This patch adds the required changes to init vcpu in vEL2 context.
Also adds a KVM selftest to execute guest code as a guest hypervisor(L1).
Signed-off-by: Ganapatrao Kulkarni <gankulkarni@xxxxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/kvm/Makefile.kvm | 1 +
.../selftests/kvm/arm64/nv_guest_hypervisor.c | 83 +++++++++++++++++++
.../kvm/include/arm64/kvm_util_arch.h | 3 +
.../selftests/kvm/include/arm64/nv_util.h | 28 +++++++
.../testing/selftests/kvm/include/kvm_util.h | 1 +
.../selftests/kvm/lib/arm64/processor.c | 59 +++++++++----
6 files changed, 161 insertions(+), 14 deletions(-)
create mode 100644 tools/testing/selftests/kvm/arm64/nv_guest_hypervisor.c
create mode 100644 tools/testing/selftests/kvm/include/arm64/nv_util.h
diff --git a/tools/testing/selftests/kvm/Makefile.kvm b/tools/testing/selftests/kvm/Makefile.kvm
index 4277b983cace..a85d3bec9fb1 100644
--- a/tools/testing/selftests/kvm/Makefile.kvm
+++ b/tools/testing/selftests/kvm/Makefile.kvm
@@ -154,6 +154,7 @@ TEST_GEN_PROGS_arm64 += arm64/vgic_irq
TEST_GEN_PROGS_arm64 += arm64/vgic_lpi_stress
TEST_GEN_PROGS_arm64 += arm64/vpmu_counter_access
TEST_GEN_PROGS_arm64 += arm64/no-vgic-v3
+TEST_GEN_PROGS_arm64 += arm64/nv_guest_hypervisor
TEST_GEN_PROGS_arm64 += access_tracking_perf_test
TEST_GEN_PROGS_arm64 += arch_timer
TEST_GEN_PROGS_arm64 += coalesced_io_test
diff --git a/tools/testing/selftests/kvm/arm64/nv_guest_hypervisor.c b/tools/testing/selftests/kvm/arm64/nv_guest_hypervisor.c
new file mode 100644
index 000000000000..5aeefe43aff7
--- /dev/null
+++ b/tools/testing/selftests/kvm/arm64/nv_guest_hypervisor.c
@@ -0,0 +1,83 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2025 Ampere Computing LLC
+ */
+#include <kvm_util.h>
+#include <nv_util.h>
+#include <processor.h>
+#include <vgic.h>
+
+static void guest_code(void)
+{
+ if (read_sysreg(CurrentEL) == CurrentEL_EL2)
+ GUEST_PRINTF("Executing guest code in vEL2\n");
+ else
+ GUEST_FAIL("Fail to run in vEL2\n");
+
+ GUEST_DONE();
+}
+
+static void guest_undef_handler(struct ex_regs *regs)
+{
+ GUEST_FAIL("Unexpected exception far_el1 = 0x%lx", read_sysreg(far_el1));
+}
+
+static void test_run_vcpu(struct kvm_vcpu *vcpu)
+{
+ struct ucall uc;
+
+ do {
+ vcpu_run(vcpu);
+
+ switch (get_ucall(vcpu, &uc)) {
+ case UCALL_ABORT:
+ REPORT_GUEST_ASSERT(uc);
+ break;
+ case UCALL_PRINTF:
+ printf("%s", uc.buffer);
+ break;
+ case UCALL_DONE:
+ printf("Test PASS\n");
+ break;
+ default:
+ TEST_FAIL("Unknown ucall %lu", uc.cmd);
+ }
+ } while (uc.cmd != UCALL_DONE);
+}
+
+static void test_nv_guest_hypervisor(void)
+{
+ struct kvm_vcpu *vcpu;
+ struct kvm_vm *vm;
+ struct kvm_vcpu_init init;
+ int gic_fd;
+
+ vm = vm_create(1);
+ vm_ioctl(vm, KVM_ARM_PREFERRED_TARGET, &init);
+
+ init.features[0] = 0;
+ init_vcpu_nested(&init);
+ vcpu = aarch64_vcpu_add(vm, 0, &init, guest_code);
+
+ __TEST_REQUIRE(is_vcpu_nested(vcpu), "Failed to Enable NV");
+
+ vm_init_descriptor_tables(vm);
+ vcpu_init_descriptor_tables(vcpu);
