Cregit: Linux 6.4: ucall.c

Contributors: 9
Author	Tokens	Token Proportion	Commits	Commit Proportion
Thomas Huth	27	28.42%	1	7.69%
Andrew Jones	20	21.05%	1	7.69%
Sean Christopherson	19	20.00%	4	30.77%
Paolo Bonzini	9	9.47%	1	7.69%
Peter Xu	7	7.37%	2	15.38%
Wei Huang	6	6.32%	1	7.69%
Peter Gonda	4	4.21%	1	7.69%
Aaron Lewis	2	2.11%	1	7.69%
Drew Schmitt	1	1.05%	1	7.69%
Total	95		13

// 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_arch_init(struct kvm_vm *vm, vm_paddr_t mmio_gpa)
{
}

void ucall_arch_do_ucall(vm_vaddr_t uc)
{
	asm volatile("in %[port], %%al"
		: : [port] "d" (UCALL_PIO_PORT), "D" (uc) : "rax", "memory");
}

void *ucall_arch_get_ucall(struct kvm_vcpu *vcpu)
{
	struct kvm_run *run = vcpu->run;

	if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
		struct kvm_regs regs;

		vcpu_regs_get(vcpu, &regs);
		return (void *)regs.rdi;
	}
	return NULL;
}