diff options
| author | Will Deacon <will@kernel.org> | 2020-09-28 11:45:24 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-09-29 16:08:17 +0100 |
| commit | 9ef2b48be9bba70ded9372fc81e678e707306060 (patch) | |
| tree | 78ee8e1e33c1baf46d920331edfa1a7980316b78 /arch/arm64/kvm | |
| parent | 31c84d6c9cde673b3866972552ec52e4c522b4fa (diff) | |
| download | linux-9ef2b48be9bba70ded9372fc81e678e707306060.tar.bz2 | |
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>
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/arm.c | 34 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/Makefile | 3 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 2 |
3 files changed, 35 insertions, 4 deletions
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c index 9b90a701462c..13e559ac7235 100644 --- a/arch/arm64/kvm/arm.c +++ b/arch/arm64/kvm/arm.c @@ -1256,6 +1256,40 @@ long kvm_arch_vm_ioctl(struct file *filp, } } +static 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 vectors 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; +} + static void cpu_init_hyp_mode(void) { phys_addr_t pgd_ptr; diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile index 89d2bf73acb5..d898f0da5802 100644 --- a/arch/arm64/kvm/hyp/Makefile +++ b/arch/arm64/kvm/hyp/Makefile @@ -10,5 +10,4 @@ subdir-ccflags-y := -I$(incdir) \ -DDISABLE_BRANCH_PROFILING \ $(DISABLE_STACKLEAK_PLUGIN) -obj-$(CONFIG_KVM) += vhe/ nvhe/ -obj-$(CONFIG_RANDOMIZE_BASE) += smccc_wa.o +obj-$(CONFIG_KVM) += vhe/ nvhe/ smccc_wa.o diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index 3cca756e9e41..7ea277b82967 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -259,7 +259,6 @@ SYM_CODE_START(__kvm_hyp_vector) valid_vect el1_error // Error 32-bit EL1 SYM_CODE_END(__kvm_hyp_vector) -#ifdef CONFIG_RANDOMIZE_BASE .macro hyp_ventry .align 7 1: esb @@ -309,4 +308,3 @@ SYM_CODE_START(__bp_harden_hyp_vecs) 1: .org __bp_harden_hyp_vecs + __BP_HARDEN_HYP_VECS_SZ .org 1b SYM_CODE_END(__bp_harden_hyp_vecs) -#endif |