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| author | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-23 16:05:14 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2021-06-25 07:47:19 +0300 |
| commit | 95839225639ba7c3d8d7231b542728dcf222bf2d (patch) | |
| tree | 9211645bad917212868155bf59df8b3514b4b477 /arch/powerpc/platforms/pseries/smp.c | |
| parent | 24d33ac5b8ffb7a0e697344fea8591376162548f (diff) | |
| download | linux-95839225639ba7c3d8d7231b542728dcf222bf2d.tar.xz | |
powerpc: Fix is_kvm_guest() / kvm_para_available()
Commit a21d1becaa3f ("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: a21d1becaa3f ("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
Diffstat (limited to 'arch/powerpc/platforms/pseries/smp.c')
| -rw-r--r-- | arch/powerpc/platforms/pseries/smp.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index c70b4be9f0a5..096629f54576 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -211,7 +211,9 @@ static __init void pSeries_smp_probe(void) if (!cpu_has_feature(CPU_FTR_SMT)) return; - if (check_kvm_guest()) { + check_kvm_guest(); + + if (is_kvm_guest()) { /* * KVM emulates doorbells by disabling FSCR[MSGP] so msgsndp * faults to the hypervisor which then reads the instruction |