hit
csource=0x0a

$ dmesg | grep "CFI failure"
[ 3526.735140] CFI failure (target: _iommu_event_show...):

Change _iommu_event_show() and 'struct amd_iommu_event_desc' to
'struct device_attribute' so that there is no more CFI violation.

Fixes: 7be6296fdd75 ("perf/x86/amd: AMD IOMMU Performance Counter PERF uncore PMU implementation")
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210415001112.3024673-1-nathan@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:26 +02:00
Masami Hiramatsu
c66229b36f x86/kprobes: Fix to check non boostable prefixes correctly
[ Upstream commit 6dd3b8c9f58816a1354be39559f630cd1bd12159 ]

There are 2 bugs in the can_boost() function because of using
x86 insn decoder. Since the insn->opcode never has a prefix byte,
it can not find CS override prefix in it. And the insn->attr is
the attribute of the opcode, thus inat_is_address_size_prefix(
insn->attr) always returns false.

Fix those by checking each prefix bytes with for_each_insn_prefix
loop and getting the correct attribute for each prefix byte.
Also, this removes unlikely, because this is a slow path.

Fixes: a8d11cd0714f ("kprobes/x86: Consolidate insn decoder users for copying code")
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/161666691162.1120877.2808435205294352583.stgit@devnote2
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:23 +02:00
Ingo Molnar
9b47b3a675 x86/platform/uv: Fix !KEXEC build failure
[ Upstream commit c2209ea55612efac75de0a58ef5f7394fae7fa0f ]

When KEXEC is disabled, the UV build fails:

  arch/x86/platform/uv/uv_nmi.c:875:14: error: ‘uv_nmi_kexec_failed’ undeclared (first use in this function)

Since uv_nmi_kexec_failed is only defined in the KEXEC_CORE #ifdef branch,
this code cannot ever have been build tested:

	if (main)
		pr_err("UV: NMI kdump: KEXEC not supported in this kernel\n");
	atomic_set(&uv_nmi_kexec_failed, 1);

Nor is this use possible in uv_handle_nmi():

                atomic_set(&uv_nmi_kexec_failed, 0);

These bugs were introduced in this commit:

    d0a9964e9873: ("x86/platform/uv: Implement simple dump failover if kdump fails")

Which added the uv_nmi_kexec_failed assignments to !KEXEC code, while making the
definition KEXEC-only - apparently without testing the !KEXEC case.

Instead of complicating the #ifdef maze, simplify the code by requiring X86_UV
to depend on KEXEC_CORE. This pattern is present in other architectures as well.

( We'll remove the untested, 7 years old !KEXEC complications from the file in a
  separate commit. )

Fixes: d0a9964e9873: ("x86/platform/uv: Implement simple dump failover if kdump fails")
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Mike Travis <travis@sgi.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:22 +02:00
Otavio Pontes
369428a646 x86/microcode: Check for offline CPUs before requesting new microcode
[ Upstream commit 7189b3c11903667808029ec9766a6e96de5012a5 ]

Currently, the late microcode loading mechanism checks whether any CPUs
are offlined, and, in such a case, aborts the load attempt.

However, this must be done before the kernel caches new microcode from
the filesystem. Otherwise, when offlined CPUs are onlined later, those
cores are going to be updated through the CPU hotplug notifier callback
with the new microcode, while CPUs previously onine will continue to run
with the older microcode.

For example:

Turn off one core (2 threads):

  echo 0 > /sys/devices/system/cpu/cpu3/online
  echo 0 > /sys/devices/system/cpu/cpu1/online

Install the ucode fails because a primary SMT thread is offline:

  cp intel-ucode/06-8e-09 /lib/firmware/intel-ucode/
  echo 1 > /sys/devices/system/cpu/microcode/reload
  bash: echo: write error: Invalid argument

Turn the core back on

  echo 1 > /sys/devices/system/cpu/cpu3/online
  echo 1 > /sys/devices/system/cpu/cpu1/online
  cat /proc/cpuinfo |grep microcode
  microcode : 0x30
  microcode : 0xde
  microcode : 0x30
  microcode : 0xde

The rationale for why the update is aborted when at least one primary
thread is offline is because even if that thread is soft-offlined
and idle, it will still have to participate in broadcasted MCE's
synchronization dance or enter SMM, and in both examples it will execute
instructions so it better have the same microcode revision as the other
cores.

