[PATCH v4 4/4] tests: check KVM ioctl commands decoding
Masatake YAMATO
yamato at redhat.com
Thu Dec 7 14:14:34 UTC 2017
On Thu, 7 Dec 2017 17:04:05 +0300, "Dmitry V. Levin" <ldv at altlinux.org> wrote:
> On Mon, Dec 04, 2017 at 10:08:17PM +0900, Masatake YAMATO wrote:
>> * tests/Makefile.am (check_PROGRAMS): Add ioctl_kvm.
>> (DECODER_TESTS): Add ioctl_kvm.test.
>> (EXTRA_DIST): Add ioctl_kvm.expected.
>> * tests/ioctl_kvm.c: New test target file.
>> Taken from https://lwn.net/Articles/658512/.
>> * tests/ioctl_kvm.expected: New expected file.
>> * tests/ioctl_kvm.test: New test driver.
>>
>> Changes in v2:
>> * Skip the test case if kvm.h is not available.
>> * Skip the test case if opening /dev/kvm is failed.
>> * Include sys/typtes.h first.
>>
>> All items are suggested by ldv.
>>
>> Highlights in v3:
>> * Build the new test case when __x86_64__ is defined.
>> * Don't use macros/functions in err.h.
>> Use macros/functions in tests.h instead.
>> * Remove redundant inclusion of header files.
>>
>> All above items are suggested by ldv.
>>
>> * Add .test and .expected file to Makefile.am.
>>
>> No Change in v4.
>
> Yet the test doesn't quite fit the test suite, so I took the liberty
> to tweak it here and there, please have a look.
>
> I also renamed it to make room for more formal KVM_* ioctl tests like
> those we already have (tests/ioctl_*.c) for other ioctl decoders.
>
> * tests/ioctl_kvm_run.c: New file.
> * tests/ioctl_kvm_run.test: New test.
> * tests/Makefile.am (DECODER_TESTS): Add ioctl_kvm_run.test.
> * tests/pure_executables.list: Add ioctl_kvm_run.
> * tests/.gitignore: Likewise.
>
> Co-authored-by: Dmitry V. Levin <ldv at altlinux.org>
> ---
> tests/.gitignore | 1 +
> tests/Makefile.am | 1 +
> tests/ioctl_kvm_run.c | 220 ++++++++++++++++++++++++++++++++++++++++++++
> tests/ioctl_kvm_run.test | 11 +++
> tests/pure_executables.list | 1 +
> 5 files changed, 234 insertions(+)
> create mode 100644 tests/ioctl_kvm_run.c
> create mode 100755 tests/ioctl_kvm_run.test
>
> diff --git a/tests/.gitignore b/tests/.gitignore
> index 93c980f..7838a5b 100644
> --- a/tests/.gitignore
> +++ b/tests/.gitignore
> @@ -128,6 +128,7 @@ ioctl_dm
> ioctl_dm-v
> ioctl_evdev
> ioctl_evdev-v
> +ioctl_kvm_run
> ioctl_loop
> ioctl_loop-nv
> ioctl_loop-v
> diff --git a/tests/Makefile.am b/tests/Makefile.am
> index 7bc2872..22a39d7 100644
> --- a/tests/Makefile.am
> +++ b/tests/Makefile.am
> @@ -206,6 +206,7 @@ DECODER_TESTS = \
> ioctl.test \
> ioctl_dm-v.test \
> ioctl_dm.test \
> + ioctl_kvm_run.test \
> ioctl_loop-nv.test \
> ioctl_nsfs.test \
> ioctl_sock_gifconf.test \
> diff --git a/tests/ioctl_kvm_run.c b/tests/ioctl_kvm_run.c
> new file mode 100644
> index 0000000..90fffba
> --- /dev/null
> +++ b/tests/ioctl_kvm_run.c
> @@ -0,0 +1,220 @@
> +/*
> + * Check decoding of KVM_* commands of ioctl syscall using /dev/kvm API.
> + * Based on kvmtest.c from https://lwn.net/Articles/658512/
> + *
> + * kvmtest.c author: Josh Triplett <josh at joshtriplett.org>
> + * Copyright (c) 2015 Intel Corporation
> + * Copyright (c) 2017 The strace developers.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to
> + * deal in the Software without restriction, including without limitation the
> + * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
> + * sell copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
> + * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> + * IN THE SOFTWARE.
