> -----Original Message----- > From: Vitaly Kuznetsov [mailto:vkuznets@xxxxxxxxxx] > Sent: Thursday, October 12, 2017 6:40 AM > To: kys@xxxxxxxxxxxxxxxxxxxxxx > Cc: gregkh@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; > devel@xxxxxxxxxxxxxxxxxxxxxx; olaf@xxxxxxxxx; apw@xxxxxxxxxxxxx; > jasowang@xxxxxxxxxx; leann.ogasawara@xxxxxxxxxxxxx; > marcelo.cerri@xxxxxxxxxxxxx; Stephen Hemminger > <sthemmin@xxxxxxxxxxxxx>; KY Srinivasan <kys@xxxxxxxxxxxxx> > Subject: Re: [PATCH 3/3] Drivers: hv: vmbus: Make pannic reporting to be > more useful > > kys@xxxxxxxxxxxxxxxxxxxxxx writes: > > > From: "K. Y. Srinivasan" <kys@xxxxxxxxxxxxx> > > > > Hyper-V allows the guest to report panic and the guest can pass additional > > information. All this is logged on the host. Currently Linux is passing back > > information that is not particularly useful. Make the following changes: > > > > 1. Windows uses crash MSR P0 to report bugcheck code. Follow the same > > convention for Linux as well. > > 2. It will be useful to know the gust ID of the Linux guest that has > > paniced. Pass back this information. > > > > These changes will help in better supporting Linux on Hyper-V > > > > Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> > > --- > > arch/x86/hyperv/hv_init.c | 11 +++++++---- > > arch/x86/include/asm/mshyperv.h | 2 +- > > drivers/hv/vmbus_drv.c | 4 ++-- > > 3 files changed, 10 insertions(+), 7 deletions(-) > > > > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > > index 1a8eb550c40f..cc30a094fb7c 100644 > > --- a/arch/x86/hyperv/hv_init.c > > +++ b/arch/x86/hyperv/hv_init.c > > @@ -205,9 +205,10 @@ void hyperv_cleanup(void) > > } > > EXPORT_SYMBOL_GPL(hyperv_cleanup); > > > > -void hyperv_report_panic(struct pt_regs *regs) > > +void hyperv_report_panic(struct pt_regs *regs, long err) > > { > > static bool panic_reported; > > + u64 guest_id; > > > > /* > > * We prefer to report panic on 'die' chain as we have proper > > @@ -218,9 +219,11 @@ void hyperv_report_panic(struct pt_regs *regs) > > return; > > panic_reported = true; > > > > - wrmsrl(HV_X64_MSR_CRASH_P0, regs->ip); > > - wrmsrl(HV_X64_MSR_CRASH_P1, regs->ax); > > - wrmsrl(HV_X64_MSR_CRASH_P2, regs->bx); > > + rdmsrl(HV_X64_MSR_GUEST_OS_ID, guest_id); > > + > > + wrmsrl(HV_X64_MSR_CRASH_P0, err); > > + wrmsrl(HV_X64_MSR_CRASH_P1, guest_id); > > This is a constant we write in hyperv_init() (0x810000040e000000 for > Linux guests). Do I get it right that we need this to basically > distinguigh Windows guests crashes from Linux guest crashes in the log? Yes; we have a huge infrastructure for analyzing the event logs on Azure hosts and guest panics are logged into this pipeline. Unfortunately, there is not a simple way to distinguish between Windows and Linux in this information stream. > > > + wrmsrl(HV_X64_MSR_CRASH_P2, regs->ip); > > wrmsrl(HV_X64_MSR_CRASH_P3, regs->cx); > > wrmsrl(HV_X64_MSR_CRASH_P4, regs->dx); > > We don't write ax and bx any more but write cx and dx. Not that I see > these regs really useful in the log but I'd change these to ax and bx > for consistency. Or mayme make it sp and ax? I will make it sp and ax. Thanks, K. Y > > > > > diff --git a/arch/x86/include/asm/mshyperv.h > b/arch/x86/include/asm/mshyperv.h > > index 63cc96f064dc..dd2dc54ddf20 100644 > > --- a/arch/x86/include/asm/mshyperv.h > > +++ b/arch/x86/include/asm/mshyperv.h > > @@ -311,7 +311,7 @@ static inline int hv_cpu_number_to_vp_number(int > cpu_number) > > void hyperv_init(void); > > void hyperv_setup_mmu_ops(void); > > void hyper_alloc_mmu(void); > > -void hyperv_report_panic(struct pt_regs *regs); > > +void hyperv_report_panic(struct pt_regs *regs, long err); > > bool hv_is_hypercall_page_setup(void); > > void hyperv_cleanup(void); > > #else /* CONFIG_HYPERV */ > > diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c > > index e8cd19095212..852f6c628836 100644 > > --- a/drivers/hv/vmbus_drv.c > > +++ b/drivers/hv/vmbus_drv.c > > @@ -65,7 +65,7 @@ static int hyperv_panic_event(struct notifier_block > *nb, unsigned long val, > > > > regs = current_pt_regs(); > > > > - hyperv_report_panic(regs); > > + hyperv_report_panic(regs, val); > > return NOTIFY_DONE; > > } > > > > @@ -75,7 +75,7 @@ static int hyperv_die_event(struct notifier_block *nb, > unsigned long val, > > struct die_args *die = (struct die_args *)args; > > struct pt_regs *regs = die->regs; > > > > - hyperv_report_panic(regs); > > + hyperv_report_panic(regs, val); > > return NOTIFY_DONE; > > } > > -- > Vitaly _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
