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dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:33660 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kTvtg-0002w9-Qr for qemu-devel@archiver.kernel.org; Sat, 17 Oct 2020 19:46:00 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:56034) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kTvse-00029O-1n for qemu-devel@nongnu.org; Sat, 17 Oct 2020 19:44:56 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:32656) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1kTvsa-0007yd-St for qemu-devel@nongnu.org; Sat, 17 Oct 2020 19:44:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1602978290; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=2TK8Zb3rx7oZpsMUG1Y5A9x7+KZC5fy92sD9+9h/wAM=; b=e7snVR6cYehKvxLnCKn8SAj40l56so//nQiaA7D2ELTxNCkE2+03G5CX9fK/XodFnUO4YN rI7DPf1cgauZBp7nVFwdLPJSjjEc2SHLlJ9rDYVwACDlMz9UsfM6GigvupAS58cnyfAneP lAGefLHB/WCEy3rptQqrEpIN++X4/cc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-53-qmqGqPH7OLWxeuZgSPZJeA-1; Sat, 17 Oct 2020 19:44:46 -0400 X-MC-Unique: qmqGqPH7OLWxeuZgSPZJeA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 4D602802B7A; Sat, 17 Oct 2020 23:44:43 +0000 (UTC) Received: from x1.home (ovpn-113-35.phx2.redhat.com [10.3.113.35]) by smtp.corp.redhat.com (Postfix) with ESMTP id 7E79E6EF58; Sat, 17 Oct 2020 23:44:37 +0000 (UTC) Date: Sat, 17 Oct 2020 17:44:37 -0600 From: Alex Williamson To: Kirti Wankhede Subject: Re: [PATCH v26 05/17] vfio: Add VM state change handler to know state of VM Message-ID: <20201017174437.2fb6b699@x1.home> In-Reply-To: <0fd89808-74b2-49de-da79-ea034d83a5de@nvidia.com> References: <1600817059-26721-1-git-send-email-kwankhede@nvidia.com> <1600817059-26721-6-git-send-email-kwankhede@nvidia.com> <20200925142023.54e2c7c0@x1.home> <0fd89808-74b2-49de-da79-ea034d83a5de@nvidia.com> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=alex.williamson@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=alex.williamson@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/10/17 19:44:50 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: cohuck@redhat.com, cjia@nvidia.com, aik@ozlabs.ru, Zhengxiao.zx@Alibaba-inc.com, shuangtai.tst@alibaba-inc.com, qemu-devel@nongnu.org, peterx@redhat.com, eauger@redhat.com, yi.l.liu@intel.com, quintela@redhat.com, ziye.yang@intel.com, armbru@redhat.com, mlevitsk@redhat.com, pasic@linux.ibm.com, felipe@nutanix.com, zhi.a.wang@intel.com, kevin.tian@intel.com, yan.y.zhao@intel.com, dgilbert@redhat.com, changpeng.liu@intel.com, eskultet@redhat.com, Ken.Xue@amd.com, jonathan.davies@nutanix.com, pbonzini@redhat.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Sun, 18 Oct 2020 02:00:44 +0530 Kirti Wankhede wrote: > On 9/26/2020 1:50 AM, Alex Williamson wrote: > > On Wed, 23 Sep 2020 04:54:07 +0530 > > Kirti Wankhede wrote: > > > >> VM state change handler gets called on change in VM's state. This is used to set > >> VFIO device state to _RUNNING. > >> > >> Signed-off-by: Kirti Wankhede > >> Reviewed-by: Neo Jia > >> Reviewed-by: Dr. David Alan Gilbert > >> --- > >> hw/vfio/migration.c | 136 ++++++++++++++++++++++++++++++++++++++++++ > >> hw/vfio/trace-events | 3 +- > >> include/hw/vfio/vfio-common.h | 4 ++ > >> 3 files changed, 142 insertions(+), 1 deletion(-) > >> > >> diff --git a/hw/vfio/migration.c b/hw/vfio/migration.c > >> index 2f760f1f9c47..a30d628ba963 100644 > >> --- a/hw/vfio/migration.c > >> +++ b/hw/vfio/migration.c > >> @@ -10,6 +10,7 @@ > >> #include "qemu/osdep.h" > >> #include > >> > >> +#include "sysemu/runstate.h" > >> #include "hw/vfio/vfio-common.h" > >> #include "cpu.h" > >> #include "migration/migration.h" > >> @@ -22,6 +23,58 @@ > >> #include "exec/ram_addr.h" > >> #include "pci.h" > >> #include "trace.h" > >> +#include "hw/hw.h" > >> + > >> +static inline int vfio_mig_access(VFIODevice *vbasedev, void *val, int count, > >> + off_t off, bool iswrite) > >> +{ > >> + int ret; > >> + > >> + ret = iswrite ? pwrite(vbasedev->fd, val, count, off) : > >> + pread(vbasedev->fd, val, count, off); > >> + if (ret < count) { > >> + error_report("vfio_mig_%s%d %s: failed at offset 0x%lx, err: %s", > >> + iswrite ? "write" : "read", count * 8, > >> + vbasedev->name, off, strerror(errno)); > > > > This would suggest from the log that there's, for example, a > > vfio_mig_read8 function, which doesn't exist. > > > > Changing to: > error_report("vfio_mig_%s %d byte %s: failed at offset 0x%lx, err: %s", > iswrite ? "write" : "read", count, > vbasedev->name, off, strerror(errno)); > Hope this address your concern. > > >> + return (ret < 0) ? ret : -EINVAL; > >> + } > >> + return 0; > >> +} > >> + > >> +static int vfio_mig_rw(VFIODevice *vbasedev, __u8 *buf, size_t count, > >> + off_t off, bool iswrite) > >> +{ > >> + int ret, done = 0; > >> + __u8 *tbuf = buf; > >> + > >> + while (count) { > >> + int bytes = 0; > >> + > >> + if (count >= 8 && !(off % 8)) { > >> + bytes = 8; > >> + } else if (count >= 4 && !(off % 4)) { > >> + bytes = 4; > >> + } else if (count >= 2 && !(off % 2)) { > >> + bytes = 2; > >> + } else { > >> + bytes = 1; > >> + } > >> + > >> + ret = vfio_mig_access(vbasedev, tbuf, bytes, off, iswrite); > >> + if (ret) { > >> + return ret; > >> + } > >> + > >> + count -= bytes; > >> + done += bytes; > >> + off += bytes; > >> + tbuf += bytes; > >> + } > >> + return done; > >> +} > >> + > >> +#define vfio_mig_read(f, v, c, o) vfio_mig_rw(f, (__u8 *)v, c, o, false) > >> +#define vfio_mig_write(f, v, c, o) vfio_mig_rw(f, (__u8 *)v, c, o, true) > >> > >> static void vfio_migration_region_exit(VFIODevice *vbasedev) > >> { > >> @@ -70,6 +123,82 @@ err: > >> return ret; > >> } > >> > >> +static int vfio_migration_set_state(VFIODevice *vbasedev, uint32_t mask, > >> + uint32_t value) > >> +{ > >> + VFIOMigration *migration = vbasedev->migration; > >> + VFIORegion *region = &migration->region; > >> + off_t dev_state_off = region->fd_offset + > >> + offsetof(struct vfio_device_migration_info, device_state); > >> + uint32_t device_state; > >> + int ret; > >> + > >> + ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state), > >> + dev_state_off); > >> + if (ret < 0) { > >> + return ret; > >> + } > >> + > >> + device_state = (device_state & mask) | value; > > > > Agree with Connie that mask and value args are not immediately obvious > > how they're used. I don't have a naming convention that would be more > > clear and the names do make some sense once they're understood, but a > > comment to indicate mask bits are preserved, value bits are set, > > remaining bits are cleared would probably help the reader. > > > > Added comment. > > >> + > >> + if (!VFIO_DEVICE_STATE_VALID(device_state)) { > >> + return -EINVAL; > >> + } > >> + > >> + ret = vfio_mig_write(vbasedev, &device_state, sizeof(device_state), > >> + dev_state_off); > >> + if (ret < 0) { > >> + ret = vfio_mig_read(vbasedev, &device_state, sizeof(device_state), > >> + dev_state_off); > >> + if (ret < 0) { > >> + return ret; > > > > Seems like we're in pretty bad shape here, should this be combined with > > below to trigger a hw_error? > > > > Ok. > > >> + } > >> + > >> + if (VFIO_DEVICE_STATE_IS_ERROR(device_state)) { > >> + hw_error("%s: Device is in error state 0x%x", > >> + vbasedev->name, device_state); > >> + return -EFAULT; > >> + } > >> + } > >> + > >> + vbasedev->device_state = device_state; > >> + trace_vfio_migration_set_state(vbasedev->name, device_state); > >> + return 0; > > > > So we return success even if we failed to write the desired state as > > long as we were able to read back any non-error