From 34ff13c0974bf94c3e61b0b8af8134a6933194ea Mon Sep 17 00:00:00 2001

From: =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= <marcandre.lureau@redhat.com>

Date: Thu, 15 Nov 2018 09:45:19 +0100

Subject: [PATCH 1/5] qga: ignore non present cpus when handling

 qmp_guest_get_vcpus()

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RH-Author: Marc-André Lureau <marcandre.lureau@redhat.com>

Message-id: <20181115094519.22641-1-marcandre.lureau@redhat.com>

Patchwork-id: 83030

O-Subject: [RHEL-7.7 qemu-guest-agent PATCH] qga: ignore non present cpus when handling qmp_guest_get_vcpus()

Bugzilla: 1611062

RH-Acked-by: Laszlo Ersek <lersek@redhat.com>

RH-Acked-by: Igor Mammedov <imammedo@redhat.com>

RH-Acked-by: Markus Armbruster <armbru@redhat.com>

From: Igor Mammedov <imammedo@redhat.com>

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 <imammedo@redhat.com>

Reviewed-by: Laszlo Ersek <lersek@redhat.com>

Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>

BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1611062

Brew: https://brewweb.engineering.redhat.com/brew/taskinfo?taskID=19189361

(cherry picked from commit b4bf912a6c19449e68af7b4173a8c6da21904d99)

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

Signed-off-by: Miroslav Rezanina <mrezanin@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 26c1863..f4d9380 100644

--- a/qga/commands-posix.c

+++ b/qga/commands-posix.c

@@ -1913,61 +1913,56 @@ 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)

@@ -1985,17 +1980,21 @@ 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) {

@@ -2016,7 +2015,11 @@ 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;

         }

-- 

1.8.3.1