 [ bp: Heavily edit and extend commit message with the reasoning behind all
   this. ]

Fixes: 30ec26da9967 ("x86/microcode: Do not upload microcode if CPUs are offline")
Signed-off-by: Otavio Pontes <otavio.pontes@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Acked-by: Ashok Raj <ashok.raj@intel.com>
Link: https://lkml.kernel.org/r/20210319165515.9240-2-otavio.pontes@intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-14 09:44:17 +02:00
Sean Christopherson
cc6623055f KVM: nVMX: Truncate bits 63:32 of VMCS field on nested check in !64-bit
commit ee050a577523dfd5fac95e6cc182ebe0293ead59 upstream.

Drop bits 63:32 of the VMCS field encoding when checking for a nested
VM-Exit on VMREAD/VMWRITE in !64-bit mode.  VMREAD and VMWRITE always
use 32-bit operands outside of 64-bit mode.

The actual emulation of VMREAD/VMWRITE does the right thing, this bug is
purely limited to incorrectly causing a nested VM-Exit if a GPR happens
to have bits 63:32 set outside of 64-bit mode.

Fixes: a7cde481b6e8 ("KVM: nVMX: Do not forward VMREAD/VMWRITE VMExits to L1 if required so by vmcs12 vmread/vmwrite bitmaps")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210422022128.3464144-6-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-14 09:44:15 +02:00
Sean Christopherson
19c8c34a8b x86/cpu: Initialize MSR_TSC_AUX if RDTSCP *or* RDPID is supported
commit b6b4fbd90b155a0025223df2c137af8a701d53b3 upstream.

Initialize MSR_TSC_AUX with CPU node information if RDTSCP or RDPID is
supported.  This fixes a bug where vdso_read_cpunode() will read garbage
via RDPID if RDPID is supported but RDTSCP is not.  While no known CPU
supports RDPID but not RDTSCP, both Intel's SDM and AMD's APM allow for
RDPID to exist without RDTSCP, e.g. it's technically a legal CPU model
for a virtual machine.

Note, technically MSR_TSC_AUX could be initialized if and only if RDPID
is supported since RDTSCP is currently not used to retrieve the CPU node.
But, the cost of the superfluous WRMSR is negigible, whereas leaving
MSR_TSC_AUX uninitialized is just asking for future breakage if someone
decides to utilize RDTSCP.

Fixes: a582c540ac1b ("x86/vdso: Use RDPID in preference to LSL when available")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210504225632.1532621-2-seanjc@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-11 14:04:16 +02:00
John Millikin
dda2bc8289 x86/build: Propagate $(CLANG_FLAGS) to $(REALMODE_FLAGS)
[ Upstream commit 8abe7fc26ad8f28bfdf78adbed56acd1fa93f82d ]

When cross-compiling with Clang, the `$(CLANG_FLAGS)' variable
contains additional flags needed to build C and assembly sources
for the target platform. Normally this variable is automatically
included in `$(KBUILD_CFLAGS)' via the top-level Makefile.

The x86 real-mode makefile builds `$(REALMODE_CFLAGS)' from a
plain assignment and therefore drops the Clang flags. This causes
Clang to not recognize x86-specific assembler directives:

  arch/x86/realmode/rm/header.S:36:1: error: unknown directive
  .type real_mode_header STT_OBJECT ; .size real_mode_header, .-real_mode_header
  ^

Explicit propagation of `$(CLANG_FLAGS)' to `$(REALMODE_CFLAGS)',
which is inherited by real-mode make rules, fixes cross-compilation
with Clang for x86 targets.

Relevant flags:

* `--target' sets the target architecture when cross-compiling. This
  flag must be set for both compilation and assembly (`KBUILD_AFLAGS')
  to support architecture-specific assembler directives.

