It is not easily reproducible, but on 5.16-rc I have several times hit
the VM_BUG_ON_PAGE(PageTail(page), page) in
page_cache_add_speculative(): usually from filemap_get_read_batch() for
an ext4 read, yesterday from next_uptodate_page() from
filemap_map_pages() for a shmem fault.
That BUG used to be placed where page_ref_add_unless() had succeeded,
but now it is placed before folio_ref_add_unless() is attempted: that is
not safe, since it is only the acquired reference which makes the page
safe from racing THP collapse or split.
We could keep the BUG, checking PageTail only when
folio_ref_try_add_rcu() has succeeded; but I don't think it adds much
value - just delete it.
Link: https://lkml.kernel.org/r/8b98fc6f-3439-8614-c3f3-945c659a1aba@google.com
Fixes: 020853b6f5 ("mm: Add folio_try_get_rcu()")
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: William Kucharski <william.kucharski@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When a memory error hits a tail page of a free hugepage,
__page_handle_poison() is expected to be called to isolate the error in
4kB unit, but it's not called due to the outdated if-condition in
memory_failure_hugetlb(). This loses the chance to isolate the error in
the finer unit, so it's not optimal. Drop the condition.
This "(p != head && TestSetPageHWPoison(head)" condition is based on the
old semantics of PageHWPoison on hugepage (where PG_hwpoison flag was
set on the subpage), so it's not necessray any more. By getting to set
PG_hwpoison on head page for hugepages, concurrent error events on
different subpages in a single hugepage can be prevented by
TestSetPageHWPoison(head) at the beginning of memory_failure_hugetlb().
So dropping the condition should not reopen the race window originally
mentioned in commit b985194c8c ("hwpoison, hugetlb:
lock_page/unlock_page does not match for handling a free hugepage")
[naoya.horiguchi@linux.dev: fix "HardwareCorrupted" counter]
Link: https://lkml.kernel.org/r/20211220084851.GA1460264@u2004
Link: https://lkml.kernel.org/r/20211210110208.879740-1-naoya.horiguchi@linux.dev
Signed-off-by: Naoya Horiguchi <naoya.horiguchi@nec.com>
Reported-by: Fei Luo <luofei@unicloud.com>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: <stable@vger.kernel.org> [5.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When booting with crashkernel= on the kernel command line a warning
similar to
Kernel command line: ro console=ttyS0 crashkernel=256M
Unknown kernel command line parameters "crashkernel=256M", will be passed to user space.
is printed.
This comes from crashkernel= being parsed independent from the kernel
parameter handling mechanism. So the code in init/main.c doesn't know
that crashkernel= is a valid kernel parameter and prints this incorrect
warning.
Suppress the warning by adding a dummy early_param handler for
crashkernel=.
Link: https://lkml.kernel.org/r/20211208133443.6867-1-prudo@redhat.com
Fixes: 86d1919a4f ("init: print out unknown kernel parameters")
Signed-off-by: Philipp Rudo <prudo@redhat.com>
Acked-by: Baoquan He <bhe@redhat.com>
Cc: Andrew Halaney <ahalaney@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pull memblock fix from Mike Rapoport:
"Fix memblock_phys_alloc() section mismatch error
There are section mismatch errors when compiler refuses to inline
one-line wrapper memblock_phys_alloc(). Make memblock_phys_alloc()
__always_inline to avoid these mismatch issues"
* tag 'fixes-2021-12-22' of git://git.kernel.org/pub/scm/linux/kernel/git/rppt/memblock:
memblock: fix memblock_phys_alloc() section mismatch error
Pull parisc architecture fixes from Helge Deller:
- Fix a bug in the C code which calculates the relevant futex spinlock
based on the futex virtual address. In some cases a wrong spinlock
(compared to what is calculated in the assembly code path) was
choosen which then can lead to deadlocks.
- The 64-bit kernel missed to clip the LWS number in the
Light-weight-syscall path for 32-bit processes.
- Prevent CPU register dump to show stale value in IIR register on
access rights traps.
- Remove unused ARCH_DEFCONFIG entries.
