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The "force" argument to write_spec_ctrl_current() is currently ambiguous
as it does not guarantee the MSR write. This is due to the optimization
that writes to the MSR happen only when the new value differs from the
cached value.
This is fine in most cases, but breaks for S3 resume when the cached MSR
value gets out of sync with the hardware MSR value due to S3 resetting
it.
When x86_spec_ctrl_current is same as x86_spec_ctrl_base, the MSR write
is skipped. Which results in SPEC_CTRL mitigations not getting restored.
Move the MSR write from write_spec_ctrl_current() to a new function that
unconditionally writes to the MSR. Update the callers accordingly and
rename functions.
[ bp: Rework a bit. ]
Fixes: caa0ff24d5d0 ("x86/bugs: Keep a per-CPU IA32_SPEC_CTRL value")
Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/806d39b0bfec2fe8f50dc5446dff20f5bb24a959.1669821572.git.pawan.kumar.gupta@linux.intel.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"15 hotfixes, 11 marked cc:stable.
Only three or four of the latter address post-6.0 issues, which is
hopefully a sign that things are converging"
* tag 'mm-hotfixes-stable-2022-12-02' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
revert "kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible"
Kconfig.debug: provide a little extra FRAME_WARN leeway when KASAN is enabled
drm/amdgpu: temporarily disable broken Clang builds due to blown stack-frame
mm/khugepaged: invoke MMU notifiers in shmem/file collapse paths
mm/khugepaged: fix GUP-fast interaction by sending IPI
mm/khugepaged: take the right locks for page table retraction
mm: migrate: fix THP's mapcount on isolation
mm: introduce arch_has_hw_nonleaf_pmd_young()
mm: add dummy pmd_young() for architectures not having it
mm/damon/sysfs: fix wrong empty schemes assumption under online tuning in damon_sysfs_set_schemes()
tools/vm/slabinfo-gnuplot: use "grep -E" instead of "egrep"
nilfs2: fix NULL pointer dereference in nilfs_palloc_commit_free_entry()
hugetlb: don't delete vma_lock in hugetlb MADV_DONTNEED processing
madvise: use zap_page_range_single for madvise dontneed
mm: replace VM_WARN_ON to pr_warn if the node is offline with __GFP_THISNODE
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When running as a Xen PV guests commit eed9a328aa1a ("mm: x86: add
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG") can cause a protection violation in
pmdp_test_and_clear_young():
BUG: unable to handle page fault for address: ffff8880083374d0
#PF: supervisor write access in kernel mode
#PF: error_code(0x0003) - permissions violation
PGD 3026067 P4D 3026067 PUD 3027067 PMD 7fee5067 PTE 8010000008337065
Oops: 0003 [#1] PREEMPT SMP NOPTI
CPU: 7 PID: 158 Comm: kswapd0 Not tainted 6.1.0-rc5-20221118-doflr+ #1
RIP: e030:pmdp_test_and_clear_young+0x25/0x40
This happens because the Xen hypervisor can't emulate direct writes to
page table entries other than PTEs.
This can easily be fixed by introducing arch_has_hw_nonleaf_pmd_young()
similar to arch_has_hw_pte_young() and test that instead of
CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG.
Link: https://lkml.kernel.org/r/20221123064510.16225-1-jgross@suse.com
Fixes: eed9a328aa1a ("mm: x86: add CONFIG_ARCH_HAS_NONLEAF_PMD_YOUNG")
Signed-off-by: Juergen Gross <jgross@suse.com>
Reported-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: Yu Zhao <yuzhao@google.com>
Tested-by: Sander Eikelenboom <linux@eikelenboom.it>
Acked-by: David Hildenbrand <david@redhat.com> [core changes]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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In order to avoid #ifdeffery add a dummy pmd_young() implementation as a
fallback. This is required for the later patch "mm: introduce
arch_has_hw_nonleaf_pmd_young()".
Link: https://lkml.kernel.org/r/fd3ac3cd-7349-6bbd-890a-71a9454ca0b3@suse.com
Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Yu Zhao <yuzhao@google.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Sander Eikelenboom <linux@eikelenboom.it>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- ioremap: mask out the bits which are not part of the physical address
*after* the size computation is done to prevent any hypothetical
ioremap failures
- Change the MSR save/restore functionality during suspend to rely on
flags denoting that the related MSRs are actually supported vs
reading them and assuming they are (an Atom one allows reading but
not writing, thus breaking this scheme at resume time)
- prevent IV reuse in the AES-GCM communication scheme between SNP
guests and the AMD secure processor
* tag 'x86_urgent_for_v6.1_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/ioremap: Fix page aligned size calculation in __ioremap_caller()
x86/pm: Add enumeration check before spec MSRs save/restore setup
x86/tsx: Add a feature bit for TSX control MSR support
virt/sev-guest: Prevent IV reuse in the SNP guest driver
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Pull kvm fixes from Paolo Bonzini:
"x86:
- Fixes for Xen emulation. While nobody should be enabling it in the
kernel (the only public users of the feature are the selftests),
the bug effectively allows userspace to read arbitrary memory.
- Correctness fixes for nested hypervisors that do not intercept INIT
or SHUTDOWN on AMD; the subsequent CPU reset can cause a
use-after-free when it disables virtualization extensions. While
downgrading the panic to a WARN is quite easy, the full fix is a
bit more laborious; there are also tests. This is the bulk of the
pull request.
- Fix race condition due to incorrect mmu_lock use around
make_mmu_pages_available().
