Commit 9f8b577f authored by Andrea Parri (Microsoft)'s avatar Andrea Parri (Microsoft) Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Deactivate sysctl_record_panic_msg by default in isolated guests 



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: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarAndrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: default avatarDexuan Cui <decui@microsoft.com>
Link: https://lore.kernel.org/r/20220301141135.2232-1-parri.andrea@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent f443e374

drivers/hv/vmbus_drv.c

+12 −6
Original line number Diff line number Diff line
@@ -77,8 +77,8 @@ 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()) {
@@ -100,8 +100,8 @@ 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);
@@ -1546,14 +1546,20 @@ 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)