* `-no-integrated-as' tells clang to assemble with GNU Assembler
  instead of its built-in LLVM assembler. This flag is set by default
  unless `LLVM_IAS=1' is set, because the LLVM assembler can't yet
  parse certain GNU extensions.

Signed-off-by: John Millikin <john@john-millikin.com>
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Link: https://lkml.kernel.org/r/20210326000435.4785-2-nathan@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-05-11 14:04:06 +02:00
Rafael J. Wysocki
55714a57f3 ACPI: x86: Call acpi_boot_table_init() after acpi_table_upgrade()
commit 6998a8800d73116187aad542391ce3b2dd0f9e30 upstream.

Commit 1a1c130ab757 ("ACPI: tables: x86: Reserve memory occupied by
ACPI tables") attempted to address an issue with reserving the memory
occupied by ACPI tables, but it broke the initrd-based table override
mechanism relied on by multiple users.

To restore the initrd-based ACPI table override functionality, move
the acpi_boot_table_init() invocation in setup_arch() on x86 after
the acpi_table_upgrade() one.

Fixes: 1a1c130ab757 ("ACPI: tables: x86: Reserve memory occupied by ACPI tables")
Reported-by: Hans de Goede <hdegoede@redhat.com>
Tested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: George Kennedy <george.kennedy@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-07 10:51:37 +02:00
Rafael J. Wysocki
b3041510f0 ACPI: tables: x86: Reserve memory occupied by ACPI tables
commit 1a1c130ab7575498eed5bcf7220037ae09cd1f8a upstream.

The following problem has been reported by George Kennedy:

 Since commit 7fef431be9c9 ("mm/page_alloc: place pages to tail
 in __free_pages_core()") the following use after free occurs
 intermittently when ACPI tables are accessed.

 BUG: KASAN: use-after-free in ibft_init+0x134/0xc49
 Read of size 4 at addr ffff8880be453004 by task swapper/0/1
 CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.12.0-rc1-7a7fd0d #1
 Call Trace:
  dump_stack+0xf6/0x158
  print_address_description.constprop.9+0x41/0x60
  kasan_report.cold.14+0x7b/0xd4
  __asan_report_load_n_noabort+0xf/0x20
  ibft_init+0x134/0xc49
  do_one_initcall+0xc4/0x3e0
  kernel_init_freeable+0x5af/0x66b
  kernel_init+0x16/0x1d0
  ret_from_fork+0x22/0x30

 ACPI tables mapped via kmap() do not have their mapped pages
 reserved and the pages can be "stolen" by the buddy allocator.

Apparently, on the affected system, the ACPI table in question is
not located in "reserved" memory, like ACPI NVS or ACPI Data, that
will not be used by the buddy allocator, so the memory occupied by
that table has to be explicitly reserved to prevent the buddy
allocator from using it.

In order to address this problem, rearrange the initialization of the
ACPI tables on x86 to locate the initial tables earlier and reserve
the memory occupied by them.

The other architectures using ACPI should not be affected by this
change.

Link: https://lore.kernel.org/linux-acpi/1614802160-29362-1-git-send-email-george.kennedy@oracle.com/
Reported-by: George Kennedy <george.kennedy@oracle.com>
Tested-by: George Kennedy <george.kennedy@oracle.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Cc: 5.10+ <stable@vger.kernel.org> # 5.10+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-05-07 10:51:36 +02:00
Mike Galbraith
699017fe0d x86/crash: Fix crash_setup_memmap_entries() out-of-bounds access
commit 5849cdf8c120e3979c57d34be55b92d90a77a47e upstream.

Commit in Fixes: added support for kexec-ing a kernel on panic using a
new system call. As part of it, it does prepare a memory map for the new
kernel.