Generic:
- Obey changes to the kvm.halt_poll_ns module parameter in VMs not
using KVM_CAP_HALT_POLL, restoring behavior from before the
introduction of the capability"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: Update gfn_to_pfn_cache khva when it moves within the same page
KVM: x86/xen: Only do in-kernel acceleration of hypercalls for guest CPL0
KVM: x86/xen: Validate port number in SCHEDOP_poll
KVM: x86/mmu: Fix race condition in direct_page_fault
KVM: x86: remove exit_int_info warning in svm_handle_exit
KVM: selftests: add svm part to triple_fault_test
KVM: x86: allow L1 to not intercept triple fault
kvm: selftests: add svm nested shutdown test
KVM: selftests: move idt_entry to header
KVM: x86: forcibly leave nested mode on vCPU reset
KVM: x86: add kvm_leave_nested
KVM: x86: nSVM: harden svm_free_nested against freeing vmcb02 while still in use
KVM: x86: nSVM: leave nested mode on vCPU free
KVM: Obey kvm.halt_poll_ns in VMs not using KVM_CAP_HALT_POLL
KVM: Avoid re-reading kvm->max_halt_poll_ns during halt-polling
KVM: Cap vcpu->halt_poll_ns before halting rather than after
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git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild
Pull Kbuild fixes from Masahiro Yamada:
- Fix CC_HAS_ASM_GOTO_TIED_OUTPUT test in Kconfig
- Fix noisy "No such file or directory" message when
KBUILD_BUILD_VERSION is passed
- Include rust/ in source tarballs
- Fix missing FORCE for ARCH=nios2 builds
* tag 'kbuild-fixes-v6.1-4' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
nios2: add FORCE for vmlinuz.gz
scripts: add rust in scripts/Makefile.package
kbuild: fix "cat: .version: No such file or directory"
init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash
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git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Fix IRTE allocation in Hyper-V PCI controller (Dexuan Cui)
- Fix handling of SCSI srb_status and capacity change events (Michael
Kelley)
- Restore VP assist page after CPU offlining and onlining (Vitaly
Kuznetsov)
- Fix some memory leak issues in VMBus (Yang Yingliang)
* tag 'hyperv-fixes-signed-20221125' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
Drivers: hv: vmbus: fix possible memory leak in vmbus_device_register()
Drivers: hv: vmbus: fix double free in the error path of vmbus_add_channel_work()
PCI: hv: Only reuse existing IRTE allocation for Multi-MSI
scsi: storvsc: Fix handling of srb_status and capacity change events
x86/hyperv: Restore VP assist page after cpu offlining/onlining
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Since commit 2df8220cc511 ("kbuild: build init/built-in.a just once"),
the .version file is not touched at all when KBUILD_BUILD_VERSION is
given.
If KBUILD_BUILD_VERSION is specified and the .version file is missing
(for example right after 'make mrproper'), "No such file or director"
is shown. Even if the .version exists, it is irrelevant to the version
of the current build.
$ make -j$(nproc) KBUILD_BUILD_VERSION=100 mrproper defconfig all
[ snip ]
BUILD arch/x86/boot/bzImage
cat: .version: No such file or directory
Kernel: arch/x86/boot/bzImage is ready (#)
Show KBUILD_BUILD_VERSION if it is given.
Fixes: 2df8220cc511 ("kbuild: build init/built-in.a just once")
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
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This brings in a few important fixes for Xen emulation.
While nobody should be enabling it, the bug effectively
allows userspace to read arbitrary memory.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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There are almost no hypercalls which are valid from CPL > 0, and definitely
none which are handled by the kernel.
Fixes: 2fd6df2f2b47 ("KVM: x86/xen: intercept EVTCHNOP_send from guests")
Reported-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: stable@kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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We shouldn't allow guests to poll on arbitrary port numbers off the end
of the event channel table.
Fixes: 1a65105a5aba ("KVM: x86/xen: handle PV spinlocks slowpath")
[dwmw2: my bug though; the original version did check the validity as a
side-effect of an idr_find() which I ripped out in refactoring.]
Reported-by: Michal Luczaj <mhal@rbox.co>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: stable@kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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make_mmu_pages_available() must be called with mmu_lock held for write.
However, if the TDP MMU is used, it will be called with mmu_lock held for
read.
This function does nothing unless shadow pages are used, so there is no
race unless nested TDP is used.
Since nested TDP uses shadow pages, old shadow pages may be zapped by this
function even when the TDP MMU is enabled.
Since shadow pages are never allocated by kvm_tdp_mmu_map(), a race
condition can be avoided by not calling make_mmu_pages_available() if the
TDP MMU is currently in use.
I encountered this when repeatedly starting and stopping nested VM.
It can be artificially caused by allocating a large number of nested TDP
SPTEs.
For example, the following BUG and general protection fault are caused in
the host kernel.
pte_list_remove: 00000000cd54fc10 many->many
------------[ cut here ]------------
kernel BUG at arch/x86/kvm/mmu/mmu.c:963!
