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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Ingo Molnar:
"Fix the 'IBPB mitigated RETBleed' mode of operation on AMD CPUs (not
turned on by default), which also need STIBP enabled (if available) to
be '100% safe' on even the shortest speculation windows"
* tag 'x86-urgent-2022-08-13' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/bugs: Enable STIBP for IBPB mitigated RETBleed
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 eIBRS fixes from Borislav Petkov:
"More from the CPU vulnerability nightmares front:
Intel eIBRS machines do not sufficiently mitigate against RET
mispredictions when doing a VM Exit therefore an additional RSB,
one-entry stuffing is needed"
* tag 'x86_bugs_pbrsb' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/speculation: Add LFENCE to RSB fill sequence
x86/speculation: Add RSB VM Exit protections
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AMD's "Technical Guidance for Mitigating Branch Type Confusion,
Rev. 1.0 2022-07-12" whitepaper, under section 6.1.2 "IBPB On
Privileged Mode Entry / SMT Safety" says:
Similar to the Jmp2Ret mitigation, if the code on the sibling thread
cannot be trusted, software should set STIBP to 1 or disable SMT to
ensure SMT safety when using this mitigation.
So, like already being done for retbleed=unret, and now also for
retbleed=ibpb, force STIBP on machines that have it, and report its SMT
vulnerability status accordingly.
[ bp: Remove the "we" and remove "[AMD]" applicability parameter which
doesn't work here. ]
Fixes: 3ebc17006888 ("x86/bugs: Add retbleed=ibpb")
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org # 5.10, 5.15, 5.19
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537
Link: https://lore.kernel.org/r/20220804192201.439596-1-kim.phillips@amd.com
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc updates from Andrew Morton:
"Updates to various subsystems which I help look after. lib, ocfs2,
fatfs, autofs, squashfs, procfs, etc. A relatively small amount of
material this time"
* tag 'mm-nonmm-stable-2022-08-06-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (72 commits)
scripts/gdb: ensure the absolute path is generated on initial source
MAINTAINERS: kunit: add David Gow as a maintainer of KUnit
mailmap: add linux.dev alias for Brendan Higgins
mailmap: update Kirill's email
profile: setup_profiling_timer() is moslty not implemented
ocfs2: fix a typo in a comment
ocfs2: use the bitmap API to simplify code
ocfs2: remove some useless functions
lib/mpi: fix typo 'the the' in comment
proc: add some (hopefully) insightful comments
bdi: remove enum wb_congested_state
kernel/hung_task: fix address space of proc_dohung_task_timeout_secs
lib/lzo/lzo1x_compress.c: replace ternary operator with min() and min_t()
squashfs: support reading fragments in readahead call
squashfs: implement readahead
squashfs: always build "file direct" version of page actor
Revert "squashfs: provide backing_dev_info in order to disable read-ahead"
fs/ocfs2: Fix spelling typo in comment
ia64: old_rr4 added under CONFIG_HUGETLB_PAGE
proc: fix test for "vsyscall=xonly" boot option
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Ingo Molnar:
- build fix for old(er) binutils
- build fix for new GCC
- kexec boot environment fix
* tag 'x86-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/entry: Build thunk_$(BITS) only if CONFIG_PREEMPTION=y
x86/numa: Use cpumask_available instead of hardcoded NULL check
x86/bus_lock: Don't assume the init value of DEBUGCTLMSR.BUS_LOCK_DETECT to be zero
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf fixes from Ingo Molnar:
"Misc fixes to kprobes and the faddr2line script, plus a cleanup"
* tag 'perf-urgent-2022-08-06' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/core: Fix ';;' typo
scripts/faddr2line: Add CONFIG_DEBUG_INFO check
scripts/faddr2line: Fix vmlinux detection on arm64
x86/kprobes: Update kcb status flag after singlestepping
kprobes: Forbid probing on trampoline and BPF code areas
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git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu
Pull iommu updates from Joerg Roedel:
- The most intrusive patch is small and changes the default allocation
policy for DMA addresses.
Before the change the allocator tried its best to find an address in
the first 4GB. But that lead to performance problems when that space
gets exhaused, and since most devices are capable of 64-bit DMA these
days, we changed it to search in the full DMA-mask range from the
beginning.
This change has the potential to uncover bugs elsewhere, in the
kernel or the hardware. There is a Kconfig option and a command line
option to restore the old behavior, but none of them is enabled by
default.
- Add Robin Murphy as reviewer of IOMMU code and maintainer for the
dma-iommu and iova code
- Chaning IOVA magazine size from 1032 to 1024 bytes to save memory
- Some core code cleanups and dead-code removal
- Support for ACPI IORT RMR node
- Support for multiple PCI domains in the AMD-Vi driver
- ARM SMMU changes from Will Deacon:
- Add even more Qualcomm device-tree compatible strings
- Support dumping of IMP DEF Qualcomm registers on TLB sync
timeout
- Fix reference count leak on device tree node in Qualcomm driver
- Intel VT-d driver updates from Lu Baolu:
- Make intel-iommu.h private
- Optimize the use of two locks
- Extend the driver to support large-scale platforms
- Cleanup some dead code
- MediaTek IOMMU refactoring and support for TTBR up to 35bit
- Basic support for Exynos SysMMU v7
- VirtIO IOMMU driver gets a map/unmap_pages() implementation
- Other smaller cleanups and fixes
* tag 'iommu-updates-v5.20-or-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/joro/iommu: (116 commits)
iommu/amd: Fix compile warning in init code
iommu/amd: Add support for AVIC when SNP is enabled
iommu/amd: Simplify and Consolidate Virtual APIC (AVIC) Enablement
ACPI/IORT: Fix build error implicit-function-declaration
drivers: iommu: fix clang -wformat warning
iommu/arm-smmu: qcom_iommu: Add of_node_put() when breaking out of loop
iommu/arm-smmu-qcom: Add SM6375 SMMU compatible
dt-bindings: arm-smmu: Add compatible for Qualcomm SM6375
MAINTAINERS: Add Robin Murphy as IOMMU SUBSYTEM reviewer
iommu/amd: Do not support IOMMUv2 APIs when SNP is enabled
iommu/amd: Do not support IOMMU_DOMAIN_IDENTITY after SNP is enabled
iommu/amd: Set translation valid bit only when IO page tables are in use
iommu/amd: Introduce function to check and enable SNP
iommu/amd: Globally detect SNP support
iommu/amd: Process all IVHDs before enabling IOMMU features
iommu/amd: Introduce global variable for storing common EFR and EFR2
iommu/amd: Introduce Support for Extended Feature 2 Register
iommu/amd: Change macro for IOMMU control register bit shift to decimal value
iommu/exynos: Enable default VM instance on SysMMU v7
iommu/exynos: Add SysMMU v7 register set
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 SGX updates from Dave Hansen:
"A set of x86/sgx changes focused on implementing the "SGX2" features,
plus a minor cleanup:
- SGX2 ISA support which makes enclave memory management much more
dynamic. For instance, enclaves can now change enclave page
permissions on the fly.