> + */
> +
> +#include "tests.h"
> +
> +#if defined HAVE_LINUX_KVM_H \
> + && defined HAVE_STRUCT_KVM_REGS \
> + && defined HAVE_STRUCT_KVM_SREGS \
> + && defined HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION \
> + &&(defined __x86_64__ || defined __i386__)
> +
> +# include <fcntl.h>
> +# include <stdint.h>
> +# include <stdio.h>
> +# include <stdlib.h>
> +# include <string.h>
> +# include <sys/ioctl.h>
> +# include <sys/mman.h>
> +# include <linux/kvm.h>
> +
> +static int
> +kvm_ioctl(int fd, unsigned long cmd, const char *cmd_str, void *arg)
> +{
> + int rc = ioctl(fd, cmd, arg);
> + if (rc < 0)
> + perror_msg_and_skip("%s", cmd_str);
> + return rc;
> +}
> +
> +#define KVM_IOCTL(fd_, cmd_, arg_) \
> + kvm_ioctl((fd_), (cmd_), #cmd_, (arg_))
> +
> +static const char dev[] = "/dev/kvm";
> +static const char vm_dev[] = "anon_inode:kvm-vm";
> +static const char vcpu_dev[] = "anon_inode:kvm-vcpu";
> +static size_t page_size;
> +
> +static void
> +code(void)
> +{
> + __asm__("mov $0xd80003f8, %edx; mov $'\n', %al; out %al, (%dx); hlt");
> +}
> +
> +static void
> +run_kvm(const int vcpu_fd, struct kvm_run *const run, const size_t mmap_size,
> + void *const mem)
> +{
> + /* Initialize CS to point at 0, via a read-modify-write of sregs. */
> + struct kvm_sregs sregs;
> + KVM_IOCTL(vcpu_fd, KVM_GET_SREGS, &sregs);
> + printf("ioctl(%d<%s>, KVM_GET_SREGS, {cs={base=%#jx, limit=%u, selector=%u"
> + ", type=%u, present=%u, dpl=%u, db=%u, s=%u, l=%u, g=%u, avl=%u}"
> + ", ...}) = 0\n", vcpu_fd, vcpu_dev, (uintmax_t) sregs.cs.base,
> + sregs.cs.limit, sregs.cs.selector, sregs.cs.type,
> + sregs.cs.present, sregs.cs.dpl, sregs.cs.db, sregs.cs.s,
> + sregs.cs.l, sregs.cs.g, sregs.cs.avl);
> +
> + sregs.cs.base = 0;
> + sregs.cs.selector = 0;
> + KVM_IOCTL(vcpu_fd, KVM_SET_SREGS, &sregs);
> + printf("ioctl(%d<%s>, KVM_SET_SREGS, {cs={base=%#jx, limit=%u"
> + ", selector=%u, type=%u, present=%u, dpl=%u, db=%u, s=%u"
> + ", l=%u, g=%u, avl=%u}, ...}) = 0\n",
> + vcpu_fd, vcpu_dev, (uintmax_t) sregs.cs.base,
> + sregs.cs.limit, sregs.cs.selector, sregs.cs.type,
> + sregs.cs.present, sregs.cs.dpl, sregs.cs.db, sregs.cs.s,
> + sregs.cs.l, sregs.cs.g, sregs.cs.avl);
> +
> + /*
> + * Initialize registers: instruction pointer for our code, addends,
> + * and initial flags required by x86 architecture.
> + */
> + struct kvm_regs regs = {
> + .rip = page_size,
> + .rax = 2,
> + .rbx = 2,
> + .rflags = 0x2,
> + };
> + KVM_IOCTL(vcpu_fd, KVM_SET_REGS, ®s);
> + printf("ioctl(%d<%s>, KVM_SET_REGS, {rax=%#jx, ..."
> + ", rsp=%#jx, rbp=%#jx, ..., rip=%#jx, rflags=%#jx}) = 0\n",
> + vcpu_fd, vcpu_dev, (uintmax_t) regs.rax,
> + (uintmax_t) regs.rsp, (uintmax_t) regs.rbp,
> + (uintmax_t) regs.rip, (uintmax_t) regs.rflags);
> +
> + /* Copy the code till the end of page */
> + size_t code_size = page_size - ((uintptr_t) code & (page_size - 1));
> + if (code_size < 16)
> + code_size = 16;
> + memcpy(mem, code, code_size);
> +
> + const char *p = "\n";
> +
> + /* Repeatedly run code and handle VM exits. */
> + for (;;) {
> + KVM_IOCTL(vcpu_fd, KVM_RUN, NULL);
> + printf("ioctl(%d<%s>, KVM_RUN, 0) = 0\n", vcpu_fd, vcpu_dev);
> +
> + switch (run->exit_reason) {
> + case KVM_EXIT_HLT:
> + if (p)
> + error_msg_and_fail("premature KVM_EXIT_HLT");
> + return;
> + case KVM_EXIT_IO:
> + if (run->io.direction == KVM_EXIT_IO_OUT
> + && run->io.size == 1
> + && run->io.port == 0x03f8
> + && run->io.count == 1
> + && run->io.data_offset < mmap_size
> + && p && *p == ((char *) run)[run->io.data_offset])
> + p = NULL;
> + else
> + error_msg_and_fail("unhandled KVM_EXIT_IO");
> + break;