* tag 'for-5.16/parisc-7' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
parisc: remove ARCH_DEFCONFIG
parisc: Fix mask used to select futex spinlock
parisc: Correct completer in lws start
parisc: Clear stale IIR value on instruction access rights trap
Pull IPMI fixes from Corey Minyard:
"Fix some IPMI crashes
Some crash fixes have come in dealing with various error handling
issues. They have sat in next for 5 days or more without issue, and
they are fairly critical"
* tag 'for-linus-5.16-3' of git://github.com/cminyard/linux-ipmi:
ipmi: Fix UAF when uninstall ipmi_si and ipmi_msghandler module
ipmi: fix initialization when workqueue allocation fails
ipmi: bail out if init_srcu_struct fails
ipmi: ssif: initialize ssif_info->client early
Pull tomoyo fixes from Tetsuo Handa:
"Two overhead reduction patches for testing/fuzzing environment"
* tag 'tomoyo-pr-20211222' of git://git.osdn.net/gitroot/tomoyo/tomoyo-test1:
tomoyo: use hweight16() in tomoyo_domain_quota_is_ok()
tomoyo: Check exceeded quota early in tomoyo_domain_quota_is_ok().
Pull crypto fix from Herbert Xu:
"Fix a regression in the qat driver"
* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: qat - do not handle PFVF sources for qat_4xxx
Fix modpost Section mismatch error in memblock_phys_alloc()
[...]
WARNING: modpost: vmlinux.o(.text.unlikely+0x1dcc): Section mismatch in reference
from the function memblock_phys_alloc() to the function .init.text:memblock_phys_alloc_range()
The function memblock_phys_alloc() references
the function __init memblock_phys_alloc_range().
This is often because memblock_phys_alloc lacks a __init
annotation or the annotation of memblock_phys_alloc_range is wrong.
ERROR: modpost: Section mismatches detected.
Set CONFIG_SECTION_MISMATCH_WARN_ONLY=y to allow them.
[...]
memblock_phys_alloc() is a one-line wrapper, make it __always_inline to
avoid these section mismatches.
Reported-by: k2ci <kernel-bot@kylinos.cn>
Suggested-by: Mike Rapoport <rppt@kernel.org>
Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
[rppt: slightly massaged changelog ]
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Link: https://lore.kernel.org/r/20211217020754.2874872-1-liu.yun@linux.dev
Commit 2a86f66121 ("kbuild: use KBUILD_DEFCONFIG as the fallback for
DEFCONFIG_LIST") removed ARCH_DEFCONFIG because it does not make much
sense.
In the same development cycle, Commit ededa081ed ("parisc: Fix
defconfig selection") added ARCH_DEFCONFIG for parisc.
Please use KBUILD_DEFCONFIG in arch/*/Makefile for defconfig selection.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Helge Deller <deller@gmx.de>
Signed-off-by: Helge Deller <deller@gmx.de>
Pull power management fix from Rafael Wysocki:
"Fix a recent regression causing the loop in dpm_prepare() to become
infinite if one of the device ->prepare() callbacks returns an error"
* tag 'pm-5.16-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: sleep: Fix error handling in dpm_prepare()
Pull kvm fixes from Paolo Bonzini:
- Fix for compilation of selftests on non-x86 architectures
- Fix for kvm_run->if_flag on SEV-ES
- Fix for page table use-after-free if yielding during exit_mm()
- Improve behavior when userspace starts a nested guest with invalid
state
- Fix missed wakeup with assigned devices but no VT-d posted interrupts
- Do not tell userspace to save/restore an unsupported PMU MSR
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: VMX: Wake vCPU when delivering posted IRQ even if vCPU == this vCPU
KVM: selftests: Add test to verify TRIPLE_FAULT on invalid L2 guest state
KVM: VMX: Fix stale docs for kvm-intel.emulate_invalid_guest_state
KVM: nVMX: Synthesize TRIPLE_FAULT for L2 if emulation is required
KVM: VMX: Always clear vmx->fail on emulation_required
selftests: KVM: Fix non-x86 compiling
KVM: x86: Always set kvm_run->if_flag
KVM: x86/mmu: Don't advance iterator after restart due to yielding
KVM: x86: remove PMU FIXED_CTR3 from msrs_to_save_all
The address bits used to select the futex spinlock need to match those used in
the LWS code in syscall.S. The mask 0x3f8 only selects 7 bits. It should
select 8 bits.
