diff --git a/docs/misc/xen-command-line.pandoc b/docs/misc/xen-command-line.pandoc index b8a09ce5c4..451d213c8c 100644 --- a/docs/misc/xen-command-line.pandoc +++ b/docs/misc/xen-command-line.pandoc @@ -1854,34 +1854,19 @@ Set the serial transmit buffer size. > Default: `diverse` -This parameter is provided to administrators to determine how the -hypervisors handle SErrors. - -In order to distinguish guest-generated SErrors from hypervisor-generated -SErrors we have to place SError checking code in every EL1 <-> EL2 paths. -That will cause overhead on entries and exits due to dsb/isb. However, not all -platforms need to categorize SErrors. For example, a host that is running with -trusted guests. The administrator can confirm that all guests that are running -on the host will not trigger such SErrors. In this case, the administrator can -use this parameter to skip categorizing SErrors and reduce the overhead of -dsb/isb. - -We provided the following 2 options to administrators to determine how the -hypervisors handle SErrors: +This parameter is provided to administrators to determine how the hypervisor +handles SErrors. * `diverse`: - The hypervisor will distinguish guest SErrors from hypervisor SErrors. - The guest generated SErrors will be forwarded to guests, the hypervisor - generated SErrors will cause the whole system to crash. - It requires: - 1. dsb/isb on all EL1 -> EL2 trap entries to categorize SErrors correctly. - 2. dsb/isb on EL2 -> EL1 return paths to prevent slipping hypervisor - SErrors to guests. + The hypervisor will distinguish guest SErrors from hypervisor SErrors: + - The guest generated SErrors will be forwarded to the currently running + guest. + - The hypervisor generated SErrors will cause the whole system to crash * `panic`: - The hypervisor will not distinguish guest SErrors from hypervisor SErrors. - All SErrors will crash the whole system. This option will avoid all overhead - of the dsb/isb pairs. + All SErrors will cause the whole system to crash. This option should only + be used if you trust all your guests and/or they don't have a gadget (e.g. + device) to generate SErrors in normal run. ### shim_mem (x86) > `= List of ( min: | max: | )`