similar to: [PATCH v3 0/3] virtio_balloon: don't push uninitialized buffers to stats virtqueue

On Fri, Mar 24, 2017 at 09:40:07PM +0100, Arnd Bergmann wrote: > On Fri, Mar 24, 2017 at 9:11 PM, Ladi Prosek <lprosek at redhat.com> wrote: > > On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david at redhat.com> wrote: > >> On 23.03.2017 16:17, Arnd Bergmann wrote: > >>> The latest gcc-7.0.1 snapshot reports a new warning: > >>> >

On Fri, Mar 24, 2017 at 09:40:07PM +0100, Arnd Bergmann wrote: > On Fri, Mar 24, 2017 at 9:11 PM, Ladi Prosek <lprosek at redhat.com> wrote: > > On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david at redhat.com> wrote: > >> On 23.03.2017 16:17, Arnd Bergmann wrote: > >>> The latest gcc-7.0.1 snapshot reports a new warning: > >>> >

On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david at redhat.com> wrote: > On 23.03.2017 16:17, Arnd Bergmann wrote: >> The latest gcc-7.0.1 snapshot reports a new warning: >> >> virtio/virtio_balloon.c: In function 'update_balloon_stats': >> virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function

On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david at redhat.com> wrote: > On 23.03.2017 16:17, Arnd Bergmann wrote: >> The latest gcc-7.0.1 snapshot reports a new warning: >> >> virtio/virtio_balloon.c: In function 'update_balloon_stats': >> virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function

On Mon, Mar 27, 2017 at 12:02:33PM +0200, Ladi Prosek wrote: > On Fri, Mar 24, 2017 at 9:59 PM, Michael S. Tsirkin <mst at redhat.com> wrote: > > On Fri, Mar 24, 2017 at 09:40:07PM +0100, Arnd Bergmann wrote: > >> On Fri, Mar 24, 2017 at 9:11 PM, Ladi Prosek <lprosek at redhat.com> wrote: > >> > On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david

On Mon, Mar 27, 2017 at 12:02:33PM +0200, Ladi Prosek wrote: > On Fri, Mar 24, 2017 at 9:59 PM, Michael S. Tsirkin <mst at redhat.com> wrote: > > On Fri, Mar 24, 2017 at 09:40:07PM +0100, Arnd Bergmann wrote: > >> On Fri, Mar 24, 2017 at 9:11 PM, Ladi Prosek <lprosek at redhat.com> wrote: > >> > On Fri, Mar 24, 2017 at 7:38 PM, David Hildenbrand <david

When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch updates the stats before pushing the initial buffer. An assertion is also added to update_balloon_stats to make sure that all stats fields are initialized.

When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch updates the stats before pushing the initial buffer. An assertion is also added to update_balloon_stats to make sure that all stats fields are initialized.

When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch initializes all tags with U16_MAX which is guaranteed to be ignored by the host. The alternative fix would be to push an empty buffer in init_vqs but that's not

When init_vqs runs, virtio_balloon.stats is either uninitialized or contains stale values. The host updates its state with garbage data because it has no way of knowing that this is just a marker buffer used for signaling. This patch initializes all tags with U16_MAX which is guaranteed to be ignored by the host. The alternative fix would be to push an empty buffer in init_vqs but that's not

On Wed, Mar 22, 2017 at 5:14 PM, Michael S. Tsirkin <mst at redhat.com> wrote: > On Wed, Mar 22, 2017 at 04:10:27PM +0100, Ladi Prosek wrote: >> When init_vqs runs, virtio_balloon.stats is either uninitialized or >> contains stale values. The host updates its state with garbage data >> because it has no way of knowing that this is just a marker buffer >> used for

On Wed, Mar 22, 2017 at 5:14 PM, Michael S. Tsirkin <mst at redhat.com> wrote: > On Wed, Mar 22, 2017 at 04:10:27PM +0100, Ladi Prosek wrote: >> When init_vqs runs, virtio_balloon.stats is either uninitialized or >> contains stale values. The host updates its state with garbage data >> because it has no way of knowing that this is just a marker buffer >> used for

The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56:

The latest gcc-7.0.1 snapshot reports a new warning: virtio/virtio_balloon.c: In function 'update_balloon_stats': virtio/virtio_balloon.c:258:26: error: 'events[2]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:260:26: error: 'events[3]' is used uninitialized in this function [-Werror=uninitialized] virtio/virtio_balloon.c:261:56:

The virtio balloon driver contained a not-so-obvious invariant that update_balloon_stats has to update exactly VIRTIO_BALLOON_S_NR counters in order to send valid stats to the host. This commit fixes it by having update_balloon_stats return the actual number of counters, and its callers use it when pushing buffers to the stats virtqueue. Note that it is still out of spec to change the number of

Linux driver part v2: - fixed typos Tom?? Golembiovsk? (1): virtio_balloon: include buffers and cached memory statistics drivers/virtio/virtio_balloon.c | 11 +++++++++++ include/uapi/linux/virtio_balloon.h | 4 +++- mm/swap_state.c | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) -- 2.14.1

Linux driver part v2: - fixed typos Tom?? Golembiovsk? (1): virtio_balloon: include buffers and cached memory statistics drivers/virtio/virtio_balloon.c | 11 +++++++++++ include/uapi/linux/virtio_balloon.h | 4 +++- mm/swap_state.c | 1 + 3 files changed, 15 insertions(+), 1 deletion(-) -- 2.14.1

On Thu, Sep 21, 2017 at 02:55:41PM +0200, Tom?? Golembiovsk? wrote: > Add a new fields, VIRTIO_BALLOON_S_BUFFERS and VIRTIO_BALLOON_S_CACHED, > to virtio_balloon memory statistics protocol. The values correspond to > 'Buffers' and 'Cached' in /proc/meminfo. > > To be able to compute the value of 'Cached' memory it is necessary to > export

On Thu, Sep 21, 2017 at 02:55:41PM +0200, Tom?? Golembiovsk? wrote: > Add a new fields, VIRTIO_BALLOON_S_BUFFERS and VIRTIO_BALLOON_S_CACHED, > to virtio_balloon memory statistics protocol. The values correspond to > 'Buffers' and 'Cached' in /proc/meminfo. > > To be able to compute the value of 'Cached' memory it is necessary to > export

ping +Gil, +Amnon... could you maybe aid in reviewing the patch, please? Tomas On Sun, 22 Oct 2017 20:05:57 +0200 Tom?? Golembiovsk? <tgolembi at redhat.com> wrote: > On Thu, 19 Oct 2017 16:12:20 +0300 > "Michael S. Tsirkin" <mst at redhat.com> wrote: > > > On Thu, Sep 21, 2017 at 02:55:41PM +0200, Tom?? Golembiovsk? wrote: > > > Add a new