- Removal of an unused structure member"
* tag 'x86_sgx_for_v6.0-2022-08-03.1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
x86/sgx: Drop 'page_index' from sgx_backing
selftests/sgx: Page removal stress test
selftests/sgx: Test reclaiming of untouched page
selftests/sgx: Test invalid access to removed enclave page
selftests/sgx: Test faulty enclave behavior
selftests/sgx: Test complete changing of page type flow
selftests/sgx: Introduce TCS initialization enclave operation
selftests/sgx: Introduce dynamic entry point
selftests/sgx: Test two different SGX2 EAUG flows
selftests/sgx: Add test for TCS page permission changes
selftests/sgx: Add test for EPCM permission changes
Documentation/x86: Introduce enclave runtime management section
x86/sgx: Free up EPC pages directly to support large page ranges
x86/sgx: Support complete page removal
x86/sgx: Support modifying SGX page type
x86/sgx: Tighten accessible memory range after enclave initialization
x86/sgx: Support adding of pages to an initialized enclave
x86/sgx: Support restricting of enclave page permissions
x86/sgx: Support VA page allocation without reclaiming
x86/sgx: Export sgx_encl_page_alloc()
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git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace
Pull tracing updates from Steven Rostedt:
- Runtime verification infrastructure
This is the biggest change here. It introduces the runtime
verification that is necessary for running Linux on safety critical
systems.
It allows for deterministic automata models to be inserted into the
kernel that will attach to tracepoints, where the information on
these tracepoints will move the model from state to state.
If a state is encountered that does not belong to the model, it will
then activate a given reactor, that could just inform the user or
even panic the kernel (for which safety critical systems will detect
and can recover from).
- Two monitor models are also added: Wakeup In Preemptive (WIP - not to
be confused with "work in progress"), and Wakeup While Not Running
(WWNR).
- Added __vstring() helper to the TRACE_EVENT() macro to replace
several vsnprintf() usages that were all doing it wrong.
- eprobes now can have their event autogenerated when the event name is
left off.
- The rest is various cleanups and fixes.
* tag 'trace-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (50 commits)
rv: Unlock on error path in rv_unregister_reactor()
tracing: Use alignof__(struct {type b;}) instead of offsetof()
tracing/eprobe: Show syntax error logs in error_log file
scripts/tracing: Fix typo 'the the' in comment
tracepoints: It is CONFIG_TRACEPOINTS not CONFIG_TRACEPOINT
tracing: Use free_trace_buffer() in allocate_trace_buffers()
tracing: Use a struct alignof to determine trace event field alignment
rv/reactor: Add the panic reactor
rv/reactor: Add the printk reactor
rv/monitor: Add the wwnr monitor
rv/monitor: Add the wip monitor
rv/monitor: Add the wip monitor skeleton created by dot2k
Documentation/rv: Add deterministic automata instrumentation documentation
Documentation/rv: Add deterministic automata monitor synthesis documentation
tools/rv: Add dot2k
Documentation/rv: Add deterministic automaton documentation
tools/rv: Add dot2c
Documentation/rv: Add a basic documentation
rv/include: Add instrumentation helper functions
rv/include: Add deterministic automata monitor definition via C macros
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git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci
Pull pci updates from Bjorn Helgaas:
"Enumeration:
- Consolidate duplicated 'next function' scanning and extend to allow
'isolated functions' on s390, similar to existing hypervisors
(Niklas Schnelle)
Resource management:
- Implement pci_iobar_pfn() for sparc, which allows us to remove the
sparc-specific pci_mmap_page_range() and pci_mmap_resource_range().
This removes the ability to map the entire PCI I/O space using
/proc/bus/pci, but we believe that's already been broken since
v2.6.28 (Arnd Bergmann)
- Move common PCI definitions to asm-generic/pci.h and rework others
to be be more specific and more encapsulated in arches that need
them (Stafford Horne)
Power management:
- Convert drivers to new *_PM_OPS macros to avoid need for '#ifdef
CONFIG_PM_SLEEP' or '__maybe_unused' (Bjorn Helgaas)
Virtualization:
- Add ACS quirk for Broadcom BCM5750x multifunction NICs that isolate
the functions but don't advertise an ACS capability (Pavan Chebbi)
Error handling:
- Clear PCI Status register during enumeration in case firmware left
errors logged (Kai-Heng Feng)
- When we have native control of AER, enable error reporting for all
devices that support AER. Previously only a few drivers enabled
this (Stefan Roese)
- Keep AER error reporting enabled for switches. Previously we
enabled this during enumeration but immediately disabled it (Stefan
Roese)
- Iterate over error counters instead of error strings to avoid
printing junk in AER sysfs counters (Mohamed Khalfella)
ASPM:
- Remove pcie_aspm_pm_state_change() so ASPM config changes, e.g.,
via sysfs, are not lost across power state changes (Kai-Heng Feng)
Endpoint framework:
- Don't stop an EPC when unbinding an EPF from it (Shunsuke Mie)
