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ANDROID: KVM: arm64: Handle permission issue while loading pKVM module

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pKVM module loading is disabled by rejecting the HVCs. This is a problem
for kvm_call_hyp_nvhe(__pkvm_alloc_module_va). First a WARN will be
trigger, then the res.a1 being very much likely non 0 the error will
not be caught. The loading would then proceed (even though no EL2 code
will be actually loaded).

Fix this behaviour by catching when the HVC is blocked, so the user gets
a meaningful error returned and the driver is not half-loaded.

Bug: 254835242
Change-Id: Ieeca6eebb083d99f8d6b79ebbc486a7c9f7d334e
Signed-off-by: Vincent Donnefort <vdonnefort@google.com>
This commit is contained in:
Vincent Donnefort
2023-04-06 10:41:18 +01:00
committed by Treehugger Robot
parent 7d3bde28a6
commit c4c48a21c0
1 changed files with 6 additions and 3 deletions
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9
arch/arm64/kvm/pkvm.c
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@@ -773,6 +773,7 @@ int __pkvm_load_el2_module(struct module *this, unsigned long *token)
{ &mod->data, KVM_PGTABLE_PROT_R | KVM_PGTABLE_PROT_W },
};
void *start, *end, *hyp_va;
struct arm_smccc_res res;
kvm_nvhe_reloc_t *endrel;
int ret, i, secs_first;
size_t offset, size;
@@ -802,12 +803,14 @@ int __pkvm_load_el2_module(struct module *this, unsigned long *token)
end = secs_map[ARRAY_SIZE(secs_map) - 1].sec->end;
size = end - start;
hyp_va = (void *)kvm_call_hyp_nvhe(__pkvm_alloc_module_va, size >> PAGE_SHIFT);
if (!hyp_va) {
arm_smccc_1_1_hvc(KVM_HOST_SMCCC_FUNC(__pkvm_alloc_module_va),
size >> PAGE_SHIFT, &res);
if (res.a0 != SMCCC_RET_SUCCESS || !res.a1) {
kvm_err("Failed to allocate hypervisor VA space for EL2 module\n");
module_put(this);
return -ENOMEM;
return res.a0 == SMCCC_RET_SUCCESS ? -ENOMEM : -EPERM;
}
hyp_va = (void *)res.a1;
/*
* The token can be used for other calls related to this module.