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Thu, 23 Apr 2020 16:02:48 +0000 (UTC) Received: from [10.36.114.136] (ovpn-114-136.ams2.redhat.com [10.36.114.136]) by smtp.corp.redhat.com (Postfix) with ESMTP id 9FA7919D9E; Thu, 23 Apr 2020 16:02:42 +0000 (UTC) Subject: Re: [PATCH v21 QEMU 4/5] virtio-balloon: Implement support for page poison tracking feature To: Alexander Duyck References: <20200422181649.12258.37077.stgit@localhost.localdomain> <20200422182120.12258.67417.stgit@localhost.localdomain> <2d335814-c7eb-970b-5973-13dcdc7e0f12@redhat.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; prefer-encrypt=mutual; keydata= mQINBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABtCREYXZpZCBIaWxk ZW5icmFuZCA8ZGF2aWRAcmVkaGF0LmNvbT6JAlgEEwEIAEICGwMFCQlmAYAGCwkIBwMCBhUI AgkKCwQWAgMBAh4BAheAFiEEG9nKrXNcTDpGDfzKTd4Q9wD/g1oFAl3pImkCGQEACgkQTd4Q 9wD/g1o+VA//SFvIHUAvul05u6wKv/pIR6aICPdpF9EIgEU448g+7FfDgQwcEny1pbEzAmiw zAXIQ9H0NZh96lcq+yDLtONnXk/bEYWHHUA014A1wqcYNRY8RvY1+eVHb0uu0KYQoXkzvu+s Dncuguk470XPnscL27hs8PgOP6QjG4jt75K2LfZ0eAqTOUCZTJxA8A7E9+XTYuU0hs7QVrWJ jQdFxQbRMrYz7uP8KmTK9/Cnvqehgl4EzyRaZppshruKMeyheBgvgJd5On1wWq4ZUV5PFM4x II3QbD3EJfWbaJMR55jI9dMFa+vK7MFz3rhWOkEx/QR959lfdRSTXdxs8V3zDvChcmRVGN8U Vo93d1YNtWnA9w6oCW1dnDZ4kgQZZSBIjp6iHcA08apzh7DPi08jL7M9UQByeYGr8KuR4i6e RZI6xhlZerUScVzn35ONwOC91VdYiQgjemiVLq1WDDZ3B7DIzUZ4RQTOaIWdtXBWb8zWakt/ ztGhsx0e39Gvt3391O1PgcA7ilhvqrBPemJrlb9xSPPRbaNAW39P8ws/UJnzSJqnHMVxbRZC Am4add/SM+OCP0w3xYss1jy9T+XdZa0lhUvJfLy7tNcjVG/sxkBXOaSC24MFPuwnoC9WvCVQ ZBxouph3kqc4Dt5X1EeXVLeba+466P1fe1rC8MbcwDkoUo65Ag0EVcufkQEQAOfX3n0g0fZz Bgm/S2zF/kxQKCEKP8ID+Vz8sy2GpDvveBq4H2Y34XWsT1zLJdvqPI4af4ZSMxuerWjXbVWb T6d4odQIG0fKx4F8NccDqbgHeZRNajXeeJ3R7gAzvWvQNLz4piHrO/B4tf8svmRBL0ZB5P5A 2uhdwLU3NZuK22zpNn4is87BPWF8HhY0L5fafgDMOqnf4guJVJPYNPhUFzXUbPqOKOkL8ojk CXxkOFHAbjstSK5Ca3fKquY3rdX3DNo+EL7FvAiw1mUtS+5GeYE+RMnDCsVFm/C7kY8c2d0G NWkB9pJM5+mnIoFNxy7YBcldYATVeOHoY4LyaUWNnAvFYWp08dHWfZo9WCiJMuTfgtH9tc75 7QanMVdPt6fDK8UUXIBLQ2TWr/sQKE9xtFuEmoQGlE1l6bGaDnnMLcYu+Asp3kDT0w4zYGsx 5r6XQVRH4+5N6eHZiaeYtFOujp5n+pjBaQK7wUUjDilPQ5QMzIuCL4YjVoylWiBNknvQWBXS lQCWmavOT9sttGQXdPCC5ynI+1ymZC1ORZKANLnRAb0NH/UCzcsstw2TAkFnMEbo9Zu9w7Kv AxBQXWeXhJI9XQssfrf4Gusdqx8nPEpfOqCtbbwJMATbHyqLt7/oz/5deGuwxgb65pWIzufa N7eop7uh+6bezi+rugUI+w6DABEBAAGJAiUEGAECAA8FAlXLn5ECGwwFCQlmAYAACgkQTd4Q 9wD/g1qA6w/+M+ggFv+JdVsz5+ZIc6MSyGUozASX+bmIuPeIecc9UsFRatc91LuJCKMkD9Uv GOcWSeFpLrSGRQ1Z7EMzFVU//qVs6uzhsNk0RYMyS0B6oloW3FpyQ+zOVylFWQCzoyyf227y GW8HnXunJSC+4PtlL2AY4yZjAVAPLK2l6mhgClVXTQ/S7cBoTQKP+jvVJOoYkpnFxWE9pn4t H5QIFk7Ip8TKr5k3fXVWk4lnUi9MTF/5L/mWqdyIO1s7cjharQCstfWCzWrVeVctpVoDfJWp 4LwTuQ5yEM2KcPeElLg5fR7WB2zH97oI6/Ko2DlovmfQqXh9xWozQt0iGy5tWzh6I0JrlcxJ ileZWLccC4XKD1037Hy2FLAjzfoWgwBLA6ULu0exOOdIa58H4PsXtkFPrUF980EEibUp0zFz GotRVekFAceUaRvAj7dh76cToeZkfsjAvBVb4COXuhgX6N4pofgNkW2AtgYu1nUsPAo+NftU CxrhjHtLn4QEBpkbErnXQyMjHpIatlYGutVMS91XTQXYydCh5crMPs7hYVsvnmGHIaB9ZMfB njnuI31KBiLUks+paRkHQlFcgS2N3gkRBzH7xSZ+t7Re3jvXdXEzKBbQ+dC3lpJB0wPnyMcX FOTT3aZT7IgePkt5iC/BKBk3hqKteTnJFeVIT7EC+a6YUFg= Organization: Red Hat GmbH Message-ID: <46fb7362-0ec7-d27d-a8bc-458e9ae0beea@redhat.com> Date: Thu, 23 Apr 2020 18:02:41 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=205.139.110.61; envelope-from=david@redhat.com; helo=us-smtp-1.mimecast.