237 lines · c
1// SPDX-License-Identifier: GPL-2.02#include <signal.h>3#include <stdio.h>4#include <stdlib.h>5#include <string.h>6#include <sys/ioctl.h>7 8#include <linux/sizes.h>9 10#include <kvm_util.h>11#include <processor.h>12 13#include "ucall_common.h"14 15struct kvm_coalesced_io {16 struct kvm_coalesced_mmio_ring *ring;17 uint32_t ring_size;18 uint64_t mmio_gpa;19 uint64_t *mmio;20 21 /*22 * x86-only, but define pio_port for all architectures to minimize the23 * amount of #ifdeffery and complexity, without having to sacrifice24 * verbose error messages.25 */26 uint8_t pio_port;27};28 29static struct kvm_coalesced_io kvm_builtin_io_ring;30 31#ifdef __x86_64__32static const int has_pio = 1;33#else34static const int has_pio = 0;35#endif36 37static void guest_code(struct kvm_coalesced_io *io)38{39 int i, j;40 41 for (;;) {42 for (j = 0; j < 1 + has_pio; j++) {43 /*44 * KVM always leaves one free entry, i.e. exits to45 * userspace before the last entry is filled.46 */47 for (i = 0; i < io->ring_size - 1; i++) {48#ifdef __x86_64__49 if (i & 1)50 outl(io->pio_port, io->pio_port + i);51 else52#endif53 WRITE_ONCE(*io->mmio, io->mmio_gpa + i);54 }55#ifdef __x86_64__56 if (j & 1)57 outl(io->pio_port, io->pio_port + i);58 else59#endif60 WRITE_ONCE(*io->mmio, io->mmio_gpa + i);61 }62 GUEST_SYNC(0);63 64 WRITE_ONCE(*io->mmio, io->mmio_gpa + i);65#ifdef __x86_64__66 outl(io->pio_port, io->pio_port + i);67#endif68 }69}70 71static void vcpu_run_and_verify_io_exit(struct kvm_vcpu *vcpu,72 struct kvm_coalesced_io *io,73 uint32_t ring_start,74 uint32_t expected_exit)75{76 const bool want_pio = expected_exit == KVM_EXIT_IO;77 struct kvm_coalesced_mmio_ring *ring = io->ring;78 struct kvm_run *run = vcpu->run;79 uint32_t pio_value;80 81 WRITE_ONCE(ring->first, ring_start);82 WRITE_ONCE(ring->last, ring_start);83 84 vcpu_run(vcpu);85 86 /*87 * Annoyingly, reading PIO data is safe only for PIO exits, otherwise88 * data_offset is garbage, e.g. an MMIO gpa.89 */90 if (run->exit_reason == KVM_EXIT_IO)91 pio_value = *(uint32_t *)((void *)run + run->io.data_offset);92 else93 pio_value = 0;94 95 TEST_ASSERT((!want_pio && (run->exit_reason == KVM_EXIT_MMIO && run->mmio.is_write &&96 run->mmio.phys_addr == io->mmio_gpa && run->mmio.len == 8 &&97 *(uint64_t *)run->mmio.data == io->mmio_gpa + io->ring_size - 1)) ||98 (want_pio && (run->exit_reason == KVM_EXIT_IO && run->io.port == io->pio_port &&99 run->io.direction == KVM_EXIT_IO_OUT && run->io.count == 1 &&100 pio_value == io->pio_port + io->ring_size - 1)),101 "For start = %u, expected exit on %u-byte %s write 0x%llx = %lx, got exit_reason = %u (%s)\n "102 "(MMIO addr = 0x%llx, write = %u, len = %u, data = %lx)\n "103 "(PIO port = 0x%x, write = %u, len = %u, count = %u, data = %x",104 ring_start, want_pio ? 4 : 8, want_pio ? "PIO" : "MMIO",105 want_pio ? (unsigned long long)io->pio_port : io->mmio_gpa,106 (want_pio ? io->pio_port : io->mmio_gpa) + io->ring_size - 1, run->exit_reason,107 run->exit_reason == KVM_EXIT_MMIO ? "MMIO" : run->exit_reason == KVM_EXIT_IO ? "PIO" : "other",108 run->mmio.phys_addr, run->mmio.is_write, run->mmio.len, *(uint64_t *)run->mmio.data,109 run->io.port, run->io.direction, run->io.size, run->io.count, pio_value);110}111 112static void vcpu_run_and_verify_coalesced_io(struct kvm_vcpu *vcpu,113 struct kvm_coalesced_io *io,114 uint32_t ring_start,115 uint32_t expected_exit)116{117 struct kvm_coalesced_mmio_ring *ring = io->ring;118 int i;119 120 vcpu_run_and_verify_io_exit(vcpu, io, ring_start, expected_exit);121 122 TEST_ASSERT((ring->last + 1) % io->ring_size == ring->first,123 "Expected ring to be full (minus 1), first = %u, last = %u, max = %u, start = %u",124 ring->first, ring->last, io->ring_size, ring_start);125 