invalid opcode: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:pte_list_remove.cold+0x16/0x48 [kvm]
Call Trace:
<TASK>
drop_spte+0xe0/0x180 [kvm]
mmu_page_zap_pte+0x4f/0x140 [kvm]
__kvm_mmu_prepare_zap_page+0x62/0x3e0 [kvm]
kvm_mmu_zap_oldest_mmu_pages+0x7d/0xf0 [kvm]
direct_page_fault+0x3cb/0x9b0 [kvm]
kvm_tdp_page_fault+0x2c/0xa0 [kvm]
kvm_mmu_page_fault+0x207/0x930 [kvm]
npf_interception+0x47/0xb0 [kvm_amd]
svm_invoke_exit_handler+0x13c/0x1a0 [kvm_amd]
svm_handle_exit+0xfc/0x2c0 [kvm_amd]
kvm_arch_vcpu_ioctl_run+0xa79/0x1780 [kvm]
kvm_vcpu_ioctl+0x29b/0x6f0 [kvm]
__x64_sys_ioctl+0x95/0xd0
do_syscall_64+0x5c/0x90
general protection fault, probably for non-canonical address
0xdead000000000122: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:kvm_mmu_commit_zap_page.part.0+0x4b/0xe0 [kvm]
Call Trace:
<TASK>
kvm_mmu_zap_oldest_mmu_pages+0xae/0xf0 [kvm]
direct_page_fault+0x3cb/0x9b0 [kvm]
kvm_tdp_page_fault+0x2c/0xa0 [kvm]
kvm_mmu_page_fault+0x207/0x930 [kvm]
npf_interception+0x47/0xb0 [kvm_amd]
CVE: CVE-2022-45869
Fixes: a2855afc7ee8 ("KVM: x86/mmu: Allow parallel page faults for the TDP MMU")
Signed-off-by: Kazuki Takiguchi <takiguchi.kazuki171@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Current code re-calculates the size after aligning the starting and
ending physical addresses on a page boundary. But the re-calculation
also embeds the masking of high order bits that exceed the size of
the physical address space (via PHYSICAL_PAGE_MASK). If the masking
removes any high order bits, the size calculation results in a huge
value that is likely to immediately fail.
Fix this by re-calculating the page-aligned size first. Then mask any
high order bits using PHYSICAL_PAGE_MASK.
Fixes: ffa71f33a820 ("x86, ioremap: Fix incorrect physical address handling in PAE mode")
Signed-off-by: Michael Kelley <mikelley@microsoft.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/1668624097-14884-2-git-send-email-mikelley@microsoft.com
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pm_save_spec_msr() keeps a list of all the MSRs which _might_ need
to be saved and restored at hibernate and resume. However, it has
zero awareness of CPU support for these MSRs. It mostly works by
unconditionally attempting to manipulate these MSRs and relying on
rdmsrl_safe() being able to handle a #GP on CPUs where the support is
unavailable.
However, it's possible for reads (RDMSR) to be supported for a given MSR
while writes (WRMSR) are not. In this case, msr_build_context() sees
a successful read (RDMSR) and marks the MSR as valid. Then, later, a
write (WRMSR) fails, producing a nasty (but harmless) error message.
This causes restore_processor_state() to try and restore it, but writing
this MSR is not allowed on the Intel Atom N2600 leading to:
unchecked MSR access error: WRMSR to 0x122 (tried to write 0x0000000000000002) \
at rIP: 0xffffffff8b07a574 (native_write_msr+0x4/0x20)
Call Trace:
<TASK>
restore_processor_state
x86_acpi_suspend_lowlevel
acpi_suspend_enter
suspend_devices_and_enter
pm_suspend.cold
state_store
kernfs_fop_write_iter
vfs_write
ksys_write
do_syscall_64
? do_syscall_64
? up_read
? lock_is_held_type
? asm_exc_page_fault
? lockdep_hardirqs_on
entry_SYSCALL_64_after_hwframe
To fix this, add the corresponding X86_FEATURE bit for each MSR. Avoid
trying to manipulate the MSR when the feature bit is clear. This
required adding a X86_FEATURE bit for MSRs that do not have one already,
but it's a small price to pay.
[ bp: Move struct msr_enumeration inside the only function that uses it. ]
Fixes: 73924ec4d560 ("x86/pm: Save the MSR validity status at context setup")
Reported-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/c24db75d69df6e66c0465e13676ad3f2837a2ed8.1668539735.git.pawan.kumar.gupta@linux.intel.com
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Support for the TSX control MSR is enumerated in MSR_IA32_ARCH_CAPABILITIES.
This is different from how other CPU features are enumerated i.e. via
CPUID. Currently, a call to tsx_ctrl_is_supported() is required for
enumerating the feature. In the absence of a feature bit for TSX control,
any code that relies on checking feature bits directly will not work.
In preparation for adding a feature bit check in MSR save/restore
during suspend/resume, set a new feature bit X86_FEATURE_TSX_CTRL when
MSR_IA32_TSX_CTRL is present. Also make tsx_ctrl_is_supported() use the
new feature bit to avoid any overhead of reading the MSR.
[ bp: Remove tsx_ctrl_is_supported(), add room for two more feature
bits in word 11 which are coming up in the next merge window. ]
Suggested-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Dave Hansen <dave.hansen@linux.intel.com>
Cc: <stable@kernel.org>
Link: https://lore.kernel.org/r/de619764e1d98afbb7a5fa58424f1278ede37b45.1668539735.git.pawan.kumar.gupta@linux.intel.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Borislav Petkov:
- Do not hold fpregs lock when inheriting FPU permissions because the
fpregs lock disables preemption on RT but fpu_inherit_perms() does
spin_lock_irq(), which, on RT, uses rtmutexes and they need to be
preemptible.
