KVM: selftests: Add arch ucall.h and inline simple arch hooks

Add an architecture specific ucall.h and inline the simple arch hooks,
e.g. the init hook for everything except ARM, and the actual "do ucall"
hook for everything except x86 (which should be simple, but temporarily
isn't due to carrying a workaround).

Having a per-arch ucall header will allow adding a #define for the
expected KVM exit reason for a ucall that is colocated (for everything
except x86) with the ucall itself.

Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
Link: https://lore.kernel.org/r/20230731203026.1192091-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

5 files changed, 65 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/include/aarch64/ucall.h b/tools/testing/selftests/kvm/include/aarch64/ucall.h
new file mode 100644
index 000000000000..fe65fdf4f0d3
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/aarch64/ucall.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_KVM_UCALL_H
+#define SELFTEST_KVM_UCALL_H
+
+#include "kvm_util_base.h"
+
+/*
+ * ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
+ * VM), it must not be accessed from host code.
+ */
+extern vm_vaddr_t *ucall_exit_mmio_addr;
+
+static inline void ucall_arch_do_ucall(vm_vaddr_t uc)
+{
+	WRITE_ONCE(*ucall_exit_mmio_addr, uc);
+}
+
+#endif
diff --git a/tools/testing/selftests/kvm/include/riscv/ucall.h b/tools/testing/selftests/kvm/include/riscv/ucall.h
new file mode 100644
index 000000000000..86ed0500972b
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/riscv/ucall.h
@@ -0,0 +1,18 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_KVM_UCALL_H
+#define SELFTEST_KVM_UCALL_H
+
+#include "processor.h"
+
+static inline void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
+{
+}
+
+static inline void ucall_arch_do_ucall(vm_vaddr_t uc)
+{
+	sbi_ecall(KVM_RISCV_SELFTESTS_SBI_EXT,
+		  KVM_RISCV_SELFTESTS_SBI_UCALL,
+		  uc, 0, 0, 0, 0, 0);
+}
+
+#endif
diff --git a/tools/testing/selftests/kvm/include/s390x/ucall.h b/tools/testing/selftests/kvm/include/s390x/ucall.h
new file mode 100644
index 000000000000..47ad4b1fbccb
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/s390x/ucall.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_KVM_UCALL_H
+#define SELFTEST_KVM_UCALL_H
+
+#include "kvm_util_base.h"
+
+static inline void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
+{
+}
+
+static inline void ucall_arch_do_ucall(vm_vaddr_t uc)
+{
+	/* Exit via DIAGNOSE 0x501 (normally used for breakpoints) */
+	asm volatile ("diag 0,%0,0x501" : : "a"(uc) : "memory");
+}
+
+#endif
diff --git a/tools/testing/selftests/kvm/include/ucall_common.h b/tools/testing/selftests/kvm/include/ucall_common.h
index 4ce11c15285a..9e5948dab030 100644
--- a/tools/testing/selftests/kvm/include/ucall_common.h
+++ b/tools/testing/selftests/kvm/include/ucall_common.h
@@ -7,6 +7,7 @@
 #ifndef SELFTEST_KVM_UCALL_COMMON_H
 #define SELFTEST_KVM_UCALL_COMMON_H
 #include "test_util.h"
+#include "ucall.h"
 
 /* Common ucalls */
 enum {
diff --git a/tools/testing/selftests/kvm/include/x86_64/ucall.h b/tools/testing/selftests/kvm/include/x86_64/ucall.h
new file mode 100644
index 000000000000..05cc69b0d550
--- /dev/null
+++ b/tools/testing/selftests/kvm/include/x86_64/ucall.h
@@ -0,0 +1,11 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+#ifndef SELFTEST_KVM_UCALL_H
+#define SELFTEST_KVM_UCALL_H
+
+#include "kvm_util_base.h"
+
+static inline void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
+{
+}
+
+#endif