However, while doing so, it wrongly accesses memory it has not
allocated: it accesses the first element of the cmem->ranges[] array in
memmap_exclude_ranges() but it has not allocated the memory for it in
crash_setup_memmap_entries(). As KASAN reports:

  BUG: KASAN: vmalloc-out-of-bounds in crash_setup_memmap_entries+0x17e/0x3a0
  Write of size 8 at addr ffffc90000426008 by task kexec/1187

  (gdb) list *crash_setup_memmap_entries+0x17e
  0xffffffff8107cafe is in crash_setup_memmap_entries (arch/x86/kernel/crash.c:322).
  317                                      unsigned long long mend)
  318     {
  319             unsigned long start, end;
  320
  321             cmem->ranges[0].start = mstart;
  322             cmem->ranges[0].end = mend;
  323             cmem->nr_ranges = 1;
  324
  325             /* Exclude elf header region */
  326             start = image->arch.elf_load_addr;
  (gdb)

Make sure the ranges array becomes a single element allocated.

 [ bp: Write a proper commit message. ]

Fixes: dd5f726076cc ("kexec: support for kexec on panic using new system call")
Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Young <dyoung@redhat.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/725fa3dc1da2737f0f6188a1a9701bead257ea9d.camel@gmx.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-28 13:19:16 +02:00
Jim Mattson
3963828959 perf/x86/kvm: Fix Broadwell Xeon stepping in isolation_ucodes[]
[ Upstream commit 4b2f1e59229b9da319d358828cdfa4ddbc140769 ]

The only stepping of Broadwell Xeon parts is stepping 1. Fix the
relevant isolation_ucodes[] entry, which previously enumerated
stepping 2.

Although the original commit was characterized as an optimization, it
is also a workaround for a correctness issue.

If a PMI arrives between kvm's call to perf_guest_get_msrs() and the
subsequent VM-entry, a stale value for the IA32_PEBS_ENABLE MSR may be
restored at the next VM-exit. This is because, unbeknownst to kvm, PMI
throttling may clear bits in the IA32_PEBS_ENABLE MSR. CPUs with "PEBS
isolation" don't suffer from this issue, because perf_guest_get_msrs()
doesn't report the IA32_PEBS_ENABLE value.

Fixes: 9b545c04abd4f ("perf/x86/kvm: Avoid unnecessary work in guest filtering")
Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Peter Shier <pshier@google.com>
Acked-by: Andi Kleen <ak@linux.intel.com>
Link: https://lkml.kernel.org/r/20210422001834.1748319-1-jmattson@google.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-28 13:19:15 +02:00
Kan Liang
319a06e58e perf/x86/intel/uncore: Remove uncore extra PCI dev HSWEP_PCI_PCU_3
[ Upstream commit 9d480158ee86ad606d3a8baaf81e6b71acbfd7d5 ]

There may be a kernel panic on the Haswell server and the Broadwell
server, if the snbep_pci2phy_map_init() return error.

The uncore_extra_pci_dev[HSWEP_PCI_PCU_3] is used in the cpu_init() to
detect the existence of the SBOX, which is a MSR type of PMON unit.
The uncore_extra_pci_dev is allocated in the uncore_pci_init(). If the
snbep_pci2phy_map_init() returns error, perf doesn't initialize the
PCI type of the PMON units, so the uncore_extra_pci_dev will not be
allocated. But perf may continue initializing the MSR type of PMON
units. A null dereference kernel panic will be triggered.

The sockets in a Haswell server or a Broadwell server are identical.
Only need to detect the existence of the SBOX once.
Current perf probes all available PCU devices and stores them into the
uncore_extra_pci_dev. It's unnecessary.
Use the pci_get_device() to replace the uncore_extra_pci_dev. Only
detect the existence of the SBOX on the first available PCU device once.

Factor out hswep_has_limit_sbox(), since the Haswell server and the
Broadwell server uses the same way to detect the existence of the SBOX.

Add some macros to replace the magic number.

Fixes: 5306c31c5733 ("perf/x86/uncore/hsw-ep: Handle systems with only two SBOXes")
Reported-by: Steve Wahl <steve.wahl@hpe.com>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lkml.kernel.org/r/1618521764-100923-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-28 13:19:15 +02:00
Piotr Krysiuk
6cce305480 bpf, x86: Validate computation of branch displacements for x86-32
commit 26f55a59dc65ff77cd1c4b37991e26497fc68049 upstream.