- Check the page offset and the length of the data supplied by
userspace for overflow when specifying a set of pages to add to an
SGX enclave
* tag 'x86_urgent_for_v6.1_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/fpu: Drop fpregs lock before inheriting FPU permissions
x86/sgx: Add overflow check in sgx_validate_offset_length()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Borislav Petkov:
- Fix an intel PT erratum where CPUs do not support single range output
for more than 4K
- Fix a NULL ptr dereference which can happen after an NMI interferes
with the event enabling dance in amd_pmu_enable_all()
- Free the events array too when freeing uncore contexts on CPU online,
thereby fixing a memory leak
- Improve the pending SIGTRAP check
* tag 'perf_urgent_for_v6.1_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/pt: Fix sampling using single range output
perf/x86/amd: Fix crash due to race between amd_pmu_enable_all, perf NMI and throttling
perf/x86/amd/uncore: Fix memory leak for events array
perf: Improve missing SIGTRAP checking
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking fix from Borislav Petkov:
- Fix a build error with clang 11
* tag 'locking_urgent_for_v6.1_rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking: Fix qspinlock/x86 inline asm error
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git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Paolo Abeni:
"Including fixes from bpf.
Current release - regressions:
- tls: fix memory leak in tls_enc_skb() and tls_sw_fallback_init()
Previous releases - regressions:
- bridge: fix memory leaks when changing VLAN protocol
- dsa: make dsa_master_ioctl() see through port_hwtstamp_get() shims
- dsa: don't leak tagger-owned storage on switch driver unbind
- eth: mlxsw: avoid warnings when not offloaded FDB entry with IPv6
is removed
- eth: stmmac: ensure tx function is not running in
stmmac_xdp_release()
- eth: hns3: fix return value check bug of rx copybreak
Previous releases - always broken:
- kcm: close race conditions on sk_receive_queue
- bpf: fix alignment problem in bpf_prog_test_run_skb()
- bpf: fix writing offset in case of fault in
strncpy_from_kernel_nofault
- eth: macvlan: use built-in RCU list checking
- eth: marvell: add sleep time after enabling the loopback bit
- eth: octeon_ep: fix potential memory leak in octep_device_setup()
Misc:
- tcp: configurable source port perturb table size
- bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)"
* tag 'net-6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (51 commits)
net: use struct_group to copy ip/ipv6 header addresses
net: usb: smsc95xx: fix external PHY reset
net: usb: qmi_wwan: add Telit 0x103a composition
netdevsim: Fix memory leak of nsim_dev->fa_cookie
tcp: configurable source port perturb table size
l2tp: Serialize access to sk_user_data with sk_callback_lock
net: thunderbolt: Fix error handling in tbnet_init()
net: microchip: sparx5: Fix potential null-ptr-deref in sparx_stats_init() and sparx5_start()
net: lan966x: Fix potential null-ptr-deref in lan966x_stats_init()
net: dsa: don't leak tagger-owned storage on switch driver unbind
net/x25: Fix skb leak in x25_lapb_receive_frame()
net: ag71xx: call phylink_disconnect_phy if ag71xx_hw_enable() fail in ag71xx_open()
bridge: switchdev: Fix memory leaks when changing VLAN protocol
net: hns3: fix setting incorrect phy link ksettings for firmware in resetting process
net: hns3: fix return value check bug of rx copybreak
net: hns3: fix incorrect hw rss hash type of rx packet
net: phy: marvell: add sleep time after enabling the loopback bit
net: ena: Fix error handling in ena_init()
kcm: close race conditions on sk_receive_queue
net: ionic: Fix error handling in ionic_init_module()
...
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This fixes three issues in nested SVM:
1) in the shutdown_interception() vmexit handler we call kvm_vcpu_reset().
However, if running nested and L1 doesn't intercept shutdown, the function
resets vcpu->arch.hflags without properly leaving the nested state.
This leaves the vCPU in inconsistent state and later triggers a kernel
panic in SVM code. The same bug can likely be triggered by sending INIT
via local apic to a vCPU which runs a nested guest.
On VMX we are lucky that the issue can't happen because VMX always
intercepts triple faults, thus triple fault in L2 will always be
redirected to L1. Plus, handle_triple_fault() doesn't reset the vCPU.
INIT IPI can't happen on VMX either because INIT events are masked while
in VMX mode.
Secondarily, KVM doesn't honour SHUTDOWN intercept bit of L1 on SVM.
A normal hypervisor should always intercept SHUTDOWN, a unit test on
the other hand might want to not do so.
Finally, the guest can trigger a kernel non rate limited printk on SVM
from the guest, which is fixed as well.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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It is valid to receive external interrupt and have broken IDT entry,
which will lead to #GP with exit_int_into that will contain the index of
the IDT entry (e.g any value).
Other exceptions can happen as well, like #NP or #SS
(if stack switch fails).
Thus this warning can be user triggred and has very little value.
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-10-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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This is SVM correctness fix - although a sane L1 would intercept
SHUTDOWN event, it doesn't have to, so we have to honour this.
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-8-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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While not obivous, kvm_vcpu_reset() leaves the nested mode by clearing
'vcpu->arch.hflags' but it does so without all the required housekeeping.
On SVM, it is possible to have a vCPU reset while in guest mode because
unlike VMX, on SVM, INIT's are not latched in SVM non root mode and in
addition to that L1 doesn't have to intercept triple fault, which should
also trigger L1's reset if happens in L2 while L1 didn't intercept it.
If one of the above conditions happen, KVM will continue to use vmcb02
while not having in the guest mode.
Later the IA32_EFER will be cleared which will lead to freeing of the
nested guest state which will (correctly) free the vmcb02, but since
KVM still uses it (incorrectly) this will lead to a use after free
and kernel crash.
This issue is assigned CVE-2022-3344
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-5-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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add kvm_leave_nested which wraps a call to nested_ops->leave_nested
into a function.
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-4-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Make sure that KVM uses vmcb01 before freeing nested state, and warn if
that is not the case.
This is a minimal fix for CVE-2022-3344 making the kernel print a warning
instead of a kernel panic.