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/04/23 03:23:21 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.61 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: virtio-dev@lists.oasis-open.org, qemu-devel@nongnu.org, "Michael S. Tsirkin" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 23.04.20 16:46, Alexander Duyck wrote: > On Thu, Apr 23, 2020 at 1:11 AM David Hildenbrand wrot= e: >> >> On 22.04.20 20:21, Alexander Duyck wrote: >>> From: Alexander Duyck >>> >>> We need to make certain to advertise support for page poison tracking i= f >>> we want to actually get data on if the guest will be poisoning pages. >>> >>> Add a value for tracking the poison value being used if page poisoning = is >>> enabled. With this we can determine if we will need to skip page report= ing >>> when it is enabled in the future. >> >> Maybe add something about the semantics >> >> "VIRTIO_BALLOON_F_PAGE_POISON will not change the behavior of free page >> hinting or ordinary balloon inflation/deflation." >> >> I do wonder if we should just unconditionally enable >> VIRTIO_BALLOON_F_PAGE_POISON here, gluing it to the QEMU compat machine >> (via a property that is default-enabled, and disabled from compat machin= es). >> >> Because, as Michael said, knowing that the guest is using page poisoning >> might be interesting even if free page reporting is not around. >=20 > I could do that. So if that is the case though would I disable page > reporting if it isn't enabled, or would I be enabling page poison if > page reporting is enabled? So, I would suggest this the following as a diff to this patch (the TODO pa= rt as a separate patch - we will have these compat properties briefly after the 5.0 release) diff --git a/hw/core/machine.c b/hw/core/machine.c index c1a444cb75..2e96cba4ff 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -28,6 +28,12 @@ #include "hw/mem/nvdimm.h" #include "migration/vmstate.h" =20 +// TODO: After 5.0 release +GlobalProperty hw_compat_5_0[] =3D { + { "virtio-balloon-device", "page-hint", "false"}, +}; +const size_t hw_compat_5_0_len =3D G_N_ELEMENTS(hw_compat_5_0); + GlobalProperty hw_compat_4_2[] =3D { { "virtio-blk-device", "queue-size", "128"}, { "virtio-scsi-device", "virtqueue_size", "128"}, diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a4729f7fc9..5ff8a669cf 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -924,6 +924,8 @@ static Property virtio_balloon_properties[] =3D { qemu_4_0_config_size, false), DEFINE_PROP_LINK("iothread", VirtIOBalloon, iothread, TYPE_IOTHREAD, IOThread *), + DEFINE_PROP_BIT("page-poison", VirtIOBalloon, host_features, + VIRTIO_BALLOON_F_PAGE_POISON, true), DEFINE_PROP_END_OF_LIST(), }; What to do with page reporting depends: I would not implicitly enable featu= res. I think we are talking about -device virtio-balloon-pci,...,page-poison=3Dfalse,free-page-reporting=3Dtr= ue a) Valid scenario. Fix Linux guests as we discussed to not use reporting if= they rely on page poisoning. b) Invalid scenario. E.g., bail out when trying to realize that device ("'f= ree-page-reporting' requires 'page-poison'"). With new QEMU machines, this should not happen with -device virtio-balloon-pci,...,free-page-reporting=3Dtrue as page-poison=3Dtrue is the new default. What's your opinion? >=20 >>> >>> Signed-off-by: Alexander Duyck >>> --- >>> hw/virtio/virtio-balloon.c | 7 +++++++ >>> include/hw/virtio/virtio-balloon.h | 1 + >>> 2 files changed, 8 insertions(+) >>> >>> diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c >>> index a1d6fb52c876..5effc8b4653b 100644 >>> --- a/hw/virtio/virtio-balloon.c >>> +++ b/hw/virtio/virtio-balloon.c >>> @@ -634,6 +634,7 @@ static void virtio_balloon_get_config(VirtIODevice = *vdev, uint8_t *config_data) >>> >>> config.num_pages =3D cpu_to_le32(dev->num_pages); >>> config.actual =3D cpu_to_le32(dev->actual); >>> + config.poison_val =3D cpu_to_le32(dev->poison_val); >>> >>> if (dev->free_page_hint_status =3D=3D FREE_PAGE_HINT_S_REQUESTED) = { >>> config.free_page_hint_cmd_id =3D >>> @@ -697,6 +698,10 @@ static void