Adapt entry.S and hyp-entry.S from arch/arm64/kvm/hyp so that guest hypervisors can save and restore GPRs, and provide exception handlers to regain control after the nested guest exits. Other system register save/restore will be added later on demand.
Signed-off-by: Wei-Lin Chang <[email protected]> --- tools/testing/selftests/kvm/Makefile.kvm | 3 + .../selftests/kvm/include/arm64/nested.h | 45 ++++++ tools/testing/selftests/kvm/lib/arm64/entry.S | 132 ++++++++++++++++++ .../selftests/kvm/lib/arm64/hyp-entry.S | 77 ++++++++++ .../testing/selftests/kvm/lib/arm64/nested.c | 12 ++ 5 files changed, 269 insertions(+) create mode 100644 tools/testing/selftests/kvm/include/arm64/nested.h create mode 100644 tools/testing/selftests/kvm/lib/arm64/entry.S create mode 100644 tools/testing/selftests/kvm/lib/arm64/hyp-entry.S create mode 100644 tools/testing/selftests/kvm/lib/arm64/nested.c diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm index 98da9fa4b8b7..3dc3e39f7025 100644 --- a/tools/testing/selftests/kvm/Makefile.kvm +++ b/tools/testing/selftests/kvm/Makefile.kvm @@ -30,10 +30,13 @@ LIBKVM_x86 += lib/x86/svm.c LIBKVM_x86 += lib/x86/ucall.c LIBKVM_x86 += lib/x86/vmx.c +LIBKVM_arm64 += lib/arm64/entry.S LIBKVM_arm64 += lib/arm64/gic.c LIBKVM_arm64 += lib/arm64/gic_v3.c LIBKVM_arm64 += lib/arm64/gic_v3_its.c LIBKVM_arm64 += lib/arm64/handlers.S +LIBKVM_arm64 += lib/arm64/hyp-entry.S +LIBKVM_arm64 += lib/arm64/nested.c LIBKVM_arm64 += lib/arm64/processor.c LIBKVM_arm64 += lib/arm64/spinlock.c LIBKVM_arm64 += lib/arm64/ucall.c diff --git a/tools/testing/selftests/kvm/include/arm64/nested.h b/tools/testing/selftests/kvm/include/arm64/nested.h new file mode 100644 index 000000000000..86d931facacb --- /dev/null +++ b/tools/testing/selftests/kvm/include/arm64/nested.h @@ -0,0 +1,45 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * ARM64 Nested virtualization defines + */ + +#ifndef SELFTEST_KVM_NESTED_H +#define SELFTEST_KVM_NESTED_H + +#define ARM_EXCEPTION_IRQ 0 +#define ARM_EXCEPTION_EL1_SERROR 1 +#define ARM_EXCEPTION_TRAP 2 +#define ARM_EXCEPTION_IL 3 +#define ARM_EXCEPTION_EL2_IRQ 4 +#define ARM_EXCEPTION_EL2_SERROR 5 +#define ARM_EXCEPTION_EL2_TRAP 6 + +#ifndef __ASSEMBLER__ + +#include <asm/ptrace.h> +#include "kvm_util.h" + +extern char hyp_vectors[]; + +struct cpu_context { + struct user_pt_regs regs; /* sp = sp_el0 */ +}; + +struct vcpu { + struct cpu_context context; +}; + +/* + * KVM has host_data and hyp_context, combine them because we're only doing + * hyp context. + */ +struct hyp_data { + struct cpu_context hyp_context; +}; + +u64 __guest_enter(struct vcpu *vcpu, struct cpu_context *hyp_context); +void __hyp_exception(u64 type); + +#endif /* !