The branch displacement logic in the BPF JIT compilers for x86 assumes
that, for any generated branch instruction, the distance cannot
increase between optimization passes.

But this assumption can be violated due to how the distances are
computed. Specifically, whenever a backward branch is processed in
do_jit(), the distance is computed by subtracting the positions in the
machine code from different optimization passes. This is because part
of addrs[] is already updated for the current optimization pass, before
the branch instruction is visited.

And so the optimizer can expand blocks of machine code in some cases.

This can confuse the optimizer logic, where it assumes that a fixed
point has been reached for all machine code blocks once the total
program size stops changing. And then the JIT compiler can output
abnormal machine code containing incorrect branch displacements.

To mitigate this issue, we assert that a fixed point is reached while
populating the output image. This rejects any problematic programs.
The issue affects both x86-32 and x86-64. We mitigate separately to
ease backporting.

Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Reviewed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10 13:34:31 +02:00
Piotr Krysiuk
a0b3927a07 bpf, x86: Validate computation of branch displacements for x86-64
commit e4d4d456436bfb2fe412ee2cd489f7658449b098 upstream.

The branch displacement logic in the BPF JIT compilers for x86 assumes
that, for any generated branch instruction, the distance cannot
increase between optimization passes.

But this assumption can be violated due to how the distances are
computed. Specifically, whenever a backward branch is processed in
do_jit(), the distance is computed by subtracting the positions in the
machine code from different optimization passes. This is because part
of addrs[] is already updated for the current optimization pass, before
the branch instruction is visited.

And so the optimizer can expand blocks of machine code in some cases.

This can confuse the optimizer logic, where it assumes that a fixed
point has been reached for all machine code blocks once the total
program size stops changing. And then the JIT compiler can output
abnormal machine code containing incorrect branch displacements.

To mitigate this issue, we assert that a fixed point is reached while
populating the output image. This rejects any problematic programs.
The issue affects both x86-32 and x86-64. We mitigate separately to
ease backporting.

Signed-off-by: Piotr Krysiuk <piotras@gmail.com>
Reviewed-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-04-10 13:34:31 +02:00
Arnd Bergmann
e2db0e6613 x86/build: Turn off -fcf-protection for realmode targets
[ Upstream commit 9fcb51c14da2953de585c5c6e50697b8a6e91a7b ]

The new Ubuntu GCC packages turn on -fcf-protection globally,
which causes a build failure in the x86 realmode code:

  cc1: error: ‘-fcf-protection’ is not compatible with this target

Turn it off explicitly on compilers that understand this option.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20210323124846.1584944-1-arnd@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-10 13:34:31 +02:00
Yonghong Song
b0e2b32712 bpf, x86: Use kvmalloc_array instead kmalloc_array in bpf_jit_comp
[ Upstream commit de920fc64cbaa031f947e9be964bda05fd090380 ]

x86 bpf_jit_comp.c used kmalloc_array to store jited addresses
for each bpf insn. With a large bpf program, we have see the
following allocation failures in our production server:

    page allocation failure: order:5, mode:0x40cc0(GFP_KERNEL|__GFP_COMP),
                             nodemask=(null),cpuset=/,mems_allowed=0"
    Call Trace:
    dump_stack+0x50/0x70
    warn_alloc.cold.120+0x72/0xd2
    ? __alloc_pages_direct_compact+0x157/0x160
    __alloc_pages_slowpath+0xcdb/0xd00
    ? get_page_from_freelist+0xe44/0x1600
    ? vunmap_page_range+0x1ba/0x340
    __alloc_pages_nodemask+0x2c9/0x320
    kmalloc_order+0x18/0x80
    kmalloc_order_trace+0x1d/0xa0
    bpf_int_jit_compile+0x1e2/0x484
    ? kmalloc_order_trace+0x1d/0xa0
    bpf_prog_select_runtime+0xc3/0x150
    bpf_prog_load+0x480/0x720
    ? __mod_memcg_lruvec_state+0x21/0x100
    __do_sys_bpf+0xc31/0x2040
    ? close_pdeo+0x86/0xe0
    do_syscall_64+0x42/0x110
    entry_SYSCALL_64_after_hwframe+0x44/0xa9
    RIP: 0033:0x7f2f300f7fa9
    Code: Bad RIP value.

