diff options
| -rw-r--r-- | arch/arm64/include/asm/kvm_asm.h | 6 | ||||
| -rw-r--r-- | arch/arm64/kvm/hyp/hyp-entry.S | 18 | ||||
| -rw-r--r-- | arch/arm64/kvm/va_layout.c | 7 |
3 files changed, 26 insertions, 5 deletions
diff --git a/arch/arm64/include/asm/kvm_asm.h b/arch/arm64/include/asm/kvm_asm.h index 2ca437ef59fa..388e1b520618 100644 --- a/arch/arm64/include/asm/kvm_asm.h +++ b/arch/arm64/include/asm/kvm_asm.h @@ -30,6 +30,12 @@ {ARM_EXCEPTION_TRAP, "TRAP" }, \ {ARM_EXCEPTION_HYP_GONE, "HYP_GONE" } +/* + * Size of the HYP vectors preamble. kvm_patch_vector_branch() generates code + * that jumps over this. + */ +#define KVM_VECTOR_PREAMBLE (1 * AARCH64_INSN_SIZE) + #ifndef __ASSEMBLY__ #include <linux/mm.h> diff --git a/arch/arm64/kvm/hyp/hyp-entry.S b/arch/arm64/kvm/hyp/hyp-entry.S index b8e045615961..318a2f3996fc 100644 --- a/arch/arm64/kvm/hyp/hyp-entry.S +++ b/arch/arm64/kvm/hyp/hyp-entry.S @@ -216,17 +216,32 @@ ENDPROC(\label) .align 11 +.macro check_preamble_length start, end +/* kvm_patch_vector_branch() generates code that jumps over the preamble. */ +.if ((\end-\start) != KVM_VECTOR_PREAMBLE) + .error "KVM vector preamble length mismatch" +.endif +.endm + .macro valid_vect target .align 7 +661: stp x0, x1, [sp, #-16]! +662: b \target + +check_preamble_length 661b, 662b .endm .macro invalid_vect target .align 7 +661: b \target +662: ldp x0, x1, [sp], #16 b \target + +check_preamble_length 661b, 662b .endm ENTRY(__kvm_hyp_vector) @@ -271,7 +286,8 @@ ENDPROC(__kvm_hyp_vector) * movk x0, #((addr >> 32) & 0xffff), lsl #32 * br x0 * - * Where addr = kern_hyp_va(__kvm_hyp_vector) + vector-offset + 4. + * Where: + * addr = kern_hyp_va(__kvm_hyp_vector) + vector-offset + KVM_VECTOR_PREAMBLE. * See kvm_patch_vector_branch for details. */ alternative_cb kvm_patch_vector_branch diff --git a/arch/arm64/kvm/va_layout.c b/arch/arm64/kvm/va_layout.c index 2947ab1b0fa5..acd8084f1f2c 100644 --- a/arch/arm64/kvm/va_layout.c +++ b/arch/arm64/kvm/va_layout.c @@ -170,11 +170,10 @@ void kvm_patch_vector_branch(struct alt_instr *alt, addr |= ((u64)origptr & GENMASK_ULL(10, 7)); /* - * Branch to the second instruction in the vectors in order to - * avoid the initial store on the stack (which we already - * perform in the hardening vectors). + * Branch over the preamble in order to avoid the initial store on + * the stack (which we already perform in the hardening vectors). */ - addr += AARCH64_INSN_SIZE; + addr += KVM_VECTOR_PREAMBLE; /* stp x0, x1, [sp, #-16]! */ insn = aarch64_insn_gen_load_store_pair(AARCH64_INSN_REG_0, |