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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If the VM was terminated while nested, we free the nested state
while the vCPU still is in nested mode.
Soon a warning will be added for this condition.
Cc: stable@vger.kernel.org
Signed-off-by: Maxim Levitsky <mlevitsk@redhat.com>
Message-Id: <20221103141351.50662-2-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip
Pull xen fixes from Juergen Gross:
"Two trivial cleanups, and three simple fixes"
* tag 'for-linus-6.1-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
xen/platform-pci: use define instead of literal number
xen/platform-pci: add missing free_irq() in error path
xen-pciback: Allow setting PCI_MSIX_FLAGS_MASKALL too
xen/pcpu: fix possible memory leak in register_pcpu()
x86/xen: Use kstrtobool() instead of strtobool()
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When compiling linux 6.1.0-rc3 configured with CONFIG_64BIT=y and
CONFIG_PARAVIRT_SPINLOCKS=y on x86_64 using LLVM 11.0, an error:
"<inline asm> error: changed section flags for .spinlock.text,
expected:: 0x6" occurred.
The reason is the .spinlock.text in kernel/locking/qspinlock.o
is used many times, but its flags are omitted in subsequent use.
LLVM 11.0 assembler didn't permit to
leave out flags in subsequent uses of the same sections.
So this patch adds the corresponding flags to avoid above error.
Fixes: 501f7f69bca1 ("locking: Add __lockfunc to slow path functions")
Signed-off-by: Guo Jin <guoj17@chinatelecom.cn>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Nathan Chancellor <nathan@kernel.org>
Link: https://lore.kernel.org/r/20221108060126.2505-1-guoj17@chinatelecom.cn
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Deal with errata TGL052, ADL037 and RPL017 "Trace May Contain Incorrect
Data When Configured With Single Range Output Larger Than 4KB" by
disabling single range output whenever larger than 4KB.
Fixes: 670638477aed ("perf/x86/intel/pt: Opportunistically use single range output mode")
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20221112151508.13768-1-adrian.hunter@intel.com
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throttling
amd_pmu_enable_all() does:
if (!test_bit(idx, cpuc->active_mask))
continue;
amd_pmu_enable_event(cpuc->events[idx]);
A perf NMI of another event can come between these two steps. Perf NMI
handler internally disables and enables _all_ events, including the one
which nmi-intercepted amd_pmu_enable_all() was in process of enabling.
If that unintentionally enabled event has very low sampling period and
causes immediate successive NMI, causing the event to be throttled,
cpuc->events[idx] and cpuc->active_mask gets cleared by x86_pmu_stop().
This will result in amd_pmu_enable_event() getting called with event=NULL
when amd_pmu_enable_all() resumes after handling the NMIs. This causes a
kernel crash:
BUG: kernel NULL pointer dereference, address: 0000000000000198
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
[...]
Call Trace:
<TASK>
amd_pmu_enable_all+0x68/0xb0
ctx_resched+0xd9/0x150
event_function+0xb8/0x130
? hrtimer_start_range_ns+0x141/0x4a0
? perf_duration_warn+0x30/0x30
remote_function+0x4d/0x60
__flush_smp_call_function_queue+0xc4/0x500
flush_smp_call_function_queue+0x11d/0x1b0
do_idle+0x18f/0x2d0
cpu_startup_entry+0x19/0x20
start_secondary+0x121/0x160
secondary_startup_64_no_verify+0xe5/0xeb
</TASK>
amd_pmu_disable_all()/amd_pmu_enable_all() calls inside perf NMI handler
were recently added as part of BRS enablement but I'm not sure whether
we really need them. We can just disable BRS in the beginning and enable
it back while returning from NMI. This will solve the issue by not
enabling those events whose active_masks are set but are not yet enabled
in hw pmu.
Fixes: ada543459cab ("perf/x86/amd: Add AMD Fam19h Branch Sampling support")
Reported-by: Linux Kernel Functional Testing <lkft@linaro.org>
Signed-off-by: Ravi Bangoria <ravi.bangoria@amd.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20221114044029.373-1-ravi.bangoria@amd.com
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DE_CFG contains the LFENCE serializing bit, restore it on resume too.
This is relevant to older families due to the way how they do S3.
Unify and correct naming while at it.
Fixes: e4d0e84e4907 ("x86/cpu/AMD: Make LFENCE a serializing instruction")
Reported-by: Andrew Cooper <Andrew.Cooper3@citrix.com>
Reported-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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strtobool() is the same as kstrtobool().
However, the latter is more used within the kernel.
In order to remove strtobool() and slightly simplify kstrtox.h, switch to
the other function name.
While at it, include the corresponding header file (<linux/kstrtox.h>)
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Link: https://lore.kernel.org/r/e91af3c8708af38b1c57e0a2d7eb9765dda0e963.1667336095.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Juergen Gross <jgross@suse.com>
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Andrii Nakryiko says:
====================
bpf 2022-11-11
We've added 11 non-merge commits during the last 8 day(s) which contain
a total of 11 files changed, 83 insertions(+), 74 deletions(-).
The main changes are:
1) Fix strncpy_from_kernel_nofault() to prevent out-of-bounds writes,
from Alban Crequy.
2) Fix for bpf_prog_test_run_skb() to prevent wrong alignment,
from Baisong Zhong.
3) Switch BPF_DISPATCHER to static_call() instead of ftrace infra, with
a small build fix on top, from Peter Zijlstra and Nathan Chancellor.
4) Fix memory leak in BPF verifier in some error cases, from Wang Yufen.
5) 32-bit compilation error fixes for BPF selftests, from Pu Lehui and
Yang Jihong.
