From: "Marc-André Lureau" <marcandre.lureau@gmail.com>
To: Lin Ma <lma@suse.com>
Cc: QEMU <qemu-devel@nongnu.org>, Michael Roth <mdroth@linux.vnet.ibm.com>
Subject: Re: [PATCH v5] qga: Correct loop count in qmp_guest_get_vcpus()
Date: Tue, 1 Dec 2020 14:23:48 +0400 [thread overview]
Message-ID: <CAJ+F1CLS+xy5Twpi0jwCGse6BvhHYm8ijohrXgM8u0sh3vvY=w@mail.gmail.com> (raw)
In-Reply-To: <20201201095607.23389-1-lma@suse.com>
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On Tue, Dec 1, 2020 at 1:56 PM Lin Ma <lma@suse.com> wrote:
> The guest-get-vcpus returns incorrect vcpu info in case we hotunplug
> vcpus(not
> the last one).
> e.g.:
> A VM has 4 VCPUs: cpu0 + 3 hotunpluggable online vcpus(cpu1, cpu2 and
> cpu3).
> Hotunplug cpu2, Now only cpu0, cpu1 and cpu3 are present & online.
>
> ./qmp-shell /tmp/qmp-monitor.sock
> (QEMU) query-hotpluggable-cpus
> {"return": [
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
> "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
> "qom-path": "/machine/peripheral/cpu2", "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
> "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
> "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
> ]}
>
> (QEMU) device_del id=cpu2
> {"return": {}}
>
> (QEMU) query-hotpluggable-cpus
> {"return": [
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 3}, "vcpus-count": 1,
> "qom-path": "/machine/peripheral/cpu3", "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 2}, "vcpus-count": 1,
> "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 1}, "vcpus-count": 1,
> "qom-path": "/machine/peripheral/cpu1", "type": "host-x86_64-cpu"},
> {"props": {"core-id": 0, "thread-id": 0, "socket-id": 0}, "vcpus-count": 1,
> "qom-path": "/machine/unattached/device[0]", "type": "host-x86_64-cpu"}
> ]}
>
> Before:
> ./qmp-shell -N /tmp/qmp-ga.sock
> Welcome to the QMP low-level shell!
> Connected
> (QEMU) guest-get-vcpus
> {"return": [
> {"online": true, "can-offline": false, "logical-id": 0},
> {"online": true, "can-offline": true, "logical-id": 1}]}
>
> After:
> ./qmp-shell -N /tmp/qmp-ga.sock
> Welcome to the QMP low-level shell!
> Connected
> (QEMU) guest-get-vcpus
> {"return": [
> {"online": true, "can-offline": false, "logical-id": 0},
> {"online": true, "can-offline": true, "logical-id": 1},
> {"online": true, "can-offline": true, "logical-id": 3}]}
>
> Signed-off-by: Lin Ma <lma@suse.com>
>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
> qga/commands-posix.c | 43 ++++++++++++++-----------------------------
> 1 file changed, 14 insertions(+), 29 deletions(-)
>
> diff --git a/qga/commands-posix.c b/qga/commands-posix.c
> index c089e38120..f66bf84126 100644
> --- a/qga/commands-posix.c
> +++ b/qga/commands-posix.c
> @@ -2376,24 +2376,6 @@ error:
> return NULL;
> }
>
> -#define SYSCONF_EXACT(name, errp) sysconf_exact((name), #name, (errp))
> -
> -static long sysconf_exact(int name, const char *name_str, Error **errp)
> -{
> - long ret;
> -
> - errno = 0;
> - ret = sysconf(name);
> - if (ret == -1) {
> - if (errno == 0) {
> - error_setg(errp, "sysconf(%s): value indefinite", name_str);
> - } else {
> - error_setg_errno(errp, errno, "sysconf(%s)", name_str);
> - }
> - }
> - return ret;
> -}
> -
> /* Transfer online/offline status between @vcpu and the guest system.
> *
> * On input either @errp or *@errp must be NULL.
> @@ -2464,24 +2446,28 @@ static void transfer_vcpu(GuestLogicalProcessor
> *vcpu, bool sys2vcpu,
>
> GuestLogicalProcessorList *qmp_guest_get_vcpus(Error **errp)
> {
> - int64_t current;
> GuestLogicalProcessorList *head, **link;
> - long sc_max;
> + const char *cpu_dir = "/sys/devices/system/cpu";
> + const gchar *line;
> + g_autoptr(GDir) cpu_gdir = NULL;
> Error *local_err = NULL;
>
> - current = 0;
> head = NULL;
> link = &head;
> - sc_max = SYSCONF_EXACT(_SC_NPROCESSORS_CONF, &local_err);
> + cpu_gdir = g_dir_open(cpu_dir, 0, NULL);
> +
> + if (cpu_gdir == NULL) {
> + error_setg_errno(errp, errno, "failed to list entries: %s",
> cpu_dir);
> + return NULL;
> + }
>
> - while (local_err == NULL && current < sc_max) {
> + while (local_err == NULL && (line = g_dir_read_name(cpu_gdir)) !=
> NULL) {
> GuestLogicalProcessor *vcpu;
> GuestLogicalProcessorList *entry;
> - 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)) {
> + int64_t id;
> + if (sscanf(line, "cpu%ld", &id)) {
> + g_autofree char *path =
> g_strdup_printf("/sys/devices/system/cpu/"
> + "cpu%" PRId64 "/",
> id);
> vcpu = g_malloc0(sizeof *vcpu);
> vcpu->logical_id = id;
> vcpu->has_can_offline = true; /* lolspeak ftw */
> @@ -2491,7 +2477,6 @@ GuestLogicalProcessorList *qmp_guest_get_vcpus(Error
> **errp)
> *link = entry;
> link = &entry->next;
> }
> - g_free(path);
> }
>
> if (local_err == NULL) {
> --
> 2.26.0
>
>
--
Marc-André Lureau
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prev parent reply other threads:[~2020-12-01 10:25 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-01 9:56 [PATCH v5] qga: Correct loop count in qmp_guest_get_vcpus() Lin Ma
2020-12-01 10:23 ` Marc-André Lureau [this message]
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