+ gic_fd = vgic_v3_setup(vm, 1, 64);
+ __TEST_REQUIRE(gic_fd >= 0, "Failed to create vgic-v3");
+
+ vm_install_sync_handler(vm, VECTOR_SYNC_CURRENT,
+ ESR_ELx_EC_UNKNOWN, guest_undef_handler);
+
+ test_run_vcpu(vcpu);
+ kvm_vm_free(vm);
+}
+
+int main(int argc, char *argv[])
+{
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_ARM_EL2));
+
+ test_nv_guest_hypervisor();
+
+ return 0;
+}
diff --git a/tools/testing/selftests/kvm/include/arm64/kvm_util_arch.h b/tools/testing/selftests/kvm/include/arm64/kvm_util_arch.h
index e43a57d99b56..ab5279c24413 100644
--- a/tools/testing/selftests/kvm/include/arm64/kvm_util_arch.h
+++ b/tools/testing/selftests/kvm/include/arm64/kvm_util_arch.h
@@ -2,6 +2,9 @@
#ifndef SELFTEST_KVM_UTIL_ARCH_H
#define SELFTEST_KVM_UTIL_ARCH_H
+#define CurrentEL_EL1 (1 << 2)
+#define CurrentEL_EL2 (2 << 2)
+
struct kvm_vm_arch {};
#endif // SELFTEST_KVM_UTIL_ARCH_H
diff --git a/tools/testing/selftests/kvm/include/arm64/nv_util.h b/tools/testing/selftests/kvm/include/arm64/nv_util.h
new file mode 100644
index 000000000000..4fecf1f18554
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/arm64/nv_util.h
@@ -0,0 +1,28 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Copyright (c) 2025 Ampere Computing
+ */
+#ifndef SELFTEST_NV_UTIL_H
+#define SELFTEST_NV_UTIL_H
+
+#include <linux/bitmap.h>
+
+/* NV helpers */
+static inline void init_vcpu_nested(struct kvm_vcpu_init *init)
+{
+ init->features[0] |= (1 << KVM_ARM_VCPU_HAS_EL2);
+}
+
+static inline bool kvm_arm_vcpu_has_el2(struct kvm_vcpu_init *init)
+{
+ unsigned long features = init->features[0];
+
+ return test_bit(KVM_ARM_VCPU_HAS_EL2, &features);
+}
+
+static inline bool is_vcpu_nested(struct kvm_vcpu *vcpu)
+{
+ return vcpu->nested;
+}
+
+#endif /* SELFTEST_NV_UTIL_H */
diff --git a/tools/testing/selftests/kvm/include/kvm_util.h b/tools/testing/selftests/kvm/include/kvm_util.h
index 4c4e5a847f67..8c53dbc17f8f 100644
--- a/tools/testing/selftests/kvm/include/kvm_util.h
+++ b/tools/testing/selftests/kvm/include/kvm_util.h
@@ -58,6 +58,7 @@ struct kvm_vcpu {
struct kvm_dirty_gfn *dirty_gfns;
uint32_t fetch_index;
uint32_t dirty_gfns_count;
+ bool nested;
};
struct userspace_mem_regions {
diff --git a/tools/testing/selftests/kvm/lib/arm64/processor.c b/tools/testing/selftests/kvm/lib/arm64/processor.c
index 7ba3aa3755f3..35ba2ace61a2 100644
--- a/tools/testing/selftests/kvm/lib/arm64/processor.c
+++ b/tools/testing/selftests/kvm/lib/arm64/processor.c
@@ -10,6 +10,7 @@
#include "guest_modes.h"
#include "kvm_util.h"
+#include "nv_util.h"
#include "processor.h"
#include "ucall_common.h"
@@ -258,14 +259,47 @@ void virt_arch_dump(FILE *stream, struct kvm_vm *vm, uint8_t indent)
}
}
+static void aarch64_vcpu_set_reg(struct kvm_vcpu *vcpu, uint64_t sctlr_el1,
+ uint64_t tcr_el1, uint64_t ttbr0_el1)
+{
+ uint64_t fpen;
+
+ /*
+ * Enable FP/ASIMD to avoid trapping when accessing Q0-Q15
+ * registers, which the variable argument list macros do.