This change fixes the glibc nptl/tst-cond24 and nptl/tst-cond25 tests.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Fixes: 53a42b6324 ("parisc: Switch to more fine grained lws locks")
Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Helge Deller <deller@gmx.de>
The completer in the "or,ev %r1,%r30,%r30" instruction is reversed, so we are
not clipping the LWS number when we are called from a 32-bit process (W=0).
We need to nulify the following depdi instruction when the least-significant
bit of %r30 is 1.
If the %r20 register is not clipped, a user process could perform a LWS call
that would branch to an undefined location in the kernel and potentially crash
the machine.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Cc: stable@vger.kernel.org # 4.19+
Signed-off-by: Helge Deller <deller@gmx.de>
Pull nfsd fix from Chuck Lever:
"Address a buffer overrun reported by Anatoly Trosinenko"
* tag 'nfsd-5.16-3' of git://git.kernel.org/pub/scm/linux/kernel/git/cel/linux:
NFSD: Fix READDIR buffer overflow
Drop a check that guards triggering a posted interrupt on the currently
running vCPU, and more importantly guards waking the target vCPU if
triggering a posted interrupt fails because the vCPU isn't IN_GUEST_MODE.
If a vIRQ is delivered from asynchronous context, the target vCPU can be
the currently running vCPU and can also be blocking, in which case
skipping kvm_vcpu_wake_up() is effectively dropping what is supposed to
be a wake event for the vCPU.
The "do nothing" logic when "vcpu == running_vcpu" mostly works only
because the majority of calls to ->deliver_posted_interrupt(), especially
when using posted interrupts, come from synchronous KVM context. But if
a device is exposed to the guest using vfio-pci passthrough, the VFIO IRQ
and vCPU are bound to the same pCPU, and the IRQ is _not_ configured to
use posted interrupts, wake events from the device will be delivered to
KVM from IRQ context, e.g.
vfio_msihandler()
|
|-> eventfd_signal()
|
|-> ...
|
|-> irqfd_wakeup()
|
|->kvm_arch_set_irq_inatomic()
|
|-> kvm_irq_delivery_to_apic_fast()
|
|-> kvm_apic_set_irq()
This also aligns the non-nested and nested usage of triggering posted
interrupts, and will allow for additional cleanups.
Fixes: 379a3c8ee4 ("KVM: VMX: Optimize posted-interrupt delivery for timer fastpath")
Cc: stable@vger.kernel.org
Reported-by: Longpeng (Mike) <longpeng2@huawei.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20211208015236.1616697-18-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull rdma fixes from Jason Gunthorpe:
"Last fixes before holidays. Nothing very exciting:
- Work around a HW bug in HNS HIP08
- Recent memory leak regression in qib
- Incorrect use of kfree() for vmalloc memory in hns"
* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma:
RDMA/hns: Replace kfree() with kvfree()
IB/qib: Fix memory leak in qib_user_sdma_queue_pkts()
RDMA/hns: Fix RNR retransmission issue for HIP08
Pull spi fix from Mark Brown:
"One small fix for a long standing issue with error handling on probe
in the Armada driver"
* tag 'spi-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi:
spi: change clk_disable_unprepare to clk_unprepare
Pull regulator fix from Mark Brown:
"Binding fix for v5.16
This fixes problems validating DT bindings using op_mode which wasn't
described as it should have been when converting to DT schema"
* tag 'regulator-fix-v5.16-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator:
regulator: dt-bindings: samsung,s5m8767: add missing op_mode to bucks
Merge xen fixes from Juergen Gross:
"Fixes for two issues related to Xen and malicious guests:
- Guest can force the netback driver to hog large amounts of memory
- Denial of Service in other guests due to event storms"
* 'xsa' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/netback: don't queue unlimited number of packages
xen/netback: fix rx queue stall detection
xen/console: harden hvc_xen against event channel storms
xen/netfront: harden netfront against event channel storms
xen/blkfront: harden blkfront against event channel storms
When a trap 7 (Instruction access rights) occurs, this means the CPU
couldn't execute an instruction due to missing execute permissions on
the memory region. In this case it seems the CPU didn't even fetched
the instruction from memory and thus did not store it in the cr19 (IIR)
register before calling the trap handler. So, the trap handler will find
some random old stale value in cr19.
