similar to: [PATCH] virtio_mem: prevent overflow with subblock size

This series is based on v5.7-rc4. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v4 This is basically a resend of v3 [1], now based on v5.7-rc4 and restested. One patch was reshuffled and two ACKs I missed to add were added. The rebase did not require any modifications to patches. Details about virtio-mem can be found in the cover letter of v2 [2]. A

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v3 Patch #1 - #10 where contained in v2 and only contain minor modifications (mostly smaller fixes). The remaining patches are new and contain smaller optimizations. Details about virtio-mem can be found in the cover letter of v2 [1]. A basic QEMU implementation was

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v3 Patch #1 - #10 where contained in v2 and only contain minor modifications (mostly smaller fixes). The remaining patches are new and contain smaller optimizations. Details about virtio-mem can be found in the cover letter of v2 [1]. A basic QEMU implementation was

On Mon, Jun 08, 2020 at 08:58:31AM +0200, David Hildenbrand wrote: > On 08.06.20 08:14, Michael S. Tsirkin wrote: > > If subblock size is large (e.g. 1G) 32 bit math involving it > > can overflow. Rather than try to catch all instances of that, > > let's tweak block size to 64 bit. > > I fail to see where we could actually trigger an overflow. The reported >

On Mon, Jun 08, 2020 at 08:58:31AM +0200, David Hildenbrand wrote: > On 08.06.20 08:14, Michael S. Tsirkin wrote: > > If subblock size is large (e.g. 1G) 32 bit math involving it > > can overflow. Rather than try to catch all instances of that, > > let's tweak block size to 64 bit. > > I fail to see where we could actually trigger an overflow. The reported >

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v2 I now have acks for all !virtio-mem changes. I'll be happy to get review feedback, testing reports, etc. for the virtio-mem changes. If there are no further comments, I guess this is good to go as a v1 soon. The basic idea of virtio-mem is to provide a

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-rfc-v4 The basic idea of virtio-mem is to provide a flexible, cross-architecture memory hot(un)plug solution that avoids many limitations imposed by existing technologies, architectures, and interfaces. More details can be found below and in linked material. This

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-rfc-v4 The basic idea of virtio-mem is to provide a flexible, cross-architecture memory hot(un)plug solution that avoids many limitations imposed by existing technologies, architectures, and interfaces. More details can be found below and in linked material. This

Long time no RFC! I finally had time to get the next version of the Linux driver side of virtio-mem into shape, incorporating ideas and feedback from previous discussions. This RFC is based on the series currently on the mm list: - [PATCH 0/3] Remove __online_page_set_limits() - [PATCH v1 0/3] mm/memory_hotplug: Export generic_online_page() - [PATCH v4 0/8] mm/memory_hotplug: Shrink zones before

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v1 The basic idea of virtio-mem is to provide a flexible, cross-architecture memory hot(un)plug solution that avoids many limitations imposed by existing technologies, architectures, and interfaces. More details can be found below and in linked material. It's

This series is based on latest linux-next. The patches are located at: https://github.com/davidhildenbrand/linux.git virtio-mem-v1 The basic idea of virtio-mem is to provide a flexible, cross-architecture memory hot(un)plug solution that avoids many limitations imposed by existing technologies, architectures, and interfaces. More details can be found below and in linked material. It's

Fixes: 676fa9ba893e ("virtio_mem: convert device block size into 64bit") Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_mem.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index 7b1bece8a331..50c689f25045 100644 --- a/drivers/virtio/virtio_mem.c +++

Virtio mem is modern-only. Use LE accessors for config space. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/virtio/virtio_mem.c | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/drivers/virtio/virtio_mem.c b/drivers/virtio/virtio_mem.c index f26f5f64ae82..c08512fcea90 100644 --- a/drivers/virtio/virtio_mem.c +++

On 08.06.20 08:14, Michael S. Tsirkin wrote: > If subblock size is large (e.g. 1G) 32 bit math involving it > can overflow. Rather than try to catch all instances of that, > let's tweak block size to 64 bit. I fail to see where we could actually trigger an overflow. The reported warning looked like a false positive to me. > > It ripples through UAPI which is an ABI change,

Each virtio-mem device owns exactly one memory region. It is responsible for adding/removing memory from that memory region on request. When the device driver starts up, the requested amount of memory is queried and then plugged to Linux. On request, further memory can be plugged or unplugged. This patch only implements the plugging part. On x86-64, memory can currently be plugged in 4MB

On 08.06.20 09:08, Michael S. Tsirkin wrote: > On Mon, Jun 08, 2020 at 08:58:31AM +0200, David Hildenbrand wrote: >> On 08.06.20 08:14, Michael S. Tsirkin wrote: >>> If subblock size is large (e.g. 1G) 32 bit math involving it >>> can overflow. Rather than try to catch all instances of that, >>> let's tweak block size to 64 bit. >> >> I fail to

On Mon 02-03-20 14:49:37, David Hildenbrand wrote: [...] > +static void virtio_mem_notify_going_offline(struct virtio_mem *vm, > + unsigned long mb_id) > +{ > + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); > + unsigned long pfn; > + int sb_id, i; > + > + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { > + if

On Mon 02-03-20 14:49:37, David Hildenbrand wrote: [...] > +static void virtio_mem_notify_going_offline(struct virtio_mem *vm, > + unsigned long mb_id) > +{ > + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); > + unsigned long pfn; > + int sb_id, i; > + > + for (sb_id = 0; sb_id < vm->nb_sb_per_mb; sb_id++) { > + if

On Tue 10-03-20 12:46:05, David Hildenbrand wrote: > On 10.03.20 12:43, Michal Hocko wrote: > > On Mon 02-03-20 14:49:37, David Hildenbrand wrote: > > [...] > >> +static void virtio_mem_notify_going_offline(struct virtio_mem *vm, > >> + unsigned long mb_id) > >> +{ > >> + const unsigned long nr_pages = PFN_DOWN(vm->subblock_size); >

Some add_memory*() users add memory in small, contiguous memory blocks. Examples include virtio-mem, hyper-v balloon, and the XEN balloon. This can quickly result in a lot of memory resources, whereby the actual resource boundaries are not of interest (e.g., it might be relevant for DIMMs, exposed via /proc/iomem to user space). We really want to merge added resources in this scenario where