search for: page_poisoning_no_san

On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin <mst at redhat.com&gt...

On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > The guest free pages should not be discarded by the live migration thread > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > skipping the transfer of such poisoned free pages will trigger false > positive when new pages are allocated and checked on the destination. > This patch skips the reporting of free pages in the above case. > > Reported-by: Michael S. Tsirkin <mst at redhat.com&gt...

The guest free pages should not be discarded by the live migration thread when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because skipping the transfer of such poisoned free pages will trigger false positive when new pages are allocated and checked on the destination. This patch adds a config field, poison_val. Guest writes to the config field to tell the host about the poisoning value. The value will be 0 in th...

...;> +} >>> + >> I think there's an issue here: if pages are poisoned and hypervisor >> subsequently drops them, testing them after allocation will >> trigger a false positive. >> >> The specific configuration: >> >> PAGE_POISONING on >> PAGE_POISONING_NO_SANITY off >> PAGE_POISONING_ZERO off >> >> >> Solutions: >> 1. disable the feature in that configuration >> suggested as an initial step > > Thanks for the finding. > Similar to this option: I'm thinking could we make > walk_free_mem_block() sim...

...;> +} >>> + >> I think there's an issue here: if pages are poisoned and hypervisor >> subsequently drops them, testing them after allocation will >> trigger a false positive. >> >> The specific configuration: >> >> PAGE_POISONING on >> PAGE_POISONING_NO_SANITY off >> PAGE_POISONING_ZERO off >> >> >> Solutions: >> 1. disable the feature in that configuration >> suggested as an initial step > > Thanks for the finding. > Similar to this option: I'm thinking could we make > walk_free_mem_block() sim...

...at 02:38:45PM +0800, Wei Wang wrote: > On 12/01/2017 11:49 PM, Michael S. Tsirkin wrote: > > On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > > > The guest free pages should not be discarded by the live migration thread > > > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > > > skipping the transfer of such poisoned free pages will trigger false > > > positive when new pages are allocated and checked on the destination. > > > This patch skips the reporting of free pages in the above case. > > > > > > Report...

...at 02:38:45PM +0800, Wei Wang wrote: > On 12/01/2017 11:49 PM, Michael S. Tsirkin wrote: > > On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: > > > The guest free pages should not be discarded by the live migration thread > > > when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because > > > skipping the transfer of such poisoned free pages will trigger false > > > positive when new pages are allocated and checked on the destination. > > > This patch skips the reporting of free pages in the above case. > > > > > > Report...

...> + virtqueue_kick(vb->free_page_vq); > + report_free_page_end(vb); > +} > + I think there's an issue here: if pages are poisoned and hypervisor subsequently drops them, testing them after allocation will trigger a false positive. The specific configuration: PAGE_POISONING on PAGE_POISONING_NO_SANITY off PAGE_POISONING_ZERO off Solutions: 1. disable the feature in that configuration suggested as an initial step 2. pass poison value to host so it can validate page content before it drops it 3. pass poison value to host so it can init allocated pages with that value In fact one nice sid...

...> + virtqueue_kick(vb->free_page_vq); > + report_free_page_end(vb); > +} > + I think there's an issue here: if pages are poisoned and hypervisor subsequently drops them, testing them after allocation will trigger a false positive. The specific configuration: PAGE_POISONING on PAGE_POISONING_NO_SANITY off PAGE_POISONING_ZERO off Solutions: 1. disable the feature in that configuration suggested as an initial step 2. pass poison value to host so it can validate page content before it drops it 3. pass poison value to host so it can init allocated pages with that value In fact one nice sid...

...are poisoned and > > > > hypervisor subsequently drops them, testing them after allocation > > > > will trigger a false positive. > > > > > > > > The specific configuration: > > > > > > > > PAGE_POISONING on > > > > PAGE_POISONING_NO_SANITY off > > > > PAGE_POISONING_ZERO off > > > > > > > > > > > > Solutions: > > > > 1. disable the feature in that configuration > > > > suggested as an initial step > > > > > > Thanks for the finding. >...

...are poisoned and > > > > hypervisor subsequently drops them, testing them after allocation > > > > will trigger a false positive. > > > > > > > > The specific configuration: > > > > > > > > PAGE_POISONING on > > > > PAGE_POISONING_NO_SANITY off > > > > PAGE_POISONING_ZERO off > > > > > > > > > > > > Solutions: > > > > 1. disable the feature in that configuration > > > > suggested as an initial step > > > > > > Thanks for the finding. >...

The guest free pages should not be discarded by the live migration thread when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because skipping the transfer of such poisoned free pages will trigger false positive when new pages are allocated and checked on the destination. This patch skips the reporting of free pages in the above case. Reported-by: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: Wei Wang...

On 12/01/2017 11:49 PM, Michael S. Tsirkin wrote: > On Wed, Nov 29, 2017 at 09:55:26PM +0800, Wei Wang wrote: >> The guest free pages should not be discarded by the live migration thread >> when page poisoning is enabled with PAGE_POISONING_NO_SANITY=n, because >> skipping the transfer of such poisoned free pages will trigger false >> positive when new pages are allocated and checked on the destination. >> This patch skips the reporting of free pages in the above case. >> >> Reported-by: Michael S. Tsirkin <m...

...> + report_free_page_end(vb); >> +} >> + > I think there's an issue here: if pages are poisoned and hypervisor > subsequently drops them, testing them after allocation will > trigger a false positive. > > The specific configuration: > > PAGE_POISONING on > PAGE_POISONING_NO_SANITY off > PAGE_POISONING_ZERO off > > > Solutions: > 1. disable the feature in that configuration > suggested as an initial step Thanks for the finding. Similar to this option: I'm thinking could we make walk_free_mem_block() simply return if that option is on? That is, at t...

...re's an issue here: if pages are poisoned and hypervisor > > > subsequently drops them, testing them after allocation will > > > trigger a false positive. > > > > > > The specific configuration: > > > > > > PAGE_POISONING on > > > PAGE_POISONING_NO_SANITY off > > > PAGE_POISONING_ZERO off > > > > > > > > > Solutions: > > > 1. disable the feature in that configuration > > > suggested as an initial step > > > > Thanks for the finding. > > Similar to this option: I'm...

This patch series is separated from the previous "Virtio-balloon Enhancement" series. The new feature, VIRTIO_BALLOON_F_FREE_PAGE_VQ, implemented by this series enables the virtio-balloon driver to report hints of guest free pages to the host. It can be used to accelerate live migration of VMs. Here is an introduction of this usage: Live migration needs to transfer the VM's memory

This patch series is separated from the previous "Virtio-balloon Enhancement" series. The new feature, VIRTIO_BALLOON_F_FREE_PAGE_VQ, implemented by this series enables the virtio-balloon driver to report hints of guest free pages to the host. It can be used to accelerate live migration of VMs. Here is an introduction of this usage: Live migration needs to transfer the VM's memory

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live

This patch series enhances the existing virtio-balloon with the following new features: 1) fast ballooning: transfer ballooned pages between the guest and host in chunks using sgs, instead of one array each time; and 2) free page block reporting: a new virtqueue to report guest free pages to the host. The second feature can be used to accelerate live migration of VMs. Here are some details: Live