KVM: arm64: Allow patching EL2 vectors even with KASLR is not enabled
Patching the EL2 exception vectors is integral to the Spectre-v2
workaround, where it can be necessary to execute CPU-specific sequences
to nobble the branch predictor before running the hypervisor text proper.
Remove the dependency on CONFIG_RANDOMIZE_BASE and allow the EL2 vectors
to be patched even when KASLR is not enabled.
Fixes: 7a132017e7a5 ("KVM: arm64: Replace CONFIG_KVM_INDIRECT_VECTORS with CONFIG_RANDOMIZE_BASE")
Reported-by: kernel test robot <lkp@intel.com>
Link: https://lore.kernel.org/r/202009221053.Jv1XsQUZ%lkp@intel.com
Signed-off-by: Will Deacon <will@kernel.org>
diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 36606ef..cff1ceb 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -9,6 +9,7 @@
#include <asm/page.h>
#include <asm/memory.h>
+#include <asm/mmu.h>
#include <asm/cpufeature.h>
/*
@@ -430,7 +431,6 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
return ret;
}
-#ifdef CONFIG_RANDOMIZE_BASE
/*
* EL2 vectors can be mapped and rerouted in a number of ways,
* depending on the kernel configuration and CPU present:
@@ -451,12 +451,9 @@ static inline int kvm_write_guest_lock(struct kvm *kvm, gpa_t gpa,
* VHE, as we don't have hypervisor-specific mappings. If the system
* is VHE and yet selects this capability, it will be ignored.
*/
-#include <asm/mmu.h>
-
extern void *__kvm_bp_vect_base;
extern int __kvm_harden_el2_vector_slot;
-/* This is called on both VHE and !VHE systems */
static inline void *kvm_get_hyp_vector(void)
{
struct bp_hardening_data *data = arm64_get_bp_hardening_data();
@@ -480,52 +477,6 @@ static inline void *kvm_get_hyp_vector(void)
return vect;
}
-/* This is only called on a !VHE system */
-static inline int kvm_map_vectors(void)
-{
- /*
- * SV2 = ARM64_SPECTRE_V2
- * HEL2 = ARM64_HARDEN_EL2_VECTORS
- *
- * !SV2 + !HEL2 -> use direct vectors
- * SV2 + !HEL2 -> use hardened vectors in place
- * !SV2 + HEL2 -> allocate one vector slot and use exec mapping
- * SV2 + HEL2 -> use hardened vertors and use exec mapping
- */
- if (cpus_have_const_cap(ARM64_SPECTRE_V2)) {
- __kvm_bp_vect_base = kvm_ksym_ref(__bp_harden_hyp_vecs);
- __kvm_bp_vect_base = kern_hyp_va(__kvm_bp_vect_base);
- }
-
- if (cpus_have_const_cap(ARM64_HARDEN_EL2_VECTORS)) {
- phys_addr_t vect_pa = __pa_symbol(__bp_harden_hyp_vecs);
- unsigned long size = __BP_HARDEN_HYP_VECS_SZ;
-
- /*
- * Always allocate a spare vector slot, as we don't
- * know yet which CPUs have a BP hardening slot that
- * we can reuse.
- */
- __kvm_harden_el2_vector_slot = atomic_inc_return(&arm64_el2_vector_last_slot);
- BUG_ON(__kvm_harden_el2_vector_slot >= BP_HARDEN_EL2_SLOTS);
- return create_hyp_exec_mappings(vect_pa, size,
- &__kvm_bp_vect_base);
- }
-
- return 0;
-}
-#else
-static inline void *kvm_get_hyp_vector(void)
-{
- return kern_hyp_va(kvm_ksym_ref(__kvm_hyp_vector));
-}
-
-static inline int kvm_map_vectors(void)
-{
- return 0;
-}
-#endif
-
#define kvm_phys_to_vttbr(addr) phys_to_ttbr(addr)
/*