linux

iv/linux

History

Sean Christopherson c8e2fe13d1 x86/perf: Use RET0 as default for guest_get_msrs to handle "no PMU" case

Initialize x86_pmu.guest_get_msrs to return 0/NULL to handle the "nop"
case.  Patching in perf_guest_get_msrs_nop() during setup does not work
if there is no PMU, as setup bails before updating the static calls,
leaving x86_pmu.guest_get_msrs NULL and thus a complete nop.  Ultimately,
this causes VMX abort on VM-Exit due to KVM putting random garbage from
the stack into the MSR load list.

Add a comment in KVM to note that nr_msrs is valid if and only if the
return value is non-NULL.

Fixes: abd562df94d1 ("x86/perf: Use static_call for x86_pmu.guest_get_msrs")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Reported-by: syzbot+cce9ef2dd25246f815ee@syzkaller.appspotmail.com
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20210309171019.1125243-1-seanjc@google.com

2021-03-10 16:45:09 +01:00

alpha

io_uring-worker.v3-2021-02-25

2021-02-27 08:29:02 -08:00

arc

arch: setup PF_IO_WORKER threads like PF_KTHREAD

2021-02-21 17:25:22 -07:00

arm

xen: branch for v5.12-rc2

2021-03-04 11:24:47 -08:00

arm64

io_uring-worker.v3-2021-02-25