diff options
Diffstat (limited to 'sys/x86/x86/mp_x86.c')
| -rw-r--r-- | sys/x86/x86/mp_x86.c | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/sys/x86/x86/mp_x86.c b/sys/x86/x86/mp_x86.c index 11b11471d736..1027c2c8972b 100644 --- a/sys/x86/x86/mp_x86.c +++ b/sys/x86/x86/mp_x86.c @@ -1594,6 +1594,24 @@ cpususpend_handler(void) mtx_assert(&smp_ipi_mtx, MA_NOTOWNED); cpu = PCPU_GET(cpuid); + +#ifdef XENHVM + /* + * Some Xen guest types (PVH) expose a very minimal set of ACPI tables, + * and for example have no support for SCI. That leads to the suspend + * stacks not being allocated, and hence when attempting to perform a + * Xen triggered suspension FreeBSD will hit a #PF. Avoid saving the + * CPU and FPU contexts if the stacks are not allocated, as the + * hypervisor will already take care of this. Note that we could even + * do this for Xen triggered suspensions on guests that have full ACPI + * support, but doing so would introduce extra complexity. + */ + if (susppcbs == NULL) { + KASSERT(vm_guest == VM_GUEST_XEN, ("Missing suspend stack")); + CPU_SET_ATOMIC(cpu, &suspended_cpus); + CPU_SET_ATOMIC(cpu, &resuming_cpus); + } else +#endif if (savectx(&susppcbs[cpu]->sp_pcb)) { #ifdef __amd64__ fpususpend(susppcbs[cpu]->sp_fpususpend); |