linux.git/arch, branch v5.6-rc4

Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

2020-03-01T21:16:35+00:00

Pull KVM fixes from Paolo Bonzini:
 "More bugfixes, including a few remaining "make W=1" issues such as too
  large frame sizes on some configurations.

  On the ARM side, the compiler was messing up shadow stacks between EL1
  and EL2 code, which is easily fixed with __always_inline"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: VMX: check descriptor table exits on instruction emulation
  kvm: x86: Limit the number of "kvm: disabled by bios" messages
  KVM: x86: avoid useless copy of cpufreq policy
  KVM: allow disabling -Werror
  KVM: x86: allow compiling as non-module with W=1
  KVM: Pre-allocate 1 cpumask variable per cpu for both pv tlb and pv ipis
  KVM: Introduce pv check helpers
  KVM: let declaration of kvm_get_running_vcpus match implementation
  KVM: SVM: allocate AVIC data structures based on kvm_amd module parameter
  arm64: Ask the compiler to __always_inline functions used by KVM at HYP
  KVM: arm64: Define our own swab32() to avoid a uapi static inline
  KVM: arm64: Ask the compiler to __always_inline functions used at HYP
  kvm: arm/arm64: Fold VHE entry/exit work into kvm_vcpu_run_vhe()
  KVM: arm/arm64: Fix up includes for trace.h

KVM: VMX: check descriptor table exits on instruction emulation

2020-03-01T18:26:31+00:00

KVM emulates UMIP on hardware that doesn't support it by setting the
'descriptor table exiting' VM-execution control and performing
instruction emulation. When running nested, this emulation is broken as
KVM refuses to emulate L2 instructions by default.

Correct this regression by allowing the emulation of descriptor table
instructions if L1 hasn't requested 'descriptor table exiting'.

Fixes: 07721feee46b ("KVM: nVMX: Don't emulate instructions in guest mode")
Reported-by: Jan Kiszka 
Cc: stable@vger.kernel.org
Cc: Paolo Bonzini 
Cc: Jim Mattson 
Signed-off-by: Oliver Upton 
Signed-off-by: Paolo Bonzini

Merge tag 'kvmarm-fixes-5.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

2020-02-28T10:50:06+00:00

KVM/arm fixes for 5.6, take #1

- Fix compilation on 32bit
- Move  VHE guest entry/exit into the VHE-specific entry code
- Make sure all functions called by the non-VHE HYP code is tagged as __always_inline

kvm: x86: Limit the number of "kvm: disabled by bios" messages

2020-02-28T10:37:20+00:00

In older version of systemd(219), at boot time, udevadm is called with :
	/usr/bin/udevadm trigger --type=devices --action=add"

This program generates an echo "add" in /sys/devices/system/cpu/cpu/uevent,
leading to the "kvm: disabled by bios" message in case of your Bios disabled
the virtualization extensions.

On a modern system running up to 256 CPU threads, this pollutes the Kernel logs.

This patch offers to ratelimit this message to avoid any userspace program triggering
this uevent printing this message too often.

This patch is only a workaround but greatly reduce the pollution without
breaking the current behavior of printing a message if some try to instantiate
KVM on a system that doesn't support it.

Note that recent versions of systemd (>239) do not have trigger this behavior.

This patch will be useful at least for some using older systemd with recent Kernels.

Signed-off-by: Erwan Velu 
Signed-off-by: Paolo Bonzini

KVM: x86: avoid useless copy of cpufreq policy

2020-02-28T09:54:50+00:00

struct cpufreq_policy is quite big and it is not a good idea
to allocate one on the stack.  Just use cpufreq_cpu_get and
cpufreq_cpu_put which is even simpler.

Reported-by: Christoph Hellwig 
Signed-off-by: Paolo Bonzini

KVM: allow disabling -Werror

2020-02-28T09:45:28+00:00

Restrict -Werror to well-tested configurations and allow disabling it
via Kconfig.

Reported-by: Christoph Hellwig 
Signed-off-by: Paolo Bonzini

KVM: x86: allow compiling as non-module with W=1

2020-02-28T09:35:37+00:00

Compile error with CONFIG_KVM_INTEL=y and W=1:

  CC      arch/x86/kvm/vmx/vmx.o
arch/x86/kvm/vmx/vmx.c:68:32: error: 'vmx_cpu_id' defined but not used [-Werror=unused-const-variable=]
   68 | static const struct x86_cpu_id vmx_cpu_id[] = {
      |                                ^~~~~~~~~~
cc1: all warnings being treated as errors

When building with =y, the MODULE_DEVICE_TABLE macro doesn't generate a
reference to the structure (or any code at all).  This makes W=1 compiles
unhappy.

Wrap both in a #ifdef to avoid the issue.

Signed-off-by: Valdis Kletnieks 
[Do the same for CONFIG_KVM_AMD. - Paolo]
Signed-off-by: Paolo Bonzini

KVM: Pre-allocate 1 cpumask variable per cpu for both pv tlb and pv ipis

2020-02-28T09:34:25+00:00

Nick Desaulniers Reported:

  When building with:
  $ make CC=clang arch/x86/ CFLAGS=-Wframe-larger-than=1000
  The following warning is observed:
  arch/x86/kernel/kvm.c:494:13: warning: stack frame size of 1064 bytes in
  function 'kvm_send_ipi_mask_allbutself' [-Wframe-larger-than=]
  static void kvm_send_ipi_mask_allbutself(const struct cpumask *mask, int
  vector)
              ^
  Debugging with:
  https://github.com/ClangBuiltLinux/frame-larger-than
  via:
  $ python3 frame_larger_than.py arch/x86/kernel/kvm.o \
    kvm_send_ipi_mask_allbutself
  points to the stack allocated `struct cpumask newmask` in
  `kvm_send_ipi_mask_allbutself`. The size of a `struct cpumask` is
  potentially large, as it's CONFIG_NR_CPUS divided by BITS_PER_LONG for
  the target architecture. CONFIG_NR_CPUS for X86_64 can be as high as
  8192, making a single instance of a `struct cpumask` 1024 B.

This patch fixes it by pre-allocate 1 cpumask variable per cpu and use it for
both pv tlb and pv ipis..

Reported-by: Nick Desaulniers 
Acked-by: Nick Desaulniers 
Reviewed-by: Vitaly Kuznetsov 
Cc: Peter Zijlstra 
Cc: Nick Desaulniers 
Signed-off-by: Wanpeng Li 
Signed-off-by: Paolo Bonzini

KVM: Introduce pv check helpers

2020-02-28T09:34:19+00:00

Introduce some pv check helpers for consistency.

Suggested-by: Vitaly Kuznetsov 
Reviewed-by: Konrad Rzeszutek Wilk 
Signed-off-by: Wanpeng Li 
Signed-off-by: Paolo Bonzini

KVM: SVM: allocate AVIC data structures based on kvm_amd module parameter

2020-02-28T09:33:17+00:00

Even if APICv is disabled at startup, the backing page and ir_list need
to be initialized in case they are needed later.  The only case in
which this can be skipped is for userspace irqchip, and that must be
done because avic_init_backing_page dereferences vcpu->arch.apic
(which is NULL for userspace irqchip).

Tested-by: rmuncrief@humanavance.com
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=206579
Reviewed-by: Miaohe Lin 
Signed-off-by: Paolo Bonzini