linux-stable.git/arch, branch v5.19.2

powerpc/kexec: Fix build failure from uninitialised variable

2022-08-17T13:16:21+00:00

commit 83ee9f23763a432a4077bf20624ee35de87bce99 upstream.

clang 14 won't build because ret is uninitialised and can be returned if
both prop and fdtprop are NULL.  Drop the ret variable and return an
error in that failure case.

Fixes: b1fc44eaa9ba ("pseries/iommu/ddw: Fix kdump to work in absence of ibm,dma-window")
Suggested-by: Christophe Leroy 
Signed-off-by: Russell Currey 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20220810054331.373761-1-ruscur@russell.cc
Signed-off-by: Greg Kroah-Hartman

Revert "s390/smp: enforce lowcore protection on CPU restart"

2022-08-17T13:16:20+00:00

commit 953503751a426413ea8aee2299ae3ee971b70d9b upstream.

This reverts commit 6f5c672d17f583b081e283927f5040f726c54598.

This breaks normal crash dump when CPU0 is offline.

Signed-off-by: Alexander Gordeev 
Signed-off-by: Greg Kroah-Hartman

powerpc64/ftrace: Fix ftrace for clang builds

2022-08-17T13:16:18+00:00

commit cb928ac192128c842f4c1cfc8b6780b95719d65f upstream.

Clang doesn't support -mprofile-kernel ABI, so guard the checks against
CONFIG_DYNAMIC_FTRACE_WITH_REGS, rather than the elf ABI version.

Fixes: 23b44fc248f4 ("powerpc/ftrace: Make __ftrace_make_{nop/call}() common to PPC32 and PPC64")
Cc: stable@vger.kernel.org # v5.19+
Reported-by: Nick Desaulniers 
Reported-by: Ondrej Mosnacek 
Signed-off-by: Naveen N. Rao 
Tested-by: Ondrej Mosnacek 
Acked-by: Nick Desaulniers 
Signed-off-by: Michael Ellerman 
Link: https://github.com/llvm/llvm-project/issues/57031
Link: https://github.com/ClangBuiltLinux/linux/issues/1682
Link: https://lore.kernel.org/r/20220809095907.418764-1-naveen.n.rao@linux.vnet.ibm.com
Signed-off-by: Greg Kroah-Hartman

powerpc: Fix eh field when calling lwarx on PPC32

2022-08-17T13:16:18+00:00

commit 18db466a9a306406dab3b134014d9f6ed642471c upstream.

Commit 9401f4e46cf6 ("powerpc: Use lwarx/ldarx directly instead of
PPC_LWARX/LDARX macros") properly handled the eh field of lwarx
in asm/bitops.h but failed to clear it for PPC32 in
asm/simple_spinlock.h

So, do as in arch_atomic_try_cmpxchg_lock(), set it to 1 if PPC64
but set it to 0 if PPC32. For that use IS_ENABLED(CONFIG_PPC64) which
returns 1 when CONFIG_PPC64 is set and 0 otherwise.

Fixes: 9401f4e46cf6 ("powerpc: Use lwarx/ldarx directly instead of PPC_LWARX/LDARX macros")
Cc: stable@vger.kernel.org # v5.15+
Reported-by: Pali Rohár 
Signed-off-by: Christophe Leroy 
Tested-by: Pali Rohár 
Reviewed-by: Segher Boessenkool 
[mpe: Use symbolic names, use 'n' constraint per Segher]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/a1176e19e627dd6a1b8d24c6c457a8ab874b7d12.1659430931.git.christophe.leroy@csgroup.eu
Signed-off-by: Greg Kroah-Hartman

KVM: nVMX: Attempt to load PERF_GLOBAL_CTRL on nVMX xfer iff it exists

2022-08-17T13:16:14+00:00

[ Upstream commit 4496a6f9b45e8cd83343ad86a3984d614e22cf54 ]

Attempt to load PERF_GLOBAL_CTRL during nested VM-Enter/VM-Exit if and
only if the MSR exists (according to the guest vCPU model).  KVM has very
misguided handling of VM_{ENTRY,EXIT}_LOAD_IA32_PERF_GLOBAL_CTRL and
attempts to force the nVMX MSR settings to match the vPMU model, i.e. to
hide/expose the control based on whether or not the MSR exists from the
guest's perspective.

KVM's modifications fail to handle the scenario where the vPMU is hidden
from the guest _after_ being exposed to the guest, e.g. by userspace
doing multiple KVM_SET_CPUID2 calls, which is allowed if done before any
KVM_RUN.  nested_vmx_pmu_refresh() is called if and only if there's a
recognized vPMU, i.e. KVM will leave the bits in the allow state and then
ultimately reject the MSR load and WARN.