Dumped assembly:

    ffffffff810b6d70 <bpf_int_jit_compile>:
    ; {
    ffffffff810b6d70: e8 eb a5 b4 00        callq   0xffffffff81c01360 <__fentry__>
    ffffffff810b6d75: 41 57                 pushq   %r15
    ...
    ffffffff810b6f39: e9 72 fe ff ff        jmp     0xffffffff810b6db0 <bpf_int_jit_compile+0x40>
    ;       addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL);
    ffffffff810b6f3e: 8b 45 0c              movl    12(%rbp), %eax
    ;       return __kmalloc(bytes, flags);
    ffffffff810b6f41: be c0 0c 00 00        movl    $3264, %esi
    ;       addrs = kmalloc_array(prog->len + 1, sizeof(*addrs), GFP_KERNEL);
    ffffffff810b6f46: 8d 78 01              leal    1(%rax), %edi
    ;       if (unlikely(check_mul_overflow(n, size, &bytes)))
    ffffffff810b6f49: 48 c1 e7 02           shlq    $2, %rdi
    ;       return __kmalloc(bytes, flags);
    ffffffff810b6f4d: e8 8e 0c 1d 00        callq   0xffffffff81287be0 <__kmalloc>
    ;       if (!addrs) {
    ffffffff810b6f52: 48 85 c0              testq   %rax, %rax

Change kmalloc_array() to kvmalloc_array() to avoid potential
allocation error for big bpf programs.

Signed-off-by: Yonghong Song <yhs@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20210309015647.3657852-1-yhs@fb.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-04-10 13:34:30 +02:00
Isaku Yamahata
dfd6627c83 x86/mem_encrypt: Correct physical address calculation in __set_clr_pte_enc()
commit 8249d17d3194eac064a8ca5bc5ca0abc86feecde upstream.

The pfn variable contains the page frame number as returned by the
pXX_pfn() functions, shifted to the right by PAGE_SHIFT to remove the
page bits. After page protection computations are done to it, it gets
shifted back to the physical address using page_level_shift().

That is wrong, of course, because that function determines the shift
length based on the level of the page in the page table but in all the
cases, it was shifted by PAGE_SHIFT before.

Therefore, shift it back using PAGE_SHIFT to get the correct physical
address.

 [ bp: Rewrite commit message. ]

Fixes: dfaaec9033b8 ("x86: Add support for changing memory encryption attribute in early boot")
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Tom Lendacky <thomas.lendacky@amd.com>
Cc: <stable@vger.kernel.org>
Link: https://lkml.kernel.org/r/81abbae1657053eccc535c16151f63cd049dcb97.1616098294.git.isaku.yamahata@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-30 14:35:29 +02:00
Johan Hovold
cf113ffd62 x86/apic/of: Fix CPU devicetree-node lookups
commit dd926880da8dbbe409e709c1d3c1620729a94732 upstream.

Architectures that describe the CPU topology in devicetree and do not have
an identity mapping between physical and logical CPU ids must override the
default implementation of arch_match_cpu_phys_id().

Failing to do so breaks CPU devicetree-node lookups using of_get_cpu_node()
and of_cpu_device_node_get() which several drivers rely on. It also causes
the CPU struct devices exported through sysfs to point to the wrong
devicetree nodes.

On x86, CPUs are described in devicetree using their APIC ids and those
do not generally coincide with the logical ids, even if CPU0 typically
uses APIC id 0.

Add the missing implementation of arch_match_cpu_phys_id() so that CPU-node
lookups work also with SMP.

