libsel4vm: guest cpu requests to vcpus from pcpus #85
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Originally the guests were able to make requests for a specific physical core based on its id. These changes associate that requested id with a vcpu instead of a pcpu. Signed-off-by: Alex Pavey <[email protected]>
axel-h
reviewed
Nov 17, 2022
| @@ -50,15 +50,24 @@ int handle_psci(vm_vcpu_t *vcpu, seL4_Word fn_number, bool convention) | |||
| smc_set_return_value(®s, 0x00010000); /* version 1 */ | |||
| break; | |||
| case PSCI_CPU_ON: { | |||
| uintptr_t target_cpu = smc_get_arg(®s, 1); | |||
| uintptr_t requested_cpu = smc_get_arg(®s, 1); | |||
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so, my question holds - we get a (v)MPIDR here from the guest and not a linear (seL4 affinity) ID?
axel-h
reviewed
Apr 16, 2023
| if (target_vcpu && start_new_vcpu(target_vcpu, entry_point_address, context_id, target_cpu) == 0) { | ||
| vm_vcpu_t *target_vcpu = NULL; | ||
| if ((requested_cpu >= 0) && (requested_cpu < vcpu->vm->num_vcpus)) { | ||
| target_vcpu = vcpu->vm->vcpus[requested_cpu]; |
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This will not work, because requested_cpu is a MPID value now - because that is what a caller passed into the SMC according to the spec. So we need to do a lookup over all our vCPUs.
axel-h
reviewed
Apr 16, 2023
| /* Automatically assign vcpu to an unassigned physical cpu */ | ||
| if (target_vcpu->target_cpu == -1) { | ||
| int selected_cpu = vm_find_free_unassigned_cpu(vcpu->vm); | ||
| if ((selected_cpu >= 0) && start_new_vcpu(target_vcpu, entry_point_address, context_id, selected_cpu) == 0) { |
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Don't we have to set the MPIDR of the vCPU here also now, so this is in sync with what the caller requested? Can the caller actually starts arbitrary cored here - shouldn't we have prepared the vCPU list in advance, about what cores the caller can start, ie. what cores the VM has.
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Originally the guests were able to make requests for a specific physical core based on its id. These changes associate that requested id with a vcpu instead of a pcpu.
Signed-off-by: Alex Pavey [email protected]