6) Ensure even distribution of per-CPU free list elements, from Xu Kuohai.
7) Fix copy_map_value() to track special zeroed out areas properly,
from Xu Kuohai.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
bpf: Fix offset calculation error in __copy_map_value and zero_map_value
bpf: Initialize same number of free nodes for each pcpu_freelist
selftests: bpf: Add a test when bpf_probe_read_kernel_str() returns EFAULT
maccess: Fix writing offset in case of fault in strncpy_from_kernel_nofault()
selftests/bpf: Fix test_progs compilation failure in 32-bit arch
selftests/bpf: Fix casting error when cross-compiling test_verifier for 32-bit platforms
bpf: Fix memory leaks in __check_func_call
bpf: Add explicit cast to 'void *' for __BPF_DISPATCHER_UPDATE()
bpf: Convert BPF_DISPATCHER to use static_call() (not ftrace)
bpf: Revert ("Fix dispatcher patchable function entry to 5 bytes nop")
bpf, test_run: Fix alignment problem in bpf_prog_test_run_skb()
====================
Link: https://lore.kernel.org/r/20221111231624.938829-1-andrii@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc hotfixes from Andrew Morton:
"22 hotfixes.
Eight are cc:stable and the remainder address issues which were
introduced post-6.0 or which aren't considered serious enough to
justify a -stable backport"
* tag 'mm-hotfixes-stable-2022-11-11' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
docs: kmsan: fix formatting of "Example report"
mm/damon/dbgfs: check if rm_contexts input is for a real context
maple_tree: don't set a new maximum on the node when not reusing nodes
maple_tree: fix depth tracking in maple_state
arch/x86/mm/hugetlbpage.c: pud_huge() returns 0 when using 2-level paging
fs: fix leaked psi pressure state
nilfs2: fix use-after-free bug of ns_writer on remount
x86/traps: avoid KMSAN bugs originating from handle_bug()
kmsan: make sure PREEMPT_RT is off
Kconfig.debug: ensure early check for KMSAN in CONFIG_KMSAN_WARN
x86/uaccess: instrument copy_from_user_nmi()
kmsan: core: kmsan_in_runtime() should return true in NMI context
mm: hugetlb_vmemmap: include missing linux/moduleparam.h
mm/shmem: use page_mapping() to detect page cache for uffd continue
mm/memremap.c: map FS_DAX device memory as decrypted
Partly revert "mm/thp: carry over dirty bit when thp splits on pmd"
nilfs2: fix deadlock in nilfs_count_free_blocks()
mm/mmap: fix memory leak in mmap_region()
hugetlbfs: don't delete error page from pagecache
maple_tree: reorganize testing to restore module testing
...
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Commit e5d9b714fe40 ("x86/hyperv: fix root partition faults when writing
to VP assist page MSR") moved 'wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE)' under
'if (*hvp)' condition. This works for root partition as hv_cpu_die()
does memunmap() and sets 'hv_vp_assist_page[cpu]' to NULL but breaks
non-root partitions as hv_cpu_die() doesn't free 'hv_vp_assist_page[cpu]'
for them. This causes VP assist page to remain unset after CPU
offline/online cycle:
$ rdmsr -p 24 0x40000073
10212f001
$ echo 0 > /sys/devices/system/cpu/cpu24/online
$ echo 1 > /sys/devices/system/cpu/cpu24/online
$ rdmsr -p 24 0x40000073
0
Fix the issue by always writing to HV_X64_MSR_VP_ASSIST_PAGE in
hv_cpu_init(). Note, checking 'if (!*hvp)', for root partition is
pointless as hv_cpu_die() always sets 'hv_vp_assist_page[cpu]' to
NULL (and it's also NULL initially).
Note: the fact that 'hv_vp_assist_page[cpu]' is reset to NULL may
present a (potential) issue for KVM. While Hyper-V uses
CPUHP_AP_ONLINE_DYN stage in CPU hotplug, KVM uses CPUHP_AP_KVM_STARTING
which comes earlier in CPU teardown sequence. It is theoretically
possible that Enlightened VMCS is still in use. It is unclear if the
issue is real and if using KVM with Hyper-V root partition is even
possible.
While on it, drop the unneeded smp_processor_id() call from hv_cpu_init().
Fixes: e5d9b714fe40 ("x86/hyperv: fix root partition faults when writing to VP assist page MSR")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20221103190601.399343-1-vkuznets@redhat.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
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Pull kvm
"This is a pretty large diffstat for this time of the release. The main
culprit is a reorganization of the AMD assembly trampoline, allowing
percpu variables to be accessed early.
This is needed for the return stack depth tracking retbleed mitigation
that will be in 6.2, but it also makes it possible to tighten the IBRS
restore on vmexit. The latter change is a long tail of the
spectrev2/retbleed patches (the corresponding Intel change was simpler
and went in already last June), which is why I am including it right
now instead of sharing a topic branch with tip.
Being assembly and being rich in comments makes the line count balloon
a bit, but I am pretty confident in the change (famous last words)
because the reorganization actually makes everything simpler and more
understandable than before. It has also had external review and has
been tested on the aforementioned 6.2 changes, which explode quite
brutally without the fix.
Apart from this, things are pretty normal.
s390:
- PCI fix
- PV clock fix
x86:
- Fix clash between PMU MSRs and other MSRs
- Prepare SVM assembly trampoline for 6.2 retbleed mitigation and
for...