126 for (i = 0; i < io->ring_size - 1; i++) {127 uint32_t idx = (ring->first + i) % io->ring_size;128 struct kvm_coalesced_mmio *entry = &ring->coalesced_mmio[idx];129 130#ifdef __x86_64__131 if (i & 1)132 TEST_ASSERT(entry->phys_addr == io->pio_port &&133 entry->len == 4 && entry->pio &&134 *(uint32_t *)entry->data == io->pio_port + i,135 "Wanted 4-byte port I/O 0x%x = 0x%x in entry %u, got %u-byte %s 0x%llx = 0x%x",136 io->pio_port, io->pio_port + i, i,137 entry->len, entry->pio ? "PIO" : "MMIO",138 entry->phys_addr, *(uint32_t *)entry->data);139 else140#endif141 TEST_ASSERT(entry->phys_addr == io->mmio_gpa &&142 entry->len == 8 && !entry->pio,143 "Wanted 8-byte MMIO to 0x%lx = %lx in entry %u, got %u-byte %s 0x%llx = 0x%lx",144 io->mmio_gpa, io->mmio_gpa + i, i,145 entry->len, entry->pio ? "PIO" : "MMIO",146 entry->phys_addr, *(uint64_t *)entry->data);147 }148}149 150static void test_coalesced_io(struct kvm_vcpu *vcpu,151 struct kvm_coalesced_io *io, uint32_t ring_start)152{153 struct kvm_coalesced_mmio_ring *ring = io->ring;154 155 kvm_vm_register_coalesced_io(vcpu->vm, io->mmio_gpa, 8, false /* pio */);156#ifdef __x86_64__157 kvm_vm_register_coalesced_io(vcpu->vm, io->pio_port, 8, true /* pio */);158#endif159 160 vcpu_run_and_verify_coalesced_io(vcpu, io, ring_start, KVM_EXIT_MMIO);161#ifdef __x86_64__162 vcpu_run_and_verify_coalesced_io(vcpu, io, ring_start, KVM_EXIT_IO);163#endif164 165 /*166 * Verify ucall, which may use non-coalesced MMIO or PIO, generates an167 * immediate exit.168 */169 WRITE_ONCE(ring->first, ring_start);170 WRITE_ONCE(ring->last, ring_start);171 vcpu_run(vcpu);172 TEST_ASSERT_EQ(get_ucall(vcpu, NULL), UCALL_SYNC);173 TEST_ASSERT_EQ(ring->first, ring_start);174 TEST_ASSERT_EQ(ring->last, ring_start);175 176 /* Verify that non-coalesced MMIO/PIO generates an exit to userspace. */177 kvm_vm_unregister_coalesced_io(vcpu->vm, io->mmio_gpa, 8, false /* pio */);178 vcpu_run_and_verify_io_exit(vcpu, io, ring_start, KVM_EXIT_MMIO);179 180#ifdef __x86_64__181 kvm_vm_unregister_coalesced_io(vcpu->vm, io->pio_port, 8, true /* pio */);182 vcpu_run_and_verify_io_exit(vcpu, io, ring_start, KVM_EXIT_IO);183#endif184}185 186int main(int argc, char *argv[])187{188 struct kvm_vcpu *vcpu;189 struct kvm_vm *vm;190 int i;191 192 TEST_REQUIRE(kvm_has_cap(KVM_CAP_COALESCED_MMIO));193 194#ifdef __x86_64__195 TEST_REQUIRE(kvm_has_cap(KVM_CAP_COALESCED_PIO));196#endif197 198 vm = vm_create_with_one_vcpu(&vcpu, guest_code);199 200 kvm_builtin_io_ring = (struct kvm_coalesced_io) {201 /*202 * The I/O ring is a kernel-allocated page whose address is203 * relative to each vCPU's run page, with the page offset204 * provided by KVM in the return of KVM_CAP_COALESCED_MMIO.205 */206 .ring = (void *)vcpu->run +207 (kvm_check_cap(KVM_CAP_COALESCED_MMIO) * getpagesize()),208 209 /*210 * The size of the I/O ring is fixed, but KVM defines the sized211 * based on the kernel's PAGE_SIZE. Thus, userspace must query212 * the host's page size at runtime to compute the ring size.213 */214 .ring_size = (getpagesize() - sizeof(struct kvm_coalesced_mmio_ring)) /215 sizeof(struct kvm_coalesced_mmio),216 217 /*218 * Arbitrary address+port (MMIO mustn't overlap memslots), with219 * the MMIO GPA identity mapped in the guest.220 */221 .mmio_gpa = 4ull * SZ_1G,222 .mmio = (uint64_t *)(4ull * SZ_1G),223 .pio_port = 0x80,224 };225 226 virt_map(vm, (uint64_t)kvm_builtin_io_ring.mmio, kvm_builtin_io_ring.mmio_gpa, 1);227 228 sync_global_to_guest(vm, kvm_builtin_io_ring);229 vcpu_args_set(vcpu, 1, &kvm_builtin_io_ring);230 231 for (i = 0; i < kvm_builtin_io_ring.ring_size; i++)232 test_coalesced_io(vcpu, &kvm_builtin_io_ring, i);233 234 kvm_vm_free(vm);235 return 0;236}237