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Diffstat (limited to 'tools/testing/selftests/kvm/lib/x86_64/ucall.c')
-rw-r--r--tools/testing/selftests/kvm/lib/x86_64/ucall.c59
1 files changed, 59 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/x86_64/ucall.c b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
new file mode 100644
index 000000000..e5f0f9e0d
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/x86_64/ucall.c
@@ -0,0 +1,59 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * ucall support. A ucall is a "hypercall to userspace".
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ */
+#include "kvm_util.h"
+
+#define UCALL_PIO_PORT ((uint16_t)0x1000)
+
+void ucall_init(struct kvm_vm *vm, void *arg)
+{
+}
+
+void ucall_uninit(struct kvm_vm *vm)
+{
+}
+
+void ucall(uint64_t cmd, int nargs, ...)
+{
+ struct ucall uc = {
+ .cmd = cmd,
+ };
+ va_list va;
+ int i;
+
+ nargs = min(nargs, UCALL_MAX_ARGS);
+
+ va_start(va, nargs);
+ for (i = 0; i < nargs; ++i)
+ uc.args[i] = va_arg(va, uint64_t);
+ va_end(va);
+
+ asm volatile("in %[port], %%al"
+ : : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "memory");
+}
+
+uint64_t get_ucall(struct kvm_vcpu *vcpu, struct ucall *uc)
+{
+ struct kvm_run *run = vcpu->run;
+ struct ucall ucall = {};
+
+ if (uc)
+ memset(uc, 0, sizeof(*uc));
+
+ if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
+ struct kvm_regs regs;
+
+ vcpu_regs_get(vcpu, &regs);
+ memcpy(&ucall, addr_gva2hva(vcpu->vm, (vm_vaddr_t)regs.rdi),
+ sizeof(ucall));
+
+ vcpu_run_complete_io(vcpu);
+ if (uc)
+ memcpy(uc, &ucall, sizeof(ucall));
+ }
+
+ return ucall.cmd;
+}