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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"
/*
* ucall_exit_mmio_addr holds per-VM values (global data is duplicated by each
* VM), it must not be accessed from host code.
*/
static vm_vaddr_t *ucall_exit_mmio_addr;
static void ucall_set_mmio_addr(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
{
vm->ucall_mmio_addr = mmio_gpa;
write_guest_global(vm, ucall_exit_mmio_addr, (vm_vaddr_t *)mmio_gpa);
}
void ucall_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
{
virt_pg_map(vm, mmio_gpa, mmio_gpa);
ucall_set_mmio_addr(vm, mmio_gpa);
}
void ucall_arch_uninit(struct kvm_vm *vm)
{
ucall_set_mmio_addr(vm, (vm_paddr_t)NULL);
}
void ucall_arch_do_ucall(vm_vaddr_t uc)
{
WRITE_ONCE(*ucall_exit_mmio_addr, uc);
}
void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
if (run->exit_reason == KVM_EXIT_MMIO &&
run->mmio.phys_addr == vcpu->vm->ucall_mmio_addr) {
vm_vaddr_t gva;
TEST_ASSERT(run->mmio.is_write && run->mmio.len == 8,
"Unexpected ucall exit mmio address access");
memcpy(&gva, run->mmio.data, sizeof(gva));
return addr_gva2hva(vcpu->vm, gva);
}
return NULL;
}
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