This patch simply overwrites the stale IIR value with a constant magic
"bad food" value (0xbaadf00d), in the hope people don't start to try to
understand the various random IIR values in trap 7 dumps.
Noticed-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Add a selftest to attempt to enter L2 with invalid guests state by
exiting to userspace via I/O from L2, and then using KVM_SET_SREGS to set
invalid guest state (marking TR unusable is arbitrary chosen for its
relative simplicity).
This is a regression test for a bug introduced by commit c8607e4a08
("KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if
!from_vmentry"), which incorrectly set vmx->fail=true when L2 had invalid
guest state and ultimately triggered a WARN due to nested_vmx_vmexit()
seeing vmx->fail==true while attempting to synthesize a nested VM-Exit.
The is also a functional test to verify that KVM sythesizes TRIPLE_FAULT
for L2, which is somewhat arbitrary behavior, instead of emulating L2.
KVM should never emulate L2 due to invalid guest state, as it's
architecturally impossible for L1 to run an L2 guest with invalid state
as nested VM-Enter should always fail, i.e. L1 needs to do the emulation.
Stuffing state via KVM ioctl() is a non-architctural, out-of-band case,
hence the TRIPLE_FAULT being rather arbitrary.
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-5-seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Update the documentation for kvm-intel's emulate_invalid_guest_state to
rectify the description of KVM's default behavior, and to document that
the behavior and thus parameter only applies to L1.
Fixes: a27685c33a ("KVM: VMX: Emulate invalid guest state by default")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-4-seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Synthesize a triple fault if L2 guest state is invalid at the time of
VM-Enter, which can happen if L1 modifies SMRAM or if userspace stuffs
guest state via ioctls(), e.g. KVM_SET_SREGS. KVM should never emulate
invalid guest state, since from L1's perspective, it's architecturally
impossible for L2 to have invalid state while L2 is running in hardware.
E.g. attempts to set CR0 or CR4 to unsupported values will either VM-Exit
or #GP.
Modifying vCPU state via RSM+SMRAM and ioctl() are the only paths that
can trigger this scenario, as nested VM-Enter correctly rejects any
attempt to enter L2 with invalid state.
RSM is a straightforward case as (a) KVM follows AMD's SMRAM layout and
behavior, and (b) Intel's SDM states that loading reserved CR0/CR4 bits
via RSM results in shutdown, i.e. there is precedent for KVM's behavior.
Following AMD's SMRAM layout is important as AMD's layout saves/restores
the descriptor cache information, including CS.RPL and SS.RPL, and also
defines all the fields relevant to invalid guest state as read-only, i.e.
so long as the vCPU had valid state before the SMI, which is guaranteed
for L2, RSM will generate valid state unless SMRAM was modified. Intel's
layout saves/restores only the selector, which means that scenarios where
the selector and cached RPL don't match, e.g. conforming code segments,
would yield invalid guest state. Intel CPUs fudge around this issued by
stuffing SS.RPL and CS.RPL on RSM. Per Intel's SDM on the "Default
Treatment of RSM", paraphrasing for brevity:
IF internal storage indicates that the [CPU was post-VMXON]
THEN
enter VMX operation (root or non-root);
restore VMX-critical state as defined in Section 34.14.1;
set to their fixed values any bits in CR0 and CR4 whose values must
be fixed in VMX operation [unless coming from an unrestricted guest];
IF RFLAGS.VM = 0 AND (in VMX root operation OR the
“unrestricted guest” VM-execution control is 0)
THEN
CS.RPL := SS.DPL;
SS.RPL := SS.DPL;
FI;
restore current VMCS pointer;
FI;
Note that Intel CPUs also overwrite the fixed CR0/CR4 bits, whereas KVM
will sythesize TRIPLE_FAULT in this scenario. KVM's behavior is allowed
as both Intel and AMD define CR0/CR4 SMRAM fields as read-only, i.e. the
only way for CR0 and/or CR4 to have illegal values is if they were
modified by the L1 SMM handler, and Intel's SDM "SMRAM State Save Map"
section states "modifying these registers will result in unpredictable
behavior".
