| Message ID | 1626793023-13830-3-git-send-email-mikelley@microsoft.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Enable Linux guests on Hyper-V on ARM64 | expand |
On Tue, Jul 20, 2021 at 07:57:00AM -0700, Michael Kelley wrote: > Add a function to inform Hyper-V about a guest panic. > > This code is built only when CONFIG_HYPERV is enabled. > > Signed-off-by: Michael Kelley <mikelley@microsoft.com> Reviewed-by: Boqun Feng <boqun.feng@gmail.com> Regards, Boqun > --- > arch/arm64/hyperv/hv_core.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c > index 4c5dc0f..b54c347 100644 > --- a/arch/arm64/hyperv/hv_core.c > +++ b/arch/arm64/hyperv/hv_core.c > @@ -127,3 +127,55 @@ u64 hv_get_vpreg(u32 msr) > return output.as64.low; > } > EXPORT_SYMBOL_GPL(hv_get_vpreg); > + > +/* > + * hyperv_report_panic - report a panic to Hyper-V. This function uses > + * the older version of the Hyper-V interface that admittedly doesn't > + * pass enough information to be useful beyond just recording the > + * occurrence of a panic. The parallel hv_kmsg_dump() uses the > + * new interface that allows reporting 4 Kbytes of data, which is much > + * more useful. Hyper-V on ARM64 always supports the newer interface, but > + * we retain support for the older version because the sysadmin is allowed > + * to disable the newer version via sysctl in case of information security > + * concerns about the more verbose version. > + */ > +void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) > +{ > + static bool panic_reported; > + u64 guest_id; > + > + /* Don't report a panic to Hyper-V if we're not going to panic */ > + if (in_die && !panic_on_oops) > + return; > + > + /* > + * We prefer to report panic on 'die' chain as we have proper > + * registers to report, but if we miss it (e.g. on BUG()) we need > + * to report it on 'panic'. > + * > + * Calling code in the 'die' and 'panic' paths ensures that only > + * one CPU is running this code, so no atomicity is needed. > + */ > + if (panic_reported) > + return; > + panic_reported = true; > + > + guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID); > + > + /* > + * Hyper-V provides the ability to store only 5 values. > + * Pick the passed in error value, the guest_id, the PC, > + * and the SP. > + */ > + hv_set_vpreg(HV_REGISTER_CRASH_P0, err); > + hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id); > + hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc); > + hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->sp); > + hv_set_vpreg(HV_REGISTER_CRASH_P4, 0); > + > + /* > + * Let Hyper-V know there is crash data available > + */ > + hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); > +} > +EXPORT_SYMBOL_GPL(hyperv_report_panic); > -- > 1.8.3.1 >
> Add a function to inform Hyper-V about a guest panic. > > This code is built only when CONFIG_HYPERV is enabled. > > Signed-off-by: Michael Kelley <mikelley@microsoft.com> > --- > arch/arm64/hyperv/hv_core.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 52 insertions(+) > > diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c > index 4c5dc0f..b54c347 100644 > --- a/arch/arm64/hyperv/hv_core.c > +++ b/arch/arm64/hyperv/hv_core.c > @@ -127,3 +127,55 @@ u64 hv_get_vpreg(u32 msr) > return output.as64.low; > } > EXPORT_SYMBOL_GPL(hv_get_vpreg); > + > +/* > + * hyperv_report_panic - report a panic to Hyper-V. This function uses > + * the older version of the Hyper-V interface that admittedly doesn't > + * pass enough information to be useful beyond just recording the > + * occurrence of a panic. The parallel hv_kmsg_dump() uses the > + * new interface that allows reporting 4 Kbytes of data, which is much > + * more useful. Hyper-V on ARM64 always supports the newer interface, but > + * we retain support for the older version because the sysadmin is allowed > + * to disable