+ */
+ fpen = 3 << 20;
+
+ if (is_vcpu_nested(vcpu)) {
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_CPTR_EL2), fpen);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_SCTLR_EL2), sctlr_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TCR_EL2), tcr_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_MAIR_EL2), DEFAULT_MAIR_EL1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TTBR0_EL2), ttbr0_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TPIDR_EL2), vcpu->id);
+ } else {
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_CPACR_EL1), fpen);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_SCTLR_EL1), sctlr_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TCR_EL1), tcr_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_MAIR_EL1), DEFAULT_MAIR_EL1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TTBR0_EL1), ttbr0_el1);
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TPIDR_EL1), vcpu->id);
+}
+}
+
void aarch64_vcpu_setup(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init)
{
struct kvm_vcpu_init default_init = { .target = -1, };
struct kvm_vm *vm = vcpu->vm;
uint64_t sctlr_el1, tcr_el1, ttbr0_el1;
- if (!init)
+ if (!init) {
init = &default_init;
+ } else {
+ /* Is this vcpu a Guest-Hypersior */
+ if (kvm_arm_vcpu_has_el2(init))
+ vcpu->nested = true;
+ }
if (init->target == -1) {
struct kvm_vcpu_init preferred;
@@ -275,12 +309,6 @@ void aarch64_vcpu_setup(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init)
vcpu_ioctl(vcpu, KVM_ARM_VCPU_INIT, init);
- /*
- * Enable FP/ASIMD to avoid trapping when accessing Q0-Q15
- * registers, which the variable argument list macros do.
- */
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_CPACR_EL1), 3 << 20);
-
sctlr_el1 = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_SCTLR_EL1));
tcr_el1 = vcpu_get_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TCR_EL1));
@@ -349,11 +377,7 @@ void aarch64_vcpu_setup(struct kvm_vcpu *vcpu, struct kvm_vcpu_init *init)
if (use_lpa2_pte_format(vm))
tcr_el1 |= (1ul << 59) /* DS */;
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_SCTLR_EL1), sctlr_el1);
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TCR_EL1), tcr_el1);
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_MAIR_EL1), DEFAULT_MAIR_EL1);
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TTBR0_EL1), ttbr0_el1);
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_TPIDR_EL1), vcpu->id);
+ aarch64_vcpu_set_reg(vcpu, sctlr_el1, tcr_el1, ttbr0_el1);
}
void vcpu_arch_dump(FILE *stream, struct kvm_vcpu *vcpu, uint8_t indent)
@@ -387,7 +411,11 @@ static struct kvm_vcpu *__aarch64_vcpu_add(struct kvm_vm *vm, uint32_t vcpu_id,
aarch64_vcpu_setup(vcpu, init);
- vcpu_set_reg(vcpu, ARM64_CORE_REG(sp_el1), stack_vaddr + stack_size);
+ if (is_vcpu_nested(vcpu))
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_SP_EL2), stack_vaddr + stack_size);
+ else
+ vcpu_set_reg(vcpu, ARM64_CORE_REG(sp_el1), stack_vaddr + stack_size);
+
return vcpu;
}
@@ -457,7 +485,10 @@ void vcpu_init_descriptor_tables(struct kvm_vcpu *vcpu)
{
extern char vectors;
- vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_VBAR_EL1), (uint64_t)&vectors);
+ if (is_vcpu_nested(vcpu))
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_VBAR_EL2), (uint64_t)&vectors);
+ else
+ vcpu_set_reg(vcpu, KVM_ARM64_SYS_REG(SYS_VBAR_EL1), (uint64_t)&vectors);
}
void route_exception(struct ex_regs *regs, int vector)
--
2.48.1