Endpoint embedded DMA controller driver:
- Simplify and clean up support for the DesignWare embedded DMA
(eDMA) controller (Frank Li, Serge Semin)
Broadcom STB PCIe controller driver:
- Avoid config space accesses when link is down because we can't
recover from the CPU aborts these cause (Jim Quinlan)
- Look for power regulators described under Root Ports in DT and
enable them before scanning the secondary bus (Jim Quinlan)
- Disable/enable regulators in suspend/resume (Jim Quinlan)
Freescale i.MX6 PCIe controller driver:
- Simplify and clean up clock and PHY management (Richard Zhu)
- Disable/enable regulators in suspend/resume (Richard Zhu)
- Set PCIE_DBI_RO_WR_EN before writing DBI registers (Richard Zhu)
- Allow speeds faster than Gen2 (Richard Zhu)
- Make link being down a non-fatal error so controller probe doesn't
fail if there are no Endpoints connected (Richard Zhu)
Loongson PCIe controller driver:
- Add ACPI and MCFG support for Loongson LS7A (Huacai Chen)
- Avoid config reads to non-existent LS2K/LS7A devices because a
hardware defect causes machine hangs (Huacai Chen)
- Work around LS7A integrated devices that report incorrect Interrupt
Pin values (Jianmin Lv)
Marvell Aardvark PCIe controller driver:
- Add support for AER and Slot capability on emulated bridge (Pali
Rohár)
MediaTek PCIe controller driver:
- Add Airoha EN7532 to DT binding (John Crispin)
- Allow building of driver for ARCH_AIROHA (Felix Fietkau)
MediaTek PCIe Gen3 controller driver:
- Print decoded LTSSM state when the link doesn't come up (Jianjun
Wang)
NVIDIA Tegra194 PCIe controller driver:
- Convert DT binding to json-schema (Vidya Sagar)
- Add DT bindings and driver support for Tegra234 Root Port and
Endpoint mode (Vidya Sagar)
- Fix some Root Port interrupt handling issues (Vidya Sagar)
- Set default Max Payload Size to 256 bytes (Vidya Sagar)
- Fix Data Link Feature capability programming (Vidya Sagar)
- Extend Endpoint mode support to devices beyond Controller-5 (Vidya
Sagar)
Qualcomm PCIe controller driver:
- Rework clock, reset, PHY power-on ordering to avoid hangs and
improve consistency (Robert Marko, Christian Marangi)
- Move pipe_clk handling to PHY drivers (Dmitry Baryshkov)
- Add IPQ60xx support (Selvam Sathappan Periakaruppan)
- Allow ASPM L1 and substates for 2.7.0 (Krishna chaitanya chundru)
- Add support for more than 32 MSI interrupts (Dmitry Baryshkov)
Renesas R-Car PCIe controller driver:
- Convert DT binding to json-schema (Herve Codina)
- Add Renesas RZ/N1D (R9A06G032) to rcar-gen2 DT binding and driver
(Herve Codina)
Samsung Exynos PCIe controller driver:
- Fix phy-exynos-pcie driver so it follows the 'phy_init() before
phy_power_on()' PHY programming model (Marek Szyprowski)
Synopsys DesignWare PCIe controller driver:
- Simplify and clean up the DWC core extensively (Serge Semin)
- Fix an issue with programming the ATU for regions that cross a 4GB
boundary (Serge Semin)
- Enable the CDM check if 'snps,enable-cdm-check' exists; previously
we skipped it if 'num-lanes' was absent (Serge Semin)
- Allocate a 32-bit DMA-able page to be MSI target instead of using a
driver data structure that may not be addressable with 32-bit
address (Will McVicker)
- Add DWC core support for more than 32 MSI interrupts (Dmitry
Baryshkov)
Xilinx Versal CPM PCIe controller driver:
- Add DT binding and driver support for Versal CPM5 Gen5 Root Port
(Bharat Kumar Gogada)"
* tag 'pci-v5.20-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci: (150 commits)
PCI: imx6: Support more than Gen2 speed link mode
PCI: imx6: Set PCIE_DBI_RO_WR_EN before writing DBI registers
PCI: imx6: Reformat suspend callback to keep symmetric with resume
PCI: imx6: Move the imx6_pcie_ltssm_disable() earlier
PCI: imx6: Disable clocks in reverse order of enable
PCI: imx6: Do not hide PHY driver callbacks and refine the error handling
PCI: imx6: Reduce resume time by only starting link if it was up before suspend
PCI: imx6: Mark the link down as non-fatal error
PCI: imx6: Move regulator enable out of imx6_pcie_deassert_core_reset()
PCI: imx6: Turn off regulator when system is in suspend mode
PCI: imx6: Call host init function directly in resume
PCI: imx6: Disable i.MX6QDL clock when disabling ref clocks
PCI: imx6: Propagate .host_init() errors to caller
PCI: imx6: Collect clock enables in imx6_pcie_clk_enable()
PCI: imx6: Factor out ref clock disable to match enable
PCI: imx6: Move imx6_pcie_clk_disable() earlier
PCI: imx6: Move imx6_pcie_enable_ref_clk() earlier
PCI: imx6: Move PHY management functions together
PCI: imx6: Move imx6_pcie_grp_offset(), imx6_pcie_configure_type() earlier
PCI: imx6: Convert to NOIRQ_SYSTEM_SLEEP_PM_OPS()
...
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Pull kvm updates from Paolo Bonzini:
"Quite a large pull request due to a selftest API overhaul and some
patches that had come in too late for 5.19.
ARM:
- Unwinder implementations for both nVHE modes (classic and
protected), complete with an overflow stack
- Rework of the sysreg access from userspace, with a complete rewrite
of the vgic-v3 view to allign with the rest of the infrastructure
- Disagregation of the vcpu flags in separate sets to better track
their use model.