Apart from fixing the broken sysfs devicetree-node links this likely does
not affect current users of mainline kernels on x86.

Fixes: 4e07db9c8db8 ("x86/devicetree: Use CPU description from Device Tree")
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210312092033.26317-1-johan@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:45 +01:00
Oleg Nesterov
de2e1603c1 x86: Introduce TS_COMPAT_RESTART to fix get_nr_restart_syscall()
commit 8c150ba2fb5995c84a7a43848250d444a3329a7d upstream.

The comment in get_nr_restart_syscall() says:

	 * The problem is that we can get here when ptrace pokes
	 * syscall-like values into regs even if we're not in a syscall
	 * at all.

Yes, but if not in a syscall then the

	status & (TS_COMPAT|TS_I386_REGS_POKED)

check below can't really help:

	- TS_COMPAT can't be set

	- TS_I386_REGS_POKED is only set if regs->orig_ax was changed by
	  32bit debugger; and even in this case get_nr_restart_syscall()
	  is only correct if the tracee is 32bit too.

Suppose that a 64bit debugger plays with a 32bit tracee and

	* Tracee calls sleep(2)	// TS_COMPAT is set
	* User interrupts the tracee by CTRL-C after 1 sec and does
	  "(gdb) call func()"
	* gdb saves the regs by PTRACE_GETREGS
	* does PTRACE_SETREGS to set %rip='func' and %orig_rax=-1
	* PTRACE_CONT		// TS_COMPAT is cleared
	* func() hits int3.
	* Debugger catches SIGTRAP.
	* Restore original regs by PTRACE_SETREGS.
	* PTRACE_CONT

get_nr_restart_syscall() wrongly returns __NR_restart_syscall==219, the
tracee calls ia32_sys_call_table[219] == sys_madvise.

Add the sticky TS_COMPAT_RESTART flag which survives after return to user
mode. It's going to be removed in the next step again by storing the
information in the restart block. As a further cleanup it might be possible
to remove also TS_I386_REGS_POKED with that.

Test-case:

  $ cvs -d :pserver:anoncvs:anoncvs@sourceware.org:/cvs/systemtap co ptrace-tests
  $ gcc -o erestartsys-trap-debuggee ptrace-tests/tests/erestartsys-trap-debuggee.c --m32
  $ gcc -o erestartsys-trap-debugger ptrace-tests/tests/erestartsys-trap-debugger.c -lutil
  $ ./erestartsys-trap-debugger
  Unexpected: retval 1, errno 22
  erestartsys-trap-debugger: ptrace-tests/tests/erestartsys-trap-debugger.c:421

Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Reported-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174709.GA17895@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:44 +01:00
Oleg Nesterov
076b60af92 x86: Move TS_COMPAT back to asm/thread_info.h
commit 66c1b6d74cd7035e85c426f0af4aede19e805c8a upstream.

Move TS_COMPAT back to asm/thread_info.h, close to TS_I386_REGS_POKED.

It was moved to asm/processor.h by b9d989c7218a ("x86/asm: Move the
thread_info::status field to thread_struct"), then later 37a8f7c38339
("x86/asm: Move 'status' from thread_struct to thread_info") moved the
'status' field back but TS_COMPAT was forgotten.

Preparatory patch to fix the COMPAT case for get_nr_restart_syscall()

Fixes: 609c19a385c8 ("x86/ptrace: Stop setting TS_COMPAT in ptrace code")
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210201174649.GA17880@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:44 +01:00
Thomas Gleixner
f546965c3a x86/ioapic: Ignore IRQ2 again
commit a501b048a95b79e1e34f03cac3c87ff1e9f229ad upstream.

Vitaly ran into an issue with hotplugging CPU0 on an Amazon instance where
the matrix allocator claimed to be out of vectors. He analyzed it down to
the point that IRQ2, the PIC cascade interrupt, which is supposed to be not
ever routed to the IO/APIC ended up having an interrupt vector assigned
which got moved during unplug of CPU0.