KVM should not force the VMX MSRs in the first place.  KVM taking control
of the MSRs was a misguided attempt at mimicking what commit 5f76f6f5ff96
("KVM: nVMX: Do not expose MPX VMX controls when guest MPX disabled",
2018-10-01) did for MPX.  However, the MPX commit was a workaround for
another KVM bug and not something that should be imitated (and it should
never been done in the first place).

In other words, KVM's ABI _should_ be that userspace has full control
over the MSRs, at which point triggering the WARN that loading the MSR
must not fail is trivial.

The intent of the WARN is still valid; KVM has consistency checks to
ensure that vmcs12->{guest,host}_ia32_perf_global_ctrl is valid.  The
problem is that '0' must be considered a valid value at all times, and so
the simple/obvious solution is to just not actually load the MSR when it
does not exist.  It is userspace's responsibility to provide a sane vCPU
model, i.e. KVM is well within its ABI and Intel's VMX architecture to
skip the loads if the MSR does not exist.

Fixes: 03a8871add95 ("KVM: nVMX: Expose load IA32_PERF_GLOBAL_CTRL VM-{Entry,Exit} control")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson 
Message-Id: <20220722224409.1336532-5-seanjc@google.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

KVM: VMX: Add helper to check if the guest PMU has PERF_GLOBAL_CTRL

2022-08-17T13:16:14+00:00

[ Upstream commit b663f0b5f3d665c261256d1f76e98f077c6e56af ]

Add a helper to check of the guest PMU has PERF_GLOBAL_CTRL, which is
unintuitive _and_ diverges from Intel's architecturally defined behavior.
Even worse, KVM currently implements the check using two different (but
equivalent) checks, _and_ there has been at least one attempt to add a
_third_ flavor.

Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson 
Message-Id: <20220722224409.1336532-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

Revert "KVM: x86/pmu: Accept 0 for absent PMU MSRs when host-initiated if !enable_pmu"

2022-08-17T13:16:14+00:00

[ Upstream commit 5d4283df5a0fc8299fba9443c33d219939eccc2d ]

Eating reads and writes to all "PMU" MSRs when there is no PMU is wildly
broken as it results in allowing accesses to _any_ MSR on Intel CPUs
as intel_is_valid_msr() returns true for all host_initiated accesses.

A revert of commit d1c88a402056 ("KVM: x86: always allow host-initiated
writes to PMU MSRs") will soon follow.

This reverts commit 8e6a58e28b34e8d247e772159b8fa8f6bae39192.

Signed-off-by: Sean Christopherson 
Message-Id: <20220611005755.753273-4-seanjc@google.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

KVM: x86/pmu: Accept 0 for absent PMU MSRs when host-initiated if !enable_pmu

2022-08-17T13:16:14+00:00

[ Upstream commit 8e6a58e28b34e8d247e772159b8fa8f6bae39192 ]

Whenever an MSR is part of KVM_GET_MSR_INDEX_LIST, as is the case for
MSR_K7_EVNTSEL0 or MSR_F15H_PERF_CTL0, it has to be always retrievable
and settable with KVM_GET_MSR and KVM_SET_MSR.

Accept a zero value for these MSRs to obey the contract.

Signed-off-by: Like Xu 
Message-Id: <20220601031925.59693-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

KVM: x86/pmu: Ignore pmu->global_ctrl check if vPMU doesn't support global_ctrl

2022-08-17T13:16:13+00:00

[ Upstream commit 98defd2e17803263f49548fea930cfc974d505aa ]

MSR_CORE_PERF_GLOBAL_CTRL is introduced as part of Architecture PMU V2,
as indicated by Intel SDM 19.2.2 and the intel_is_valid_msr() function.

So in the absence of global_ctrl support, all PMCs are enabled as AMD does.

Signed-off-by: Like Xu 
Message-Id: <20220509102204.62389-1-likexu@tencent.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin

KVM: VMX: Mark all PERF_GLOBAL_(OVF)_CTRL bits reserved if there's no vPMU

2022-08-17T13:16:13+00:00

[ Upstream commit 93255bf92939d948bc86d81c6bb70bb0fecc5db1 ]

Mark all MSR_CORE_PERF_GLOBAL_CTRL and MSR_CORE_PERF_GLOBAL_OVF_CTRL bits
as reserved if there is no guest vPMU.  The nVMX VM-Entry consistency
checks do not check for a valid vPMU prior to consuming the masks via
kvm_valid_perf_global_ctrl(), i.e. may incorrectly allow a non-zero mask
to be loaded via VM-Enter or VM-Exit (well, attempted to be loaded, the
actual MSR load will be rejected by intel_is_valid_msr()).

Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson 
Message-Id: <20220722224409.1336532-3-seanjc@google.com>
Signed-off-by: Paolo Bonzini 
Signed-off-by: Sasha Levin