KVM's ioctl() behavior is less straightforward. Because KVM allows
ioctls() to be executed in any order, rejecting an ioctl() if it would
result in invalid L2 guest state is not an option as KVM cannot know if
a future ioctl() would resolve the invalid state, e.g. KVM_SET_SREGS, or
drop the vCPU out of L2, e.g. KVM_SET_NESTED_STATE. Ideally, KVM would
reject KVM_RUN if L2 contained invalid guest state, but that carries the
risk of a false positive, e.g. if RSM loaded invalid guest state and KVM
exited to userspace. Setting a flag/request to detect such a scenario is
undesirable because (a) it's extremely unlikely to add value to KVM as a
whole, and (b) KVM would need to consider ioctl() interactions with such
a flag, e.g. if userspace migrated the vCPU while the flag were set.
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-3-seanjc@google.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Revert a relatively recent change that set vmx->fail if the vCPU is in L2
and emulation_required is true, as that behavior is completely bogus.
Setting vmx->fail and synthesizing a VM-Exit is contradictory and wrong:
(a) it's impossible to have both a VM-Fail and VM-Exit
(b) vmcs.EXIT_REASON is not modified on VM-Fail
(c) emulation_required refers to guest state and guest state checks are
always VM-Exits, not VM-Fails.
For KVM specifically, emulation_required is handled before nested exits
in __vmx_handle_exit(), thus setting vmx->fail has no immediate effect,
i.e. KVM calls into handle_invalid_guest_state() and vmx->fail is ignored.
Setting vmx->fail can ultimately result in a WARN in nested_vmx_vmexit()
firing when tearing down the VM as KVM never expects vmx->fail to be set
when L2 is active, KVM always reflects those errors into L1.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 21158 at arch/x86/kvm/vmx/nested.c:4548
nested_vmx_vmexit+0x16bd/0x17e0
arch/x86/kvm/vmx/nested.c:4547
Modules linked in:
CPU: 0 PID: 21158 Comm: syz-executor.1 Not tainted 5.16.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:nested_vmx_vmexit+0x16bd/0x17e0 arch/x86/kvm/vmx/nested.c:4547
Code: <0f> 0b e9 2e f8 ff ff e8 57 b3 5d 00 0f 0b e9 00 f1 ff ff 89 e9 80
Call Trace:
vmx_leave_nested arch/x86/kvm/vmx/nested.c:6220 [inline]
nested_vmx_free_vcpu+0x83/0xc0 arch/x86/kvm/vmx/nested.c:330
vmx_free_vcpu+0x11f/0x2a0 arch/x86/kvm/vmx/vmx.c:6799
kvm_arch_vcpu_destroy+0x6b/0x240 arch/x86/kvm/x86.c:10989
kvm_vcpu_destroy+0x29/0x90 arch/x86/kvm/../../../virt/kvm/kvm_main.c:441
kvm_free_vcpus arch/x86/kvm/x86.c:11426 [inline]
kvm_arch_destroy_vm+0x3ef/0x6b0 arch/x86/kvm/x86.c:11545
kvm_destroy_vm arch/x86/kvm/../../../virt/kvm/kvm_main.c:1189 [inline]
kvm_put_kvm+0x751/0xe40 arch/x86/kvm/../../../virt/kvm/kvm_main.c:1220
kvm_vcpu_release+0x53/0x60 arch/x86/kvm/../../../virt/kvm/kvm_main.c:3489
__fput+0x3fc/0x870 fs/file_table.c:280
task_work_run+0x146/0x1c0 kernel/task_work.c:164
exit_task_work include/linux/task_work.h:32 [inline]
do_exit+0x705/0x24f0 kernel/exit.c:832
do_group_exit+0x168/0x2d0 kernel/exit.c:929
get_signal+0x1740/0x2120 kernel/signal.c:2852
arch_do_signal_or_restart+0x9c/0x730 arch/x86/kernel/signal.c:868
handle_signal_work kernel/entry/common.c:148 [inline]
exit_to_user_mode_loop kernel/entry/common.c:172 [inline]
exit_to_user_mode_prepare+0x191/0x220 kernel/entry/common.c:207
__syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:300
do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86
entry_SYSCALL_64_after_hwframe+0x44/0xae
Fixes: c8607e4a08 ("KVM: x86: nVMX: don't fail nested VM entry on invalid guest state if !from_vmentry")
Reported-by: syzbot+f1d2136db9c80d4733e8@syzkaller.appspotmail.com
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211207193006.120997-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Attempting to compile on a non-x86 architecture fails with
include/kvm_util.h: In function ‘vm_compute_max_gfn’:
include/kvm_util.h:79:21: error: dereferencing pointer to incomplete type ‘struct kvm_vm’
return ((1ULL << vm->pa_bits) >> vm->page_shift) - 1;
^~
This is because the declaration of struct kvm_vm is in
lib/kvm_util_internal.h as an effort to make it private to
the test lib code. We can still provide arch specific functions,
though, by making the generic function symbols weak. Do that to
fix the compile error.
