In order to restore HYP mode to its original condition, KVM currently implements __kvm_hyp_reset(). As we're moving towards a hyp-stub defined API, it becomes necessary to implement HVC_RESET_VECTORS. This patch adds the HVC_RESET_VECTORS hypercall to the KVM init code, which so far lacked any form of hypercall support. Signed-off-by: Marc Zyngier <marc.zyngier@xxxxxxx> --- arch/arm/include/asm/virt.h | 1 + arch/arm/kernel/hyp-stub.S | 2 +- arch/arm/kvm/init.S | 33 +++++++++++++++++++++++++++------ 3 files changed, 29 insertions(+), 7 deletions(-) diff --git a/arch/arm/include/asm/virt.h b/arch/arm/include/asm/virt.h index 5186718aab68..8d5625b790b5 100644 --- a/arch/arm/include/asm/virt.h +++ b/arch/arm/include/asm/virt.h @@ -54,6 +54,7 @@ static inline void sync_boot_mode(void) void __hyp_set_vectors(unsigned long phys_vector_base); unsigned long __hyp_get_vectors(void); +void __hyp_reset_vectors(void); #else #define __boot_cpu_mode (SVC_MODE) #define sync_boot_mode() diff --git a/arch/arm/kernel/hyp-stub.S b/arch/arm/kernel/hyp-stub.S index 21794d4a8f36..3cb01e8a291d 100644 --- a/arch/arm/kernel/hyp-stub.S +++ b/arch/arm/kernel/hyp-stub.S @@ -280,7 +280,7 @@ ENDPROC(__hyp_reset_vectors) #endif .align 5 -__hyp_stub_vectors: +ENTRY(__hyp_stub_vectors) __hyp_stub_reset: W(b) . __hyp_stub_und: W(b) . __hyp_stub_svc: W(b) . diff --git a/arch/arm/kvm/init.S b/arch/arm/kvm/init.S index bf89c919efc1..9b0c735a68f7 100644 --- a/arch/arm/kvm/init.S +++ b/arch/arm/kvm/init.S @@ -23,6 +23,7 @@ #include <asm/kvm_asm.h> #include <asm/kvm_arm.h> #include <asm/kvm_mmu.h> +#include <asm/virt.h> /******************************************************************** * Hypervisor initialization @@ -39,6 +40,10 @@ * - Setup the page tables * - Enable the MMU * - Profit! (or eret, if you only care about the code). + * + * Another possibility is to get a HYP stub hypercall. + * We discriminate between the two by checking if r0 contains a value + * that is less than HVC_STUB_HCALL_NR. */ .text @@ -58,6 +63,10 @@ __kvm_hyp_init: W(b) . __do_hyp_init: + @ Check for a stub hypercall + cmp r0, #HVC_STUB_HCALL_NR + blo __kvm_handle_stub_hvc + @ Set stack pointer mov sp, r0 @@ -112,19 +121,31 @@ __do_hyp_init: eret - @ r0 : stub vectors address +ENTRY(__kvm_handle_stub_hvc) + cmp r0, #HVC_RESET_VECTORS + bne 1f ENTRY(__kvm_hyp_reset) /* We're now in idmap, disable MMU */ mrc p15, 4, r1, c1, c0, 0 @ HSCTLR - ldr r2, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I) - bic r1, r1, r2 + ldr r0, =(HSCTLR_M | HSCTLR_A | HSCTLR_C | HSCTLR_I) + bic r1, r1, r0 mcr p15, 4, r1, c1, c0, 0 @ HSCTLR - /* Install stub vectors */ - mcr p15, 4, r0, c12, c0, 0 @ HVBAR - isb + /* + * Install stub vectors, using ardb's VA->PA trick. + */ +0: adr r0, 0b @ PA(0) + movw r1, #:lower16:__hyp_stub_vectors - 0b @ VA(stub) - VA(0) + movt r1, #:upper16:__hyp_stub_vectors - 0b + add r1, r1, r0 @ PA(stub) + mcr p15, 4, r1, c12, c0, 0 @ HVBAR + b exit + +1: mov r0, #-1 +exit: eret +ENDPROC(__kvm_handle_stub_hvc) ENDPROC(__kvm_hyp_reset) .ltorg -- 2.11.0