virtio_balloon_set_config(VirtIODevice= *vdev, >>> qapi_event_send_balloon_change(vm_ram_size - >>> ((ram_addr_t) dev->actual << VIRTIO_BALLOON_PF= N_SHIFT)); >>> } >>> + dev->poison_val =3D 0; >>> + if (virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON)) { >>> + dev->poison_val =3D le32_to_cpu(config.poison_val); >>> + } >>> trace_virtio_balloon_set_config(dev->actual, oldactual); >>> } >>> >>> @@ -854,6 +859,8 @@ static void virtio_balloon_device_reset(VirtIODevic= e *vdev) >>> g_free(s->stats_vq_elem); >>> s->stats_vq_elem =3D NULL; >>> } >>> + >>> + s->poison_val =3D 0; >>> } >>> >>> static void virtio_balloon_set_status(VirtIODevice *vdev, uint8_t stat= us) >>> diff --git a/include/hw/virtio/virtio-balloon.h b/include/hw/virtio/vir= tio-balloon.h >>> index 108cff97e71a..3ca2a78e1aca 100644 >>> --- a/include/hw/virtio/virtio-balloon.h >>> +++ b/include/hw/virtio/virtio-balloon.h >>> @@ -70,6 +70,7 @@ typedef struct VirtIOBalloon { >>> uint32_t host_features; >>> >>> bool qemu_4_0_config_size; >>> + uint32_t poison_val; >>> } VirtIOBalloon; >>> >>> #endif >>> >> >> You still have to migrate poison_val if I am not wrong, otherwise you >> would lose it during migration if I am not mistaking. >=20 > So what are the requirements to migrate a value? Would I need to add a > property so it can be retrieved/set? >=20 Something like this would do the trick: diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a4729f7fc9..ea0afec5f6 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -522,6 +522,13 @@ static bool virtio_balloon_free_page_support(void *opa= que) return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_FREE_PAGE_HINT); } =20 +static bool virtio_balloon_page_poison_support(void *opaque) +{ + VirtIODevice *vdev =3D VIRTIO_DEVICE(opaque); + + return virtio_vdev_has_feature(vdev, VIRTIO_BALLOON_F_PAGE_POISON); +} + static void virtio_balloon_free_page_start(VirtIOBalloon *s) { VirtIODevice *vdev =3D VIRTIO_DEVICE(s); @@ -755,6 +762,17 @@ static const VMStateDescription vmstate_virtio_balloon= _free_page_report =3D { } }; =20 +static const VMStateDescription vmstate_virtio_balloon_page_poison =3D { + .name =3D "vitio-balloon-device/page-poison", + .version_id =3D 1, + .minimum_version_id =3D 1, + .needed =3D virtio_balloon_page_poison_support, + .fields =3D (VMStateField[]) { + VMSTATE_UINT32(poison_val, VirtIOBalloon), + VMSTATE_END_OF_LIST() + } +}; + static const VMStateDescription vmstate_virtio_balloon_device =3D { .name =3D "virtio-balloon-device", .version_id =3D 1, @@ -767,6 +785,7 @@ static const VMStateDescription vmstate_virtio_balloon_= device =3D { }, .subsections =3D (const VMStateDescription * []) { &vmstate_virtio_balloon_free_page_report, + &vmstate_virtio_balloon_page_poison, NULL } }; But I *think* the following should work as well IIRC (could be that migrati= ng new QEMU -> old QEMU would be an issue, I don't recall if both directions are safe): diff --git a/hw/virtio/virtio-balloon.c b/hw/virtio/virtio-balloon.c index a4729f7fc9..01bccf26fb 100644 --- a/hw/virtio/virtio-balloon.c +++ b/hw/virtio/virtio-balloon.c @@ -757,12 +757,13 @@ static const VMStateDescription vmstate_virtio_balloo= n_free_page_report =3D { =20 static const VMStateDescription vmstate_virtio_balloon_device =3D { .name =3D "virtio-balloon-device", - .version_id =3D 1, + .version_id =3D 2, .minimum_version_id =3D 1, .post_load =3D virtio_balloon_post_load_device, .fields =3D (VMStateField[]) { VMSTATE_UINT32(num_pages, VirtIOBalloon), VMSTATE_UINT32(actual, VirtIOBalloon), + VMSTATE_UINT32_V(poison_val, VirtIOBalloon, 2), VMSTATE_END_OF_LIST() }, .subsections =3D (const VMStateDescription * []) { --=20 Thanks, David / dhildenb