Fixes: c8cc43c1ea ("selftests: KVM: avoid failures due to reserved HyperTransport region")
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Jones <drjones@redhat.com>
Message-Id: <20211214151842.848314-1-drjones@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The kvm_run struct's if_flag is a part of the userspace/kernel API. The
SEV-ES patches failed to set this flag because it's no longer needed by
QEMU (according to the comment in the source code). However, other
hypervisors may make use of this flag. Therefore, set the flag for
guests with encrypted registers (i.e., with guest_state_protected set).
Fixes: f1c6366e30 ("KVM: SVM: Add required changes to support intercepts under SEV-ES")
Signed-off-by: Marc Orr <marcorr@google.com>
Message-Id: <20211209155257.128747-1-marcorr@google.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
After dropping mmu_lock in the TDP MMU, restart the iterator during
tdp_iter_next() and do not advance the iterator. Advancing the iterator
results in skipping the top-level SPTE and all its children, which is
fatal if any of the skipped SPTEs were not visited before yielding.
When zapping all SPTEs, i.e. when min_level == root_level, restarting the
iter and then invoking tdp_iter_next() is always fatal if the current gfn
has as a valid SPTE, as advancing the iterator results in try_step_side()
skipping the current gfn, which wasn't visited before yielding.
Sprinkle WARNs on iter->yielded being true in various helpers that are
often used in conjunction with yielding, and tag the helper with
__must_check to reduce the probabily of improper usage.
Failing to zap a top-level SPTE manifests in one of two ways. If a valid
SPTE is skipped by both kvm_tdp_mmu_zap_all() and kvm_tdp_mmu_put_root(),
the shadow page will be leaked and KVM will WARN accordingly.
WARNING: CPU: 1 PID: 3509 at arch/x86/kvm/mmu/tdp_mmu.c:46 [kvm]
RIP: 0010:kvm_mmu_uninit_tdp_mmu+0x3e/0x50 [kvm]
Call Trace:
<TASK>
kvm_arch_destroy_vm+0x130/0x1b0 [kvm]
kvm_destroy_vm+0x162/0x2a0 [kvm]
kvm_vcpu_release+0x34/0x60 [kvm]
__fput+0x82/0x240
task_work_run+0x5c/0x90
do_exit+0x364/0xa10
? futex_unqueue+0x38/0x60
do_group_exit+0x33/0xa0
get_signal+0x155/0x850
arch_do_signal_or_restart+0xed/0x750
exit_to_user_mode_prepare+0xc5/0x120
syscall_exit_to_user_mode+0x1d/0x40
do_syscall_64+0x48/0xc0
entry_SYSCALL_64_after_hwframe+0x44/0xae
If kvm_tdp_mmu_zap_all() skips a gfn/SPTE but that SPTE is then zapped by
kvm_tdp_mmu_put_root(), KVM triggers a use-after-free in the form of
marking a struct page as dirty/accessed after it has been put back on the
free list. This directly triggers a WARN due to encountering a page with
page_count() == 0, but it can also lead to data corruption and additional
errors in the kernel.