__ASSEMBLER__ */ + +#endif /* SELFTEST_KVM_NESTED_H */ diff --git a/tools/testing/selftests/kvm/lib/arm64/entry.S b/tools/testing/selftests/kvm/lib/arm64/entry.S new file mode 100644 index 000000000000..33bedf5e7fb2 --- /dev/null +++ b/tools/testing/selftests/kvm/lib/arm64/entry.S @@ -0,0 +1,132 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * adapted from arch/arm64/kvm/hyp/entry.S + */ + +/* + * Manually define these for now + */ +// offsetof(struct vcpu, context) +#define CPU_CONTEXT 0 +// offsetof(struct cpu_context, regs) +#define CPU_USER_PT_REGS 0 + +#define CPU_XREG_OFFSET(x) (CPU_USER_PT_REGS + 8*x) +#define CPU_LR_OFFSET CPU_XREG_OFFSET(30) +#define CPU_SP_EL0_OFFSET (CPU_LR_OFFSET + 8) + +.macro save_callee_saved_regs ctxt + str x18, [\ctxt, #CPU_XREG_OFFSET(18)] + stp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] + stp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] + stp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] + stp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] + stp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] + stp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] +.endm + +.macro restore_callee_saved_regs ctxt + ldr x18, [\ctxt, #CPU_XREG_OFFSET(18)] + ldp x19, x20, [\ctxt, #CPU_XREG_OFFSET(19)] + ldp x21, x22, [\ctxt, #CPU_XREG_OFFSET(21)] + ldp x23, x24, [\ctxt, #CPU_XREG_OFFSET(23)] + ldp x25, x26, [\ctxt, #CPU_XREG_OFFSET(25)] + ldp x27, x28, [\ctxt, #CPU_XREG_OFFSET(27)] + ldp x29, lr, [\ctxt, #CPU_XREG_OFFSET(29)] +.endm + +.macro save_sp_el0 ctxt, tmp + mrs \tmp, sp_el0 + str \tmp, [\ctxt, #CPU_SP_EL0_OFFSET] +.endm + +.macro restore_sp_el0 ctxt, tmp + ldr \tmp, [\ctxt, #CPU_SP_EL0_OFFSET] + msr sp_el0, \tmp +.endm + +/* + * u64 __guest_enter(struct vcpu *vcpu, struct cpu_context *hyp_context); + */ +.globl __guest_enter +__guest_enter: + // x0: vcpu + // x1: hyp context + + // Store vcpu and hyp context pointer on the stack + stp x0, x1, [sp, #-16]! + + // Store the hyp regs + save_callee_saved_regs x1 + + // Save hyp's sp_el0 + save_sp_el0 x1, x2 + + // x29 = vCPU user pt regs + add x29, x0, #CPU_CONTEXT + + // Restore the guest's sp_el0 + restore_sp_el0 x29, x0 + + // Restore guest regs x0-x17 + ldp x0, x1, [x29, #CPU_XREG_OFFSET(0)] + ldp x2, x3, [x29, #CPU_XREG_OFFSET(2)] + ldp x4, x5, [x29, #CPU_XREG_OFFSET(4)] + ldp x6, x7, [x29, #CPU_XREG_OFFSET(6)] + ldp x8, x9, [x29, #CPU_XREG_OFFSET(8)] + ldp x10, x11, [x29, #CPU_XREG_OFFSET(10)] + ldp x12, x13, [x29, #CPU_XREG_OFFSET(12)] + ldp x14, x15, [x29, #CPU_XREG_OFFSET(14)] + ldp x16, x17, [x29, #CPU_XREG_OFFSET(16)] + + // Restore guest regs x18-x29, lr + restore_callee_saved_regs x29 + + // Do not touch any register after this! + eret + +.globl __guest_exit +__guest_exit: + // x0: return code + // x1: vcpu + // x2-x29,lr: vcpu regs + // vcpu x0-x1 on the stack + + add x1, x1, #CPU_CONTEXT + + // Store the guest regs x2 and x3 + stp x2, x3, [x1, #CPU_XREG_OFFSET(2)] + + // Retrieve the guest regs x0-x1 from the stack + ldp x2, x3, [sp], #16 // x0, x1 + + // Store the guest regs x0-x1 and x4-x17 + stp x2, x3, [x1, #CPU_XREG_OFFSET(0)] + stp x4, x5, [x1, #CPU_XREG_OFFSET(4)] + stp x6, x7, [x1, #CPU_XREG_OFFSET(6)] + stp x8, x9, [x1, #CPU_XREG_OFFSET(8)] + stp x10, x11, [x1, #CPU_XREG_OFFSET(10)] + stp x12, x13, [x1, #CPU_XREG_OFFSET(12)] + stp