Quoting Igor Mammedov (2018-09-06 07:51:54)
> If VM has VCPUs plugged sparselly (for example a VM started with
> 3 VCPUs (cpu0, cpu1 and cpu2) and then cpu1 was hotunplugged so
> only cpu0 and cpu2 are present), QGA will rise a error
> error: internal error: unable to execute QEMU agent command
> 'guest-get-vcpus':
> open("/sys/devices/system/cpu/cpu1/"): No such file or directory
> when
> virsh vcpucount FOO --guest
> is executed.
> Fix it by ignoring non present CPUs when fetching CPUs status from sysfs.
>
> Signed-off-by: Igor Mammedov <imamm...@redhat.com>
Thanks, applied to qga tree:
https://github.com/mdroth/qemu/commits/qga
> ---
> v2:
> do not create CPU entry if cpu isn't present
> (Laszlo Ersek <ler...@redhat.com>)
> ---
> qga/commands-posix.c | 115
> ++++++++++++++++++++++++++-------------------------
> 1 file changed, 59 insertions(+), 56 deletions(-)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index 37e8a2d..42d30f0 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -2035,61 +2035,56 @@ static long sysconf_exact(int name, const char
> *name_str, Error **errp)
> * Written members remain unmodified on error.
> */
> static void transfer_vcpu(GuestLogicalProcessor *vcpu, bool sys2vcpu,
> - Error **errp)
> + char *dirpath, Error **errp)
> {
> - char *dirpath;
> + int fd;
> + int res;
> int dirfd;
> + static const char fn[] = "online";
>
> - dirpath = g_strdup_printf("/sys/devices/system/cpu/cpu%" PRId64 "/",
> - vcpu->logical_id);
> dirfd = open(dirpath, O_RDONLY | O_DIRECTORY);
> if (dirfd == -1) {
> error_setg_errno(errp, errno, "open(\"%s\")", dirpath);
> - } else {
> - static const char fn[] = "online";
> - int fd;
> - int res;
> -
> - fd = openat(dirfd, fn, sys2vcpu ? O_RDONLY : O_RDWR);
> - if (fd == -1) {
> - if (errno != ENOENT) {
> - error_setg_errno(errp, errno, "open(\"%s/%s\")", dirpath,
> fn);
> - } else if (sys2vcpu) {
> - vcpu->online = true;
> - vcpu->can_offline = false;
> - } else if (!vcpu->online) {
> - error_setg(errp, "logical processor #%" PRId64 " can't be "
> - "offlined", vcpu->logical_id);
> - } /* otherwise pretend successful re-onlining */
> - } else {
> - unsigned char status;
> -
> - res = pread(fd, &status, 1, 0);
> - if (res == -1) {
> - error_setg_errno(errp, errno, "pread(\"%s/%s\")", dirpath,
> fn);
> - } else if (res == 0) {
> - error_setg(errp, "pread(\"%s/%s\"): unexpected EOF", dirpath,
> - fn);
> - } else if (sys2vcpu) {
> - vcpu->online = (status != '0');
> - vcpu->can_offline = true;
> - } else if (vcpu->online != (status != '0')) {
> - status = '0' + vcpu->online;
> - if (pwrite(fd, &status, 1, 0) == -1) {
> - error_setg_errno(errp, errno, "pwrite(\"%s/%s\")",
> dirpath,
> - fn);
> - }
> - } /* otherwise pretend successful re-(on|off)-lining */
> + return;
> + }
>
> - res = close(fd);
> - g_assert(res == 0);
> - }
> + fd = openat(dirfd, fn, sys2vcpu ? O_RDONLY : O_RDWR);
> + if (fd == -1) {
> + if (errno != ENOENT) {
> + error_setg_errno(errp, errno, "open(\"%s/%s\")", dirpath, fn);
> + } else if (sys2vcpu) {
> + vcpu->online = true;
> + vcpu->can_offline = false;
> + } else if (!vcpu->online) {
> + error_setg(errp, "logical processor #%" PRId64 " can't be "
> + "offlined", vcpu->logical_id);
> + } /* otherwise pretend successful re-onlining */
> + } else {
> + unsigned char status;
> +
> + res = pread(fd, &status, 1, 0);
> + if (res == -1) {
> + error_setg_errno(errp, errno, "pread(\"%s/%s\")", dirpath, fn);
> + } else if (res == 0) {
> + error_setg(errp, "pread(\"%s/%s\"): unexpected EOF", dirpath,
> + fn);
> + } else if (sys2vcpu) {
> + vcpu->online = (status != '0');
> + vcpu->can_offline = true;
> + } else if (vcpu->online != (status != '0')) {
> + status = '0' + vcpu->online;
> + if (pwrite(fd, &status, 1, 0) == -1) {
> + error_setg_errno(errp, errno, "pwrite(\"%s/%s\")", dirpath,
> + fn);
> + }
> + } /* otherwise pretend successful re-(on|off)-lining */
>
> - res = close(dirfd);
> + res = close(fd);
> g_assert(res == 0);
> }
>
> - g_free(dirpath);
> + res = close(dirfd);
> + g_assert(res == 0);
> }
>
> GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
> @@ -2107,17 +2102,21 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error
> **errp)
> while (local_err == NULL && current < sc_max) {
> GuestLogicalProcessor *vcpu;
> GuestLogicalProcessorList *entry;
> -
> - vcpu = g_malloc0(sizeof *vcpu);
> - vcpu->logical_id = current++;
> - vcpu->has_can_offline = true; /* lolspeak ftw */
> - transfer_vcpu(vcpu, true, &local_err);
> -
> - entry = g_malloc0(sizeof *entry);
> - entry->value = vcpu;
> -
> - *link = entry;
> - link = &entry->next;
> + int64_t id = current++;
> + char *path = g_strdup_printf("/sys/devices/system/cpu/cpu%" PRId64
> "/",
> + id);
> +
> + if (g_file_test(path, G_FILE_TEST_EXISTS)) {
> + vcpu = g_malloc0(sizeof *vcpu);
> + vcpu->logical_id = id;
> + vcpu->has_can_offline = true; /* lolspeak ftw */
> + transfer_vcpu(vcpu, true, path, &local_err);
> + entry = g_malloc0(sizeof *entry);
> + entry->value = vcpu;
> + *link = entry;
> + link = &entry->next;
> + }
> + g_free(path);
> }
>
> if (local_err == NULL) {
> @@ -2138,7 +2137,11 @@ int64_t qmp_guest_set_vcpus(GuestLogicalProcessorList
> *vcpus, Error **errp)
>
> processed = 0;
> while (vcpus != NULL) {
> - transfer_vcpu(vcpus->value, false, &local_err);
> + char *path = g_strdup_printf("/sys/devices/system/cpu/cpu%" PRId64
> "/",
> + vcpus->value->logical_id);
> +
> + transfer_vcpu(vcpus->value, false, path, &local_err);
> + g_free(path);
> if (local_err != NULL) {
> break;
> }
> --
> 2.7.4
>