WARNING: CPU: 7 PID: 1995658 at arch/x86/kvm/../../../virt/kvm/kvm_main.c:171
RIP: 0010:kvm_is_zone_device_pfn.part.0+0x9e/0xd0 [kvm]
Call Trace:
<TASK>
kvm_set_pfn_dirty+0x120/0x1d0 [kvm]
__handle_changed_spte+0x92e/0xca0 [kvm]
__handle_changed_spte+0x63c/0xca0 [kvm]
__handle_changed_spte+0x63c/0xca0 [kvm]
__handle_changed_spte+0x63c/0xca0 [kvm]
zap_gfn_range+0x549/0x620 [kvm]
kvm_tdp_mmu_put_root+0x1b6/0x270 [kvm]
mmu_free_root_page+0x219/0x2c0 [kvm]
kvm_mmu_free_roots+0x1b4/0x4e0 [kvm]
kvm_mmu_unload+0x1c/0xa0 [kvm]
kvm_arch_destroy_vm+0x1f2/0x5c0 [kvm]
kvm_put_kvm+0x3b1/0x8b0 [kvm]
kvm_vcpu_release+0x4e/0x70 [kvm]
__fput+0x1f7/0x8c0
task_work_run+0xf8/0x1a0
do_exit+0x97b/0x2230
do_group_exit+0xda/0x2a0
get_signal+0x3be/0x1e50
arch_do_signal_or_restart+0x244/0x17f0
exit_to_user_mode_prepare+0xcb/0x120
syscall_exit_to_user_mode+0x1d/0x40
do_syscall_64+0x4d/0x90
entry_SYSCALL_64_after_hwframe+0x44/0xae
Note, the underlying bug existed even before commit 1af4a96025 ("KVM:
x86/mmu: Yield in TDU MMU iter even if no SPTES changed") moved calls to
tdp_mmu_iter_cond_resched() to the beginning of loops, as KVM could still
incorrectly advance past a top-level entry when yielding on a lower-level
entry. But with respect to leaking shadow pages, the bug was introduced
by yielding before processing the current gfn.
Alternatively, tdp_mmu_iter_cond_resched() could simply fall through, or
callers could jump to their "retry" label. The downside of that approach
is that tdp_mmu_iter_cond_resched() _must_ be called before anything else
in the loop, and there's no easy way to enfornce that requirement.
Ideally, KVM would handling the cond_resched() fully within the iterator
macro (the code is actually quite clean) and avoid this entire class of
bugs, but that is extremely difficult do while also supporting yielding
after tdp_mmu_set_spte_atomic() fails. Yielding after failing to set a
SPTE is very desirable as the "owner" of the REMOVED_SPTE isn't strictly
bounded, e.g. if it's zapping a high-level shadow page, the REMOVED_SPTE
may block operations on the SPTE for a significant amount of time.
Fixes: faaf05b00a ("kvm: x86/mmu: Support zapping SPTEs in the TDP MMU")
Fixes: 1af4a96025 ("KVM: x86/mmu: Yield in TDU MMU iter even if no SPTES changed")
Reported-by: Ignat Korchagin <ignat@cloudflare.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211214033528.123268-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The fixed counter 3 is used for the Topdown metrics, which hasn't been
enabled for KVM guests. Userspace accessing to it will fail as it's not
included in get_fixed_pmc(). This breaks KVM selftests on ICX+ machines,
which have this counter.
To reproduce it on ICX+ machines, ./state_test reports:
==== Test Assertion Failure ====
lib/x86_64/processor.c:1078: r == nmsrs
pid=4564 tid=4564 - Argument list too long
1 0x000000000040b1b9: vcpu_save_state at processor.c:1077
2 0x0000000000402478: main at state_test.c:209 (discriminator 6)
3 0x00007fbe21ed5f92: ?? ??:0
4 0x000000000040264d: _start at ??:?
Unexpected result from KVM_GET_MSRS, r: 17 (failed MSR was 0x30c)
With this patch, it works well.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
Message-Id: <20211217124934.32893-1-wei.w.wang@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull kvm fixes from Paolo Bonzini:
"Two small fixes, one of which was being worked around in selftests"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86: Retry page fault if MMU reload is pending and root has no sp
KVM: selftests: vmx_pmu_msrs_test: Drop tests mangling guest visible CPUIDs
KVM: x86: Drop guest CPUID check for host initiated writes to MSR_IA32_PERF_CAPABILITIES
Pull block revert from Jens Axboe:
"It turns out that the fix for not hammering on the delayed work timer
too much caused a performance regression for BFQ, so let's revert the
change for now.
