From: "Andrea Parri (Microsoft)" parri.andrea@gmail.com
[ Upstream commit 9f8b577f7b43b2170628d6c537252785dcc2dcea ]
hv_panic_page might contain guest-sensitive information, do not dump it over to Hyper-V by default in isolated guests.
While at it, update some comments in hyperv_{panic,die}_event().
Reported-by: Dexuan Cui decui@microsoft.com Signed-off-by: Andrea Parri (Microsoft) parri.andrea@gmail.com Reviewed-by: Dexuan Cui decui@microsoft.com Link: https://lore.kernel.org/r/20220301141135.2232-1-parri.andrea@gmail.com Signed-off-by: Wei Liu wei.liu@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/hv/vmbus_drv.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c index 44bd0b6ff505..75e0a0994619 100644 --- a/drivers/hv/vmbus_drv.c +++ b/drivers/hv/vmbus_drv.c @@ -76,8 +76,8 @@ static int hyperv_panic_event(struct notifier_block *nb, unsigned long val,
/* * Hyper-V should be notified only once about a panic. If we will be - * doing hyperv_report_panic_msg() later with kmsg data, don't do - * the notification here. + * doing hv_kmsg_dump() with kmsg data later, don't do the notification + * here. */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE && hyperv_report_reg()) { @@ -99,8 +99,8 @@ static int hyperv_die_event(struct notifier_block *nb, unsigned long val,
/* * Hyper-V should be notified only once about a panic. If we will be - * doing hyperv_report_panic_msg() later with kmsg data, don't do - * the notification here. + * doing hv_kmsg_dump() with kmsg data later, don't do the notification + * here. */ if (hyperv_report_reg()) hyperv_report_panic(regs, val, true); @@ -1545,14 +1545,20 @@ static int vmbus_bus_init(void) if (ret) goto err_connect;
+ if (hv_is_isolation_supported()) + sysctl_record_panic_msg = 0; + /* * Only register if the crash MSRs are available */ if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) { u64 hyperv_crash_ctl; /* - * Sysctl registration is not fatal, since by default - * reporting is enabled. + * Panic message recording (sysctl_record_panic_msg) + * is enabled by default in non-isolated guests and + * disabled by default in isolated guests; the panic + * message recording won't be available in isolated + * guests should the following registration fail. */ hv_ctl_table_hdr = register_sysctl_table(hv_root_table); if (!hv_ctl_table_hdr)