- ... tightening IBRS restore on vmexit, moving it before the first
RET or indirect branch
- Fix log level for VMSA dump
- Block all page faults during kvm_zap_gfn_range()
Tools:
- kvm_stat: fix incorrect detection of debugfs
- kvm_stat: update vmexit definitions"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
KVM: x86/mmu: Block all page faults during kvm_zap_gfn_range()
KVM: x86/pmu: Limit the maximum number of supported AMD GP counters
KVM: x86/pmu: Limit the maximum number of supported Intel GP counters
KVM: x86/pmu: Do not speculatively query Intel GP PMCs that don't exist yet
KVM: SVM: Only dump VMSA to klog at KERN_DEBUG level
tools/kvm_stat: update exit reasons for vmx/svm/aarch64/userspace
tools/kvm_stat: fix incorrect detection of debugfs
x86, KVM: remove unnecessary argument to x86_virt_spec_ctrl and callers
KVM: SVM: move MSR_IA32_SPEC_CTRL save/restore to assembly
KVM: SVM: restore host save area from assembly
KVM: SVM: move guest vmsave/vmload back to assembly
KVM: SVM: do not allocate struct svm_cpu_data dynamically
KVM: SVM: remove dead field from struct svm_cpu_data
KVM: SVM: remove unused field from struct vcpu_svm
KVM: SVM: retrieve VMCB from assembly
KVM: SVM: adjust register allocation for __svm_vcpu_run()
KVM: SVM: replace regs argument of __svm_vcpu_run() with vcpu_svm
KVM: x86: use a separate asm-offsets.c file
KVM: s390: pci: Fix allocation size of aift kzdev elements
KVM: s390: pv: don't allow userspace to set the clock under PV
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git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Fix TSC MSR write for root partition (Anirudh Rayabharam)
- Fix definition of vector in pci-hyperv driver (Dexuan Cui)
- A few other misc patches
* tag 'hyperv-fixes-signed-20221110' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
PCI: hv: Fix the definition of vector in hv_compose_msi_msg()
MAINTAINERS: remove sthemmin
x86/hyperv: fix invalid writes to MSRs during root partition kexec
clocksource/drivers/hyperv: add data structure for reference TSC MSR
Drivers: hv: fix repeated words in comments
x86/hyperv: Remove BUG_ON() for kmap_local_page()
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When zapping a GFN range, pass 0 => ALL_ONES for the to-be-invalidated
range to effectively block all page faults while the zap is in-progress.
The invalidation helpers take a host virtual address, whereas zapping a
GFN obviously provides a guest physical address and with the wrong unit
of measurement (frame vs. byte).
Alternatively, KVM could walk all memslots to get the associated HVAs,
but thanks to SMM, that would require multiple lookups. And practically
speaking, kvm_zap_gfn_range() usage is quite rare and not a hot path,
e.g. MTRR and CR0.CD are almost guaranteed to be done only on vCPU0
during boot, and APICv inhibits are similarly infrequent operations.
Fixes: edb298c663fc ("KVM: x86/mmu: bump mmu notifier count in kvm_zap_gfn_range")
Reported-by: Chao Peng <chao.p.peng@linux.intel.com>
Cc: stable@vger.kernel.org
Cc: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221111001841.2412598-1-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Mike Galbraith reported the following against an old fork of preempt-rt
but the same issue also applies to the current preempt-rt tree.
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:46
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1, name: systemd
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
Preemption disabled at:
fpu_clone
CPU: 6 PID: 1 Comm: systemd Tainted: G E (unreleased)
Call Trace:
<TASK>
dump_stack_lvl
? fpu_clone
__might_resched
rt_spin_lock
fpu_clone
? copy_thread
? copy_process
? shmem_alloc_inode
? kmem_cache_alloc
? kernel_clone
? __do_sys_clone
? do_syscall_64
? __x64_sys_rt_sigprocmask
? syscall_exit_to_user_mode
? do_syscall_64
? syscall_exit_to_user_mode
? do_syscall_64
? syscall_exit_to_user_mode
? do_syscall_64
? exc_page_fault
? entry_SYSCALL_64_after_hwframe
</TASK>
Mike says:
The splat comes from fpu_inherit_perms() being called under fpregs_lock(),
and us reaching the spin_lock_irq() therein due to fpu_state_size_dynamic()
returning true despite static key __fpu_state_size_dynamic having never
been enabled.
Mike's assessment looks correct. fpregs_lock on a PREEMPT_RT kernel disables
preemption so calling spin_lock_irq() in fpu_inherit_perms() is unsafe. This
problem exists since commit
9e798e9aa14c ("x86/fpu: Prepare fpu_clone() for dynamically enabled features").
Even though the original bug report should not have enabled the paths at
all, the bug still exists.
fpregs_lock is necessary when editing the FPU registers or a task's FP
state but it is not necessary for fpu_inherit_perms(). The only write
of any FP state in fpu_inherit_perms() is for the new child which is
not running yet and cannot context switch or be borrowed by a kernel
thread yet. Hence, fpregs_lock is not protecting anything in the new
child until clone() completes and can be dropped earlier. The siglock
still needs to be acquired by fpu_inherit_perms() as the read of the
parent's permissions has to be serialised.
[ bp: Cleanup splat. ]
Fixes: 9e798e9aa14c ("x86/fpu: Prepare fpu_clone() for dynamically enabled features")
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20221110124400.zgymc2lnwqjukgfh@techsingularity.net
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https://git.kernel.org/pub/scm/linux/kernel/git/kvms390/linux into HEAD
A PCI allocation fix and a PV clock fix.
|
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The AMD PerfMonV2 specification allows for a maximum of 16 GP counters,
but currently only 6 pairs of MSRs are accepted by KVM.