x14, x15, [x1, #CPU_XREG_OFFSET(14)] + stp x16, x17, [x1, #CPU_XREG_OFFSET(16)] + + // Store the guest regs x18-x29, lr + save_callee_saved_regs x1 + + // Store the guest's sp_el0 + save_sp_el0 x1, x2 + + // At this point x0 and x1 on the stack is popped, so next is vCPU + // pointer, then hyp_context pointer + // *sp == vCPU, *(sp + 8) == hyp_context + // load x2 = hyp_context, x3 is just for ldp and popping sp + ldp x3, x2, [sp], #16 + + // Restore hyp's sp_el0 + restore_sp_el0 x2, x3 + + // Now restore the hyp regs + restore_callee_saved_regs x2 + + dsb sy // Synchronize against in-flight ld/st + ret diff --git a/tools/testing/selftests/kvm/lib/arm64/hyp-entry.S b/tools/testing/selftests/kvm/lib/arm64/hyp-entry.S new file mode 100644 index 000000000000..6341f6e05c90 --- /dev/null +++ b/tools/testing/selftests/kvm/lib/arm64/hyp-entry.S @@ -0,0 +1,77 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * adapted from arch/arm64/kvm/hyp/hyp-entry.S + */ + +#include "nested.h" + +// skip over x0, x1 saved on entry, must be used only before the stack is modified +.macro get_vcpu_ptr vcpu + ldr \vcpu, [sp, #16] +.endm + + .text + +el1_sync: // Guest trapped into EL2 + + get_vcpu_ptr x1 + mov x0, #ARM_EXCEPTION_TRAP + b __guest_exit + +el1_irq: +el1_fiq: + get_vcpu_ptr x1 + mov x0, #ARM_EXCEPTION_IRQ + b __guest_exit + +el1_error: + get_vcpu_ptr x1 + mov x0, #ARM_EXCEPTION_EL1_SERROR + b __guest_exit + +el2_sync: + mov x0, #ARM_EXCEPTION_EL2_TRAP + b __hyp_exception + +el2_irq: +el2_fiq: + mov x0, #ARM_EXCEPTION_EL2_IRQ + b __hyp_exception + +el2_error: + mov x0, #ARM_EXCEPTION_EL2_SERROR + b __hyp_exception + + + .ltorg + + .align 11 + +.globl hyp_vectors +hyp_vectors: + +.macro exception_vector target + .align 7 + stp x0, x1, [sp, #-16]! + b \target +.endm + + exception_vector el2_sync // Synchronous EL2t + exception_vector el2_irq // IRQ EL2t + exception_vector el2_fiq // FIQ EL2t + exception_vector el2_error // Error EL2t + + exception_vector el2_sync // Synchronous EL2h + exception_vector el2_irq // IRQ EL2h + exception_vector el2_fiq // FIQ EL2h + exception_vector el2_error // Error EL2h + + exception_vector el1_sync // Synchronous 64-bit EL1 + exception_vector el1_irq // IRQ 64-bit EL1 + exception_vector el1_fiq // FIQ 64-bit EL1 + exception_vector el1_error // Error 64-bit EL1 + + exception_vector el1_sync // Synchronous 32-bit EL1 + exception_vector el1_irq // IRQ 32-bit EL1 + exception_vector el1_fiq // FIQ 32-bit EL1 + exception_vector el1_error // Error 32-bit EL1 diff --git a/tools/testing/selftests/kvm/lib/arm64/nested.c b/tools/testing/selftests/kvm/lib/arm64/nested.c new file mode 100644 index 000000000000..06ddaab2436f --- /dev/null +++ b/tools/testing/selftests/kvm/lib/arm64/nested.c @@ -0,0 +1,12 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ARM64 Nested virtualization helpers + */ + +#include "nested.h" +#include "test_util.h" + +void __hyp_exception(u64 type) +{ + GUEST_FAIL("Unexpected hyp exception! type: %lx\n", type); +} -- 2.43.0