state? > > vbasedev->device_state remains correct, but it seems confusing form a > > caller perspective that a set-state can succeed but it's then necessary > > to check the state. > > > > Correcting here. If vfio_mig_write() had retured error, return error > from vfio_migration_set_state() > > >> +} > >> + > >> +static void vfio_vmstate_change(void *opaque, int running, RunState state) > >> +{ > >> + VFIODevice *vbasedev = opaque; > >> + > >> + if ((vbasedev->vm_running != running)) { > >> + int ret; > >> + uint32_t value = 0, mask = 0; > >> + > >> + if (running) { > >> + value = VFIO_DEVICE_STATE_RUNNING; > >> + if (vbasedev->device_state & VFIO_DEVICE_STATE_RESUMING) { > >> + mask = ~VFIO_DEVICE_STATE_RESUMING; > >> + } > >> + } else { > >> + mask = ~VFIO_DEVICE_STATE_RUNNING; > >> + } > >> + > >> + ret = vfio_migration_set_state(vbasedev, mask, value); > >> + if (ret) { > >> + /* > >> + * vm_state_notify() doesn't support reporting failure. If such > >> + * error reporting support added in furure, migration should be > >> + * aborted. > >> + */ > >> + error_report("%s: Failed to set device state 0x%x", > >> + vbasedev->name, value & mask); > >> + } > > > > Here for instance we assume that success means the device is now in the > > desired state, but we'd actually need to evaluate > > vbasedev->device_state to determine that. > > > > Updating. > > >> + vbasedev->vm_running = running; > >> + trace_vfio_vmstate_change(vbasedev->name, running, RunState_str(state), > >> + value & mask); > >> + } > >> +} > >> + > >> static int vfio_migration_init(VFIODevice *vbasedev, > >> struct vfio_region_info *info) > >> { > >> @@ -87,8 +216,11 @@ static int vfio_migration_init(VFIODevice *vbasedev, > >> vbasedev->name); > >> g_free(vbasedev->migration); > >> vbasedev->migration = NULL; > >> + return ret; > >> } > >> > >> + vbasedev->vm_state = qemu_add_vm_change_state_handler(vfio_vmstate_change, > >> + vbasedev); > >> return ret; > >> } > >> > >> @@ -131,6 +263,10 @@ add_blocker: > >> > >> void vfio_migration_finalize(VFIODevice *vbasedev) > >> { > >> + if (vbasedev->vm_state) { > >> + qemu_del_vm_change_state_handler(vbasedev->vm_state); > >> + } > >> + > >> if (vbasedev->migration_blocker) { > >> migrate_del_blocker(vbasedev->migration_blocker); > >> error_free(vbasedev->migration_blocker); > >> diff --git a/hw/vfio/trace-events b/hw/vfio/trace-events > >> index 8fe913175d85..6524734bf7b4 100644 > >> --- a/hw/vfio/trace-events > >> +++ b/hw/vfio/trace-events > >> @@ -149,4 +149,5 @@ vfio_display_edid_write_error(void) "" > >> > >> # migration.c > >> vfio_migration_probe(const char *name, uint32_t index) " (%s) Region %d" > >> - > >> +vfio_migration_set_state(char *name, uint32_t state) " (%s) state %d" > >> +vfio_vmstate_change(char *name, int running, const char *reason, uint32_t dev_state) " (%s) running %d reason %s device state %d" > >> diff --git a/include/hw/vfio/vfio-common.h b/include/hw/vfio/vfio-common.h > >> index 8275c4c68f45..25e3b1a3b90a 100644 > >> --- a/include/hw/vfio/vfio-common.h > >> +++ b/include/hw/vfio/vfio-common.h > >> @@ -29,6 +29,7 @@ > >> #ifdef CONFIG_LINUX > >> #include > >> #endif > >> +#include "sysemu/sysemu.h" > >> > >> #define VFIO_MSG_PREFIX "vfio %s: " > >> > >> @@ -119,6 +120,9 @@ typedef struct VFIODevice { > >> unsigned int flags; > >> VFIOMigration *migration; > >> Error *migration_blocker; > >> + VMChangeStateEntry *vm_state; > >> + uint32_t device_state; > >> + int vm_running; > > > > Could these be placed in VFIOMigration? Thanks, > > > > I think device_state should be part of VFIODevice since its about device > rather than only related to migration, others can be moved to VFIOMigration. But these are only valid when migration is supported and thus when VFIOMigration exists. Thanks, Alex