The underlying issue is that IRQ2 for various reasons (see commit
af174783b925 ("x86: I/O APIC: Never configure IRQ2" for details) is treated
as a reserved system vector by the vector core code and is not accounted as
a regular vector. The Amazon BIOS has an routing entry of pin2 to IRQ2
which causes the IO/APIC setup to claim that interrupt which is granted by
the vector domain because there is no sanity check. As a consequence the
allocation counter of CPU0 underflows which causes a subsequent unplug to
fail with:

  [ ... ] CPU 0 has 4294967295 vectors, 589 available. Cannot disable CPU

There is another sanity check missing in the matrix allocator, but the
underlying root cause is that the IO/APIC code lost the IRQ2 ignore logic
during the conversion to irqdomains.

For almost 6 years nobody complained about this wreckage, which might
indicate that this requirement could be lifted, but for any system which
actually has a PIC IRQ2 is unusable by design so any routing entry has no
effect and the interrupt cannot be connected to a device anyway.

Due to that and due to history biased paranoia reasons restore the IRQ2
ignore logic and treat it as non existent despite a routing entry claiming
otherwise.

Fixes: d32932d02e18 ("x86/irq: Convert IOAPIC to use hierarchical irqdomain interfaces")
Reported-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20210318192819.636943062@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:44 +01:00
Kan Liang
da326ba3b8 perf/x86/intel: Fix a crash caused by zero PEBS status
commit d88d05a9e0b6d9356e97129d4ff9942d765f46ea upstream.

A repeatable crash can be triggered by the perf_fuzzer on some Haswell
system.
https://lore.kernel.org/lkml/7170d3b-c17f-1ded-52aa-cc6d9ae999f4@maine.edu/

For some old CPUs (HSW and earlier), the PEBS status in a PEBS record
may be mistakenly set to 0. To minimize the impact of the defect, the
commit was introduced to try to avoid dropping the PEBS record for some
cases. It adds a check in the intel_pmu_drain_pebs_nhm(), and updates
the local pebs_status accordingly. However, it doesn't correct the PEBS
status in the PEBS record, which may trigger the crash, especially for
the large PEBS.

It's possible that all the PEBS records in a large PEBS have the PEBS
status 0. If so, the first get_next_pebs_record_by_bit() in the
__intel_pmu_pebs_event() returns NULL. The at = NULL. Since it's a large
PEBS, the 'count' parameter must > 1. The second
get_next_pebs_record_by_bit() will crash.

Besides the local pebs_status, correct the PEBS status in the PEBS
record as well.

Fixes: 01330d7288e0 ("perf/x86: Allow zero PEBS status with only single active event")
Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Suggested-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Kan Liang <kan.liang@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/1615555298-140216-1-git-send-email-kan.liang@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-24 11:26:43 +01:00
Ard Biesheuvel
6c3d86e6ff crypto: x86/aes-ni-xts - use direct calls to and 4-way stride
commit 86ad60a65f29dd862a11c22bb4b5be28d6c5cef1 upstream.

The XTS asm helper arrangement is a bit odd: the 8-way stride helper
consists of back-to-back calls to the 4-way core transforms, which
are called indirectly, based on a boolean that indicates whether we
are performing encryption or decryption.

Given how costly indirect calls are on x86, let's switch to direct
calls, and given how the 8-way stride doesn't really add anything
substantial, use a 4-way stride instead, and make the asm core
routine deal with any multiple of 4 blocks. Since 512 byte sectors
or 4 KB blocks are the typical quantities XTS operates on, increase
the stride exported to the glue helper to 512 bytes as well.

As a result, the number of indirect calls is reduced from 3 per 64 bytes
of in/output to 1 per 512 bytes of in/output, which produces a 65% speedup
when operating on 1 KB blocks (measured on a Intel(R) Core(TM) i7-8650U CPU)

Fixes: 9697fa39efd3f ("x86/retpoline/crypto: Convert crypto assembler indirect jumps")
Tested-by: Eric Biggers <ebiggers@google.com> # x86_64
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[ardb: rebase onto stable/linux-5.4.y]
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-20 10:39:47 +01:00