[email protected] writes: > From: Marc-André Lureau <[email protected]> > > The documentation stated that writing to HV_X64_MSR_CRASH_CTL > unconditionally causes the guest to shutdown. In reality, it triggers > qemu_system_guest_panicked() via KVM_SYSTEM_EVENT_CRASH and the > resulting action depends on the generic panic action policy > (-action panic=...), which defaults to shutdown.
Indeed, > > Signed-off-by: Marc-André Lureau <[email protected]> > --- > docs/system/i386/hyperv.rst | 12 ++++++++---- > 1 file changed, 8 insertions(+), 4 deletions(-) > > diff --git a/docs/system/i386/hyperv.rst b/docs/system/i386/hyperv.rst > index 1c1de77feb6..e1babffb0f9 100644 > --- a/docs/system/i386/hyperv.rst > +++ b/docs/system/i386/hyperv.rst > @@ -71,8 +71,11 @@ Existing enlightenments > by the guest when it crashes, HV_X64_MSR_CRASH_P0..HV_X64_MSR_CRASH_P5 MSRs > contain additional crash information. This information is outputted in > QEMU log > and through QAPI. > - Note: unlike under genuine Hyper-V, write to HV_X64_MSR_CRASH_CTL causes > guest > - to shutdown. This effectively blocks crash dump generation by Windows. > + Note: unlike under genuine Hyper-V, write to HV_X64_MSR_CRASH_CTL triggers > + ``qemu_system_guest_panicked()`` via ``KVM_SYSTEM_EVENT_CRASH`` and the > + resulting action depends on the ``-action panic=...`` policy (default: > + ``shutdown``). With the default action, this effectively blocks crash dump > + generation by Windows. > > ``hv-time`` > Enables two Hyper-V-specific clocksources available to the guest: MSR-based > @@ -304,8 +307,9 @@ currently implemented Hyper-V enlightenments with the > following exceptions: > ``hv-version-id-snumber`` can be left unchanged, guests are not supposed to > behave differently when different Hyper-V version is presented to them. > - ``hv-crash`` must only be enabled if the crash information is consumed via > - QAPI by higher levels of the virtualization stack. Enabling this feature > - effectively prevents Windows from creating dumps upon crashes. > + QAPI by higher levels of the virtualization stack. With the default > + ``-action panic=shutdown`` policy, enabling this feature effectively > + prevents Windows from creating dumps upon crashes. > - ``hv-reenlightenment`` can only be used on hardware which supports TSC > scaling or when guest migration is not needed. > - ``hv-spinlocks`` should be set to e.g. 0xfff when host CPUs are > overcommited Reviewed-by: Vitaly Kuznetsov <[email protected]> Thanks! -- Vitaly
