Messages in this thread Patch in this message |  | | Date | Tue, 17 Feb 2015 10:02:42 +0100 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH] vhost: support upto 509 memory regions |
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On Fri, Feb 13, 2015 at 03:49:59PM +0000, Igor Mammedov wrote: > since commit > 1d4e7e3 kvm: x86: increase user memory slots to 509 > > it became possible to use a bigger amount of memory > slots, which is used by memory hotplug for > registering hotplugged memory. > However QEMU aborts if it's used with more than ~60 > pc-dimm devices and vhost-net since host kernel > in module vhost-net refuses to accept more than 65 > memory regions. > > Increasing VHOST_MEMORY_MAX_NREGIONS from 65 to 509 > to match KVM_USER_MEM_SLOTS fixes issue for vhost-net. > > Signed-off-by: Igor Mammedov <imammedo@redhat.com>
This scares me a bit: each region is 32byte, we are talking a 16K allocation that userspace can trigger. How does kvm handle this issue?
> --- > drivers/vhost/vhost.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c > index 2ee2826..ecbd7a4 100644 > --- a/drivers/vhost/vhost.c > +++ b/drivers/vhost/vhost.c > @@ -29,7 +29,7 @@ > #include "vhost.h" > > enum { > - VHOST_MEMORY_MAX_NREGIONS = 64, > + VHOST_MEMORY_MAX_NREGIONS = 509, > VHOST_MEMORY_F_LOG = 0x1, > }; > > -- > 1.8.3.1
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