the newer version via sysctl in case of information security > + * concerns about the more verbose version. > + */ > +void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) > +{ > + static bool panic_reported; > + u64 guest_id; > + > + /* Don't report a panic to Hyper-V if we're not going to panic */ > + if (in_die && !panic_on_oops) > + return; > + > + /* > + * We prefer to report panic on 'die' chain as we have proper > + * registers to report, but if we miss it (e.g. on BUG()) we need > + * to report it on 'panic'. > + * > + * Calling code in the 'die' and 'panic' paths ensures that only > + * one CPU is running this code, so no atomicity is needed. > + */ > + if (panic_reported) > + return; > + panic_reported = true; > + > + guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID); > + > + /* > + * Hyper-V provides the ability to store only 5 values. > + * Pick the passed in error value, the guest_id, the PC, > + * and the SP. > + */ > + hv_set_vpreg(HV_REGISTER_CRASH_P0, err); > + hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id); > + hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc); > + hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->sp); > + hv_set_vpreg(HV_REGISTER_CRASH_P4, 0); > + > + /* > + * Let Hyper-V know there is crash data available > + */ > + hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); > +} > +EXPORT_SYMBOL_GPL(hyperv_report_panic); > -- > 1.8.3.1 Reviewed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
diff --git a/arch/arm64/hyperv/hv_core.c b/arch/arm64/hyperv/hv_core.c index 4c5dc0f..b54c347 100644 --- a/arch/arm64/hyperv/hv_core.c +++ b/arch/arm64/hyperv/hv_core.c @@ -127,3 +127,55 @@ u64 hv_get_vpreg(u32 msr) return output.as64.low; } EXPORT_SYMBOL_GPL(hv_get_vpreg); + +/* + * hyperv_report_panic - report a panic to Hyper-V. This function uses + * the older version of the Hyper-V interface that admittedly doesn't + * pass enough information to be useful beyond just recording the + * occurrence of a panic. The parallel hv_kmsg_dump() uses the + * new interface that allows reporting 4 Kbytes of data, which is much + * more useful. Hyper-V on ARM64 always supports the newer interface, but + * we retain support for the older version because the sysadmin is allowed + * to disable the newer version via sysctl in case of information security + * concerns about the more verbose version. + */ +void hyperv_report_panic(struct pt_regs *regs, long err, bool in_die) +{ + static bool panic_reported; + u64 guest_id; + + /* Don't report a panic to Hyper-V if we're not going to panic */ + if (in_die && !panic_on_oops) + return; + + /* + * We prefer to report panic on 'die' chain as we have proper + * registers to report, but if we miss it (e.g. on BUG()) we need + * to report it on 'panic'. + * + * Calling code in the 'die' and 'panic' paths ensures that only + * one CPU is running this code, so no atomicity is needed. + */ + if (panic_reported) + return; + panic_reported = true; + + guest_id = hv_get_vpreg(HV_REGISTER_GUEST_OSID); + + /* + * Hyper-V provides the ability to store only 5 values. + * Pick the passed in error value, the guest_id, the PC, + * and the SP. + */ + hv_set_vpreg(HV_REGISTER_CRASH_P0, err); + hv_set_vpreg(HV_REGISTER_CRASH_P1, guest_id); + hv_set_vpreg(HV_REGISTER_CRASH_P2, regs->pc); + hv_set_vpreg(HV_REGISTER_CRASH_P3, regs->sp); + hv_set_vpreg(HV_REGISTER_CRASH_P4, 0); + + /* + * Let Hyper-V know there is crash data available + */ + hv_set_vpreg(HV_REGISTER_CRASH_CTL, HV_CRASH_CTL_CRASH_NOTIFY); +} +EXPORT_SYMBOL_GPL(hyperv_report_panic);
Add a function to inform Hyper-V about a guest panic. This code is built only when CONFIG_HYPERV is enabled. Signed-off-by: Michael Kelley <mikelley@microsoft.com> --- arch/arm64/hyperv/hv_core.c | 52 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+)