cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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ucall.c (1186B)

      1// SPDX-License-Identifier: GPL-2.0
      2/*
      3 * ucall support. A ucall is a "hypercall to userspace".
      4 *
      5 * Copyright (C) 2018, Red Hat, Inc.
      6 */
      7#include "kvm_util.h"
      8
      9#define UCALL_PIO_PORT ((uint16_t)0x1000)
     10
     11void ucall_init(struct kvm_vm *vm, void *arg)
     12{
     13}
     14
     15void ucall_uninit(struct kvm_vm *vm)
     16{
     17}
     18
     19void ucall(uint64_t cmd, int nargs, ...)
     20{
     21	struct ucall uc = {
     22		.cmd = cmd,
     23	};
     24	va_list va;
     25	int i;
     26
     27	nargs = nargs <= UCALL_MAX_ARGS ? nargs : UCALL_MAX_ARGS;
     28
     29	va_start(va, nargs);
     30	for (i = 0; i < nargs; ++i)
     31		uc.args[i] = va_arg(va, uint64_t);
     32	va_end(va);
     33
     34	asm volatile("in %[port], %%al"
     35		: : [port] "d" (UCALL_PIO_PORT), "D" (&uc) : "rax", "memory");
     36}
     37
     38uint64_t get_ucall(struct kvm_vm *vm, uint32_t vcpu_id, struct ucall *uc)
     39{
     40	struct kvm_run *run = vcpu_state(vm, vcpu_id);
     41	struct ucall ucall = {};
     42
     43	if (uc)
     44		memset(uc, 0, sizeof(*uc));
     45
     46	if (run->exit_reason == KVM_EXIT_IO && run->io.port == UCALL_PIO_PORT) {
     47		struct kvm_regs regs;
     48
     49		vcpu_regs_get(vm, vcpu_id, &regs);
     50		memcpy(&ucall, addr_gva2hva(vm, (vm_vaddr_t)regs.rdi),
     51		       sizeof(ucall));
     52
     53		vcpu_run_complete_io(vm, vcpu_id);
     54		if (uc)
     55			memcpy(uc, &ucall, sizeof(ucall));
     56	}
     57
     58	return ucall.cmd;
     59}