> + default:
> + error_msg_and_fail("exit_reason = %#x",
> + run->exit_reason);
> + }
> + }
> +}
> +
> +int
> +main(void)
> +{
> + skip_if_unavailable("/proc/self/fd/");
> +
> + int kvm = open(dev, O_RDWR);
> + if (kvm < 0)
> + perror_msg_and_skip("open: %s", dev);
> +
> + /* Make sure we have the stable version of the API */
> + int ret = KVM_IOCTL(kvm, KVM_GET_API_VERSION, 0);
> + if (ret != KVM_API_VERSION)
> + error_msg_and_skip("KVM_GET_API_VERSION returned %d"
> + ", KVM_API_VERSION is %d",
> + kvm, KVM_API_VERSION);
> + printf("ioctl(%d<%s>, KVM_GET_API_VERSION, 0) = %d\n",
> + kvm, dev, ret);
> +
> + int vm_fd = KVM_IOCTL(kvm, KVM_CREATE_VM, 0);
> + printf("ioctl(%d<%s>, KVM_CREATE_VM, 0) = %d<%s>\n",
> + kvm, dev, vm_fd, vm_dev);
> +
> + /* Allocate one aligned page of guest memory to hold the code. */
> + page_size = get_page_size();
> + void *const mem = mmap(NULL, page_size, PROT_READ | PROT_WRITE,
> + MAP_SHARED | MAP_ANONYMOUS, -1, 0);
> + if (mem == MAP_FAILED)
> + perror_msg_and_fail("mmap page");
> +
> + /* Map it to the second page frame (to avoid the real-mode IDT at 0). */
> + struct kvm_userspace_memory_region region = {
> + .slot = 0,
> + .guest_phys_addr = page_size,
> + .memory_size = page_size,
> + .userspace_addr = (uintptr_t) mem,
> + };
> + KVM_IOCTL(vm_fd, KVM_SET_USER_MEMORY_REGION, ®ion);
> + printf("ioctl(%d<%s>, KVM_SET_USER_MEMORY_REGION"
> + ", {slot=0, flags=0, guest_phys_addr=%#lx, memory_size=%lu"
> + ", userspace_addr=%p) = 0\n", vm_fd, vm_dev,
Please, look at [PATCH v5 1/4] and [PATCH v5 4/4]. I found I missed
printing '}' at the end. I added the last '}' in the above patch.
Masatake YAMATO
> + (unsigned long) page_size, (unsigned long) page_size, mem);
> +
> + int vcpu_fd = KVM_IOCTL(vm_fd, KVM_CREATE_VCPU, NULL);
> + printf("ioctl(%d<%s>, KVM_CREATE_VCPU, 0) = %d<%s>\n",
> + vm_fd, vm_dev, vcpu_fd, vcpu_dev);
> +
> + /* Map the shared kvm_run structure and following data. */
> + ret = KVM_IOCTL(kvm, KVM_GET_VCPU_MMAP_SIZE, NULL);
> + struct kvm_run *run;
> + if (ret < (int) sizeof(*run))
> + error_msg_and_fail("KVM_GET_VCPU_MMAP_SIZE returned %d < %d",
> + ret, (int) sizeof(*run));
> + printf("ioctl(%d<%s>, KVM_GET_VCPU_MMAP_SIZE, 0) = %d\n",
> + kvm, dev, ret);
> +
> + const size_t mmap_size = (ret + page_size - 1) & -page_size;
> + run = mmap(NULL, mmap_size, PROT_READ | PROT_WRITE,
> + MAP_SHARED, vcpu_fd, 0);
> + if (run == MAP_FAILED)
> + perror_msg_and_fail("mmap vcpu");
> +
> + run_kvm(vcpu_fd, run, mmap_size, mem);
> +
> + puts("+++ exited with 0 +++");
> + return 0;
> +}
> +
> +#else /* !HAVE_LINUX_KVM_H */
> +
> +SKIP_MAIN_UNDEFINED("HAVE_LINUX_KVM_H && HAVE_STRUCT_KVM_REGS && "
> + "HAVE_STRUCT_KVM_SREGS && "
> + "HAVE_STRUCT_KVM_USERSPACE_MEMORY_REGION && "
> + "(__x86_64__ || __i386__)")
> +
> +#endif
> diff --git a/tests/ioctl_kvm_run.test b/tests/ioctl_kvm_run.test
> new file mode 100755
> index 0000000..a23cbeb
> --- /dev/null
> +++ b/tests/ioctl_kvm_run.test
> @@ -0,0 +1,11 @@
> +#!/bin/sh
> +
> +# Check decoding of KVM_* ioctl commands.
> +
> +. "${srcdir=.}/init.sh"
> +
> +check_prog grep
> +run_prog > /dev/null
> +run_strace -a36 -y -eioctl $args > "$EXP"
> +grep -v '^ioctl([012],' < "$LOG" > "$OUT"
> +match_diff "$OUT" "$EXP"
> diff --git a/tests/pure_executables.list b/tests/pure_executables.list
> index 7ab52ef..0d1964d 100755
> --- a/tests/pure_executables.list
> +++ b/tests/pure_executables.list
> @@ -103,6 +103,7 @@ ioctl
> ioctl_block
> ioctl_dm
> ioctl_evdev
> +ioctl_kvm_run
> ioctl_loop
> ioctl_mtd
> ioctl_rtc
>
> --
> ldv
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