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tests/ioctl_kvm_run.c: handle cpuid at the end of vcpu dentry

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Since Linux 4.16, kernel appends the cpuid as suffix to the entry
for a kvm vcpu in /proc/$pid/fd like:

    anon_inode:kvm-vcpu:0

That was

    anon_inode:kvm-vcpu

This kernel change causes the test case failure on newer kernels.
Update the test to deal with the new name as well as the old one.

* tests/ioctl_kvm_run.c: Include unistd.h for using readlink(2).
(vcpu_dev_should_have_cpuid): New function for detecting whether
a proc entry for given fd has the cpuid suffix or not.
(main): Trim vcpu_dev to remove the cpuid suffix if needed.
(vcpu_dev): Remove const modifier.
This commit is contained in:
Masatake YAMATO
2018-05-02 17:11:07 +09:00
committed by Dmitry V. Levin
parent f12aa97aab
commit bcff87c31c
1 changed files with 28 additions and 1 deletions
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29
tests/ioctl_kvm_run.c
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@ -40,6 +40,7 @@
# include <string.h>
# include <sys/ioctl.h>
# include <sys/mman.h>
# include <unistd.h>
# include <linux/kvm.h>
static int
@ -56,7 +57,7 @@ kvm_ioctl(int fd, unsigned long cmd, const char *cmd_str, void *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 char vcpu_dev[] = "anon_inode:kvm-vcpu:0";
static size_t page_size;
extern const char code[];
@ -165,6 +166,23 @@ run_kvm(const int vcpu_fd, struct kvm_run *const run, const size_t mmap_size,
}
}
static int
vcpu_dev_should_have_cpuid(int fd)
{
int r = 0;
char *filename = NULL;
char buf[sizeof(vcpu_dev)];
if (asprintf(&filename, "/proc/%d/fd/%d", getpid(), fd) < 0)
error_msg_and_fail("asprintf");
if (readlink(filename, buf, sizeof(buf)) == sizeof(buf) - 1
&& (memcmp(buf, vcpu_dev, sizeof(buf) - 1) == 0))
r = 1;
free(filename);
return r;
}
int
main(void)
{
@ -208,6 +226,15 @@ main(void)
(unsigned long) page_size, (unsigned long) page_size, mem);
int vcpu_fd = KVM_IOCTL(vm_fd, KVM_CREATE_VCPU, NULL);
if (!vcpu_dev_should_have_cpuid(vcpu_fd))
/*
* This is an older kernel that doesn't place a cpuid
* at the end of the dentry associated with vcpu_fd.
* Trim the cpuid part of vcpu_dev like:
* "anon_inode:kvm-vcpu:0" -> "anon_inode:kvm-vcpu"
*/
vcpu_dev[strlen (vcpu_dev) - 2] = '\0';
printf("ioctl(%d<%s>, KVM_CREATE_VCPU, 0) = %d<%s>\n",
vm_fd, vm_dev, vcpu_fd, vcpu_dev);