- A fix for the GICv2-on-v3 selftest
- A small set of cosmetic fixes
RISC-V:
- Track ISA extensions used by Guest using bitmap
- Added system instruction emulation framework
- Added CSR emulation framework
- Added gfp_custom flag in struct kvm_mmu_memory_cache
- Added G-stage ioremap() and iounmap() functions
- Added support for Svpbmt inside Guest
s390:
- add an interface to provide a hypervisor dump for secure guests
- improve selftests to use TAP interface
- enable interpretive execution of zPCI instructions (for PCI
passthrough)
- First part of deferred teardown
- CPU Topology
- PV attestation
- Minor fixes
x86:
- Permit guests to ignore single-bit ECC errors
- Intel IPI virtualization
- Allow getting/setting pending triple fault with
KVM_GET/SET_VCPU_EVENTS
- PEBS virtualization
- Simplify PMU emulation by just using PERF_TYPE_RAW events
- More accurate event reinjection on SVM (avoid retrying
instructions)
- Allow getting/setting the state of the speaker port data bit
- Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls
are inconsistent
- "Notify" VM exit (detect microarchitectural hangs) for Intel
- Use try_cmpxchg64 instead of cmpxchg64
- Ignore benign host accesses to PMU MSRs when PMU is disabled
- Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior
- Allow NX huge page mitigation to be disabled on a per-vm basis
- Port eager page splitting to shadow MMU as well
- Enable CMCI capability by default and handle injected UCNA errors
- Expose pid of vcpu threads in debugfs
- x2AVIC support for AMD
- cleanup PIO emulation
- Fixes for LLDT/LTR emulation
- Don't require refcounted "struct page" to create huge SPTEs
- Miscellaneous cleanups:
- MCE MSR emulation
- Use separate namespaces for guest PTEs and shadow PTEs bitmasks
- PIO emulation
- Reorganize rmap API, mostly around rmap destruction
- Do not workaround very old KVM bugs for L0 that runs with nesting enabled
- new selftests API for CPUID
Generic:
- Fix races in gfn->pfn cache refresh; do not pin pages tracked by
the cache
- new selftests API using struct kvm_vcpu instead of a (vm, id)
tuple"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (606 commits)
selftests: kvm: set rax before vmcall
selftests: KVM: Add exponent check for boolean stats
selftests: KVM: Provide descriptive assertions in kvm_binary_stats_test
selftests: KVM: Check stat name before other fields
KVM: x86/mmu: remove unused variable
RISC-V: KVM: Add support for Svpbmt inside Guest/VM
RISC-V: KVM: Use PAGE_KERNEL_IO in kvm_riscv_gstage_ioremap()
RISC-V: KVM: Add G-stage ioremap() and iounmap() functions
KVM: Add gfp_custom flag in struct kvm_mmu_memory_cache
RISC-V: KVM: Add extensible CSR emulation framework
RISC-V: KVM: Add extensible system instruction emulation framework
RISC-V: KVM: Factor-out instruction emulation into separate sources
RISC-V: KVM: move preempt_disable() call in kvm_arch_vcpu_ioctl_run
RISC-V: KVM: Make kvm_riscv_guest_timer_init a void function
RISC-V: KVM: Fix variable spelling mistake
RISC-V: KVM: Improve ISA extension by using a bitmap
KVM, x86/mmu: Fix the comment around kvm_tdp_mmu_zap_leafs()
KVM: SVM: Dump Virtual Machine Save Area (VMSA) to klog
KVM: x86/mmu: Treat NX as a valid SPTE bit for NPT
KVM: x86: Do not block APIC write for non ICR registers
...
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tl;dr: The Enhanced IBRS mitigation for Spectre v2 does not work as
documented for RET instructions after VM exits. Mitigate it with a new
one-entry RSB stuffing mechanism and a new LFENCE.
== Background ==
Indirect Branch Restricted Speculation (IBRS) was designed to help
mitigate Branch Target Injection and Speculative Store Bypass, i.e.
Spectre, attacks. IBRS prevents software run in less privileged modes
from affecting branch prediction in more privileged modes. IBRS requires
the MSR to be written on every privilege level change.
To overcome some of the performance issues of IBRS, Enhanced IBRS was
introduced. eIBRS is an "always on" IBRS, in other words, just turn
it on once instead of writing the MSR on every privilege level change.
When eIBRS is enabled, more privileged modes should be protected from
less privileged modes, including protecting VMMs from guests.
== Problem ==
Here's a simplification of how guests are run on Linux' KVM:
void run_kvm_guest(void)
{
// Prepare to run guest
VMRESUME();
// Clean up after guest runs
}
The execution flow for that would look something like this to the
processor:
1. Host-side: call run_kvm_guest()
2. Host-side: VMRESUME
3. Guest runs, does "CALL guest_function"
4. VM exit, host runs again
5. Host might make some "cleanup" function calls
6. Host-side: RET from run_kvm_guest()
Now, when back on the host, there are a couple of possible scenarios of
post-guest activity the host needs to do before executing host code:
* on pre-eIBRS hardware (legacy IBRS, or nothing at all), the RSB is not
touched and Linux has to do a 32-entry stuffing.
* on eIBRS hardware, VM exit with IBRS enabled, or restoring the host
IBRS=1 shortly after VM exit, has a documented side effect of flushing
the RSB except in this PBRSB situation where the software needs to stuff
the last RSB entry "by hand".
IOW, with eIBRS supported, host RET instructions should no longer be
influenced by guest behavior after the host retires a single CALL
instruction.
However, if the RET instructions are "unbalanced" with CALLs after a VM
exit as is the RET in #6, it might speculatively use the address for the
instruction after the CALL in #3 as an RSB prediction. This is a problem
since the (untrusted) guest controls this address.
Balanced CALL/RET instruction pairs such as in step #5 are not affected.
== Solution ==
The PBRSB issue affects a wide variety of Intel processors which
support eIBRS. But not all of them need mitigation. Today,
X86_FEATURE_RSB_VMEXIT triggers an RSB filling sequence that mitigates
PBRSB. Systems setting RSB_VMEXIT need no further mitigation - i.e.,
eIBRS systems which enable legacy IBRS explicitly.
However, such systems (X86_FEATURE_IBRS_ENHANCED) do not set RSB_VMEXIT
and most of them need a new mitigation.
Therefore, introduce a new feature flag X86_FEATURE_RSB_VMEXIT_LITE
which triggers a lighter-weight PBRSB mitigation versus RSB_VMEXIT.
The lighter-weight mitigation performs a CALL instruction which is
immediately followed by a speculative execution barrier (INT3). This
steers speculative execution to the barrier -- just like a retpoline
-- which ensures that speculation can never reach an unbalanced RET.
Then, ensure this CALL is retired before continuing execution with an
LFENCE.
In other words, the window of exposure is opened at VM exit where RET
behavior is troublesome. While the window is open, force RSB predictions
sampling for RET targets to a dead end at the INT3. Close the window
with the LFENCE.
There is a subset of eIBRS systems which are not vulnerable to PBRSB.
Add these systems to the cpu_vuln_whitelist[] as NO_EIBRS_PBRSB.
Future systems that aren't vulnerable will set ARCH_CAP_PBRSB_NO.
[ bp: Massage, incorporate review comments from Andy Cooper. ]
Signed-off-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Co-developed-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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git://git.kernel.org/pub/scm/linux/kernel/git/crng/random
Pull random number generator updates from Jason Donenfeld:
"Though there's been a decent amount of RNG-related development during
this last cycle, not all of it is coming through this tree, as this
cycle saw a shift toward tackling early boot time seeding issues,
which took place in other trees as well.
Here's a summary of the various patches:
- The CONFIG_ARCH_RANDOM .config option and the "nordrand" boot
option have been removed, as they overlapped with the more widely
supported and more sensible options, CONFIG_RANDOM_TRUST_CPU and
"random.trust_cpu". This change allowed simplifying a bit of arch
code.