I've got some ideas on how to fix it appropriately, but they should
wait for 5.17"
* tag 'block-5.16-2021-12-19' of git://git.kernel.dk/linux-block:
Revert "block: reduce kblockd_mod_delayed_work_on() CPU consumption"
Pull irq fixes from Borislav Petkov:
- Clear the PCI_MSIX_FLAGS_MASKALL bit too on the error path so that it
is restored to its reset state
- Mask MSI-X vectors late on the init path in order to handle
out-of-spec Marvell NVME devices which apparently look at the MSI-X
mask even when MSI-X is disabled
* tag 'irq_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
PCI/MSI: Clear PCI_MSIX_FLAGS_MASKALL on error
PCI/MSI: Mask MSI-X vectors only on success
Pull timer fix from Borislav Petkov:
- Make sure the CLOCK_REALTIME to CLOCK_MONOTONIC offset is never
positive
* tag 'timers_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
timekeeping: Really make sure wall_to_monotonic isn't positive
Pull locking fix from Borislav Petkov:
- Fix the rtmutex condition checking when the optimistic spinning of a
waiter needs to be terminated
* tag 'locking_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/rtmutex: Fix incorrect condition in rtmutex_spin_on_owner()
Pull signal handlign fix from Borislav Petkov:
- Prevent lock contention on the new sigaltstack lock on the
common-case path, when no changes have been made to the alternative
signal stack.
* tag 'core_urgent_for_v5.16_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
signal: Skip the altstack update when not needed
Pull MIPS fix from Thomas Bogendoerfer:
- only enable pci_remap_iospace() for Ralink devices
* tag 'mips-fixes_5.16_3' of git://git.kernel.org/pub/scm/linux/kernel/git/mips/linux:
MIPS: Only define pci_remap_iospace() for Ralink
Pull powerpc fixes from Michael Ellerman:
"Fix a recently introduced oops at boot on 85xx in some configurations.
Fix crashes when loading some livepatch modules with
STRICT_MODULE_RWX.
Thanks to Joe Lawrence, Russell Currey, and Xiaoming Ni"
* tag 'powerpc-5.16-4' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
powerpc/module_64: Fix livepatching for RO modules
powerpc/85xx: Fix oops when CONFIG_FSL_PMC=n
Pull cifs fixes from Steve French:
"Two cifs/smb3 fixes, one fscache related, and one mount parsing
related for stable"
* tag '5.16-rc5-smb3-client-fixes' of git://git.samba.org/sfrench/cifs-2.6:
cifs: sanitize multiple delimiters in prepath
cifs: ignore resource_id while getting fscache super cookie
Play nice with a NULL shadow page when checking for an obsolete root in
the page fault handler by flagging the page fault as stale if there's no
shadow page associated with the root and KVM_REQ_MMU_RELOAD is pending.
Invalidating memslots, which is the only case where _all_ roots need to
be reloaded, requests all vCPUs to reload their MMUs while holding
mmu_lock for lock.
The "special" roots, e.g. pae_root when KVM uses PAE paging, are not
backed by a shadow page. Running with TDP disabled or with nested NPT
explodes spectaculary due to dereferencing a NULL shadow page pointer.
Skip the KVM_REQ_MMU_RELOAD check if there is a valid shadow page for the
root. Zapping shadow pages in response to guest activity, e.g. when the
guest frees a PGD, can trigger KVM_REQ_MMU_RELOAD even if the current
vCPU isn't using the affected root. I.e. KVM_REQ_MMU_RELOAD can be seen
with a completely valid root shadow page. This is a bit of a moot point
as KVM currently unloads all roots on KVM_REQ_MMU_RELOAD, but that will
be cleaned up in the future.
Fixes: a955cad84c ("KVM: x86/mmu: Retry page fault if root is invalidated by memslot update")
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20211209060552.2956723-2-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Host initiated writes to MSR_IA32_PERF_CAPABILITIES should not depend
on guest visible CPUIDs and (incorrect) KVM logic implementing it is
about to change. Also, KVM_SET_CPUID{,2} after KVM_RUN is now forbidden
and causes test to fail.
Reported-by: kernel test robot <oliver.sang@intel.com>
Fixes: feb627e8d6 ("KVM: x86: Forbid KVM_SET_CPUID{,2} after KVM_RUN")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211216165213.338923-2-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The ability to write to MSR_IA32_PERF_CAPABILITIES from the host should
not depend on guest visible CPUID entries, even if just to allow
creating/restoring guest MSRs and CPUIDs in any sequence.
Fixes: 27461da310 ("KVM: x86/pmu: Support full width counting")
Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Message-Id: <20211216165213.338923-3-vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
