> -----Original Message----- > From: Andrew Cooper > Sent: 16 August 2018 10:40 > To: Paul Durrant <paul.durr...@citrix.com>; xen-devel@lists.xenproject.org > Cc: Jan Beulich <jbeul...@suse.com> > Subject: Re: [PATCH] x86/hvm/viridian: set shutdown_code in response to > CrashNotify > > On 10/08/18 16:59, Paul Durrant wrote: > >> -----Original Message----- > >> From: Andrew Cooper > >> Sent: 10 August 2018 16:57 > >> To: Paul Durrant <paul.durr...@citrix.com>; xen- > de...@lists.xenproject.org > >> Cc: Jan Beulich <jbeul...@suse.com> > >> Subject: Re: [PATCH] x86/hvm/viridian: set shutdown_code in response > to > >> CrashNotify > >> > >> On 10/08/18 16:43, Paul Durrant wrote: > >>> When Windows writes the CrashNotify bit in the CRASH_CTL MSR then > we > >> know > >>> it is crashing, so set the domain shutdown code appropriately. > >>> > >>> Signed-off-by: Paul Durrant <paul.durr...@citrix.com> > >>> --- > >>> Cc: Jan Beulich <jbeul...@suse.com> > >>> Cc: Andrew Cooper <andrew.coop...@citrix.com> > >>> --- > >>> xen/arch/x86/hvm/viridian.c | 4 ++++ > >>> 1 file changed, 4 insertions(+) > >>> > >>> diff --git a/xen/arch/x86/hvm/viridian.c b/xen/arch/x86/hvm/viridian.c > >>> index 486065182c..294cf486cc 100644 > >>> --- a/xen/arch/x86/hvm/viridian.c > >>> +++ b/xen/arch/x86/hvm/viridian.c > >>> @@ -645,6 +645,10 @@ int wrmsr_viridian_regs(uint32_t idx, uint64_t > val) > >>> if ( !ctl.u.CrashNotify ) > >>> break; > >>> > >>> + spin_lock(&d->shutdown_lock); > >>> + d->shutdown_code = SHUTDOWN_crash; > >>> + spin_unlock(&d->shutdown_lock); > >> How does the domain eventually shut down? > > I assume it shuts down when the guest writes to the PIIX. > > > >> It feels slightly odd to have > >> a shutdown code before the domain has finished executing code. > >> > > That's the norm. The PV drivers (if they are installed) set it via a > > schedop. > This just makes sure it is set even if the PV drivers aren't there. > > What happens if the user has configured windows to reboot after a crash? >
That's exactly what this is trying to fix. Without the patch a VM without PV drivers will appear to just shut down (because nothing will set the shutdown code to anything else) so the actions-after-crash will not take effect. Paul > ~Andrew _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