- x86's RDRAND boot time test has been made a bit more robust, with
RDRAND disabled if it's clearly producing bogus results. This would
be a tip.git commit, technically, but I took it through random.git
to avoid a large merge conflict.
- The RNG has long since mixed in a timestamp very early in boot, on
the premise that a computer that does the same things, but does so
starting at different points in wall time, could be made to still
produce a different RNG state. Unfortunately, the clock isn't set
early in boot on all systems, so now we mix in that timestamp when
the time is actually set.
- User Mode Linux now uses the host OS's getrandom() syscall to
generate a bootloader RNG seed and later on treats getrandom() as
the platform's RDRAND-like faculty.
- The arch_get_random_{seed_,}_long() family of functions is now
arch_get_random_{seed_,}_longs(), which enables certain platforms,
such as s390, to exploit considerable performance advantages from
requesting multiple CPU random numbers at once, while at the same
time compiling down to the same code as before on platforms like
x86.
- A small cleanup changing a cmpxchg() into a try_cmpxchg(), from
Uros.
- A comment spelling fix"
More info about other random number changes that come in through various
architecture trees in the full commentary in the pull request:
https://lore.kernel.org/all/20220731232428.2219258-1-Jason@zx2c4.com/
* tag 'random-6.0-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random:
random: correct spelling of "overwrites"
random: handle archrandom with multiple longs
um: seed rng using host OS rng
random: use try_cmpxchg in _credit_init_bits
timekeeping: contribute wall clock to rng on time change
x86/rdrand: Remove "nordrand" flag in favor of "random.trust_cpu"
random: remove CONFIG_ARCH_RANDOM
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git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity
Pull integrity updates from Mimi Zohar:
"Aside from the one EVM cleanup patch, all the other changes are kexec
related.
On different architectures different keyrings are used to verify the
kexec'ed kernel image signature. Here are a number of preparatory
cleanup patches and the patches themselves for making the keyrings -
builtin_trusted_keyring, .machine, .secondary_trusted_keyring, and
.platform - consistent across the different architectures"
* tag 'integrity-v6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar/linux-integrity:
kexec, KEYS, s390: Make use of built-in and secondary keyring for signature verification
arm64: kexec_file: use more system keyrings to verify kernel image signature
kexec, KEYS: make the code in bzImage64_verify_sig generic
kexec: clean up arch_kexec_kernel_verify_sig
kexec: drop weak attribute from functions
kexec_file: drop weak attribute from functions
evm: Use IS_ENABLED to initialize .enabled
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be zero
It's possible that this kernel has been kexec'd from a kernel that
enabled bus lock detection, or (hypothetically) BIOS/firmware has set
DEBUGCTLMSR_BUS_LOCK_DETECT.
Disable bus lock detection explicitly if not wanted.
Fixes: ebb1064e7c2e ("x86/traps: Handle #DB for bus lock")
Signed-off-by: Chenyi Qiang <chenyi.qiang@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Tony Luck <tony.luck@intel.com>
Link: https://lore.kernel.org/r/20220802033206.21333-1-chenyi.qiang@intel.com
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Fix kprobes to update kcb (kprobes control block) status flag to
KPROBE_HIT_SSDONE even if the kp->post_handler is not set.
This bug may cause a kernel panic if another INT3 user runs right
after kprobes because kprobe_int3_handler() misunderstands the
INT3 is kprobe's single stepping INT3.
Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Reported-by: Daniel Müller <deso@posteo.net>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Tested-by: Daniel Müller <deso@posteo.net>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/all/20220727210136.jjgc3lpqeq42yr3m@muellerd-fedora-PC2BDTX9
Link: https://lore.kernel.org/r/165942025658.342061.12452378391879093249.stgit@devnote2
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
"This was a fairly quiet cycle for the locking subsystem:
- lockdep: Fix a handful of the more complex lockdep_init_map_*()
primitives that can lose the lock_type & cause false reports. No
such mishap was observed in the wild.
- jump_label improvements: simplify the cross-arch support of initial
NOP patching by making it arch-specific code (used on MIPS only),
and remove the s390 initial NOP patching that was superfluous"
* tag 'locking-core-2022-08-01' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
locking/lockdep: Fix lockdep_init_map_*() confusion
jump_label: make initial NOP patching the special case
jump_label: mips: move module NOP patching into arch code
jump_label: s390: avoid pointless initial NOP patching
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 kdump updates from Borislav Petkov:
- Add the ability to pass early an RNG seed to the kernel from the boot
loader
- Add the ability to pass the IMA measurement of kernel and bootloader
to the kexec-ed kernel
* tag 'x86_kdump_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/setup: Use rng seeds from setup_data
x86/kexec: Carry forward IMA measurement log on kexec
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 build updates from Borislav Petkov:
- Fix stack protector builds when cross compiling with Clang
- Other Kbuild improvements and fixes
* tag 'x86_build_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/purgatory: Omit use of bin2c
x86/purgatory: Hard-code obj-y in Makefile
x86/build: Remove unused OBJECT_FILES_NON_STANDARD_test_nx.o
x86/Kconfig: Fix CONFIG_CC_HAS_SANE_STACKPROTECTOR when cross compiling with clang
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull misc x86 updates from Borislav Petkov:
- Add a bunch of PCI IDs for new AMD CPUs and use them in k10temp
- Free the pmem platform device on the registration error path
* tag 'x86_misc_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
hwmon: (k10temp): Add support for new family 17h and 19h models
x86/amd_nb: Add AMD PCI IDs for SMN communication
x86/pmem: Fix platform-device leak in error path
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 cpu updates from Borislav Petkov:
- Remove the vendor check when selecting MWAIT as the default idle
state
- Respect idle=nomwait when supplied on the kernel cmdline
- Two small cleanups
* tag 'x86_cpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/cpu: Use MSR_IA32_MISC_ENABLE constants
x86: Fix comment for X86_FEATURE_ZEN
x86: Remove vendor checks from prefer_mwait_c1_over_halt
x86: Handle idle=nomwait cmdline properly for x86_idle
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fpu update from Borislav Petkov:
- Add machinery to initialize AMX register state in order for
AMX-capable CPUs to be able to enter deeper low-power state
* tag 'x86_fpu_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
intel_idle: Add a new flag to initialize the AMX state
x86/fpu: Add a helper to prepare AMX state for low-power CPU idle
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 vmware cleanup from Borislav Petkov:
- A single statement simplification by using the BIT() macro
* tag 'x86_vmware_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/vmware: Use BIT() macro for shifting
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|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull RAS update from Borislav Petkov:
"A single RAS change:
- Probe whether hardware error injection (direct MSR writes) is
possible when injecting errors on AMD platforms. In some cases, the
platform could prohibit those"
* tag 'ras_core_for_v6.0_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/mce: Check whether writes to MCA_STATUS are getting ignored
|
|
KVM/s390, KVM/x86 and common infrastructure changes for 5.20
x86:
* Permit guests to ignore single-bit ECC errors
* Fix races in gfn->pfn cache refresh; do not pin pages tracked by the cache
* Intel IPI virtualization
* Allow getting/setting pending triple fault with KVM_GET/SET_VCPU_EVENTS
* PEBS virtualization
* Simplify PMU emulation by just using PERF_TYPE_RAW events
* More accurate event reinjection on SVM (avoid retrying instructions)
* Allow getting/setting the state of the speaker port data bit
* Refuse starting the kvm-intel module if VM-Entry/VM-Exit controls are inconsistent
* "Notify" VM exit (detect microarchitectural hangs) for Intel
* Cleanups for MCE MSR emulation
s390:
* add an interface to provide a hypervisor dump for secure guests
* improve selftests to use TAP interface
* enable interpretive execution of zPCI instructions (for PCI passthrough)
* First part of deferred teardown
* CPU Topology
* PV attestation
* Minor fixes
Generic:
* new selftests API using struct kvm_vcpu instead of a (vm, id) tuple
x86:
* Use try_cmpxchg64 instead of cmpxchg64
* Bugfixes
* Ignore benign host accesses to PMU MSRs when PMU is disabled
* Allow disabling KVM's "MONITOR/MWAIT are NOPs!" behavior
* x86/MMU: Allow NX huge pages to be disabled on a per-vm basis
* Port eager page splitting to shadow MMU as well
* Enable CMCI capability by default and handle injected UCNA errors
* Expose pid of vcpu threads in debugfs
* x2AVIC support for AMD
* cleanup PIO emulation
* Fixes for LLDT/LTR emulation
* Don't require refcounted "struct page" to create huge SPTEs
x86 cleanups:
* Use separate namespaces for guest PTEs and shadow PTEs bitmasks
* PIO emulation
* Reorganize rmap API, mostly around rmap destruction
* Do not workaround very old KVM bugs for L0 that runs with nesting enabled
* new selftests API for CPUID
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|
When a ftrace_bug happens (where ftrace fails to modify a location) it is
helpful to have what was at that location as well as what was expected to
be there.
But with the conversion to text_poke() the variable that assigns the
expected for debugging was dropped. Unfortunately, I noticed this when I
needed it. Add it back.
Link: https://lkml.kernel.org/r/20220726101851.069d2e70@gandalf.local.home
Cc: "x86@kernel.org" <x86@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@vger.kernel.org
Fixes: 768ae4406a5c ("x86/ftrace: Use text_poke()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
|
|
The setup_profiling_timer() is mostly un-implemented by many
architectures. In many places it isn't guarded by CONFIG_PROFILE which is
needed for it to be used. Make it a weak symbol in kernel/profile.c and
remove the 'return -EINVAL' implementations from the kenrel.
There are a couple of architectures which do return 0 from the
setup_profiling_timer() function but they don't seem to do anything else
with it. To keep the /proc compatibility for now, leave these for a
future update or removal.
On ARM, this fixes the following sparse warning:
arch/arm/kernel/smp.c:793:5: warning: symbol 'setup_profiling_timer' was not declared. Should it be static?
Link: https://lkml.kernel.org/r/20220721195509.418205-1-ben-linux@fluff.org
Signed-off-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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'virtio', 'x86/vt-d', 'x86/amd' and 'core' into next
|
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Some cloud hypervisors do not provide IBPB on very recent CPU processors,
including AMD processors affected by Retbleed.
Using IBPB before firmware calls on such systems would cause a GPF at boot
like the one below. Do not enable such calls when IBPB support is not
present.
EFI Variables Facility v0.08 2004-May-17
general protection fault, maybe for address 0x1: 0000 [#1] PREEMPT SMP NOPTI
CPU: 0 PID: 24 Comm: kworker/u2:1 Not tainted 5.19.0-rc8+ #7
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 0.0.0 02/06/2015
Workqueue: efi_rts_wq efi_call_rts
RIP: 0010:efi_call_rts
Code: e8 37 33 58 ff 41 bf 48 00 00 00 49 89 c0 44 89 f9 48 83 c8 01 4c 89 c2 48 c1 ea 20 66 90 b9 49 00 00 00 b8 01 00 00 00 31 d2 <0f> 30 e8 7b 9f 5d ff e8 f6 f8 ff ff 4c 89 f1 4c 89 ea 4c 89 e6 48
RSP: 0018:ffffb373800d7e38 EFLAGS: 00010246
RAX: 0000000000000001 RBX: 0000000000000006 RCX: 0000000000000049
RDX: 0000000000000000 RSI: ffff94fbc19d8fe0 RDI: ffff94fbc1b2b300
RBP: ffffb373800d7e70 R08: 0000000000000000 R09: 0000000000000000
R10: 000000000000000b R11: 000000000000000b R12: ffffb3738001fd78
R13: ffff94fbc2fcfc00 R14: ffffb3738001fd80 R15: 0000000000000048
FS: 0000000000000000(0000) GS:ffff94fc3da00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff94fc30201000 CR3: 000000006f610000 CR4: 00000000000406f0
Call Trace:
<TASK>
? __wake_up
process_one_work
worker_thread
? rescuer_thread
kthread
? kthread_complete_and_exit
ret_from_fork
</TASK>
Modules linked in:
Fixes: 28a99e95f55c ("x86/amd: Use IBPB for firmware calls")
Reported-by: Dimitri John Ledkov <dimitri.ledkov@canonical.com>
Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20220728122602.2500509-1-cascardo@canonical.com
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This reverts commit 007faec014cb5d26983c1f86fd08c6539b41392e.
Now that hyperv does its own protocol negotiation:
49d6a3c062a1 ("x86/Hyper-V: Add SEV negotiate protocol support in Isolation VM")
revert this exposure of the sev_es_ghcb_hv_call() helper.
Cc: Wei Liu <wei.liu@kernel.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by：Tianyu Lan <tiala@microsoft.com>
Link: https://lore.kernel.org/r/20220614014553.1915929-1-ltykernel@gmail.com
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|
x86/kernel/cpu/cyrix.c now needs to include <linux/isa-dma.h> since the
'isa_dma_bridge_buggy' variable was moved to it.