While AMD64_NUM_COUNTERS_CORE is already equal to 6, increasing without
adjusting msrs_to_save_all[] could result in out-of-bounds accesses.
Therefore introduce a macro (named KVM_AMD_PMC_MAX_GENERIC) to
refer to the number of counters supported by KVM.
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220919091008.60695-3-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
The Intel Architectural IA32_PMCx MSRs addresses range allows for a
maximum of 8 GP counters, and KVM cannot address any more. Introduce a
local macro (named KVM_INTEL_PMC_MAX_GENERIC) and use it consistently to
refer to the number of counters supported by KVM, thus avoiding possible
out-of-bound accesses.
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220919091008.60695-2-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
The SDM lists an architectural MSR IA32_CORE_CAPABILITIES (0xCF)
that limits the theoretical maximum value of the Intel GP PMC MSRs
allocated at 0xC1 to 14; likewise the Intel April 2022 SDM adds
IA32_OVERCLOCKING_STATUS at 0x195 which limits the number of event
selection MSRs to 15 (0x186-0x194).
Limiting the maximum number of counters to 14 or 18 based on the currently
allocated MSRs is clearly fragile, and it seems likely that Intel will
even place PMCs 8-15 at a completely different range of MSR indices.
So stop at the maximum number of GP PMCs supported today on Intel
processors.
There are some machines, like Intel P4 with non Architectural PMU, that
may indeed have 18 counters, but those counters are in a completely
different MSR address range and are not supported by KVM.
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: stable@vger.kernel.org
Fixes: cf05a67b68b8 ("KVM: x86: omit "impossible" pmu MSRs from MSR list")
Suggested-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Message-Id: <20220919091008.60695-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
|
Explicitly print the VMSA dump at KERN_DEBUG log level, KERN_CONT uses
KERNEL_DEFAULT if the previous log line has a newline, i.e. if there's
nothing to continuing, and as a result the VMSA gets dumped when it
shouldn't.
The KERN_CONT documentation says it defaults back to KERNL_DEFAULT if the
previous log line has a newline. So switch from KERN_CONT to
print_hex_dump_debug().
Jarkko pointed this out in reference to the original patch. See:
https://lore.kernel.org/all/YuPMeWX4uuR1Tz3M@kernel.org/
print_hex_dump(KERN_DEBUG, ...) was pointed out there, but
print_hex_dump_debug() should similar.
Fixes: 6fac42f127b8 ("KVM: SVM: Dump Virtual Machine Save Area (VMSA) to klog")
Signed-off-by: Peter Gonda <pgonda@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Harald Hoyer <harald@profian.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: kvm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Message-Id: <20221104142220.469452-1-pgonda@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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x86_virt_spec_ctrl only deals with the paravirtualized
MSR_IA32_VIRT_SPEC_CTRL now and does not handle MSR_IA32_SPEC_CTRL
anymore; remove the corresponding, unused argument.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Restoration of the host IA32_SPEC_CTRL value is probably too late
with respect to the return thunk training sequence.
With respect to the user/kernel boundary, AMD says, "If software chooses
to toggle STIBP (e.g., set STIBP on kernel entry, and clear it on kernel
exit), software should set STIBP to 1 before executing the return thunk
training sequence." I assume the same requirements apply to the guest/host
boundary. The return thunk training sequence is in vmenter.S, quite close
to the VM-exit. On hosts without V_SPEC_CTRL, however, the host's
IA32_SPEC_CTRL value is not restored until much later.
To avoid this, move the restoration of host SPEC_CTRL to assembly and,
for consistency, move the restoration of the guest SPEC_CTRL as well.
This is not particularly difficult, apart from some care to cover both
32- and 64-bit, and to share code between SEV-ES and normal vmentry.
Cc: stable@vger.kernel.org
Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk")
Suggested-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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Allow access to the percpu area via the GS segment base, which is
needed in order to access the saved host spec_ctrl value. In linux-next
FILL_RETURN_BUFFER also needs to access percpu data.
For simplicity, the physical address of the save area is added to struct
svm_cpu_data.
Cc: stable@vger.kernel.org
Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk")
Reported-by: Nathan Chancellor <nathan@kernel.org>
Analyzed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Tested-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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It is error-prone that code after vmexit cannot access percpu data
because GSBASE has not been restored yet. It forces MSR_IA32_SPEC_CTRL
save/restore to happen very late, after the predictor untraining
sequence, and it gets in the way of return stack depth tracking
(a retbleed mitigation that is in linux-next as of 2022-11-09).
As a first step towards fixing that, move the VMCB VMSAVE/VMLOAD to
assembly, essentially undoing commit fb0c4a4fee5a ("KVM: SVM: move
VMLOAD/VMSAVE to C code", 2021-03-15). The reason for that commit was
that it made it simpler to use a different VMCB for VMLOAD/VMSAVE versus
VMRUN; but that is not a big hassle anymore thanks to the kvm-asm-offsets
machinery and other related cleanups.
The idea on how to number the exception tables is stolen from
a prototype patch by Peter Zijlstra.
Cc: stable@vger.kernel.org
Fixes: a149180fbcf3 ("x86: Add magic AMD return-thunk")
Link: <https://lore.kernel.org/all/f571e404-e625-bae1-10e9-449b2eb4cbd8@citrix.com/>
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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The svm_data percpu variable is a pointer, but it is allocated via
svm_hardware_setup() when KVM is loaded. Unlike hardware_enable()
this means that it is never NULL for the whole lifetime of KVM, and
static allocation does not waste any memory compared to the status quo.
It is also more efficient and more easily handled from assembly code,
so do it and don't look back.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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