[PATCH v4 4/4] tests: check KVM ioctl commands decoding
Dmitry V. Levin
ldv at altlinux.org
Thu Dec 7 14:18:50 UTC 2017
On Thu, Dec 07, 2017 at 11:14:34PM +0900, Masatake YAMATO wrote:
> 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.
Yes, I missed it, too. Thanks, fixed locally.
> > + (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
What about the patch itself? Are you OK with the changes?
--
ldv
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