Fixes this build error:
../arch/x86/kernel/cpu/cyrix.c: In function ‘init_cyrix’:
../arch/x86/kernel/cpu/cyrix.c:277:17: error: ‘isa_dma_bridge_buggy’ undeclared (first use in this function)
277 | isa_dma_bridge_buggy = 2;
Fixes: abb4970ac335 ("PCI: Move isa_dma_bridge_buggy out of asm/dma.h")
Link: https://lore.kernel.org/r/20220725202224.29269-1-rdunlap@infradead.org
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Stafford Horne <shorne@gmail.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
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|
The archrandom interface was originally designed for x86, which supplies
RDRAND/RDSEED for receiving random words into registers, resulting in
one function to generate an int and another to generate a long. However,
other architectures don't follow this.
On arm64, the SMCCC TRNG interface can return between one and three
longs. On s390, the CPACF TRNG interface can return arbitrary amounts,
with four longs having the same cost as one. On UML, the os_getrandom()
interface can return arbitrary amounts.
So change the api signature to take a "max_longs" parameter designating
the maximum number of longs requested, and then return the number of
longs generated.
Since callers need to check this return value and loop anyway, each arch
implementation does not bother implementing its own loop to try again to
fill the maximum number of longs. Additionally, all existing callers
pass in a constant max_longs parameter. Taken together, these two things
mean that the codegen doesn't really change much for one-word-at-a-time
platforms, while performance is greatly improved on platforms such as
s390.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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|
IBRS mitigation for spectre_v2 forces write to MSR_IA32_SPEC_CTRL at
every kernel entry/exit. On Enhanced IBRS parts setting
MSR_IA32_SPEC_CTRL[IBRS] only once at boot is sufficient. MSR writes at
every kernel entry/exit incur unnecessary performance loss.
When Enhanced IBRS feature is present, print a warning about this
unnecessary performance loss.
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/2a5eaf54583c2bfe0edc4fea64006656256cca17.1657814857.git.pawan.kumar.gupta@linux.intel.com
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Debugging missing return thunks is easier if we can see where they're
happening.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/Ys66hwtFcGbYmoiZ@hirez.programming.kicks-ass.net/
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Add support for SMN communication on family 17h model A0h and family 19h
models 60h-70h.
[ bp: Merge into a single patch. ]
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Yazen Ghannam <yazen.ghannam@amd.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com> # pci_ids.h
Acked-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220719195256.1516-1-mario.limonciello@amd.com
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Instead of the magic numbers 1<<11 and 1<<12 use the constants
from msr-index.h. This makes it obvious where those bits
of MSR_IA32_MISC_ENABLE are consumed (and in fact that Linux
consumes them at all) to simple minds that grep for
MSR_IA32_MISC_ENABLE_.*_UNAVAIL.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220719174714.2410374-1-pbonzini@redhat.com
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When a CPU enters an idle state, a non-initialized AMX register state may
be the cause of preventing a deeper low-power state. Other extended
register states whether initialized or not do not impact the CPU idle
state.
The new helper can ensure the AMX state is initialized before the CPU is
idle, and it will be used by the intel idle driver.
Check the AMX_TILE feature bit before using XGETBV1 as a chain of
dependencies was established via cpuid_deps[]: AMX->XFD->XGETBV1.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20220608164748.11864-2-chang.seok.bae@intel.com
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On AMD IBRS does not prevent Retbleed; as such use IBPB before a
firmware call to flush the branch history state.
And because in order to do an EFI call, the kernel maps a whole lot of
the kernel page table into the EFI page table, do an IBPB just in case
in order to prevent the scenario of poisoning the BTB and causing an EFI
call using the unprotected RET there.
[ bp: Massage. ]
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220715194550.793957-1-cascardo@canonical.com
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The decision of whether or not to trust RDRAND is controlled by the
"random.trust_cpu" boot time parameter or the CONFIG_RANDOM_TRUST_CPU
compile time default. The "nordrand" flag was added during the early
days of RDRAND, when there were worries that merely using its values
could compromise the RNG. However, these days, RDRAND values are not
used directly but always go through the RNG's hash function, making
"nordrand" no longer useful.
Rather, the correct switch is "random.trust_cpu", which not only handles
the relevant trust issue directly, but also is general to multiple CPU
types, not just x86.
However, x86 RDRAND does have a history of being occasionally
problematic. Prior, when the kernel would notice something strange, it'd
warn in dmesg and suggest enabling "nordrand". We can improve on that by
making the test a little bit better and then taking the step of
automatically disabling RDRAND if we detect it's problematic.
Also disable RDSEED if the RDRAND test fails.
Cc: x86@kernel.org
Cc: Theodore Ts'o <tytso@mit.edu>
Suggested-by: H. Peter Anvin <hpa@zytor.com>
Suggested-by: Borislav Petkov <bp@suse.de>
Acked-by: Borislav Petkov <bp@suse.de>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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When RDRAND was introduced, there was much discussion on whether it
should be trusted and how the kernel should handle that. Initially, two
mechanisms cropped up, CONFIG_ARCH_RANDOM, a compile time switch, and
"nordrand", a boot-time switch.
Later the thinking evolved. With a properly designed RNG, using RDRAND
values alone won't harm anything, even if the outputs are malicious.
Rather, the issue is whether those values are being *trusted* to be good
or not. And so a new set of options were introduced as the real
ones that people use -- CONFIG_RANDOM_TRUST_CPU and "random.trust_cpu".
With these options, RDRAND is used, but it's not always credited. So in
the worst case, it does nothing, and in the best case, maybe it helps.
Along the way, CONFIG_ARCH_RANDOM's meaning got sort of pulled into the
center and became something certain platforms force-select.
The old options don't really help with much, and it's a bit odd to have
special handling for these instructions when the kernel can deal fine
with the existence or untrusted existence or broken existence or
non-existence of that CPU capability.
Simplify the situation by removing CONFIG_ARCH_RANDOM and using the
ordinary asm-generic fallback pattern instead, keeping the two options
that are actually used. For now it leaves "nordrand" for now, as the
removal of that will take a different route.
Acked-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Borislav Petkov <bp@suse.de>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
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Patch series "cpumask: Fix invalid uniprocessor assumptions", v4.
On uniprocessor builds, it is currently assumed that any cpumask will
contain the single CPU: cpu0. This assumption is used to provide
optimised implementations.
