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arm64: hyperv: Add panic handler 

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: Sunil Muthuswamy <sunilmut@microsoft.com>
Reviewed-by: Boqun Feng <boqun.feng@gmail.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Link: https://lore.kernel.org/r/1628092359-61351-3-git-send-email-mikelley@microsoft.com
Signed-off-by: Wei Liu <wei.liu@kernel.org>
This commit is contained in:
Michael Kelley 2021-08-04 08:52:36 -07:00 committed by Wei Liu
parent 57d276bbbd
commit 512c1117fb
1 changed files with 52 additions and 0 deletions
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52
arch/arm64/hyperv/hv_core.c
View File

@ -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);