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Author SHA1 Message Date
Nick Child
d276960d92 powerpc/kernel: Add __init attribute to eligible functions
Some functions defined in `arch/powerpc/kernel` (and one in `arch/powerpc/
kexec`) are deserving of an `__init` macro attribute. These functions are
only called by other initialization functions and therefore should inherit
the attribute.
Also, change function declarations in header files to include `__init`.

Signed-off-by: Nick Child <nick.child@ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20211216220035.605465-2-nick.child@ibm.com
2021-12-23 22:33:10 +11:00
Michael Ellerman
9583922563 powerpc: Fix is_kvm_guest() / kvm_para_available()
Commit a21d1becaa ("powerpc: Reintroduce is_kvm_guest() as a fast-path
check") added is_kvm_guest() and changed kvm_para_available() to use it.

is_kvm_guest() checks a static key, kvm_guest, and that static key is
set in check_kvm_guest().

The problem is check_kvm_guest() is only called on pseries, and even
then only in some configurations. That means is_kvm_guest() always
returns false on all non-pseries and some pseries depending on
configuration. That's a bug.

For PR KVM guests this is noticable because they no longer do live
patching of themselves, which can be detected by the omission of a
message in dmesg such as:

  KVM: Live patching for a fast VM worked

To fix it make check_kvm_guest() an initcall, to ensure it's always
called at boot. It needs to be core so that it runs before
kvm_guest_init() which is postcore. To be an initcall it needs to return
int, where 0 means success, so update that.

We still call it manually in pSeries_smp_probe(), because that runs
before init calls are run.

Fixes: a21d1becaa ("powerpc: Reintroduce is_kvm_guest() as a fast-path check")
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20210623130514.2543232-1-mpe@ellerman.id.au
2021-06-25 14:47:19 +10:00
Srikar Dronamraju
a21d1becaa powerpc: Reintroduce is_kvm_guest() as a fast-path check
Introduce a static branch that would be set during boot if the OS
happens to be a KVM guest. Subsequent checks to see if we are on KVM
will rely on this static branch. This static branch would be used in
vcpu_is_preempted() in a subsequent patch.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202050456.164005-4-srikar@linux.vnet.ibm.com
2020-12-04 01:01:22 +11:00
Srikar Dronamraju
16520a858a powerpc: Rename is_kvm_guest() to check_kvm_guest()
We want to reuse the is_kvm_guest() name in a subsequent patch but
with a new body. Hence rename is_kvm_guest() to check_kvm_guest(). No
additional changes.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: kernel test robot <lkp@intel.com> # int -> bool fix
[mpe: Fold in fix from lkp to use true/false not 0/1]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202050456.164005-3-srikar@linux.vnet.ibm.com
2020-12-04 01:01:21 +11:00
Srikar Dronamraju
92cc6bf01c powerpc: Refactor is_kvm_guest() declaration to new header
Only code/declaration movement, in anticipation of doing a KVM-aware
vcpu_is_preempted(). No additional changes.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: Waiman Long <longman@redhat.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20201202050456.164005-2-srikar@linux.vnet.ibm.com
2020-12-04 01:01:21 +11:00