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// 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, ®s);
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;
}
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