The current assumption also appears to be wrong, by ignoring the fact that
users can provide empty cpumasks. This can result in bugs as explained in
[1] - for_each_cpu() will run one iteration of the loop even when passed
an empty cpumask.
This series introduces some basic tests, and updates the optimisations for
uniprocessor builds.
The x86 patch was written after the kernel test robot [2] ran into a
failed build. I have tried to list the files potentially affected by the
changes to cpumask.h, in an attempt to find any other cases that fail on
!SMP. I've gone through some of the files manually, and ran a few cross
builds, but nothing else popped up. I (build) checked about half of the
potientally affected files, but I do not have the resources to do them
all. I hope we can fix other issues if/when they pop up later.
[1] https://lore.kernel.org/all/20220530082552.46113-1-sander@svanheule.net/
[2] https://lore.kernel.org/all/202206060858.wA0FOzRy-lkp@intel.com/
This patch (of 5):
The maps to keep track of shared caches between CPUs on SMP systems are
declared in asm/smp.h, among them specifically cpu_llc_shared_map. These
maps are externally defined in cpu/smpboot.c. The latter is only compiled
on CONFIG_SMP=y, which means the declared extern symbols from asm/smp.h do
not have a corresponding definition on uniprocessor builds.
The inline cpu_llc_shared_mask() function from asm/smp.h refers to the map
declaration mentioned above. This function is referenced in cacheinfo.c
inside for_each_cpu() loop macros, to provide cpumask for the loop. On
uniprocessor builds, the symbol for the cpu_llc_shared_map does not exist.
However, the current implementation of for_each_cpu() also (wrongly)
ignores the provided mask.
By sheer luck, the compiler thus optimises out this unused reference to
cpu_llc_shared_map, and the linker therefore does not require the
cpu_llc_shared_mask to actually exist on uniprocessor builds. Only on SMP
bulids does smpboot.o exist to provide the required symbols.
To no longer rely on compiler optimisations for successful uniprocessor
builds, move the definitions of cpu_llc_shared_map and cpu_l2c_shared_map
from smpboot.c to cacheinfo.c.
Link: https://lkml.kernel.org/r/cover.1656777646.git.sander@svanheule.net
Link: https://lkml.kernel.org/r/e8167ddb570f56744a3dc12c2149a660a324d969.1656777646.git.sander@svanheule.net
Signed-off-by: Sander Vanheule <sander@svanheule.net>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Marco Elver <elver@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Valentin Schneider <vschneid@redhat.com>
Cc: Yury Norov <yury.norov@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
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:
- Improve the check whether the kernel supports WP mappings so that it
can accomodate a XenPV guest due to how the latter is setting up the
PAT machinery
- Now that the retbleed nightmare is public, here's the first round of
fallout fixes:
* Fix a build failure on 32-bit due to missing include
* Remove an untraining point in espfix64 return path
* other small cleanups
* tag 'x86_urgent_for_v5.19_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/bugs: Remove apostrophe typo
um: Add missing apply_returns()
x86/entry: Remove UNTRAIN_RET from native_irq_return_ldt
x86/bugs: Mark retbleed_strings static
x86/pat: Fix x86_has_pat_wp()
x86/asm/32: Fix ANNOTATE_UNRET_SAFE use on 32-bit
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull ACPI fix from Rafael Wysocki:
"Fix more fallout from recent changes of the ACPI CPPC handling on AMD
platforms (Mario Limonciello)"
* tag 'acpi-5.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
ACPI: CPPC: Fix enabling CPPC on AMD systems with shared memory
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Remove a superfluous ' in the mitigation string.
Fixes: e8ec1b6e08a2 ("x86/bugs: Enable STIBP for JMP2RET")
Signed-off-by: Kim Phillips <kim.phillips@amd.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
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commit 278311e417be ("kexec, KEYS: Make use of platform keyring for
signature verify") adds platform keyring support on x86 kexec but not
arm64.
The code in bzImage64_verify_sig uses the keys on the
.builtin_trusted_keys, .machine, if configured and enabled,
.secondary_trusted_keys, also if configured, and .platform keyrings
to verify the signed kernel image as PE file.
Cc: kexec@lists.infradead.org
Cc: keyrings@vger.kernel.org
Cc: linux-security-module@vger.kernel.org
Reviewed-by: Michal Suchanek <msuchanek@suse.de>
Signed-off-by: Coiby Xu <coxu@redhat.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
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tboot_force_iommu() is only called by the Intel IOMMU driver. Move the
helper into that driver. No functional change intended.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Steve Wahl <steve.wahl@hpe.com>
Link: https://lore.kernel.org/r/20220514014322.2927339-7-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
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This symbol is not used outside of bugs.c, so mark it static.
Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20220714072939.71162-1-jiapeng.chong@linux.alibaba.com
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When commit 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all
and when CPPC_LIB is supported") was introduced, we found collateral
damage that a number of AMD systems that supported CPPC but
didn't advertise support in _OSC stopped having a functional
amd-pstate driver. The _OSC was only enforced on Intel systems at that
time.
This was fixed for the MSR based designs by commit 8b356e536e69f
("ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported")
but some shared memory based designs also support CPPC but haven't
advertised support in the _OSC. Add support for those designs as well by
hardcoding the list of systems.
Fixes: 72f2ecb7ece7 ("ACPI: bus: Set CPPC _OSC bits for all and when CPPC_LIB is supported")
Fixes: 8b356e536e69f ("ACPI: CPPC: Don't require _OSC if X86_FEATURE_CPPC is supported")
Link: https://lore.kernel.org/all/3559249.JlDtxWtqDm@natalenko.name/
Cc: 5.18+ <stable@vger.kernel.org> # 5.18+
Reported-and-tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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The build on x86_32 currently fails after commit
9bb2ec608a20 (objtool: Update Retpoline validation)
with:
arch/x86/kernel/../../x86/xen/xen-head.S:35: Error: no such instruction: `annotate_unret_safe'
ANNOTATE_UNRET_SAFE is defined in nospec-branch.h. And head_32.S is
missing this include. Fix this.
Fixes: 9bb2ec608a20 ("objtool: Update Retpoline validation")
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/63e23f80-033f-f64e-7522-2816debbc367@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull lockdep fix for x86 retbleed from Borislav Petkov:
- Fix lockdep complaint for __static_call_fixup()
* tag 'x86_bugs_retbleed' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/static_call: Serialize __static_call_fixup() properly
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